Hi All, I have a 7Dii and always shoot MANUAL. I use the Tamron 18-400 lens. Today I had my camera settings at: MANUAL / 1/800 th. / f:3.5 / ISO=100 / Eval Metering / Single Shooting I took a shot at 18mm, reviewed it and the settings were showing correct on the screen as to what I had set up for manual shooting. I zoomed in to 400mm, took a shot, reviewed it and the the ISO had changed to 320. I zoomed in to 100mm, took a shot, reviewed it and the the ISO had changed to 250. Does anyone know why the ISO would change from what I had set up at 100? Is there a setting that I need to alter to keep the ISO at what I set it to in Manual Mode? Thanks for any help - appreciated. Greg
I don't know the camera but it looks as though it has auto-ISO set and is maintaining your aperture/shutter settings as the effective maximum aperture of the lens changes with focal length. Just a thought .....
Yeah what thumbnail has said would also be my assumption, Auto ISO i believe operates despite of the M shutter/Aperture setting. Double check you locked in the ISO manually as well. Mine is always on manual there too.
Hi guys, thanks for the reply. the OP says "MANUAL / 1/800 th. / f:3.5 / ISO=100 / Eval Metering / Single Shooting". The ISO was not set to AUTO. I set it manually to 100.
Thanks all for all your analasys gents. It's great that you took the time to help me figure this out. Perhaps it had something to do with the Tamron 18-400 zoom lens as referenced in the manual under "Same exposure for new aperture". In there they mention scenarios 1, 2 and 3. For 1: I haven't changed the lens. for 2: I don't use an extender. So I thought it must be the maximum aperture changing on the zoom lens that is mentioned in 3: It still had me puzzled, so I cleared all camera settings, reset a few settings and options back to my preferences and all is back to normal. I can set Shutter Speed, Aperture and ISO (not Auto) in Manual Mode and as I zoom, those 3 settings stay the same throughout the zoom range. All fixed. I don't know what setting I obviously made that caused this strange behaviour, but glad it's been sorted. Again, thanks for your efforts.
