Does auto ISO impact AF performance?

Started 2 months ago | Questions
I Love Furry Animals New Member • Posts: 23
Does auto ISO impact AF performance?

So I'm learning photographing bird. I need to be able to focus on the moving bird as quickly as possible.

Was thinking that the camera might need to "think" more to calculate the right exposure and then going to be slower to focus? Is this even a valid concern? If so, is it camera dependent?

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Nikon D5600 Nikon Z6 Nikon AF-S Nikkor 50mm f/1.8G Nikon AP-F 70-300mm F4.5-5.6E
ANSWER:
Chris R-UK Forum Pro • Posts: 20,014
Re: Does auto ISO impact AF performance?
3

I Love Furry Animals wrote:

So I'm learning photographing bird. I need to be able to focus on the moving bird as quickly as possible.

Was thinking that the camera might need to "think" more to calculate the right exposure and then going to be slower to focus? Is this even a valid concern? If so, is it camera dependent?

I can’t imagine that auto ISO and the exposure calculation has any affect on focus speed.  However, other settings can on specific cameras.

Some photographers, myself included, think that IBIS can interfere with high speed shooting because IBIS may be moving the sensor when the on-sensor AF system is trying to determine focus.

Selecting the option to confirm focus before releasing the shutter definitely slowed down the shutter release on one of my cameras.  It checked the focus even when I had focus locked..  It also introduced a delay at the beginning of a burst.  This setting can also affect FPS rates.

Ask for recommended bird photography settings on the forum for your camera.

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Chris R

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John Sheehy Forum Pro • Posts: 22,753
Re: Does auto ISO impact AF performance?

I Love Furry Animals wrote:

So I'm learning photographing bird. I need to be able to focus on the moving bird as quickly as possible.

Was thinking that the camera might need to "think" more to calculate the right exposure and then going to be slower to focus? Is this even a valid concern? If so, is it camera dependent?

I can't vouch for every camera model, but as someone who has spent time writing software code, I can say that there is no reason for it to take any extra time at all to automate any one parameter vs another.

There isn't a whole lot for the camera to "think" about. No judgement or mulling is used. Hard and fast rules are followed to complete an equation involving metering plus EC bias, shutter speed, f-number, and ISO, and may also include focal length for shutter speed in some situations, and user limits imposed on floating values.

The bottom line is that ISO automation is not necessarily any more computation-intensive than automation of any other parameter.

D Lynch Veteran Member • Posts: 4,395
Re: Does auto ISO impact AF performance?

Welcome to the forum. You show you have good gear...Nikon 5600 and Z6?

Auto ISO won't slow you down. It will help you. that wasn't the case a few years ago.

How are your images now? Check your ISO on images you like and don't like. Remember you need high shutter speeds with longer lenses; you need higher shutter speeds for moving subjects, if you want feathers in focus

I believe camera choice and lens choice affects focus speed more.

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DaveL
Hazeltown

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