# High ISO Questions



## smoke665 (Feb 4, 2017)

The advent of the mega ISO cameras being released has prompted me to read up on the subject, which in turn brings more questions.


In the past there has been some discussion as to the effect a higher ISO has on dynamic range. My understanding on the new, mega high ISO cameras while not necessarily practical from a use standpoint at the maximum level, have actually raised the bar on the lower levels, making practical use of 50,000 ISO possible.  While there have been improvements in the sensors, most of the increase seems to have come  in the CPU and image acceleration software, which combined, limits downstream/upstream noise. My question is has the dynamic range capability improved in addition to the downstream/upstream noise reduction, or has the noise control simply created an appearance of an improvement in DR?
My current K3II includes menu options for highlight/shadow correction (assume others have something similar), which can only be used at ISOs above 200 up to the camera maximum. Turning this option on, extends the s shape on either the highlights or shadows, which effectively extends the dynamic range of a JPEG. Granted it doesn't change the raw file, but it does set a flag in the metadata that will automatically apply the extended curve during development in most current raw convertors.  So the question is "if you have this menu option available, do you use it on high ISO shots, and if not why"?
Considering the increases in ISO, have you already or do you intend on altering your exposures to make use of the higher limits? How exactly?
I've read so many articles on the subject that my head is spinning, so I'd prefer you not post links for further reading, unless it's to illustrate your point. Looking for personal opinions and knowledge please.


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## Designer (Feb 4, 2017)

I'll make the popcorn.


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## Destin (Feb 4, 2017)

Subscribing, as I just bought a D500 and would like to know more about this.


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## Ysarex (Feb 4, 2017)

Designer said:


> I'll make the popcorn.



You better make a lot!!

Joe


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## Peeb (Feb 4, 2017)

I cut my teeth before ISO- we called it ASA.

Anything over 400 was crazy talk, and anything over 800 was obscene!

Nowadays- tech is opening a lot of opportunities.  My shots of the milky way are SO simple now.  I actively look for ways to exploit my camera sensor in ways to create interesting shots.  This has never changed.  The opportunities, however, have grown tremendously with the tech.


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## Gary A. (Feb 4, 2017)

Interestingly enough, I shot at ISO 12,800 and 6400 on Wednesday of this week.  Using a X-T2 and a X-Pro2 for a candlelight vigil in front of a very very dark school.  I just took a peek at some of the files and they are quite usable in a photojournalistic manner.  Yes, they have noise and yes, there is less dynamic range ... but as a tool to document the event they are quite useable and reflect, to a much greater degree, the tone of the event.  In fact, much much better than had I used a flash.  I've been shooting in low light for much of my old life.  Back in the film-only days I learned how to shoot at low shutter speeds with ASA's no greater than 1600.  With IS and high ISO's you can do so much more with a greater variety of lenses. Most of my shots were taken at 200mm w/ an APS-C sensors.

As to metering, in low light I always use spot and focus on the primary subject(s) and let the rest fall where they may.  I shoot in RAW and I tend/try to shoot and process without the camera automatically adding anything into the mix. That's just me.  In the end, the only thing that matters is the final image ... the only person(s) that cares about the path to a successful image is yourself and maybe your mother.


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## jsecordphoto (Feb 4, 2017)

"Practical use" is certainly a novel idea. Will it be useable for documentation? Maybe, I guess depending on what you're using the images for. Even the Sony A7s, arguably the king of current high ISO, is really only useable up to around 12,800 in my opinion, and even that depends on what you're using the photos for. The DR at higher ISOs is still not great. Try pushing your shadows on an iso10,000 shot and see how quickly things fall apart. 

If my camera had the option for shadow/highlight recovery, I don't see the point in using it when all it takes is a two second curve adjustment in LR or PS. 

I currently shoot all my astrophotography at ISO10k, which is very clean, but darker scenes tend to hide a lot of noise anyway. 99% of the time I'm at base ISO because the DR is best there and I'm almost always tripod mounted anyway. Your needs or style of shooting may vary. A lot of the high ISO war that's going on now between brands is purely marketing and shows almost no real world benefit, past a certain point. Who cares if your camera CAN shoot at ISO400k if the files are useless past 12,800. Yes, the advances in high ISO capability will be better with each new advance in sensor tech, and you will see better performance as "useable" high ISOs, but I cringe whenever I see the newest camera announcements with these ridiculous high ISO ranges that mean almost nothing in real world use. My 2 cents


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## Ysarex (Feb 4, 2017)

smoke665 said:


> The advent of the mega ISO cameras being released has prompted me to read up on the subject, which in turn brings more questions.
> 
> In the past there has been some discussion as to the effect a higher ISO has on dynamic range. My understanding on the new, mega high ISO cameras while not necessarily practical from a use standpoint at the maximum level, have actually raised the bar on the lower levels, making practical use of 50,000 ISO possible.  While there have been improvements in the sensors, most of the increase seems to have come  in the CPU and image acceleration software, which combined, limits downstream/upstream noise. My question is has the dynamic range capability improved in addition to the downstream/upstream noise reduction, or has the noise control simply created an appearance of an improvement in DR?



So both. Sensors have progressively gotten better (increased DR) and the processing electronics (squeeze the max out of the sensor) have gotten better. Put the two together and you get some pretty impressive performance.



smoke665 said:


> My current K3II includes menu options for highlight/shadow correction (assume others have something similar), which can only be used at ISOs above 200 up to the camera maximum. Turning this option on, extends the s shape on either the highlights or shadows, which effectively extends the dynamic range of a JPEG. Granted it doesn't change the raw file, but it does set a flag in the metadata that will automatically apply the extended curve during development in most current raw convertors.  So the question is "if you have this menu option available, do you use it on high ISO shots, and if not why"?



