# Overexposure vs Underexposure



## ronlane (Aug 9, 2013)

Okay so this is a multi-part question/discussion. From some of the discussions that I have read, it seems that most photographers would rather overexpose a little than underexpose. It is my understanding that this is because it is easier to process the shadows with this case.

Is this correct?

The second part of this discussion is about LR post processing. Is the most of your processing involve lowering the exposure?

It seems like in my processing, that I hardly ever have to lower the exposure, most of the time I have to raise it 0.36 (roughly 1/3) or more at times.

The third part would be this. If you got what the camera says is proper exposure in the camera, how often do you have to adjust the exposure in post? Is it typically increase or decrease?


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## Derrel (Aug 9, 2013)

I think the over or under issue depends on a couple things. First off--the "new-sensor" Nikons have very wide dynamic range that they can bridge, and they also have amazing highlight recovery ability in their RAW files. So...with those kinds of cameras (D3-series, D700, D800, D7000 and other new APS-C Exmor-generation sensors) I think in RAW capture mode, the best thing to do is to overexpose a bit, and then "pull" the highlights back down in post processing.

With older cameras, like my Nikon D2x or Canon 5D classic, the dynamic range the sensor can handle is significantly, noticeably much LESS. With those cameras, and with cameras of that older era, blowing highlights was a terrible No-No, and often resulted in images that could not be saved in blown highlight areas.

I've argued with a few people who dismiss this point of view, but I own three d-slrs, which I have used within the last year, to greater or lesser degree: a Nikon D2x, a Canon 5D, and a Nikon D3x. The best way to expose with these three cameras is as described above; over-exposure with the D2x or 5D is often disastrous; with the D3x, the sensor performance is so amazing that overexposure is not an issue. If you own a 5D and think it can handle the same DR as a newer-generation Nikon, you're full of ***+. Period.

If you consistently have to raise the exposure .36 EV or whatever, maybe it would be good to dial in + .3 EV on the exposure compensation, or if your camera allows for it, make an "exposure offset", or whatever your camera maker/model calls it. THis will calibrate, or offset, the meter, so that a 0.0 =/- match needle reading is already biased the .33 EV it needs to be.


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## SCraig (Aug 9, 2013)

Paraphrased from Here.  Read that article for more detail.

A 12-bit image is capable of recording 4,096 discrete values.  Since each f-stop change allows 1/2 the light of the previous stop, and if we assume a dynamic range of 5 f-stops, the brightest f/stop will contain 2,048 discrete tones, the second f/stop half that or 1,024 discrete tones, the third half that or 512 discrete tones, the fourth half that or 256 tones, and the fifth f/stop half the previous or only 128 discrete tones.

So in the brightest areas of the shot you have 2,048 discrete tones of "White" whereas in the shadows you only have 128 discrete tones.  If you limit the dark parts of the image and get the light parts right where they are on the verge of blowing out by effectively shifting things to the right as much as possible, then you will have more discrete tones in the shadows than if you had allowed them to go all the way down to "Black".


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## ronlane (Aug 9, 2013)

Derrel said:


> I think the over or under issue depends on a couple things. First off--the "new-sensor" Nikons have very wide dynamic range that they can bridge, and they also have amazing highlight recovery ability in their RAW files. So...with those kinds of cameras (D3-series, D700, D800, D7000 and other new APS-C Exmor-generation sensors) I think in RAW capture mode, the best thing to do is to overexpose a bit, and then "pull" the highlights back down in post processing.
> 
> With older cameras, like my Nikon D2x or Canon 5D classic, the dynamic range the sensor can handle is significantly, noticeably much LESS. With those cameras, and with cameras of that older era, blowing highlights was a terrible No-No, and often resulted in images that could not be saved in blown highlight areas.
> 
> ...



Thanks Derrel, I'm still not convinced it is the camera that needs to be calibrated. It may be the operator. I think what I need to do is get together with a local photographer and go on a shoot to compare my SOOC and post to theirs.


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## ronlane (Aug 9, 2013)

Thanks Scott. I'm going to have to chew on that a little bit to understand it. I can admit that it is WAY over my head.


