I was recently curious about this, as I often find I might make slight exposure adjustments in Lightroom. I wondered just how much of an effect on noise and colour pushing it in post was having as opposed to maybe shoot at one stop higher iso in my camera would have. So today I did a very un-scientific test, and tried it out.
- Camera – D600
- Lens – Sigma 28 ƒ/1.8
- Subject… random stuff around my house put on a stool!
What I did
I set my camera up on my tripod, aperture at ƒ/8, focused using live view, and took a bunch of shots at different shutter speeds and ISO’s. Shutter was remote fired with a delay so I didn’t cause any vibration (I hope!) I then brought all the raws into lightroom, corrected the white balance using the grey card, and for every underexposed shot, I pushed the exposure slider to exactly +1. Nothing else was done to them in lightroom, no noise reduction or sharpening. Then were exported as TIFS, brought into Photoshop to align on top of each other, and do 100% crops of different parts of the image.
0.7 Sec – ƒ/8.0 – Iso 800 0.7 Sec – ƒ/8.0 – Iso 400 – Pushed +1 in Exposure
1/10 Sec – ƒ/8.0 – Iso 6400 1/10 Sec – ƒ/8.0 – Iso 3200 – Pushed +1 in Exposure
So what kind of conclusion do we come to after this? Well looking at the images, there really does not seem to much noticeable difference in terms of the amount or quality of noise. The biggest thing that I notice, is there appears to be more colour shifting when using lightroom to brighten up your image, as opposed to just using 1 stop higher ISO. Of course colour shifting is expected to happen at higher ISO’s but this is a bit more on top of that, nothing major that I feel it would overly detract from an image, but something to keep in mind.