[jake]

Just wondered, when I am altering the EV in RAW am I doing the same thing as altering the ISO on the camera or is some different process happening?

[samleo]

Far as I know the process is the same as jpeg.

[morlandroger]

Someone will put me right I am sure, but yes you are effectively altering the ISO. Not entirely sure what difference with camera setings and ISO though.

[silkstone]

What application are you using to process the RAW?

An exposure adjustment will probably just increase or decrease the luminance (brightness) of the whole image - you can think of it as an ISO adjustment if you like, but without the noise issues. However, some RAW converters by default try to stop you blowing highlights when increasing exposure, so the tones are not adjusted uniformly across the whole range.

[LJR69]

Well, here's how I thought it worked (on my Nikon D300). If you are in Shutter mode it will alter the aperture by the number of stops you alter the EV. If you are in Aperture mode it will alter the Shutter likewise. If you have the camera in an Auto-ISO mode then it will alter the ISO if altering the aperture (in Shutter mode) or shutter (in Aperture mode) are unable to change to the level you are requesting them to through your EV setting (err...if that makes sense).

However, I rarely use this feature personally and so perhaps I'm wrong.

[Edit] Doh! You mean in the software. Not when changing it on the camera. Sorry. My bad.

[silkstone]

No it may be my bad! I assumed that Jake meant in software, but I'm not sure.

[jake]

Hi guys thanks for the input. I was meaning the software. I have been trying to decide whether it was better to increase the EV via the software (within its limits, about 2.5 EV) rather than just dial in a higher ISO. I did wonder whether I was doing exactly the same thing or whether there was a difference in the end result?
The software I'm using came with the camera and is Sony Image converterSR ver. 2 I did think the noise was less but it could just have been wishfull thinking

[Steve_Turner]

Just My 2p

I think that when you change the ISO or the EV on the camera the aperture and / or the shutter speed will change as a result, dependent on the camera program used. However this can't happen during post capture manipulation.

I guess that excessively changing the EV at this time might lead to saturation problems.

This seams to lead to the time honored principle of getting it as correct as possible in the camera, as any film photographer will tell you. Anyhow the better the photo is in the camera the less time spent messing around in photoshop and more time spent taking photos.

[silkstone]

Ideally, choose an exposure on the camera that does not burn out highlights - unless they don't matter. The easiest way to see this is if the camera can display the histogram either on preview or review. A spike up the right hand side means blown highlights.

You can then use your RAW software to adjust the tones. Recovering blown highlights is sometimes possible but not recommended. Boosting shadows and mid-tones is usually a lot easier, although you will get some noise or posterisation if this is done too much.