What you describe here has become pretty much standard now on most cameras and it goes by different names. There is some variation in methodology but most function as you've described. The ISO increase they require is designed to force an underexposure of the sensor and then the ISO brightening boost is withheld from the raw file which then receives special tone curve processing to produce the JPEG. Paradoxically this technique reduces DR and that includes DR in the raw file. *The raw file is effected by the withholding of the ISO post processing.* If you want the JPEG this method produces that's fine, but if you think you may ever want to use the raw file don't ever do this!! To answer your direct question, my Fuji has the same function. I always want the raw file and so I never have and never will use this function.



smoke665 said:


> Considering the increases in ISO, have you already or do you intend on altering your exposures to make use of the higher limits? How exactly?



I recently upgraded to a new Fuji X-T2 which has the same sensor as the D500 that Destin mentions above. I have no intention of changing my exposure behavior. My goal is always the same: I want the best photo I can get and I want the most DR I can get. *That goal is directly tied to exposure* and improved sensors and processing in no way alters that: more exposure (up to the sensor's max capacity) = better and less exposure = worse. The sensor is a data collector with a fixed capacity. Exposing the sensor to max capacity is best and anything that isn't best is less. Circumstances at times force us to accept less -- it's always better to get the photo than not -- and when that happens I do the best I can.

Joe



smoke665 said:


> I've read so many articles on the subject that my head is spinning, so I'd prefer you not post links for further reading, unless it's to illustrate your point. Looking for personal opinions and knowledge please.


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## Designer (Feb 4, 2017)

O.K., so far I've got three kinds of popcorn; straight yellow with just a touch of butter (native ISO), black-hull with lots of real butter (high ISO) and white hull low-fat (no butter) (the lowest ISO).  Put in your order and pay the lady at the end of the counter.  Also if you want a special order, pay double in advance, and take a number.


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## Peeb (Feb 4, 2017)




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## MSnowy (Feb 4, 2017)

I'm doing something wrong. I go out and take pictures and really don't over analyze stuff.


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## table1349 (Feb 4, 2017)

Designer said:


> O.K., so far I've got three kinds of popcorn; straight yellow with just a touch of butter (native ISO), black-hull with lots of real butter (high ISO) and white hull low-fat (no butter) (the lowest ISO).  Put in your order and pay the lady at the end of the counter.  Also if you want a special order, pay double in advance, and take a number.


How about caramel corn, have you got any caramel corn?  I like caramel corn.


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## Designer (Feb 4, 2017)

gryphonslair99 said:


> How about caramel corn, have you got any caramel corn?  I like caramel corn.


Uh, sure, but you know caramel corn is for filmies, so you'll have to show your film camera when you pick it up.  

And pay double.  

In advance.


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## smoke665 (Feb 4, 2017)

Designer said:


> I'll make the popcorn.



Uh oh, didn't think about this being one of those kind of posts.

@Destin glad you chimed in on the D500. It's my understanding that it comes native with ISO 52,100 and base ISO 100, then uses software to bump down to an equivalent ISO 50 and the option of  bumping up to 102400, 204,800, 409,600, 892,200, 1,600,000 equivalents via camera software. As opposed to some of the others actually having native high ISO options, which supposedly has less effect on dynamic range. Have you actually had a chance to explore the high ISO options on the D500???


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## Destin (Feb 4, 2017)

smoke665 said:


> Designer said:
> 
> 
> > I'll make the popcorn.
> ...



Still waiting for it to get here so I'll let you know Tuesday haha

But I've read and watched every review I can find on the internet and the general consensus is that the "Hi" ranges are unusable and only a marketing ploy. This has been the case with every nikon I've ever owned, so it doesn't surprise me. 

That being said, looking at the reviews, everything up to 12,800 and even into the high teens looks VERY good for a crop sensor, and I'm excited to see what it can do for my low light sports shooting.


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## smoke665 (Feb 4, 2017)

Gary A. said:


> Yes, they have noise and yes, there is less dynamic range ... but as a tool to document the event they are quite useable and reflect, to a much greater degree, the tone of the event



Is this Luminance noise,  Chrominance noise, or both???



jsecordphoto said:


> Even the Sony A7s, arguably the king of current high ISO,



Might want to research that. I think even the A7ii is only 25.6k.  I haven't had the opportunity to see some images from the D500 at the 50k range, but some of the samples I've seen from the Pentax KP at the 51.2k mark are pretty darn good. Maybe not something that you'd want to blow up to a wall size poster, but still not bad.


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## Gary A. (Feb 4, 2017)

Mainly luminance, very little color noise.


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## smoke665 (Feb 4, 2017)

Ysarex said:


> The ISO increase they require is designed to force an underexposure of the sensor and then the ISO brightening boost is withheld from the raw file which then receives special tone curve processing to produce the JPEG. Paradoxically this technique reduces DR and that includes DR in the raw file. *The raw file is effected by the withholding of the ISO post processing*



Agree with this to a point. It's my understanding (at least for Pentax) that the s curve expansion instructions are saved in the metadata file of the raw image. Until you choose to develop the image with those instruction nothing happens to the raw file. I can't find anything to refute your comment that at that point the raw file would be changed forever, but I was under the assumption that it wasn't.

I agree as a whole, the process works by forcing an overexposure in the shadows, and an underexposure in the highlights, but again, I was under the assumption it was a post process and the image data should still be in the raw file, so how would this create a loss dynamic range?


