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Home: Video University Forums: Digital Photography for Videographers:
Backfocusing problem?

Shadow
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Feb 27, 2007, 10:59 PM

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Backfocusing problem?	Can't Post

Anyone ever have any trouble with their camera backfocusing?

Ever since I bought my 20D my shots up close have been sharp as tack. But shots that are with the subject about 20 - 30 feet away aren't as sharp. I wasn't sure if I was expecting too much from my camera but felt that I should be seeing a sharper image.

The photos were still very nice, nobody I showed could tell it was soft except for the camera store employee today. We did a number of tests in the store for me to be able to show him what was going on. Turns out it is a backfocus problem (which has happened with some Canons in the past I am told).

I was about 25 ' away from the camera when he took the photo, I was very slightly out of focus (centre focusing point used on me) but when we zoomed in x6 we saw that another 20' or so behind me was in perfect focus even though he metered right on me for the focus.

So my camera is in being repaired for 6-8 weeks. I felt sad leaving without it. Frown

My camera bag just won't be the same until it is returned.
Funny how we get attached to such things.

Anyway, I thought I would post this in case anyone else notices this problem. I found it really hard to find someone who knew what I was talking about, spoke to a few people in various camera places and showed lots of people the photos, only that one guy knew what I was talking about and saw the difference.

RustyB
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Feb 28, 2007, 1:43 AM

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Re: [Shadow] Backfocusing problem? [In reply to]	Can't Post

Was that with the same used lens that gave you trouble a while back? http://www.videouniversity.com/...orum.cgi?post=334836

Hopefully they can get it figured out, and you can be done with it. Good luck!

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Shadow
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Feb 28, 2007, 6:44 AM

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Re: [RustyB] Backfocusing problem? [In reply to]	Can't Post

That was it, you were right! I remember you writing that now but had forgot at the time.

I had taken the lens in for service (another 8 weeks), and they had noted on the repair form that they fixed the auto focus. So I had figured it was the lens, until I took a closer look recently. :(

I hope it gets fixed right, I see that on the work order backfocusing problem wasn't listed. Hopefully they'll figure it out.

(This post was edited by Shadow on Feb 28, 2007, 6:46 AM)

Brian M
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Mar 1, 2007, 7:11 PM

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Re: [Shadow] Backfocusing problem? [In reply to]	Can't Post

I'v had simliar issues. Can't tell if it's my imagination or not. Where did you send it for repair? I've read posts about sending the lenses to Canon for adjustment. Anyone else ever do this?
Brian M

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Photographer & Videographer

Shadow
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Mar 1, 2007, 8:10 PM

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Re: [Brian M] Backfocusing problem? [In reply to]	Can't Post

Hi Brian,

It's hard to detect isn't it? My problem was very slight. There are actually some charts and instructions on the internet for determining the back focus.
How we figured it out was I stood about 20' away from the camera, there was a wall another maybe 30' behind me. The centre focus point was focused right on me, yet when zoomed in 6x I was very slightly out of focus, but the writing on the back was was sharp as a tack.

Funny thing is that the portraits I have done all still look good. There was something just slightly off about them, but most people couldn't see anything wrong.

Try taking that photo I described, and check out some charts on the internet. It is appearantly a problem that Canon had for a while (since figured it out).

I took the camera to the store that I purchased it from, but since I bought the camera in the summer it was under manufacturer's warranty. The store that you purchased it from should be able to send it for you and it shouldn't cost you anything.

Hope this helps. :)
Heidi

WLR
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Mar 1, 2007, 11:06 PM

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Re: [Shadow] Backfocusing problem? [In reply to]	Can't Post

Which lens?

Friends don't let friends shoot jpeg.

Shadow
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Mar 1, 2007, 11:14 PM

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Re: [WLR] Backfocusing problem? [In reply to]	Can't Post

I mostly noticed it in my sigma 24 - 60 2.8 I thought it was a lens problem so I had it serviced. But then noticed it in other lenses. We tried a few at the camera store (can't remember which ones) and had a similar problem.

The best lens on there is the canon 17 - 50 2.8 IS (I think that's what it is) - sharp but I haven't used it more than a couple of shots so I am not sure if it would have caused the probem as well.

WLR
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Mar 1, 2007, 11:32 PM

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Re: [Shadow] Backfocusing problem? [In reply to]	Can't Post

24-60? or did you mean 24-70 2.8 ? anyway here's a review link on the 24-70
http://the-digital-picture.com/...-DG-Lens-Review.aspx

Friends don't let friends shoot jpeg.

Shadow
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Mar 2, 2007, 12:00 AM

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Re: [WLR] Backfocusing problem? [In reply to]	Can't Post

Hey WLR
Thanks for the link, pretty informative page.

It is the 24-60 that I have http://www.dpreview.com/...4051202sigma2460.asp
Never had a problem with flare (as described in the other link) but I do have a polarizer for it which I use on occasion.

I really like that lens.

One of my other fav is a real cheap one a canon 35-80 variable, it was only about $80 used. I was a 2nd shooter at a wedding last year and actally shot most of a wedding with that lens using natural light and loved the photos. The photographer I was working with was impressed that it produced such great pictures, (he even used many of them on his website). Mind you, the lighting was perfect that day and the backdrop and couple were beautiful too. I wouldn't rely on it as a main lens, but I do like it, even if it is a cheap lens. I don't think you can buy it new anymore but if you ever see it used it's worth the $80. I mostly like to have it on the camera to take out to the park or beach when I'm goofing around taking pics.

WLR
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Mar 2, 2007, 12:24 AM

Post #10 of 10 (630 views)
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Re: [Shadow] Backfocusing problem? [In reply to]	Can't Post

Hey, if it works for you and you are getting good consistant results, it's a keeper.
My main lens is the Canon 17-85 and at 5.6 it seems to be sharper than the 85 f1.2 at 5.6.
I had a chance to play with one last week.

Friends don't let friends shoot jpeg.