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## hirejn (Aug 9, 2013)

If you're looking to get this settled, you won't. Exposure is as subjective as art. I personally practice shooting to the right when possible, meaning I place the highlights as close to the right edge of the histogram as possible without clipping, when there is a highlight. I do this by spot metering the highlight and opening up to the maximum range my camera can capture, which is about 2.8 stops. The reason people STTR is because the highlights in digital files hold more detail than shadows, so we want to push the exposure to where there's more to play with.

Most of the time I don't adjust exposure in post; I simply move the white and black clipping points. Raising the exposure in post creates noise, so I want to avoid that. This isn't a problem because I'm rarely off by more than 1/3 stop from where I want to be. I consider 1/3 stop inconsequential, but an adjustment of 2/3 stop or more is something I consider a repair because that can easily be done in capture. Perfect exposure is a matter of understanding light, metering and using the tools available correctly. In most situations I can get perfect creative exposure, with full detail in highlights and shadows, in one click, and so should any pro. Perfect exposure is done and taught throughout the industry every day.

I rarely use what the "camera says" is correct exposure. The camera is capable of telling you only one exposure, and that is the correct exposure to render the subject medium gray. Sometimes it uses algorithms to appear to be a bit more creative, but I'd rather not rely on the camera to make those decisions. When possible, I use a hand-held meter, either in incident mode or spot mode off of a highlight, to get the exact exposure and then decide if I want that or want to make creative decisions. I also use the Sekonic L-758's averaging functions to find the dynamic range of the scene to be sure I can capture it in one shot. For this to work you must use the meter and Sekonic software to calibrate the meter to your camera's dynamic range.


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## Derrel (Aug 9, 2013)

ronlane said:
			
		

> Thanks Derrel, I'm still not convinced it is the camera that needs to be calibrated. It may be the operator. I think what I need to do is get together with a local photographer and go on a shoot to compare my SOOC and post to theirs.



Well, it could be, Ron! I wonder too if the "plus" exposure you need to add is just the factory's default "highlight protection"? 1/3 of an EV is not that far off. I am assuming you are saying the images typically need + .36 EV based on so-called proper histogram of the files in Lightroom or PS? Or are you judging this by how the images appear on a specific monitor?

1/3 of a stop is not a whole lot; it "might" be as I said, a built-in factory bias, a design decision, based on an average scene, or a specific Tone Curve that the camera is set to. When reading a camera-generated JPEG file, or in the field and looking at the histogram on the back of the camera, the Blinkies, and the RGB channel indicators, and so on are ALL made up from the embedded JPEG, which DOES take into account the Tone Curve (the degree of contrast the camera's processing engine applies to the data) the camera is set to. So...it's "possible" that a number of camera set-up factors could be affecting the overall light metering the camera is giving you.

Exposure metering, and exposure setting needs to take into account the Tone Curve's impact on the way the capture data is going to be made into a photo. On the SOOC JPEG files, I think having a bias toward having them come out a bit DARKER, is a good general compromise for JPEG images.


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## KmH (Aug 9, 2013)

ronlane said:


> Thanks Scott. I'm going to have to chew on that a little bit to understand it. I can admit that it is WAY over my head.


What it said is that fully 1/2 of the image information is in the brightest stop of exposure. The concept is the basis of ETTR - Expose To The Right.
Each dimmer stop of exposure has 1/2 of the luminosity info that remains, which is why underexposure makes image noise more visible.

Capture every photon you can.

Note that ETTR only works if the dynamic range in the scene can be captured by the image sensor in your camera.
Indeed, knowing the dynamic range your camera is capable of capturing is a critical specification you need to be aware of.


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## pixmedic (Aug 9, 2013)

I usually shoot to the right. 
sometimes though, it can be inconveniencing having to turn a few times to get something that is on my left side. 
I kinda feel when that happens, it would have just been better to shoot to the left. 
but, rules are rules.


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## 480sparky (Aug 9, 2013)

I expose to the right only because my right leg is shorter than my left.


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## kundalini (Aug 9, 2013)

I tend to hang to the left, but then I tend to ETTR when possible in camera.  In post, will bring down Exposure and bump up Fill and Blacks to taste.


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## ronlane (Aug 9, 2013)

Thank you all. I will continue to read and digest this more as I practice. Part of my problem may have been how I had changed the camera to back button focusing. When I did this, I put in the wrong setting where I lost my exposure lock. I wasn't able to set the exposure for the correct portion of the composition. I have read the manual and changed this to where I have bbf and can exposure lock with the shutter button. We shall see how this does for me this weekend.


