so I bought my 70-200 2.8 is (version i) from a family friend about a year ago.
the lens was working perfectly fine up until yesterday:
when I took some shots at F13, I noticed that my images was blown out, like they were shot at F2.8
it seems that for some reason, the lens not always use the aperture I select on my camera.
for example, if I put my camera on F2.8, take a shot, then changing to F32, there is no differnce in the image in terms of exposure.
I looked at the inside of the lens, and when I press the DOF preview button on my t3i, the aperture ring on the lens not always move to the selected aperture, but only after a few clicks. I can shoots 10 images at F32, and only 1 will actually be at F32, the rest will be with open aperture.
I thought that my camera is faulty, but my 18-135 seems to work fine.
I turned off the camera, took the lens out and put it back in, but nothing seems to work.
I don't know if its related to the problem that I have since the month I bought the lens:
sometimes when I press the shutter button, I get the message: connection between lens and camera body is faulty. please check your connections" - something like that. then i have to turn the camera off and back on, and that usually solves the problem.
Do you guys know this problem? Im really frustruated and Im looking for help please!
I put the camera in AV mode, pressed on the DOF-preview button, and turned the dial to move the aperture in real time. I did it for a minute or so, and it seems to fix the problem.
I also cleaned the lens and body contacts for extra care, I hope that this will solve the problem. I will update this post in case that something will occure.