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## Destin (Feb 4, 2017)

smoke665 said:


> Gary A. said:
> 
> 
> > Yes, they have noise and yes, there is less dynamic range ... but as a tool to document the event they are quite useable and reflect, to a much greater degree, the tone of the event
> ...



@smoke665 watch this video. 






Granted it's a YouTube video. But he offers the raw file to view if you wanna download it, and it looks pretty damn good considering we're talking ISO 51,000!

It wasn't long ago I was shooting a pair of Nikon D80s, and 3200 looked FAR worse than what 51,200 does on the D500.


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## smoke665 (Feb 4, 2017)

Gary A. said:


> Mainly luminance, very little color noise.



Interesting, I could live with that. So many of my earlier attempts to utilize higher ISO had both.


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## smoke665 (Feb 4, 2017)

Destin said:


> But he offers the raw file to view if you wanna download it, and it looks pretty damn good considering we're talking ISO 51,000!



This pretty much follows along with what I've seen in the Pentax release. 51.2 in both seems to be pretty much the threshold. Granted there is some visible noise but not objectionable and as @Gary A. pointed out earlier in some case could actually enhance the mood of the photo.


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## jsecordphoto (Feb 4, 2017)

smoke665 said:


> Gary A. said:
> 
> 
> > Yes, they have noise and yes, there is less dynamic range ... but as a tool to document the event they are quite useable and reflect, to a much greater degree, the tone of the event
> ...



When I say king of high ISO, I don't it has the highest ISO values, I mean it performs the best at high ISO and in low light.


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## MSnowy (Feb 4, 2017)

This is the only 51,200 iso  picture I have taken with d500. Straight out of the camera


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## Destin (Feb 4, 2017)

I'll be shooting a hockey game in a dimly lit rink Tuesday. Will try some real life 51,200 shots and post them up here.


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## Designer (Feb 4, 2017)

GETCHUR DR. PEPPER HERE!



ICY DR. PEPPER!



ICE COLD DR. PEPPER!


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## Ysarex (Feb 4, 2017)

Off to the grocery store and I took the X-T2 along (same sensor as D500).

The highest ISO setting on the T2 is 25K here's that shot:






And here's the full-res file for pixel-peeping popcorn eaters: ISO25K.jpg

Same photo with one stop underexposure. So I just left the ISO at 25K and stopped the lens down +1 to get an equivalent ISO 51K exposure:






And again the full-res file: ISO51K.jpg

Low DR weather unfortunately but look under the truck and you can see the pretty rapid fall off.

Joe


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## Ysarex (Feb 4, 2017)

smoke665 said:


> Ysarex said:
> 
> 
> > The ISO increase they require is designed to force an underexposure of the sensor and then the ISO brightening boost is withheld from the raw file which then receives special tone curve processing to produce the JPEG. Paradoxically this technique reduces DR and that includes DR in the raw file. *The raw file is effected by the withholding of the ISO post processing*
> ...



Nothing ever happens to a raw file -- you can't alter them.



smoke665 said:


> I can't find anything to refute your comment that at that point the raw file would be changed forever, but I was under the assumption that it wasn't.



The effect of the D-range function on the raw file occurs in the camera when the photo is taken. My use of the term "ISO post processing" is probably the problem here. I'm referring to the post processing applied to the sensor signal by the camera. In digital cameras raising ISO
1) biases the metering system and
2) post processes the sensor signal.
ISO doesn't alter the sensor's response to exposure it alters how the sensor data is processed. Pentax's D-range highlight function forces an ISO increase to at least 200. You can't use it at base ISO 100. Without the D-range function engaged, raising the ISO from 100 to 200 would do both items 1) and 2) above. With the D-range function active item 2) is withheld. At ISO values above 200 1 stop of ISO brightening is withheld. The raw file is therefore effected.



smoke665 said:


> I agree as a whole, the process works by forcing an overexposure in the shadows, and an underexposure in the highlights, but again, I was under the assumption it was a post process and the image data should still be in the raw file, so how would this create a loss dynamic range?



The raw file is effected by the D-range function's forced underexposure. Maximum DR = a full sensor capacity exposure at base ISO. Any reduction in that full capacity exposure = reduction in DR. So the raw file is effected by having it's DR capacity hamstrung as it were.

Joe


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## smoke665 (Feb 4, 2017)

MSnowy said:


> This is the only 51,200 iso picture I have taken with d500. Straight out of the camera



Wow, that's insanely clean for 51.2. Did/have you attempted any cleanup post??? Are the lower ISOs progressively cleaner? I had to take the my K3ii out for a test run, two shots 51.2 straight out except for the crop, with a 300 mm Sigma. Seems to be more color noise in mine, though that might be partly lens and focal length related. I did notice that the inside shot closer to the subject seemed cleaner. 



 




IMGP2833.jpg by William Raber, on Flickr



 




IMGP2843.jpg by William Raber, on Flickr


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## smoke665 (Feb 4, 2017)

Ysarex said:


> Low DR weather unfortunately but look under the truck and you can see the pretty rapid fall off.



Probably more noticeable on your original, but as internet images on my end I'm not seeing much difference between the two. I guess it comes down to knowing all of your camera's features and abilities, and then using the best settings for the job at hand. To me having the High ISO capability is just another tool in the box.


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## astroNikon (Feb 5, 2017)

I bought the D500 to go alongside my D750.

Before I bought it I took sample shots at various ISOs on a D5500,  D7200, D610, D750, D810 for comparison.  I had on my Flickr shots of all those cameras compared at various ISOs, but have since deleted them.

