Hello. I could use some help diagnosing an issue I'm having with a recently acquired Tamron 150-600 G2 lens and also recently acquired 7D Mk II body. I purchased them both from members here. The 7D Mk II body arrived a few days ago, and I've been learning the features, making setting adjustments, and using it with my 100 2.8 Macro lens (the only lens I had at the time) to get familiar with it. Everything seemed to function just fine.
Yesterday, I received the clean, used 150-600 G2 Tamron. It looks like it's never been used - it's that clean. I also got the tap-in console with it.
Immediately I noticed focusing issues with it when zoomed to 600mm. It took me a while to realize what the problem was. Somewhere between 500 and 600 mm, the aperture changes from f/6.3 to (briefly) f/5, then straight from f/5 to f/9 just before 600 mm. It is consistent, and starts this right at 550-560mm. The reason I was having trouble focusing is because the body was reading f/9 at 600mm. I can shoot pictures at 600mm by manually focusing, but the widest aperture I can get the combo to register is f/9.
Has anyone else seen a problem like this? If so, how did you get it resolved?
I have another body I'll be able to test the lens on this weekend, so at least then I may learn whether it's a lens issue or a body issue. However, since the camera functions fine with the Canon Macro lens (although it's not a zoom) and the issue shows up very consistently at the same zoom range, I think it's probably a lens issue. Hopefully I know more this weekend, but I'd love to have some help if someone thinks they know how to work through this.