XL1 / XL1S focus hunting backfocus problems - Page 7 at DVinfo.net

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Canon XL1S / XL1 Watchdog
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Old July 24th, 2002, 11:55 PM   #91
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That lens can focus as close as 3/16th of an inch in front of the glass, so it's highly possible that a speck of dust or lint on your filter stack was causing the AF to hunt quite a bit. Just a theory.
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Old July 25th, 2002, 04:42 AM   #92
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I had some problems with the sky and autofocus. It just didn't
know to focus on the bird or on the clouds behind it.....
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Old July 25th, 2002, 06:54 AM   #93
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I do a fair amount of nature work, including hawks in flight. I almost always use manual focus. The AF usually doesn't have enough contrast to focus accuratly. Also, the constant movement of the wings and background (panning with subject) doesn't help the AF either, it's constantly hunting for something to lock onto.

Jeff
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Old July 25th, 2002, 07:10 AM   #94
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AF needs contrast; i.e., generally vertical edges to work best. It does not work well if edges are horizontal (e.g., venetian blinds) of if the subject is low contrast, like an open or overcast sky. Manual focus is the better way to go, especially since most air show action is likely to be at a good distance (near optical infinity).

Also, on a bright day the XL1 can try to focus on dirt/dust on a filter, especially if that is the highest contrast item in the image. Even in manual focus mode, when stoped down the depth of field is so great that any crud on the filter may become visible in the image.
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Old July 25th, 2002, 07:19 AM   #95
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I rarely use filters for this type of work, either. Maybe a polarizer, or ND but I never stack filters. It's like asking for problems with flare or ghost images.

Jeff
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Old July 25th, 2002, 07:23 AM   #96
 
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As everyone has said, for what you were doing, the auto focus should have been turned off. I very seldom use the auto focus feature. Recently, I had to shoot aircraft taking off and landing. In shooting a test prior, I saw that I could not use the auto focus. Shot everything manually. Turned out fine.

Jay
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Old July 25th, 2002, 08:07 AM   #97
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Focus

Okay, Thanks everyone. Appreciate your help. I was trying to
autofocus on fast aircraft, but stationary objects were hard to nail
also.

Looking Glass
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Old August 16th, 2002, 09:50 AM   #98
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A question about XL1 cameras. Help!

Hello everyone!

My first post and let me begin with how cool I think this site is!

I host, write and produce a series on TNN, and for the last 5 years, have used Sony-DSR300 & Sony PD-150 cameras. I've done a couple of episodes with an XL1, as well.

I love the XL1 design, but I had continuing problems with the back focus not working. (What I mean is, if I push in tight on someone's face, get a crystal clear focus, the camera goes out of focus if I pull wider on the shot).

A few days ago I bought an XL1S and right out of the box, it will not hold a back focus either. Am I doing something wrong? Is there an adjustment? Or, have I just had a run of bad luck and 2 out of the 2 XL1 cameras I bought were lemons?

Any advise would be appreciated.

Thanks, & good shooting!

Dave Watson
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Old August 16th, 2002, 10:11 AM   #99
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I have both an XL1and XL1s and have the fortune of not having this problem. I would talk to the dealer first and see if an exchange is in order for the defective camera. If the dealer provides no assistence I would call Canon and make arrangements to send the camera in for service. I use 3 different lenses, in addition to the EOS EF adapter, with my XL's and I've yet to have this problem (knock on wood?). So, I don't think this is relaited to use. My best guess is that something occured in shipping.

Canon is a fairly responsive company. If your relate your expierences to them on the phone they may be willing to expedite your repair if it comes to that. Post back how things work out.

Jeff
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Old August 16th, 2002, 10:31 AM   #100
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What lens did you get with the XL1s? I haven't had a look on mine yet (haven't had a reason), but most cameras have a small screw on the lens where you can adjust the back focus - however it is very sensitive and you might be better off going back to the dealer who should be able to fix it for you.

If Canon haven't enabled people to adjust the back focus I'd be very surprised - but on the other hand, I do tend to be surprised a lot nowadays...;)

Good luck anyway!

Regards
Jon
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Old August 16th, 2002, 10:38 AM   #101
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The 16x (white lens) that most people get as part of the kit does not have a user adjustable back focus, nor does the 3x wide angle. The Canon manual focus lenses (old 14x and new 16x) do have user adjustable back focus. If you do have a manual focus lens with your XL, adjusting the back focus is fairly easy. do a search on key words back focus and you see several threads on how to adjust it.

Jeff
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Old August 17th, 2002, 09:19 PM   #102
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re: back focus problem

I have encountered the same problem with the 16x IS II lens: When zooming out, the picture goes out of focus!

There was another problem that taught me a valuable lesson. NEVER use the auto focus on the 16x IS II lens!! Also don't let your sublects stand too close to walls...

I had a close-up head shot in which I used auto-focus. Now I've done this with cheaper DV cameras like the Sony PD100 and everything was fine. But with the IS II, the lens kept on focusing on the wall in the backgroud (which was a feet away from my subject) whenever my subject moved her head.

Is there something wrong with my lens (like Jeff suggested)??
Has anyone encountered any similar problems??

thanks
JOe
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Old August 18th, 2002, 06:37 AM   #103
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Hi Joe,

It sounds like you have several problems or areas of confusion, but I think your situation is different from Dave's. The loss of AF with a subject so close to another subject is very common. Your subject turned her head and the AF sensor saw either more of a pattern in the wall or the subject's head became smaller (sideways) and the sensor saw the large wall as the subject. An easy fix is to switch to MF in those situations.

There can be several causes for the lens going out of focus as you zoom from tele to wide. This is discused in the articles here on the XL1 Watchdog. The following articles will address your concerns

Backfocus Issue, Yes or No?
Soft Focus Problem and Workaround

Canon also suggests that a slower zoom speed may be necessary for the AF to maintain focus while you zoom.

Jeff
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Old August 18th, 2002, 07:44 AM   #104
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Dave,

I had the same problem with the stock lens, to the point where I thought the XL1 wasn't really a viable camera for everyday use.

Then I bought the 16x manual lens. It performs much more like the "pro" lenses you're used to.

I use the XL1 almost exclusively now.

Mike Avery
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Old August 18th, 2002, 12:59 PM   #105
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It is probably a soft focus issue...

The Canon auto lenses for the XLs lack back focus. Yes this has been a long discussed issue with the XL-1/1S. Early editions of the XL-1 may have had a problem with soft focus and there was lots of fussing about this. The short story was that it was finally resolved.

I recommend reading the lens articles on the dvinfo.net site, especially the ones that Jeff Donald mentions. If nothing else they really do explain how the auto lens system works.

After that if you are still having problems, a visit to Canon about the soft focus would be in order.

Finally, if you really like the Canon but hate the lens, you might want to try some of the manual lens options: they are really good.
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