With the D500 Hi-1 would be the max, "I gotta absolutely get the shot" but isn't recommended.

In test shooting the D500 against the D750 in bad lighting / low lighting indoor soccer I've found the D500 just could not keep up with the D750, using the same lens.  Sports is very demanding as you *have* to have a minimum shutter speed so it's up to the ISO to compensate the exposure along with the sensors light gathering ability.   

Nikon also has excellent software to handle the image processing.  I've always been curious how much of the image is software versus if it came from the sensor right to a file.   And as mentioned the higher the ISO the less DR you can obtain.


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## smoke665 (Feb 5, 2017)

@astroNikon  Sports and Wildlife were the two areas I first thought of when looking at the high ISOs. I'm not really up on the Nikon but in the case of the Pentax they went with a slightly different sensor, a new CPU, and system software. As manufacturers develop new technology I honestly believe they will one day mimic or even surpass the human eye in the ability to capture light and dynamic range.


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## dasmith232 (Feb 5, 2017)

jsecordphoto said:


> "Practical use" is certainly a novel idea. Will it be useable for documentation? Maybe, I guess depending on what you're using the images for....


There are lots of decisions and compromises to be made in photography. ISO Speed is one of the them, and it's important, but so is getting the shot. And for that matter, just getting out there and getting any shots. Especially for PJ, an image with some noise is a whole lot better than motion blur or camera shake with no noise. I think?

I find that if I'm reasonably careful about controlling exposure (beyond the ISO setting), I don't really find myself worry about noise all that much. Then put the power of post-processing to work, and things usually work out pretty well.



MSnowy said:


> I'm doing something wrong. I go out and take pictures and really don't over analyze stuff.


Yeah, you're just crazy... 

Oh, and the other thing, if you're not shooting everything at ISO 100, then ... uh, nevermind.


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## JasonC (Feb 5, 2017)

In my film days I considered anything over ISO 100 to be too grainy. In fact, ISO 64 was my film speed of choice in my AE-1 and ISO 100 was regularly wound in my little pocket Olympus XA.  However, with digital technology and full-frame cameras, the noise of ISO 1600 seems to be comparable to the grain found in between ISO 100 and 400.

Just this weekend I was at an outdoor car show with overcast skies and was forced to take hand-held pics at ISO 1600. Surprisingly, the pics, which were taken with a Canon 760 D and a cheap kit lens (18-55mm) were not what I would consider excessively noisy. Indeed I was pleasantly surprised! 

Best,

Jason


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## greybeard (Feb 5, 2017)

My D750 allows me to set my camera to Aperture priority, set the ISO to AUTO, set the minimum shutter speed to whatever (usually 1/125-1/250) and set the Aperture to whatever (usually) f/5.6-f/8.  Because of the camera's ability to handle high ISO (6400 and above) I don't worry about noisy photos and because my shutter speed is set to minimum 1/125-1/250 etc. I don't worry about motion blur.  Because these cameras have shutters that operate at 1/4000 and above I don't worry about overexposure either.  When it is necessary, I can go full manual and have complete creative control.

  My 1st cameras didn't have a light meter so I learned using a handheld light meter.  I shot most of my stuff on Kodachrome 25 (that's ISO (ASA) 25) .  Today's super high ISO cameras represent freedom to me.


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## smoke665 (Feb 6, 2017)

For those who've weighed in that they are using the higher ISO settings, have you noticed any significant differences in noise between focal lenght and/other distance to the subject?


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## astroNikon (Feb 6, 2017)

FYI, the D750 (d6x0, d5x00, d3x00) shutter speed only goes to 1/4000.
whereas the D500 (and D7x00, d8x0, etc) goes to 1/8000.

99.9% of the time I'm in manual where I can set the exact Aperture, and the exact Shutter Speed I want and in sports/wildlife I use AUTO ISO.  In other scenarios I manually set ISO.  

I've never liked the results of allowing the camera to select either the Aperture or Shutter speed because when I see a scene I know what Aperture (DOF) I want and what Shutter speed is needed (in kids sports as they get bigger the speed go up, and the camera doesn't know that).  The computer can just take a guess and if you set your lower limits high enough you'll get what you want most of the time.


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## JasonC (Feb 6, 2017)

smoke665 said:


> For those who've weighed in that they are using the higher ISO settings, have you noticed any significant differences in noise between focal lenght and/other distance to the subject?



No I haven't, but then I've only just begun experimenting with "high" ISOs. Great question, though.

Best,

Jason


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## Destin (Feb 7, 2017)

Alright so I just got my D500 from Santa in a brown UPS suit. I'll put together a real life test in a separate thread in the coming days, but for now, here's a quick preview compared to my D7100. Both images were captured as compressed RAW files, SOOC and converted to .jpg in lightroom. No adjustments applied. 

D500@ 51,200:






D500 @ 12,800:





D7100 @ 12,800:


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## smoke665 (Feb 7, 2017)

@Destin you can see the difference at least on my tablet. Looking forward to reading about your experiences.


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## Ysarex (Feb 7, 2017)

A little fly in the ointment here that has to be considered: Processing software matters.

I'm not a low light shooter and it's the odd occasion that you find me taking photos into the ISO 1600 range, but I do take extreme contrast high DR photos and then squeeze the max out of them. When you get down to the bottom of your sensor data it really matters how you process that data. Too busy right now to shoot an example but here's a instance where I had to take some low-light photos (some event snaps recently for some friends). Not the best example but should serve. Here's the snap:





Now we're going to zoom in to the darkest area of the photo were we can watch a tone transition into black:





First: Default open in both Adobe and Capture One with default noise processing. The difference is subtle but subtle matters when you're trying to squeeze out that last little drop. Adobe's transition is splotchy by comparison. What you're seeing is the difference between floating point precision versus whole numbers. Adobe has made a compromise choice for speed over precision. Capture One has made the same compromise in the other direction.

