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Bad Coma? Or Focus issue?

Chip_Orm
Contributor

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? Bad Coma

Issues.

20 REPLIES 20

Waddizzle
Legend

I once had a similar problem with the same model.  My lens was loose, and could not focus accurately.  I could shake the camera/lens combo and hear a click. As it turned out, my lens was missing the rubber ring that goes around the lens mount.

------------------------------------------------------------------------------------------------

"Doctor told me to get out and walk, so I bought a Canon."

Chip_Orm
Contributor
Oh man, I wish that was the case. Unfortunately(or not?) The seal is perfectly in place and it mounts firmly and without issue to the camera body.

I have around 40 lenses currently.  I have had over a hundred or so.   I have had both versions of the ef 70-200mm f2.8L.  Neither exhibited this either.   Now I know it makes little difference to you but I have never had or seen this problem.

But to get to your porblem, I would send the lens to Canon for a C&C. Today ! There is really no other way to make sure it is good.

What bothers me is you said it works sometime? The lens does this on several cameras?  The lens do not do it at 125mm or less FL?  OK, last question.  Are you the only person to test it or have others seen the same results with the same rig?

EB
EOS 1DX and 1D Mk IV and several lenses!

Yeah, that's where I'm a bit stumped. I don't own nearly as many lenses, but I have probably rented/ borrowed about 20 different copies of this lens since 2011. I've never experienced this issue. Only one copy with a bad auto-focus mechanism. But I usually photograph using manual focus anyway, so that wasn't an issue for me. 

I was disturbed to find this issue on the first copy of the lens I purchased (used), but as I was saying elswhere, the lens had damage that was not noted in the description. So I sent it back in and got this copy of the lens. It seemed to work perfect at first. I did two photo shoots with it and on the second one, I noticed some of the shots looked like the previously noted shots. Since I do use auto focus when doing portraits, I chalked it up to just missed focus. 
However, when I finally got to go out into the woods and photograph, every shot out past about 125-135 exhibited that odd blur as seen in the nest photo. I shot that with Manual focus on a very heavy 90's Gitzo tripod The nest is literally the sharpest I could achieve from 6 yards away at 200mm. Well within the focal range. This was also at 1/640th of a second shutter speed. IS off and on gave the same results, both on setting 1 and 2. 

Thinking it might be my camera, like with the first used copy I purchased, I sought out all of my friends who also use Canon cameras. Same results on a 7D, a 5DMIII, a 5DMII, a 6D and a t1i. 

As far as photography and technology are concerned, I tend to fall into the catagory of people who spends a lot of time researching how the lenses themselves work. Watching videos on lens construction with aspirations on being able to repair them myself. I've done so for several Sigma lenses and have repaired/ replaced various internal components on at least a dozen camera bodies from a t2i to soldering a new USB port onto a 5DMIII. 

This isn't my first rodeo, but it is the strangest. However, I've never had this issue with this particular line of lenses. I just assumed they were all nearly perfect with very small batch variation as goes most lenses. Looking at videos of out of calibration lenses, these issues are in line with that, but what bothers me is that every photo from the first shoot I did was sharp. Or at least, they seemed to be. I might have kept most photos well under 200mm. I don't normally pay attention to my focal length when shooting unless there's an issue. 

Side note: I just found out my mother has lung cancer (not surprising, as she smokes like a chimney, but still...) and my friend has been going through some pretty bad stuff as well. So we went for a nice drive around the countryside. Obviously this means stopping to photograph something every ten feet. I was using the 70-200 beause it photographed fine at wider angles... Or so I thought. Looking closely at the photos I took the same "blur" is present, but less noticeable due to the wider field of view/ less magnification.

Anyway, thank you for your response. It was the most reasonable and less patronizing than most.

I viewed countless numbers of posts about people having similar issues with this particular lens and, on this forum n particular, the poster was usually new to photography and the comments section would univerally patronize the OP and tell them they're just using the lens wrong or that it was obviously branches or some other obstruction in the foreground. When looking at the images, it was definitely not the case.

As somebody else replied to me claiming it was just objects in the forground. No, definitely not objects in the forground. Shooting at the photo studio/ gallery/ print shop/ customing framing shop where I've worked for the last 5 years, there was nothing in the foreground that would have caused this there. And the couple of branches in front of the nest are apparent. The blur is visible across the frame. If I had to guess, the calibration is off and/ or the calibration screws are somehow loose. 
My other guess is that it could involve the IS system not quite working properly and shifting a little bit while exposing the image. I guess that due to a similar looking effect as shown to happen with a particular Sigma lens as noted by another photographer from an article on Petapixel. 

Anyway, I apologize for what is likely a very lengthy response. My plan is to just send it in. I was really hoping it was just user error/ something noted on a particular camera body or perhaps just an update needed by the lens. IE: Issues that could be solved for little to no money. 


TTMartin
Authority

@Chip_Ormwrote:

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? Bad Coma

Issues.


In the thread photo I expect you are at or close to the Minimum Focus Distance of the lens.

 

In the nest photos, there are just out of focus branches in the foreground. 

 

I see nothing that looks out of the ordinary. Remember with a long wide aperture lens you have a very shallow depth of field, objects in front of and behind the plane of focus will be blurry. 

"I see nothing that looks out of the ordinary."

 

I agree.  I suspected operator error.

EB
EOS 1DX and 1D Mk IV and several lenses!


@ebiggs1wrote:

"I see nothing that looks out of the ordinary."

 

I agree.  I suspected operator error.


Something clearly doesn't look right, but there are still two potentially important data items that I haven't managed to extract from the verbiage:

a)  What camera is being used?

b)  How much magnification has been applied to what we're seeing?

In particular, at least something in the bird's nest picture should be sharper than it is, UNLESS we're looking at a very small portion of the original image.

Bob
Philadelphia, Pennsylvania USA

"I suspected operator error."

 

Since two lenses, in a row, the OP has tried exhibited the same flaw, especially from one of the best made lenses in the world, I suspect he is doing something wrong.

EB
EOS 1DX and 1D Mk IV and several lenses!

You'd think that, but I've probably used about 20 different copies of this lens since 2011. If I'm suddenly doing something wrong, that would be a surprise.
This lens can and does fall out of calibration. And that's what I'm trying to find out. Best or not (my opinion is that it is the best), **bleep** happens. And that these are both used copies who's origins are unknown outside of seller description. The first used copy that did it had some flaws it the lens that weren't noted by the seller. Such as a tear in the rubber seal on the mount. But this one is perfect, physically. 
The only idea I really have is that the screw used to calibrate the lens is somehow loose. Which seems crazy

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