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## weepete (Aug 9, 2013)

I find I'm almost allways slightly under exposing my shots and have to lighten them (somewhere in between 0.2 and 0.7 normally) in post. I frequently shoot in non ideal conditions but I'm not entirely sure whither I'm dailing in EC manually and then forgetting or whither I'm screwing up with the metering mode. I do know that my camera can produce properly exposed shots as there are times when it looks ok and I don't need to adjust so I'm pretty sure its me that's messing up a bit. The way I understand ETTR is basically your more likley to introduce noise by underexposing and pulling exposeure up than the opposite, so its best to ETTR as long as you don't blow out the highlights and plan on editing.

Most of my time in post is taken up with sharpening and tone curves or masking.


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## Stevepwns (Aug 9, 2013)

pixmedic said:


> I usually shoot to the right.
> sometimes though, it can be inconveniencing having to turn a few times to get something that is on my left side.
> I kinda feel when that happens, it would have just been better to shoot to the left.
> but, rules are rules.



I tend to follow this set of ideas. But I am left handed and get confused. So I just hit the shutter and pray it works out.


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## kundalini (Aug 9, 2013)

weepete said:


> ..... so its best to ETTR *as long as you don't blow out the highlights *and plan on editing.


That's why I prefer to set the LCD display to "Highlights" rather than Histogram.  It must be my old eyes because I can't read a thing (text) within the length of my outstretched arms without reading glasses on.  I do not wear glasses while shooting and often forget to bring a pair along.  So with the LCD set to "Highlights" or "Blinkeys", I can tell immediately what is blown out in the frame.  If a part is blown out and intregal to the image, I can make a quick setting adjustment so that part of the frame is still recoverable.  I think of the Highlights vs Histogram much like an analogue clock vs a digital.  If I walk past an analogue, I can tell you the time of day straight away.  If I walk past a digital clock, I have to read the time, which may or may not tell me what I want to know as I cruise by.

Sorry, didn't mean to tilt the conversation.


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## weepete (Aug 9, 2013)

I use the blinkies too mate, they can be really useful. I also have a peek at the histogram too mind you


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## gsgary (Aug 9, 2013)

I dont have a screen to look at, but know it will be ok because i know how to use sunny 16 rule


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## kathyt (Aug 9, 2013)

I use my blinkies and histogram. I will go about 1/3 to 1 stop above, but I spot meter with that. I still find myself bumping the exposure in post most of the time. It is very rare that I overexpose SOOC.


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## gsgary (Aug 9, 2013)

kathythorson said:


> I use my blinkies and histogram. I will go about 1/3 to 1 stop above, but I spot meter with that. I still find myself bumping the exposure in post most of the time. It is very rare that I overexpose SOOC.



Get yourself a good handheld meter


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## SCraig (Aug 9, 2013)

kundalini said:


> ...I think of the Highlights vs Histogram much like an analogue clock vs a digital.  If I walk past an analogue, I can tell you the time of day straight away.  If I walk past a digital clock, I have to read the time, which may or may not tell me what I want to know as I cruise by.


Believe it or not this is why many race cars still have analog instruments.  You have to READ a digital readout whereas with analog all you have to do is GLANCE at it to see where the needle is pointed.


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## kundalini (Aug 9, 2013)

kathythorson said:


> It is very rare that I overexpose.


Which has been the detriment to many among the male (and possible female) TPF membership.


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## weepete (Aug 9, 2013)

gsgary said:


> I dont have a screen to look at, but know it will be ok because i know how to use sunny 16 rule



Yeah mate, but you've left a lot of what you do out of that post too, it's not just knowledge about the sunny 16 rule but how you set up your shots too. Ultimatley its a tool like anything else, feel free not to use it if you wish.


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## cynicaster (Aug 10, 2013)

ronlane said:


> Thanks Scott. I'm going to have to chew on that a little bit to understand it. I can admit that it is WAY over my head.



If the technical nitty-gritty of analog/digital conversion doesn't sink in, I wouldn't sweat it.  Just try it for yourself--expose to the left and right, then adjust each one in post to get roughly the same result, and compare the quality.  

It takes very little increasing of exposure in post to coax out the fugly noise in the shadows, but you can decrease it all day, with the only potential consequence being loss of detail in the darker areas if you go too far. 

