# How to make ISO 1600 look like ISO 100



## Sw1tchFX (Mar 2, 2010)

OK, so I read about this a coupla weeks ago, but haven't actually had the time to go and test it out, but found a little time tonight and I happened to have my camera with me at the same time. Although the example picture I have isn't that great, it will work with what i'm about to show you.

At least it's better than something in my house 

Nikon D700, Nikkor 50mm f/1.4G AF-S @ f/4, Mirror Lock up, 8 seconds, ISO 100. Converted in Lightroom 3 beta, no noise reduction at all.














OK...so here's the idea, some of you may already know this already, but i'm assuming most don't. 


Below I have two pictures. one was shot at ISO 100 (Lo 1), and the other was shot at ISO 1600, scrutinize them carefully:










Not a whole lot of difference is there? 

aside from slightly better noise in the ISO 100 shot and slightly different highlight tonality in the ISO 1600 shot, they're about the same.

But they're shot at ISO's that are 4 stops apart!



The concept is called image stacking. Image stacking has been used for years with most people who do astro photography as a way to combat amp noise in exposures that are in the realm of minutes or hours. 

If you shoot with a Nikon D90, D2/3/700, D2h/x or D3/s/x, you can do this _in camera_ without Photoshop. 

So here's the same shot three times:

----*ISO100*----






----*ISO1600*----






----*ISO1600 Stacked*----







Well how do you do it?

Of course, put the camera on a sturdy tripod.

Rack off a picture at a higher ISO with obvious grain so you have something for reference. 


On your Nikon hit *Menu* on the back of the body.

Go to *Shooting Menu*=>scroll down to *Multiple Exposure*=>than you want your *Number of Shots* set to *10* (if you can't do 10, do as many as you can), and *Auto Gain* set to *ON*.


Rack out however many images you set it to and take a look!

The result should be dramatic. 


With this technique, using the D700 and D3, ISO 1600 with 10 shots looks about like ISO 100-200, ISO 6400 looks more like 400-800, and 12,800 aside from banding, and slight hue shifts looks alot like 1600. 

a normally 10 second long exposure just takes a few 1/2 second or so long exposures, and at the same time, you avoid hot pixeling from heat, and different dynamic range in the highlights.


So yeah, if you've got any of the cameras I listed, give it a shot!


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## Garbz (Mar 2, 2010)

Worth noting that this feature is not limited to the D700. Anyone into astrophotography has long known that the only way to take really decent photos of stars is to crank the ISO and stack images to average out the noise issues. 

A great free program to achieve on the computer what was achievable above is Deep Sky Stacker.

One problem with this though is that the images need to line up. Which usually implies non-moving targets / tripods, and once you have those, why not just shoot at ISO100 to begin with? 

*makes sense in astrophotography because stars move slowly and the stacking software will normally align the image.


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## Mulewings~ (Mar 2, 2010)

Cool...I can learn something every day!


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## Eco (Mar 2, 2010)

Hmm, I tried this on my D90 but while the images show up on my camera I can't load them into Iphoto......any ideas?


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## usayit (Mar 2, 2010)

Garbz said:


> One problem with this though is that the images need to line up. Which usually implies non-moving targets / tripods, and once you have those, why not just shoot at ISO100 to begin with?



That's the first in my mind... so what's the advantage of the stacking?  Excluding astrophotography applications.


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## Overread (Mar 3, 2010)

Interesting - I knew I had heard of stacking in astrophotography, but had always assumed it was the same method as used for macro photography - ie stacking depth of field or slow changes over time (eg star trails done instages so the sensor did not overheat). 
Oddly the macro stacking software I have (combineZP) will do the very same as you example - stack and addup the sharpness and details whilst cutting the noise out) but it oddly won't do it for identical frames and I've never really thought of doing a series of shots like the above for the method - I'll have to try it and see if its possible

(since you know incamera editing is always worse than out of camera editing    )


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## skieur (Mar 3, 2010)

Stacking is based on the idea that random picture noise does not take place in the same area of two images even if they were shot at the same time in the same location.

New Sony cameras are coming out with an in-camera stacking and blending mode.  Their new chip permits 10 to 15 frames per second, so multiple shots are automatically taken, stacked, and blended together in camera.

skieur


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## usayit (Mar 3, 2010)

> Their new chip permits 10 to 15 frames per second, so multiple shots are automatically taken, stacked, and blended together in camera.



So in conclusion,

Right now.. there is no benefit of shooting ISO 100 on a tripod versus stacking.  The benefit can only be realized once multiple shots (very fast) can be taken in succession.  Even then, moving objects will be a limitation.


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## bigtwinky (Mar 3, 2010)

Great thread.  I like learning about things I have never heard of before.  Now time to see how I can apply this to my own photography.

I think I need a new Photo tool belt, mine is getting a bit cramped


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## Overread (Mar 3, 2010)

I'm considering getting a note book to log all these things down in! I find these days (especailly in editing) there is so much that can be done you can get a little overloaded!


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## bigtwinky (Mar 3, 2010)

I just throw out a Thanks to the posts that provide useful information like this, so that I can simply go to the list of posts I thanked and review them there


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## wiredhernandez (Mar 3, 2010)

Great information. Thanks for posting.


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## skieur (Mar 3, 2010)

usayit said:


> > Their new chip permits 10 to 15 frames per second, so multiple shots are automatically taken, stacked, and blended together in camera.
> 
> 
> 
> ...


 
Apparently moving objects are not a limitation. Somehow the camera can sense and make adjustments accordingly or so the specifications indicate. 

skieur


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## Overread (Mar 3, 2010)

Ouch that sounds like quite a revolution for moving photography - especially things like wildlife and band/gig photography where high ISOs are often needed. I would think if it could be tested to work on very fast moving subjects (hummingbird wings?) and shown to work it could be the next big thing after high usable ISOs


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