Canon 70-200 f/2.8 seems soft

Blind leading the blind here. My sister is having problems with the focus on her 70-200 lens. She is complaining that she just cant get it to focus. I tried comparing it to my Tamron 18-270 and the photos were just as sharp (200mm f/5.6 manual focus, stabilization off, on a tripod with cable release and mirror lockup). The photos are acceptably sharp as long as you dont pixel peep. Shouldn't her nicer lens being sharper than mine? She bought this used a few years ago. Should she have the lens adjusted? (Im away from the computer and don't have the ability to upload photos right now.)

It is all relative so it is hard to give you an answer without pictures to look at. The 70-200 is a great lens, but I know the version I can be softer wide open compared to the newer mark II version. But stopped down to f/5.6, it should be very sharp.

Don't manual focus to compare. Use live view to acquire focus. This takes away any micro-adjustment or manual error. Compare then... If still soft, it is possible something came out of alignment and should send to Canon to get checked/calibrated, but can cost upwards of $200 if out of warranty.

Good luck! But more information would be helpful... What camera bodies, version of the lens (Mark I or II?), and sample images. This way those with the lens can tell you if it is normal or not.

Upload it, it would be nice to see them to know the problem. What are her setings? Shutter speed?
Is that 70-200 new, or maybe bought not long ago?
Maybe she could play with microadjustment a little bit if she has it.

Invertalon wrote in post #15408624
Don't manual focus to compare. Use live view to acquire focus. This takes away any micro-adjustment or manual error. Compare then... If still soft, it is possible something came out of alignment and should send to Canon to get checked/calibrated, but can cost upwards of $200 if out of warranty.

Good luck! But more information would be helpful... What camera bodies, version of the lens (Mark I or II?), and sample images. This way those with the lens can tell you if it is normal or not.

Thanks. You're right, when I switched to auto focus, the photos from the 70-200 lens were slightly sharper than those from the tamron 18-270 on the camera LCD like i would expect. (I don't have the computer with me, just the iPad, and forgot the camera connection kit, so can't upload photos.) Settings were 200mm, f5.6, .3sec. I'm using my t1i body to test. My sister has an old xs body. She has the first version of the lens and bought it used a few years ago.

She is thinking about buying a new lens, but I think she might be better off buying a new body.

I just can't imagine any copy of the 70-200 not being razor sharp at f5.6