The first time I learned this concept and saw it at play was one of the biggest eureka moments in my hobby thus far.


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## Gavjenks (Aug 10, 2013)

Derrel said:


> I think the over or under issue depends on a couple things. First off--the "new-sensor" Nikons have very wide dynamic range that they can bridge, and they also have amazing highlight recovery ability in their RAW files. So...with those kinds of cameras (D3-series, D700, D800, D7000 and other new APS-C Exmor-generation sensors) I think in RAW capture mode, the best thing to do is to overexpose a bit, and then "pull" the highlights back down in post processing.
> 
> With older cameras, like my Nikon D2x or Canon 5D classic, the dynamic range the sensor can handle is significantly, noticeably much LESS. With those cameras, and with cameras of that older era, blowing highlights was a terrible No-No, and often resulted in images that could not be saved in blown highlight areas.
> 
> ...



A couple of points of comment here:

1) Jpegs only have 8 stops of dynamic range by definition, and recent technology Canon and Nikons (and presumably other brands) all exceed this already by several stops at lower ISOs. So as long as you are shooting RAW, even if one brand is one or two stops better in dynamic range than another, it will only come up as an issue if you over or under-exposed part of your image by MULTIPLE stops and need to compensate later by multiple stops, which in most cases, you shouldn't be doing if you're paying attention at all.  Or if you are shooting at very high ISOs, where dynamic range is lower (see point #2 though).

2) Nikons indeed have superior dynamic range at low ISOs that you would normally use in full lighting, like daytime photography or studio work.  Dynamic range is not a static value, though, and in fact represents as a curve across ISO values. Other cameras end up having better dynamic range at very high ISOs like 800+ For example, compare the 6D with the D800 on DxO Mark: DxOMark - Compare cameras side by side <---Click on the "measurements" tab, and then go to "dynamic range" to see the full curves.  At the lowest ISO, the Nikon is 2 stops ahead, but at high ISOs, the Canon is 1 stop ahead.  Thus, the choices you make about how to aim your exposure depend on what model and what ISO you're shooting at.  There is no catch-all solution. It will depend on studio versus night shots, brand, etc.

3) Keep in mind that if you want the full advantage of 14 stops of dynamic range on a recent generation full frame Nikon, you have to choose the 14 bit RAW format option.  If you do 12 bit, then your dynamic range is 12 EVs max, no matter how good the sensor is.  


But rarely does any of this matter, IMO, unless you shoot JPEG alone, or routinely shoot very dark scenes at 6400-12800+ ISO or so. Then you need to worry a lot about this stuff (if JPEG, then you can't adjust much in post, and with high ISOs, your sensor's dynamic range approaches that of a jpeg, so RAW doesn't help a whole lot).  If you shoot RAW, though, at low-ish to medium ISOs, then you'll be fine as long as you don't miss your exposure by something like over 2 whole stops in either direction, with just about any recent generation camera.


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## Derrel (Aug 10, 2013)

Gavjenks said:
			
		

> But rarely does any of this matter,>



Sorry, but that is utter nonsense.Period.

The new-sensor Nikons offer the best performance in term sof dynamic range that the world has ever seen. Canon cannot even put a camera within the Top 10 on DxO Marfk's sensor performance tests.

The actual imaging performance of the D3x versus the Canon 5D is WORLD'S better for the Nikon, with its better sensor. In everyday, real, regulkar, normal photo situations, in low light, when shooting in backlight, or whenever shooting in daylight. Even when both cameras are shooting in 12-bit RAW capture. How do I know??? I actually own the two cameras...

You can theorize alllll you want...but when the camera go into the real world, the superiority of SONY's Exmor sensors is easily apparent.

If you want to see head to head how far Canon has fallen behind SONY in sensor tech and real-world imaging quality, look at Fred Miranda, Canon 5D-III vs Nikon D800 + head to head comparison.

Google it. Canon's best sensor falls flat. IN DAYLIGHT and at its base ISO value. At 100 ISO, the Canon 5D-III sensor has terrible noise in the shadows, and pattern banding!!!!

