Is it normal for RF 15-35mm F2.8 L to get lighter or darker when zooming

[chance001]

I just purchased the RF 15-35 F2.8 and when testing on a Red Komodo  when zooming from 35 to 15mm the image gets brighter.  The opposite happens when 15 to 35mm the image gets darker.  This seems odd because its a F2.8.  Any Ideas?

Thanks,
Chance

[ebiggs1]

I have no idea but it will not do that on a Canon camera.

[jrhoffman75]

You probably need to post that question on the Red site.