NOTE: This is not to be critical of one over the other -- both choices are good choices and we can't have it all. Personally I endorse Adobe's choice in this case and when people ask me what software to use the word Lightroom is out of my mouth before they finish their sentence.

We live in an Adobe dominated world and so when we evaluate our camera's performance Adobe is typically the default arbiter. In those instances where you're trying to use a camera sensor underexposed by as much as 5 to 7 stops Adobe may not be your best friend.

Joe


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## smoke665 (Feb 7, 2017)

Good point Joe. I found that processing my raw files in Pentax proprietary utility, will consistently yield better results, but it's such a PITA that it's not worth the effort. The presets I use in LR and PS are close enough.


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## TCampbell (Feb 7, 2017)

smoke665 said:


> The advent of the mega ISO cameras being released has prompted me to read up on the subject, which in turn brings more questions.
> 
> 
> In the past there has been some discussion as to the effect a higher ISO has on dynamic range. My understanding on the new, mega high ISO cameras while not necessarily practical from a use standpoint at the maximum level, have actually raised the bar on the lower levels, making practical use of 50,000 ISO possible.  While there have been improvements in the sensors, most of the increase seems to have come  in the CPU and image acceleration software, which combined, limits downstream/upstream noise. My question is has the dynamic range capability improved in addition to the downstream/upstream noise reduction, or has the noise control simply created an appearance of an improvement.




This depends on the sensor.  Some sensors don't do any (or at least not much) "upstream" amplification and rely entirely on "downstream" amplification.  Downstream amplification results in a loss of DR (1 stop of DR is lost for every 1 stop of ISO boost).

If the sensor does "upstream" amplification, then that happens before the analog to digital conversion (ADC) and you can get some ISO gain without much of a loss in DR.

Noise can be randomly anywhere on the sensor.  But since the noise represents a spike in reported values for that photo-site (as compared to it's neighbors) and bright regions of your image already have very high values, the noise doesn't stand out as being so different than it's background.  But when this happens in dark regions of your images, the contrast difference is very noticeable.

When you apply global noise reduction, you try to compare the value of a pixel as compared to it's neighbors and "average them out".  This process, unfortunately, also results in a softening of the image (which most people don't want.)

You can use software to selectively apply noise reduction based on the brightness of it's neighboring pixels so that it more aggressively goes after noise in shadows and does very little for noise in highlights.   Another technique some software uses is to detect edges of contrast and generate a mask that blocks the noise reduction from happening in those areas... but allows noise reduction in areas with little to no contrast.

So while you may not be able to stop the noise from being in the image straight-out-of-the-camera... you can do something about it once you get the image onto the computer.


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## Derrel (Feb 7, 2017)

Destin,
 One thing to note is that the D500's shot at ISO 12,800 is considerably "brighter" than the ISO 12,800 shot made with the D7100. I did not look at EXIF information, but one would want to compare the two cameras in two ways: at the same or identical f/stop and shutter speed setting for both cameras, and also at the same level of "exposure" in terms of brightness/histogram, even if that means slowing the shutter down for one camera (in this case the D7100) in order to achievce that same level of "exposure".

 It looks to me that at 12,800 the D500 has improved over the D7100's sensor. The one knock against the D7100 was that pattern banding that can been seen in deeply under-exposed areas that are later brightened in software; THAT is the single biggest difference ebtween the D7100 and the D7200--the pattern banding in deeply under-exposed parts of D7100-shot frames has been eliminated in the D7200's images.

The whole* question of High ISO is plagued by viewpoints that are 15,12,10,9,5, 3 years behind the current state of the art* in sensor tech.

Ask a Nikon D200 shooter about High ISO issues and then ask the same question to a Nikon D500 owner; ask a Canon 5D-Mark II shooter about underexposing by 5 stops and lifting the shadows later in software and then ask a Nikon D750 owner the same question and you'll get a huge, "No way!" and a, "Yeah, sure, if I want to, I can do that."; ask a Nikon D2x user what ISO 1600 is like and then ask a Nikon D500 shooter the same issue; sensor technology AND camera electronics AND software processing tools--all three of these things have changed, markedly, within the past five years. How people view High ISO, and how people view AUTO ISO, and how people view a number of things related to this depends, in many instances, on viewpoints that were set, or developed, with what is now outdated technology.

A lot of shooters hold ideas that are four,three,two camera generations behind what is possible with TODAY'S sensors, camera's and their internal electronics, and today's software tools.


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## smoke665 (Feb 7, 2017)

Derrel said:


> A lot of shooters hold ideas that are four,three,two camera generations behind what is possible with TODAY'S sensors, camera's and their internal electronics, and today's software



Think you nailed It!


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## Ysarex (Feb 7, 2017)

TCampbell said:


> This depends on the sensor.  Some sensors don't do any (or at least not much) "upstream" amplification and rely entirely on "downstream" amplification.  Downstream amplification results in a loss of DR (1 stop of DR is lost for every 1 stop of ISO boost).
> 
> If the sensor does "upstream" amplification, then that happens before the analog to digital conversion (ADC) and you can get some ISO gain without much of a loss in DR.



