HUGE Focus error with new Eos 85 1.8 EF
I just bought a brand new Eos 85 1.8 EF and popped it on one of my my Eos 3 bodies. The lens focuses fine through the viewfinder and images appear to be in sharp focus; however, when I inspected the negs they are not even remotely in focus.
Frames shot close up, say 1-2 metres show the camera is focusing behind the subject by about 5-6cm and when I shot at a target about 100ft away, correct focus was about another 50-70ft behind that (the subject area looked like the bokeh and what should have been bokeh was sharp)! Infinity subjects looked like the camera was focusing way beyond infinity because as blurry as they were, closer scenery was even worse!
For subjects at about 1m, the blurry images gets WORSE as I stop down in many cases.
I have not used this Eos 3 body for a while, but have never had problems with it. I am inclined to think the issue is with the lens. The problem is that I am away from home and will be for months so cannot test it on another body. The only option I have would be to return it and get a replacement by post.
Is it possible for a lens to *appear to focus* thru an SLR viewfinder but actually be miles out due to a lens (rather than body) fault? As it stands the set up it completely unusable at any aperture or distance. Images don't even look remotely in focus and I am getting much less resolution on the film than I am wide open through the viewfinder. The body remains in very clean condition and has had no knocks. I just inspected it and cannot see any damage, but of course I cannot be sure...
Any thoughts? If the lens, I don't get how it could appear to be focusing but registering very badly on the film. My instinct suggests a body problem, but this body has been perfect in the past and I am unaware of it suffering any damage.
This is a huge pain in the ass as I brought the body out here to augment the Ms for a particular project. I ordered the lens, did a quick test and now have no idea whether the lens or camera is the issue...
Last edited by Tom Stanworth; 08-24-2009 at 04:53 AM. Click to view previous post history.
I understand your feelings. My EOS3 + 85/1.8 is THE perfect combo for 35mm, and this focusing issue is a killer... My vote would be for a camera issue, simply because having a crisp image in the viewfinder would indicate an offset between the autofocus and the film plane.
Do you have a chance to test the lens on any Canon body ?
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I have had no problems with this lens on any EOS body I have used it on (1, 3, 5, 1D, 1DIIN, 10D, 20D, 1Ds). If anything lens wise is the problem, it is the individual copy you got, not every copy of this lens. IME it is one of the best lenses in the entire EF lineup, especially considering how little it costs.
My first idea would be to look at how you are focusing the lens.
If using AF, have you put your camera on One Shot AF mode, selected a single AF point, and moved the autofocus command from the shutter to the AE lock button? It is the only way that makes the slightest bit of sense to me, personally. Having the AF command default to the shutter button is one of my pet peeves about AF cameras. It causes nothing but trouble in most shooting situations in which I might find myself.
If using manual focus, your focusing screen could be loose or otherwise out of its proper place. Your viewfinder diopter could have been moved from where it should be. Your pressure plate could be tweaked out of position (unlikely).
Due to the fact that most modern focusing screens are designed with the idea that nothing but slow lenses will be used, and are thus optimized for f/2.8 or slower lenses, it is possible for any lens faster than f/2.8 to make something appear in focus in the viewfinder, yet not actually have it in focus. I constantly run into this problem with lenses faster than f/2.8 (especially the 50mm f/1.2). These modern screens are yet another reason that I am generally annoyed by AF cameras.
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Have you got the eye correction set correctly on the viewfinder? If you have that set wrongly then the image in the viewfinder can appear sharp, when the film plane is not. The best indicator is whether the "focus confirm" light comes on when you tink you are in focus. If it does then you know that at least the camera believes it is in focus (independent of your eyesight).
In my opinion it is highly unlikely that the lens looks in focus, and the film is not when using an SLR....
You could also go in to a shop with the pretence of testing a lens, put a different lens on the camera and take a couple of shots. If the images are out of focus on the film, then it is definitely the body?
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I've never had one, but I have heard of problem lenses like this. You should be able to return it for a replacement, that's what I'd be doing. As far as checking the camera body, presumably you have another Canon lens you can use for a test?
I would test the body first and than decide to return the lens or not.
Are you shure that mirror and focussing screen are in the right place and not moving when carefully toching with a toothpick ?
I'm in Kabul with one body and that lens only. Found a colleague with a 30D and the lens is miles out on his body too. Oddly, the images appeared less sharp in his smaller VF than in mine. I thought they appeared a touch soft.
I will check the diopter adjustment on my body to see if that will explain why the frames appeared roughly sharp but were not on film, but for whatever reason, the lens moves into focus (slower than I am used to with EF lenses I have to admit) and gives focus confirmation via the flashing red square/beep, but is nowhere near focus.... on either body. How odd. mind you, it was amazing to see as we zoomed in on the 30D screen that the images appeared sharp until you zoomed in then suddenly revealed how off they were. Looks like the issue with the EOS3 is just that the screen has poor resolution and what we see as sharp is actually pretty low resolution.
To be 100000% sure I will put one of my colleagues lenses on my EOS 3 to be sure fo good focus with that.
the EOS 3 does not have an adjustable diopter like most other modern cameras.
I checked the body over and mirror/prism seem secure. The lens is on its way back to the dealer and I will see what happens with the next one. In the meantime I will try to find another lens to test the body. Problem is everyone is a digital user and they have EFS lenses!