DPReview.com is closing April 10th - Find out more

What's the downside to 25600?

Started 6 months ago | Discussions thread
OP stevet1 Senior Member • Posts: 1,300
Re: What's the downside to 25600?
1

Dunlin wrote:

Steve, another downside is decreased dynamic range: low ISOs have the best dynamic range.

.

I can't help with your specific camera (t8i) questions.

My 7D only goes up to ISO 12800, and that's pretty terrible. But, your t8i is bound to be worlds better IQ wise - it's 10 years younger!

Dunlin,

Thanks. You got me to reading up on Dynamic Range, and I think I understand a little better now..

Just as an experiment, I took two shots of an overhead fan in very dim light with no flash from about five feet away.

The picture on the left was taken at ISO 25600, and the one on the right at ISO 12800. They were taken in aperture priority.

At 25600, the camera was flooded with light sensitivity (or however you choose to define ISO), so the camera set ss speed at 1/10th. The highlights were slightly more blown out and detail was lost in the shadows and darker wood blades.

When I lowered the ISO max to 12800, the camera dropped shutter speed three stops to 1/5th to allow for more light. More detail was revealed in the darker wood of the fan blades. You have to more aware of camera shake at the slower shutter speeds.

If you blow it up to original size, the difference is a little more apparent.

I think I'll keep my ISO max at 12800. My T8i seems to handle that pretty well, I think.

Steve Thomas

 stevet1's gear list:stevet1's gear list
Canon EOS Rebel T8i (EOS 850D) Canon EF-S 55-250mm f/4-5.6 IS STM Canon EF 50mm F1.8 STM Canon EF-S 18-135mm F3.5-5.6 IS USM
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow