Jeff Gaunt sent me this interesting set of photos the other day and I just have to get your thoughts – his theory is that you can shoot at low ISO and boost the exposure in post with photoshop instead of shooting with higher ISOs and not end up with more noise.

I’m curious to see what you think… here’s Jeff’s notes:

Exposures don’t matter

From Jeff Gaunt:

I ran an exposure test on a Canon EOS 5D Mark III recently which I thought your readers would find interesting.

Its a different test to what most people do but the result was interesting and I think it will change how people think about exposures whilst shooting night time scenes. I have written up the results of my test below.

Recently I had some time at the end of a shoot to run some exposure tests on my Canon EOS 5D Mark III.

I know many people have done exposure tests but there was test that I haven’t seen but thought was interesting to try.

I have worked on many projects that have involved filming time lapses of the night sky. There is always a balance of wanting to keep the ISO low but still get a beautiful bright exposure of the stars.

I always found in post that I wanted to brighten the shot even more, and in doing so wound up with the same amount of noise in shots no matter what the ISO was.

This lead me to the conclusion that changing the iso on the camera gives the same result as changing the exposure in post.

My test involved shooting exposures ranging from 400 to 6400 ISO in 1 stop increments and leaving all the other settings on the camera the same.

In post I took all the exposures into Photoshop, using the 6400 as my base I increased the exposure on all the other shots to match 6400.

The top half of the image shows the original shots as they were imported into Photoshop. The bottom half of the image is the result of changing the exposures in photoshop.

Click Image for Full Resolution
Click Image for Full Resolution

My conclusion is that there is nothing magical happening inside the camera at a high ISO, this means there is no benefit from running the camera at high iso when shooting at night as you can achieve the exact same result in post from a low iso.

Now I have settled on my ideal camera settings for these situations at an iso of 1600 iso and use a fast f/1.4 lens.

What’s your experience?

Is Jeff crazy? Have you seen the same results? Do you shoot high ISO only to be disappointed?

We’ve got active comments below – join the conversation and let everyone know your thoughts on high ISO and Jeff’s testing.

See more of Jeff Gaunt’s masterpieces, visit his website

(cover photo credit: snap from Jeff Gaunt)


chief astronomer at planet5D LLC
Mitch "planetMitch" Aunger is the creator and mastermind behind

He's incredibly happy running planet5D and sharing so much joy of photography and filmmaking with his readers.