Is there a difference in the low-light performance of a full-frame camera in full-frame versus crop-sensor mode?

[alexjieh]

Is there a difference in the low-light performance of a full-frame camera in full-frame versus crop-sensor mode?

Reason: I am aware that there are many lens options. For upcoming travel, I am considering a Sony 70-350 mm crop-sensor lens for my A7RIV (26 mp files are fine with me) because of the lightweight and excellent reported performance. While APS-C sensors are reportedly less sensitive than full-frame ones in low-light conditions, I wonder if using an APS-C lens on a full-frame sensor has any negative impact. I get that the image size will be smaller due to using only the center portion of the full-size sensor, but the pixel size does not change, and logic says there should be no difference, but I am unsure. I appreciate any advice.

Equipment: A7RIV

This unrelated image of a fly is for visual interest.

 

[Brownie]

In APS-C mode you'll be gathering less light and your DOF will change somewhat. Both are negligible. Practically speaking, that's about it.

 

[Uncle Kevriano]

As Brownie says, not in real terms. no. I have never noticed it.

 

[pointreyes]

As Brownie says, not in real terms. no. I have never noticed it.

Same for me and it was one of the reasons I got the 70-300 G. I still wanted the full frame when possible and then for more reach use crop mode on the A7Riv. I rarely need to go beyond 400mm though.