Hello all/ anybody who can help! I'm having a problem with my 70-200 F2.8L IS II.
I've rented and used many copies of this lens over the years and have never had an issue with it. Granted, the people over at Lens Rentals always tests and recalibrates their lenses on arrival. After a bit of luck at work and just the right amount of room in my budget, I was able to grab a copy for myself. At first, all seemed well, it was used, but not a single mark on it. Not even a bit of dust. And indeed, all through the range, the lens performed as expected.
And that's when the trouble started.
On day two with the lens, I went out to shoot some wild life and noticed I wasn't getting anything sharp at 200. No matter the aperture, everythign appeared to be slightly off. Heavy tripod, no wind, manual focus, fast shutter, 2.8 - 11, nothing sharp. No sense testing any more since the results aren't going to change. The images are in fact, sharp, but they're off. As though a second, very out of focus image is smudged across it. My guess, a slight stigmatism is going on.
Anyway, I got a refund on the lens, sent it back, and picked up a new copy. First thing I did when I got the new (still used) copy of the lens, everything tested just as sharp as any good copy I've used. Fast forward a few days, that issue cropped up again. Same exact thing. Slightly off. Everything from at least 125mm-200mm clearly shows the problem. Though it's a gradient from not terrible to crippling at 200mm. Sometimes it's not particularly present. But it usually is there in full force.
Perhaps that it comes and goes could be a symptom of the ambient temperature of Michigan currently being somewhere between the Arctic and Pluto.
The lens works fine belwee 100mm with literally no issues, sharp as a razor and very much matches my 24-70l IS II.
The image of the nest, looking closely, you can see the image is actually very sharp, but there appears to be the effect of petroluem jelly being smeared across the front element. It's very obnoxious. This has always been my dream lens. 😕
The image of the thread right below should show the stygmatism I was referring to. That's at the sharpest possible focus. Going in either direction on the focus ring from here will either result in the highlights becoming bokeh balls or just shifts the "focus" back further.
I would like to make sure everybody knows that this is in now way a back or front focus problem and no amount of MFA will fix this. It's not a camera issue as I've tested it with almost a dozen different cameras at this point. One thing I've noticed with both this lens and the first one I got was the front bit of the barrel is a bit loose, but that pretty much does nothing to the image. And searching all over the internet shows that it is pretty common, I've noticed other people post about this here and in other forums and the answers are never found, but I their description is similar to my issue, but poorly described. I followed up with a couple of different people on another site and their problems were never fully solved, they just either returned the lens, sold it was broken, or sent it in and got it fixed.
I tend to fall on the hardware engineering side of things and have read/ watched a lot about lens calibrations in the past and the stigmatism here seems to fall in line with an off-kilter calibration. But since it's noticeable as you zoom past 100mm and not really an issue until around 125mm, perhaps it's something entirely? Maybe somebody could help me?
"Or at least confirmation that I wasn't insane."
I am not sure this qualifies you as not being insane but it will get you perfect working lens. Good luck. 
These were taken on a t3i. But the same results come from a 7D, a 5DMIII, a 5DMII, a 6D, and a T1i.
I'm at 200mm in both photos. The nest is a crop from the original to show what I'm talking about. I wish I had a different copy for comparison, but I don't currently. However, on a tripod, using manual focus, there is no sharpness achievable. Literally none. That nest was only ~5 yards from me. Over the last decade, I have used and/ or rented this particular lens model about twice a year. I've never once had a problem with it, regardless of camera body.
Which is why this is baffling. This is the full image. I was about 5 yards away. I have shot many portraits at this distance with this lens. Always tack sharp.
@Chip_Ormwrote:These were taken on a t3i. But the same results come from a 7D, a 5DMIII, a 5DMII, a 6D, and a T1i.
I'm at 200mm in both photos. The nest is a crop from the original to show what I'm talking about. I wish I had a different copy for comparison, but I don't currently. However, on a tripod, using manual focus, there is no sharpness achievable. Literally none. That nest was only ~5 yards from me. Over the last decade, I have used and/ or rented this particular lens model about twice a year. I've never once had a problem with it, regardless of camera body.
Which is why this is baffling. This is the full image. I was about 5 yards away. I have shot many portraits at this distance with this lens. Always tack sharp.
This is one of the more difficult focusing scenarios. Trying focus on a subject that is within a cluster of branches. It will test your gear, and your skill equally. I typically use One Shot focusing mode, with BBF enabled, for these types of shots. Using AI Servo does not give photos as sharp as One Shot, even with a high shutter speed >1/1000.
I copied this from my Facebook page, so I do not have exposure settings. 6D, EF 70-200mm f/2.8L IS II USM, heavy crop.
I am sure I cropped this photo, but not how much. But, I do recall that I used One Shot with BBF. Once I focused, I could shoot away without worrying about the camera refocusing.