This has me a little concerned. DR is a function of exposure period. The engineering implementation in the camera that processes the sensor signal can employ a boost to the analog signal prior to ADC, digital scaling in the ADC and/or a hybrid combination of both. Regardless of implementation the method used to process the signal will do a better or worse job of retaining the sensor data but not create data. Exposure creates data. *The light sensitivity of the sensor is in no way altered by the methodology engineered into the system to process the sensor output.* A full sensor exposure = maximum DR. Any reduction in exposure = reduction in DR.

Joe

Pass the popcorn.


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## table1349 (Feb 7, 2017)

If this doesn't clear it up, nothing will. 

Noise, Dynamic Range and Bit Depth in Digital SLRs


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## Ysarex (Feb 7, 2017)

gryphonslair99 said:


> If this doesn't clear it up, nothing will.
> 
> Noise, Dynamic Range and Bit Depth in Digital SLRs



I hope you have an industrial size popcorn maker -- get started.

Joe


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## smoke665 (Feb 7, 2017)

@Ysarex  Not as up on this as you guys, but part of my understanding of the Higher ISOs was that they included an upgrade to the sensitivity of the sensor. As a lot of the downstream noise is generated by variance in the light being captured, wouldn't shortened exposure times decrease the amount of shot noise, but the DR remain the same due to the increased sensitivity?


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## Ysarex (Feb 7, 2017)

smoke665 said:


> @Ysarex  Not as up on this as you guys, but part of my understanding of the Higher ISOs was that they included an upgrade to the sensitivity of the sensor. As a lot of the downstream noise is generated by variance in the light being captured, wouldn't shortened exposure times decrease the amount of shot noise, but the DR remain the same due to the increased sensitivity?



Shot noise is the primary source of noise. Shot noise is exposure period. More exposure = less noise and vice versa. It really is just that simple. Noise from the camera electronics by comparison is minor. It's not the light sensitivity of the sensors that's being increased as much as their total recording capacity -- DR range. I guess you can think of that as a sensitivity increase in the low end, but I think the key is that as we increase the DR range of the sensor we push the shot noise farther and farther away from a base ISO exposure -- all ISO exposures benefit.

Secondarily now with the D500 we get further improvement in the processing of the sensor signal to squeeze out every last drop by using Sony's new dual gain sensor.

Take a journey through time along with a re-read of Derrel's post from earlier today: Photographic Dynamic Range versus ISO Setting

Bill Claff is a great independent source for data. That tech article that Gryph linked is explained on Bill's site. I listed on the linked graph Bill's data for:

Nikon D100
Nikon D90
Nikon D7200
Nikon D750
Nikon D500

Note the increase in DR capacity over time. Each time the line goes higher the sensor's DR capacity is increasing.

Each time we increase the sensor's DR capacity we push the noise farther and farther away. With the D100 the noise was only 3 stops away from a base ISO exposure. With the D7200 that noise is 6 stops away from a base ISO exposure. And with the D750 it's a solid 7 stops away. That's a staggering breathtaking increase over 12 years time. Nothing of that magnitude ever happened in the progress of film tech.

Now look at the graph for the D500 (orange). It goes farther down than the other cameras because the ISO is adjustable to higher values. Compare it with the D750 at ISO 51K and the D750 has a higher DR rating. Why take the D500 so far then if it's not keeping up with the older D750? Because the increase on the other end from Sony's sensor is doing a better job at noise processing so why not. But Bill lists only a 2.16 DR for the D500 at 51K. This is where the complaints about these 51K and higher ISO values have some merit. Once you drop below 4 stops DR range on the sensor you're running a deficit overall that has to be made up with some heavy lifting in post processing. Drop below 2 stops DR on the sensor and you should start feeling like Micky here:






You don't have enough DR left to fill 1/3 of a normal histogram.

Joe


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## astroNikon (Feb 7, 2017)

..


smoke665 said:


> Derrel said:
> 
> 
> > A lot of shooters hold ideas that are four,three,two camera generations behind what is possible with TODAY'S sensors, camera's and their internal electronics, and today's software
> ...


you can research all you want but until you make the jump you'll never really find out.

I know many ppl would say a DX is close to a FX camera.  But when I made the jump to a D600 from a d7000 I was totally amazed by the low light ability.  So now I have the d500 and d750. but then I tend to shot in more extreme lighting conditions.

If you compare a D700 12mp FF to a D6x0 24mp FF, you'll first notice that the d700's pixels are, for simplicity, twice the size of the d600s.  But the D600 of course is much better in low light.  And a change from Expeed to Expeed 3 processors (wiki has a large page about this too).
So it's an entire system that is moving forward not just the sensor.


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## smoke665 (Feb 7, 2017)

@astroNikon my research was more in understanding what I already have. The K3ii has a max ISO of 51200, but frankly it's not that usable. The new KP  with 819,200 Max brings the bar up on the low end, making 51200 usable but sacrifices some of the things I like about the K3ii. Supposedly there's one in the works to replace the K3ii that will stretch the ISO limit higher yet, so that's the one I'm waiting on.


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## smoke665 (Feb 7, 2017)

Ysarex said:


> More exposure = less noise and vice versa. It really is just that simple.



Don't you mean "LESS" Exposure time = less noise. As in the less time the shutter is open the less chance there is for light variations to hit the sensor????


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## Ysarex (Feb 7, 2017)

smoke665 said:


> Ysarex said:
> 
> 
> > More exposure = less noise and vice versa. It really is just that simple.
> ...



Shot noise is the dominant noise source and shot noise decreases with more exposure and increases with less exposure: What's that noise? Part one: Shedding some light on the sources of noise

Joe


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## astroNikon (Feb 7, 2017)

smoke665 said:


> @astroNikon my research was more in understanding what I already have. The K3ii has a max ISO of 51200, but frankly it's not that usable. The new KP  with 819,200 Max brings the bar up on the low end, making 51200 usable but sacrifices some of the things I like about the K3ii. Supposedly there's one in the works to replace the K3ii that will stretch the ISO limit higher yet, so that's the one I'm waiting on.


