Under-Expose RAW files in Low Light and "Push" in Photoshop?

I have a Nikon D100.

 

Is it better to shoot at ISO 800 and then boost a stop during RAW Conversion rather than

shooting @ 1600?

 

Can that concept be taken even further? Say a Stop and a Half....Two Stops?

 

I convert using Photoshop 7 Adobe Camera Raw

 

jmp

Why don't you just try?

 

Galen Rowell used that with film, underexposing film by couple of stops and then making a 'correctly exposed' duplicate. Not recommended unless it is really necessary. But sometimes it may be.

 

I general, underexposing digital is not a good idea so at least in theory it should be better to use higher ISO.

Well Thats what i do with my 10D if I'm shooting horseback riding competitions (and one concert) in dark places... I shoot at ISO 800 but one to 1,5 stops underexposed, and then overexpose in the raw converter... This will create a lot more noise in the shadows, so you have to use a noise removal program like noise ninja or neatimage afterwards anyway... I have one noise ninja profile for ISO 800 1 stop underexposure, and I find the files look better (not cleaner) that way than ISO 1600 (also after noise ninja)... YMMV

I don't think there is any difference between underexposing at ISO 800 (1 stop) and just shooting 1600, if you are shooting RAW. To answer the second question: you can push it an extra stop to achieve ISOs the camera doesn't permit (e.g. 3200 on a 300d/drebel) - I think it comes out just like ISO 3200 ie significant increase in noise.

1 stop isn't that big of a deal. But realize that half your details are in the brightest stop of the sensor.<p>

 

See <a href="http://www.luminous-landscape.com/tutorials/expose-right.shtml">this article from Luminous Landscapes</a> for more info.<p>

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Don't go too far. On the left is an underexposed shot pushed 2.5 stops in Capture1. On the right it's correctly exposed.<p>

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<img src="http://www.itsanadventure.com/postimages/3stopcompare.jpg"><p>

 

When you increase exposure in RAW you will gain some noise and lose some detail. Again, though, one stop is usually fine.

Underexposure will help you capture more highlight details, at the expense of shadow

details. (But you'll have to do more than a simple +1 exposure comp in ACR to get the

additional highlight detail out.) So it's your choice. I'm not sure how "push" noise

compares to higher ISO noise -- it probably depends on the specific camera and RAW

conversion software. However, excessive "pushing" can introduce posterization in addition

to noise. So, I wouldn't deliberately underexpose unless I really need the additional

highlight details.