REALLY High ISO Comparison - 20 Dec 2023

I was out photographing a flock of Bonaparte's Gulls this morning at Sunrise and accidentally bumped my ISO to 80,000! This gave me a 1/32,000 sec exposure at f/5.6 using the Sony a1 + Sony 600 mm f/4 lens. I quickly realized my mistake and switched back to my Auto-ISO settings (ISO to 12,800 to maintain 1/2000 sec), but decided it might be interesting to compare image quality under the different settings.

Here is the image at ISO 80,000 and 1/32,000 sec at 100% and 300% zoom BEFORE any adjustments:

This is what it looked like AFTER I adjusted exposure, highlights, and applied AI Denoise at 85%:

I think the results are quite impressive and usable should the situation ever arise to need an ISO this high. Before today the highest I'd ever shot was ISO 25,6000. 

For comparison, once I switched back to normal exposures (ISO 1250 and 1/2000 sec) the images exposed much more to expectation:

This is what the image looks like AFTER exposure adjustment, highlights, and AI Denoise (50%):

One of the shortcomings of shooting high ISO, besides grain, is the loss of dynamic range. At lower ISO it was easier to recover highlights and avoid blowing out the whites.