Most Rpi cameras can't change their depth of field, right?

[quitmeyer]

We have an arducam 64mp camera, it has autofocus and basic parameters you can change like most rpi cameras, but there's no way to change the aperture (that i know of). Which means there shouldn't be any controls i can change that should substantially impact the depth of field of the camera, right?

So I don't know if im seeing things, but me and some of my users have felt that when we changed some software from auto exposure mode to manual exposure mode, it seems like the depth of field has gotten smaller? We basically take photos of moths on a flat sheet at a fixed distance, and with the manual exposure , it kinda feels like the moths further from the center are suddenly more out of focus than they used to be.

Is there something I'm missing here? Just changing the exposure time or gain shouldn't change the depth of field at all in my understanding

[quitmeyer]

Ok, here's some images that may help explain what i'm talking about:
These two images have the exact same focal length (ignore my different attempts at formatting exif data)
but the one with ISO 16.0 instead of 1.0 is slightly sharper! Why is this?! is the depth of field changing somehow?

[quitmeyer]

Is this perhaps not actually changing the depth of field but the additional noise is triggering the sharpening algorithms to make it look more in focus?