It all comes down to what do *you* consider acceptable based upon the type of photography that *you* do.

Do you need fast shutter speed, shallow DOF and high ISOs
or slower shutter speeds, deep DOF and high ISOs?
or fast shutter, deep DOF and high ISOs?

I went to BestBuy probably 4 times taking shots comparing the D500 to various cameras.
In all my tests and doing the exposure math I came to the conclusion that it would *not* be able to do the indoor sports scenario that I shot in, but it would be fine in other situations.  Looking on paper it should have done just fine.

So I bought it (twice actually).  And when I tested it my math proved correct. It could not.
But that doesn't mean it's a bad camera, just not able to do what my d600 and d750 can do in low & bad light.

My D7000 (from several years ago) was only good up to 1600 ISO, based on my preferences.  But it went higher.

For instance, the D500 can go to 1Million ISO.
At 1/8000, f/32 at 1M ISO do you find this image acceptable ?



D500_ISO_Tests (28 of 28)
..
..
51200



..
..
25600



or this
other at 25600



..

btw, the last one was the D5500 at 25600


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## Derrel (Feb 7, 2017)

smoke665 said:


> Ysarex said:
> 
> 
> > More exposure = less noise and vice versa. It really is just that simple.
> ...



Not to speak for Ysarex, but I think you are thinking about long exposure noise, and say the associated Long Exposure Noise Reduction setting that most d-slr manufacturers offer as an in-camera setting, which is something that was a big problem at one time. Pretty sure what Ysarex meant was that "more exposure" means a longer exposure time, rather than a faster speed, or a bigger lens opening, rather than a smaller one, and in general "more exposure" means an exposure that is at least somewhat close to what "_the light meter says is the needed level of exposure_".


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## droaingsong (Feb 8, 2017)

astroNikon said:


> smoke665 said:
> 
> 
> > @astroNikon my research was more in understanding what I already have. The K3ii has a max ISO of 51200, but frankly it's not that usable. The new KP  with 819,200 Max brings the bar up on the low end, making 51200 usable but sacrifices some of the things I like about the K3ii. Supposedly there's one in the works to replace the K3ii that will stretch the ISO limit higher yet, so that's the one I'm waiting on.
> ...


Very well explained. At the end, it all boils down to what you like to do with it.


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## smoke665 (Feb 8, 2017)

astroNikon said:


> It all comes down to what do *you* consider acceptable based upon the type of photography that *you* do.



To me I consider color or chromatic noise objectionable, shot noise - not so much.



Derrel said:


> I think you are thinking about long exposure noise, and say the associated Long Exposure Noise Reduction setting that most d-slr manufacturers offer as an in-camera setting,



Negative. Referring to the length of time the shutter is open. The longer it's open the more chance for random variations of light to strike the sensor.


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## john.margetts (Feb 8, 2017)

smoke665 said:


> Derrel said:
> 
> 
> > I think you are thinking about long exposure noise, and say the associated Long Exposure Noise Reduction setting that most d-slr manufacturers offer as an in-camera setting,
> ...


Noise is not caused by random variations in the light hitting the sensor. Such variations are so small compared to the general level of light hitting the sensor they will remain invisible.


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## smoke665 (Feb 8, 2017)

john.margetts said:


> smoke665 said:
> 
> 
> > Derrel said:
> ...



From: What's that noise? Part one: Shedding some light on the sources of noise

_Probably the most significant and certainly least recognized source of noise is what we call 'shot noise' or 'photon shot noise'. In the simplest terms, this is you being able to see the impact of light's inherent randomness.

You might remember talk of photons from science classes, and the key thing to remember is that, although we perceive light as being pretty uniform, it actually travels as a series of packets. That is: light is quantized. These packets (photons) arrive at your eye or your camera sensor at random intervals. Because of the way the eye and the brain work, you don't notice this, but when you look at a scene, you're being bombarded by little packets of randomly occurring light from every part of that scene
_
Other sites have similar discussions on the randomness of light.


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## TCampbell (Feb 8, 2017)

Ysarex said:


> TCampbell said:
> 
> 
> > This depends on the sensor.  Some sensors don't do any (or at least not much) "upstream" amplification and rely entirely on "downstream" amplification.  Downstream amplification results in a loss of DR (1 stop of DR is lost for every 1 stop of ISO boost).
> ...



Joe, part of this is correct... in that the "light sensitivity of the sensor" isn't altered.  However... the dynamic range of the image saved to your memory card can be altered by boosting ISO.  But this happens as a result of what happens to the data after it leaves the sensor.  You certainly can lose DR by increasing ISO (there's lots of data to back this up.)

This is because you're dealing with "digital" data and you cannot record any values that overflow the bit-depth of the system.  If we increase ISO by 1 stop then with "downstream" amplification it means we multiply all values by 2.  

A 14-bit register can hold values from 0 to 16,383 (16384 possible values - that's 2^14th).  So if we had a pixel with a value of, say, 10,000 (which is in the range that the camera can handle) and we double it.. it's now 20,000 and that's beyond what our 14-bit system can store.  Data is clipped and we lose dynamic range.  We can also try to "scale" the image (squeeze the histogram proportionally) to avoid clipping... (so really you're boosting shadows but not boosting highlights) but again... that means we're reducing the dynamic range.  Either way, you lose dynamic range (but you can create an illusion of dynamic range because the data isn't clipping).    (I suppose Nikon D-Lighting or Canon Highlight Tone Priority modes might be examples of this.)