All your theorizing falls away   http://www.fredmiranda.com/5DIII-D800/index_controlled-tests.html


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## Gavjenks (Aug 10, 2013)

Um, I posted the link to results from DxO mark.  That's where I got my numbers from... The single score is fairly useless, as it seems to refer merely to the maximum dynamic range at any ISO, *not *an average or anything that covers the full range of actual use cases. Thus, I suggested looking at the full curves instead.

DxO mark CURVES show that:

D800 vs. 6D (low end full frames):
*ISO 100: *Comparable models, Nikon is about 2 stops better dynamic range than Canons
*ISO 800:* About equal.
*ISO 6400:* Canon is about 1 stop better than Nikon. 

D4 vs. 1Dx (high end full frames):
*ISO 100-800:* Nikon is about 1 stop better than Canon
*ISO 1600+:* They are the same, or Canon is 1/2 a stop better, or so.

D7000 vs. 7D (high end crop frames. No numbers yet for 70D):
*ISO 100:* Nikon 2 stops better.
*ISO 200:* Nikon 1 stop better.
*ISO 400+:* Nikon plateaus at about 1/2 stop better from here on out.


In all cases, at low ISOs, all cameras are many stops better than a jpeg, meaning it won't matter really if you shoot RAW, unless you majorly blow your exposure or are shooting _extremely _contrasty scenes at rock bottom ISOs (which is very rare. Backlit sunsets of people is about all I can think of, but only if shot at ISO 100, which I personally probably wouldn't do... Doorways would qualify too, but you could easily just do an HDR for a scene of non moving objects like that anyway, for an effective dynamic range of up to 20+ EV easily with any camera).  At low ISOs, the brands get closer to one another, but also closer to the range of a jpeg, making the differences matter a little bit more.

But meh/shrug. Not much practical utility difference either way in most real life situations. And when there is, it depends what you want to shoot.  If you do a lot of sunsets at low ISOs, then Nikons are better for you. If you shoot a lot of things at ISO 6400+, then Canons are better for low end full frame (not enough to really make a purchasing decision), or about equal for other types of bodies.

In the vast majority of non-extreme situations in between where a typical person will take 98% of their shots, it simply doesn't matter, because you won't need or really utilize the difference anyway in your final jpeg, since your camera will already be very capable of pulling in extra highlights and shadows no matter what.




I think that similar to megapixels, dynamic range has already been more or less maxxed out in usefulness for most normal situations. Actually useful technological advances in the future are IMO going to be in physically larger sensors for less money, and in faster data transfer speeds (allowing cheaper high FPS and supporting the feasibility of larger sensors). 

Also better sensor-based AF. With sufficiently high data transfer speed + better sensor based AF, we could also do away with mirrors and shutters (since the live view would update at near light speed, AF just as well, and the shutter could effectively be electronic only).  Solid state cameras won't break nearly as easily (lifetimes of *millions *of shots rather than 100,000), would be cheaper and easier to manufacture, weigh less, and have much cheaper and higher quality wide angle lenses, without any of the relative disadvantages that mirrorless cameras currently have versus DSLRs.

And possibly exotic new technologies like fresnel lenses, multi sensor arrays, light field cameras, etc.


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## Johndow (Aug 13, 2013)

In response to the OP's original post, my default tends to be +1/3 over exposed.

The majority of my photos are of my family, 95% of which would be outside in good (bright) weather. I find that my camera will under expose on bright days. This wouldn't be such an issue if i were just taking landscapes, but faces tend to always be underexposed. Even at +1/3 i sometimes have to increase in PP by 1/3 if i had the camera pointing up and took in a lot of sky.

However, i have found that with LR4, i don't have to increase the shadows, but may have to reduce the highlights sometimes. In high ISO photos it helps to overexpose, because recovering detail from an underexposed photo produces awful noise.

If i was indoors or in low light i would leave the compensation at +1/3 unless I really needed the extra shutter speed to counter blur.

As my subjects are my family and any sky is just background, large dynamic range is not a requirement. If the sky is well exposed it's a bonus, but if it's blown out it doesn't matter, as long as the exposure on the main subject is spot on.


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## RacePhoto (Aug 13, 2013)

Depends on what you are shooting. If light subjects, you may want to under expose, intentionally. If normal or dark, I have the camera set EV to 1/3rd over All The Time! I'd prefer to lose some highlights and not have confetti and spots in the shadows. It's that simple.

When you have to raise the exposure, (in processing) you raise the noise. When you lower it, you lower the noise.


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