Set R5 to bracket exposures using ISO instead of shutter speed.

[Kit Lens Jockey]

Hello, I can't seem to figure out how to set up the R5 to do auto exposure bracketing but in a way that it adjusts the ISO for each bracketed shot instead of adjusting the shutter speed. I want to lock down shutter speed and aperture to certain settings, and have the camera vary the ISO when using auto exposure bracketing. This post seems to allude that it's possible, but I cannot figure out how. Is it possible? Thanks.

R5 Inconsistent auto ISO bracketing exposures

Camera is set up for auto ISO bracketing (change EV by adjsting ISO instead of shutter speed or f/stop): exposure mode is M with e.g. shutter speed to set e.g. 1/200 s and aperture at f/8. ISO is set to auto ISO (auto ISO range set to 100-6400). Occasionally I see inconsistent exposures, i.e...

community.usa.canon.com

 

[Kit Lens Jockey]

Hmm, ok, I think I might have figured it out. It seems that setting the "safety shift" setting to ISO instead of disabled achieves the result I want. It seems like a little bit of a confusing explanation in the camera menus of how this setting works. But, it seems like that is the key to doing this.

 

[Kit Lens Jockey]

Alright so I have discovered that even with "safety shift ISO" turned on, there are still circumstances when the camera seems to adjust the shutter speed to achieve bracketed exposures.

Auto exposure bracketing seems to be some truly dark magic as far as camera settings and how they all interact are concerned.

 

[neuroanatomist]

Maybe I'm missing something, can you not just use M mode with shutter and aperture values selected and ISO set to Auto? Or Fv mode with shutter and aperture values selected, which should amount to the same thing.

Or perhaps you're running into problems at the extreme of the bracketing range? For example, when shooting the eclipse yesterday, I wanted only the shutter speed to vary (low, fixed ISO and the same aperture). I set the R3 for a 7-shot AE bracket covering a 12-stop range, and most of the time only shutter speed changed but I noticed that just before and after the totality there was >1 shot in the bracket with a 30 s exposure (actually, I powered the camera off and on to interrupt the sequence so I could start over for the totality with the solar filter off). I haven't checked the EXIF, but I assume it would have first bumped the ISO down to 100, then stopped down the aperture if another bracket was needed.

Logically, if you're at the extreme of the range, e.g. ISO 100 and the camera needs to expose more negative to meet the bracket conditions, the camera is going to have to vary something other than ISO.

 

[koenkooi]

Hello, I can't seem to figure out how to set up the R5 to do auto exposure bracketing but in a way that it adjusts the ISO for each bracketed shot instead of adjusting the shutter speed. […]

Which ISO ranges are you planning to use? The R5 is ISO invariant in most of its ISO range, so changing exposure in post has the same effect as changing ISO during capture.

 

[AlanF]

Which ISO ranges are you planning to use? The R5 is ISO invariant in most of its ISO range, so changing exposure in post has the same effect as changing ISO during capture.

Very good point! It is isoinvariant from 800-51200 so if you set it to underexpose at iso 800 you have six stops to 51200 from just one exposure without any need for bracketing. And, it wouldn't be too bad even starting at iso 50.