85mm f/1.8 Front Focus Problem

[Virgo]

Hi All,

I'd just like to find out for you if anyone here has encountered the 85mm f/1.8 having front focus with the 10D, or any other body?

I'm not sure if mine has got this problem, but some of my photos appeared front focused, especially when using large aperatures like f/2.8.

Let me know yah?

[grantyale]

From my experience 10D / 300D tends to backfocus with 85/1.8...by a small margin but noticable and varies from one body to another, mine being a bit terrible...
Just to double check...you do mean 'focusing on something closer than desired' by 'front' right?

[Virgo]

Yep. Let's say when I focus on the eye of a person, the eye seems out of focus, but the lips is sharply in focus, as the lips tends to be more 'forward' than the eyes.

But you mentioned it tends to be back focus, not front. Then what after that?

Originally Posted by grantyale From my experience 10D / 300D tends to backfocus with 85/1.8...by a small margin but noticable and varies from one body to another, mine being a bit terrible... Just to double check...you do mean 'focusing on something closer than desired' by 'front' right?

[grantyale]

I own 85/1.8 no more... stupid Canon keeps telling me my camera is okay, while 5 samples of 85 in TCW showed clear backfocus. Interestingly, their 2nd hand 300D on the shelf is also a bit back but better than mine...

In your case, it could be the lens.

Edited: the body does so even with 135/2L ... sh*t

[Virgo]

oic. It's your body's issue. In my case, it's my lens, cos the rest of the lens worked perfectly OK for my body.

Originally Posted by grantyale I own 85/1.8 no more... stupid Canon keeps telling me my camera is okay, while 5 samples of 85 in TCW showed clear backfocus. Interestingly, their 2nd hand 300D on the shelf is also a bit back but better than mine... In your case, it could be the lens. Edited: the body does so even with 135/2L ... sh*t

[grantyale]

Send in for calibration then... carefully check everything before collecting. Things like - stiff MF ring, crazy aperture blades and possibly dust do happen.

[Virgo]

Thanks for the advice bro.

Anyone else with the same problem? Care to share your experience?

[TrailsofLife]

Mine have back focus only after like 15m-infinity. Its very obvious, when I focus on a subject, the thing behind the subject will be focus, but not the subject...

Initially, thought its user-error ;P but alot trying alot of shot, even on tripod, then I realised its a back-focus problem.

[shinken]

Do a focus test using a focus test chart such as this one

If verified there is focusing error, just send down to Canon. Since the lens is also a Canon, send both the body and lens in.

[+evenstar]

Mine slightly backfocuses by 4mm on my 1D II

[Virgo]

Cool stuff! I'll test it out and see if it's really front focused. Also, any particular settings to use for this test? Apologies, I haven't finished reading the entire article.

Originally Posted by shinken Do a focus test using a focus test chart such as this one If verified there is focusing error, just send down to Canon. Since the lens is also a Canon, send both the body and lens in.

[shinken]

Set a few inches back the minimum autofocus distance. The directions are all in the pdf file, but a quick guide to use the chart is from Page 12 onwards. The pages before that talks alot about backfocusing of D70.

Basically, many, and I mean many users on the web claim their camera and/or lens backfocuses, because we are unable to know for sure, especially in many of the systems, focus point is not part of the information. (It's going to be in D200 right? That's so cool). Many 10D, 20D users "experience" backfocusing, and surprise surprise, so do D70 users. That's why this focus chart could at least confirm some of users' beliefs.

Thing is, some lenses work fine on a camera which might have backfocusing with other lenses. It's not that consistent a thing, unless the photographer calliberates all his lenses with his camera.

[kaki4to]

i think not only 85mm got focusing problem,i found my 70-200 f2.8L have some front and back focusing problem too at different focal length.For example,at 70-100mm,i found front focusing is obvious but at 200mm,i found it actually back focus,but not so obvious like when at 70-100mm.The most unbeleiveable issue is not only auto focus,it happen also with manual focus.....

I suspect it's len problem cos it's ok with kit len 18-55mm and 50mm f1.8.Anyway,like shinken mentioned "Thing is, some lenses work fine on a camera which might have backfocusing with other lenses. It's not that consistent a thing, unless the photographer calliberates all his lenses with his camera",i found this is true and also discuss in some chinese forum.Pls refer here for more details:

http://beb.anyday.com.tw/forum/viewt...B0%BB%F2%A8%C6

Now i'm so disappointed with Canon DSLR,it happen on 10D,300D,20D......... ,but i heard D70 also have same issue,what about D70s ,anyone with D70s mind to share? Thinking of changing system if that's the case.....

D70 focusing issue can be found here,the article also "teach" how to calibrate by ur own,i found Canon 300D can also be calibrate,but only AF,not MF.... :

just to share,hopr this help

http://dvdhelp.narod.ru/D70_back_focus.html

[grantyale]

Note on the use of test chart -

At close range, DOF distribution is close to 1:2 while shooting from a distance, DOF is like 1:1. This should be the ideal case, and something like 2:1 should work fine though is a bit off. If DOF turns out to be 4:1 or something, chances are, the line of interest sill looks fine but in actual shooting (3 - 5m subject distance, let's say) the picture won't be sharp. This is because focus error is proportional to subject distance.

[Virgo]

I'm confused now. Mine is a prime (85mm). So what do you think I should do?

Originally Posted by grantyale Note on the use of test chart - At close range, DOF distribution is close to 1:2 while shooting from a distance, DOF is like 1:1. This should be the ideal case, and something like 2:1 should work fine though is a bit off. If DOF turns out to be 4:1 or something, chances are, the line of interest sill looks fine but in actual shooting (3 - 5m subject distance, let's say) the picture won't be sharp. This is because focus error is proportional to subject distance.

[madmacs]

Originally Posted by Virgo I'm confused now. Mine is a prime (85mm). So what do you think I should do?

bring BOTH your 10D AND 85mm to canon and have them test it. request to discuss with one of their engineers, preferably andry, he's very helpful. 10d seems to be quite notorious for focus issues. one of my lenses was tested to be spot-on with their test 10d, but severe backfocus with my 10d. if your 85mm is spot on with their test 10d, then you have the option of calibrating your 85mm to match your 10d, or calibrate your 10d to match the 85mm...but that would mean that all your other lenses will need to be calibrated too - maybe a better option in the long term.

[Virgo]

I'd rather they calibrate my85mm with my 10D, cos the rest of the lenses are working perfectly with it.

Thanks for the very helpful comments.

Originally Posted by madmacs bring BOTH your 10D AND 85mm to canon and have them test it. request to discuss with one of their engineers, preferably andry, he's very helpful. 10d seems to be quite notorious for focus issues. one of my lenses was tested to be spot-on with their test 10d, but severe backfocus with my 10d. if your 85mm is spot on with their test 10d, then you have the option of calibrating your 85mm to match your 10d, or calibrate your 10d to match the 85mm...but that would mean that all your other lenses will need to be calibrated too - maybe a better option in the long term.

[madmacs]

Originally Posted by Virgo I'd rather they calibrate my85mm with my 10D, cos the rest of the lenses are working perfectly with it. Thanks for the very helpful comments.

i had them calibrate my lens too. hopefully it turns out to be the right decision. time will tell...

[knoxknocks]

i've used the 85 f/1.8 on my 1D2, so far no back/front-focus issues - or maybe i haven't blown up big enough to notice.