Problems with 85mm1.8

I bought this used lens and it is almost like new. I started playing with it and I can only get it to focus properly 50% if the time. I micro adjusted it, but it's still back/front focusing or not focusing well at all. I'm thinking of sending it to Canon. Do any of you have any experience with this and how much it would cost? I focused on the face. As you can see it is really bad but the other photo is ok.

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Photo 1 looks fine, as you say. I am not totally sure photo 2 is OOF. It looks like glare/flare/whatever from the EXTREME backlighting. Do photos w/o this kind of backlight come out OK?

On the 2nd image, were you using one shot or servo drive AF? I ask because if you did either, focused, then moved or repositioned, etc, it would explain things. It's very front focused in your 2nd image (with the other person).

Seems you've had issues with this lens for a while now, as this is one of several threads regarding this very issue.
Have you tried this lens on another body? You seem to have some camera friends, see if it does the same thing on their cameras?

The cost to send it in, get serviced, etc, probably is too similar to the cost of simply buying a used one for $250.

Very best,

I have never really been that happy with my 85/1.8 on my 7D but it’s better than 50% for sure. More like 80%. But my other fast primes are hitting like 90-95%. Even my 50/1.4, which many people complain about inconsistent AF, does better. I have never been able to put my finger on it though: sometimes it’s front focused and others it’s back.

I unfortunately am not sure what it would cost to send in because every time I sent a lens to Canon, it was still under warranty.

I have an 85F1.8 that I bought new from AMZN. The first copy I bought front focused and I sent it back for a replacement, which was OK. The lens has great AF, accurate and fast. A properly focusing Canon 85 F1.8 is perfect for low light and sports.
Depth of field will be shallow at F2 on the lens and it needs to nail focus. I would try formal testing with a test chart to see if AF is off and the lens needs mocroadjusment. Your camera supports this adjustment. Are you using centerpont AF?
You can get an estimate online from Canon for this sort of repair. The cost varies with the lens. I paid about $109 5 years ago to get the iris replaced on a 35F2, but this didn't include shipping costs. I used the Virginia center and they did a good job.

First i put it on a tripod and try about 30 random photos on your camera shot far away close up and what ever at all different setting myself. Before you pull the trigger on sending it back.

I bought it used, so I can't send it back; that's why I'm trying to see if it's me or the lens. I have 3 more lenses and never had an issue with back/front focus or missing focus and I had the 50mm 1.8 and I never got a bad shot with it so I don know how to shoot with narrow dept of field.

it's really out of focus. really bad!

what is your experience with AFMA?

have you fixed the problem with other lens/body combos?

what distance are you using when AFMA?

have you tested it in a more controlled environment? Maybe a largish room where you can focus far then near, taking a pic each time with center point on a specific spot. Then compare each on the computer later.

AFMA?? auto focus ??

anitaw2 wrote in post #18531629
AFMA?? auto focus ??

AFMA = Auto Focus Micro-Adjustment. Most Canon cameras (not sure about Rebels/XXXD) can do it for lenses, but it is not the case here. It only works when one has either backfocus or frontfocus, but in the original posting there is no focus anywhere.

Yes, I did the micro adjust. but even that isn't going well. It seems this lens is all over the map. I'm going to play with it again this weekend, but what is bothering me is that it often totally misses focus. the red light blinks (meaning it is focus locked) but I take the shot and when I look at the picture on my computer, realize that everything is out of focus. So it's telling me it's focusing but it's not.

How does it focus with the camera on a tripod and Live View ?

really well, it's when I'm outside and try to shoot people. it just doesn't lock focus (but the red light is on) so I don't know what is going on.

anitaw2 wrote in post #18531714
really well, it's when I'm outside and try to shoot people. it just doesn't lock focus (but the red light is on) so I don't know what is going on.

Then whatever the problem is, has to do with the AF mechanism. Try to shoot a high contrast subject, with the accurate center point (expansion mode?) at different distances and different apertures using a tripod. This will remove any chance for operator error and also define whether the problem is systematic (consistent front or back focus) or more random like (especially if the results change with aperture).

The first copy of my EF 24-70 MkII was all over the place out of the box. I did a very extensive test to convince myself that it was not an operator's error, or a systematic lens error. Then I returned it to B&H and got a second copy which was razor sharp out of the box.

Unfortunately for you, as it has already been mentioned, fixing it might cost as much as getting another used one.

Should you decide to do 'bench tests' you can easily construct the target shown in this article and follow the methodology. For a prime, it is actually pretty easy.

http://www.peleng8.com …k-focus.html#.Wkz5gHWnEz​M