If you're doubling the data, then you have a math limitation based on the bit-depth of the system. 

If you boost exposure on your computer... instead of your camera... the computer has significantly higher bit-depth.  I suppose one might say this is a bit of a cheat because you wouldn't boost ISO in the camera... you'd do in the computer (so the camera is shooting at low ISO where it still retains it's maximum dynamic range.)  

I'm wondering what you mean by "DR is a function of exposure period."  Can you elaborate on what you mean by that?

BTW, you can see plots of the data at dslr-astrophotography.com.  Here for example, are plots for Nikon cameras.

Best ISO values for Nikon cameras

Take a look, for example, at the plot of the D3100 vs. the D3200.  

On the D3100, you can see the DR remains reasonably stead as ISO increases from 100 to 200 and then 400.  But when the ISO goes to 800 there's a slight (but not quite linear) loss in DR.  When it increases to 1600 there's a steeper, but still not quite linear loss in DR.  But from 1600 on there's literally a linear loss in DR for every stop of ISO.

Meanwhile on the D3200 there is immediately a linear loss in DR for every stop of ISO.  

You can see that the D3200 has just over 12 stops of DR at ISO 100.   The D3100 has just over 10 stops of DR at ISO 100.

But since the D3100 can make it to just about ISO 1600 before it starts the linear loss of DR, you can shoot a D3100 at ISO 1600 and get nearly 10 stops (I think they report that it's 9.6) of DR.  If you tried to shoot a D3200 at that ISO, you'd get just a little over  8 stops of DR (it's hard to see based on the graph... maybe 8.5)    So a D3100 outperforms the DR of a D3200 _at ISO 1600_ by a little more than a stop (maybe 1.5 stops) even though the D3200 outperforms the D3100 _at ISO 100_.

BTW, the bend in the graph of the D3100's ISO vs. DR plot represents the difference between "upstream" and "downstream" boost.   When the graph is staying reasonably flat (at the left side) that's "upstream" boost.  When the graph starts to bend downward (and ultimately goes linear) thats "downstream" boost.  The manufacturers don't publish enough specs to tell us if and how much "upstream" vs. "downstream" they do, but you can reverse-engineer your way into it and figure out where it's happening for any particular camera model.


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## smoke665 (Feb 8, 2017)

TCampbell said:


> the "light sensitivity of the sensor" isn't altered.



I was under the impression that there was an increase in sensitivity on the new sensors somehow in their ability to translate and transfer the analog voltage from each pixel. From what I've read of that it appears there are limitations in future technology.  Have you read or know anything about the research into memory chips as the the sensor where light photons actually alter the bits. Because it can theoretically achieve imaging with 100 times as many pixels on a chip of the same area as a conventional CMOS sensor, an inexpensive gigapixel camera could be a reality.


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## greybeard (Feb 8, 2017)

smoke665 said:


> For those who've weighed in that they are using the higher ISO settings, have you noticed any significant differences in noise between focal lenght and/other distance to the subject?


No I haven't noticed any difference from 24-120.   or  70-300


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## greybeard (Feb 8, 2017)

One big thing I think these cameras that can operate at such high ISO's allows us to do is use slower lenses in situations where in the past we need f/2.8 or faster.  I've been able to use my 24-120 f/4 and my 70-300 f/4.5-5.6 in situations where in the past they would have been worthless.  

Shot at 24mm f/4 ISO 7000




Bella Watching the computer by TOM STRAIGHT, on Flickr


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## Ysarex (Feb 8, 2017)

TCampbell said:


> Ysarex said:
> 
> 
> > TCampbell said:
> ...



No argument there.

What caught my attention was your comment, "....you can get some ISO gain without much of a loss in DR." That raised a flag for me thinking there might be an implication that sensitivity was being changed. But your affirmation that the light sensitivity of the sensor isn't (can't be) altered makes me happy.



TCampbell said:


> I'm wondering what you mean by "DR is a function of exposure period."  Can you elaborate on what you mean by that?



What I mean is that in very simple terms, since the light sensitivity of the sensor is fixed and unalterable, then the data you capture is ultimately a function of the data you expose for.

I understand that when the engineers test a sensor they expose it to a DR range that exceeds both upper and lower sensor limits. Then depending on how ISO brightening is implemented they measure the DR loss per stop of ISO brightening. I don't know for sure but I'll suspect that in the D3100 that you noted the DR loss of less than a stop per stop of exposure change at the lower ISO values is the result of a hybrid (analog gain/digital scaling) method similar to what's used in my old Fuji. Bill Claff identifies the DR change between 1/3 to 1/2 stop per exposure stop. That's the engineers.

We're not engineers. I think we use cameras to take photographs. And assuming we're photographers and not fauxtographers (more popcorn!!) let's consider this scenario: You're using a Nikon D3100 set to ISO 100. You've tested your camera and know it's limits and you meter a landscape with puffy white clouds as the brightest diffuse highlight in the scene. You place that diffuse highlight at the sensor threshhold (where it belongs). At ISO 100 you will be able to record X DR (the sensor's maximum). But oh no! you want 1 f/stop more DOF and can't afford to drop the shutter speed any further so you make the f/stop change and set the ISO to 200. How much DR did you just lose? X - .5 stop or X - 1 stop.

Instead of the Nikon D3100 consider instead the Simga Merrills. They use no variable gain at all. Therefore they have the same DR at all ISO values? The engineers would say yes. As a photographer I'd say you get the DR you expose for.

Joe


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