Do all standard 16x II lenses have back focus issues?
 

I've read a lot of posts from people with focus problems with the standard XL1S lens. A lot seem to deal with only autofocus hunting, but some seem to indicate that the back focus will eventually go "bad" on all XL1S cams, necessitating a trip to Canon for repair. Is this true? Or is this issue only with the standard ;ens that came with the old XL1?

It was not unusual for early production XL1 models to have poorly set back focus, and some early lenses did have a problem (mine was replaced under warranty). Have not heard much comment with respect to this in late production XL1 or XL1s models.

Back focus setting control for the standard lense is electronic, a value is stored in the internal XL1 memory (set using the RM-95 Adjusting controller). Installing a lens from a different body might result in a less than optimum backfocus setting for that lense-body combination.

Changes to the relative positions of the lens mount and CCD block (e.g., from being dropped, abused) or similar treatment of the lens could also result in a change to the effective backfocus setting.

Backfocus should be checked as part of routine maintenance.

I think a lot of the posts are made by people with limited experience with AF lenses and sensor and/or limited experience focusing. Many of the posts read something like, "I just shot my first (insert favorite avocation . . job, wedding etc.) and all my shots are out of focus." What usually follows is a plea for help in diagnosing their problem. Invariably someone pops up and suggests a back focus issue, remembering the problems with the early XL1.

Except for the early cameras and lenses, all the so-called back focus problems I've seen are actually operator error.

ronluc8667,
I just finished my first project (wedding) that that was done in total manual mode....what a dramatic improvement over previous shoots with various levels of automatic settings. To prepare my son and I for this, I spent an afternoon with the Canon hooked to a monitor and trying different settings and its effect on the overall look. It was well worth the time spent.

XL1S back focus problems?
 

Below is my email to Canon Technical Support and their response. Are they right?

Q:
With my XL1s in the Auto recording program and the lens in manual, I can zoom in on an object to get a focus, but when I zoom out focus is lost. Should this be happening?

A:
Thank you for your e-mail inquiry regarding your XL-1s. This is normal. When the manual focus mode is enabled on your camcorder the XL-1s will not achieve focus automatically. When in this mode you may use the focus ring around the lens to refocus when zooming.

Should you require further assistance, please feel free to email us or visit our customer support website.

I don't think they understood your question and were thrown-off by your "Auto" remark.

Put the camera on a tripod. Place the camera in full MANUAL mode, the lens in Manual Focus, zoom in to an object perhaps 10-15 feet away, press the "Push AF" button on the lens to set focus, release it then pull back out. How does focus look now? (Are you jusdging the focus in the color viewfinder, on the b&w viewfinder or on a tv?

I’ve shot several tests using the set up you recommended. I can get a sharp focus when I zoom in, but when I zoom out the focus is lost. I’ve hooked the camera up to a colour monitor and you can easily see the image go soft. When I press the “Push AF” button again the zoomed out image becomes sharp. Any ideas?

Thanks
David

I'm pretty sure that adjusting the back-focus of the lens will require sending the camera and lens to Canon service. To my knowledge the back-focus of the 16x IIS auto lens (I assume that's the lens we're talking about) can only be performed by Canon service.

Instructions on how to set back focus with the autofocus lenses are in the service manual. An RM-95 adjusting controller is required. Net investment on the order of $200 required for these items. Not something for the average user to try becuase a slip of the finger could make things worse. A bit more complex than programming a VCR.

This is the first time I've heard about this back-focus issue. Is it possible that this can happen only sometimes? I know this sounds crazy but it seems to be happening to me randomly. I posted a topic ( in the lens & optics forum) titled, "1.6 extender won't hold focus?" thinking it had something to do with using the extender with different lighting (I think everyone lost interest due to my ignorance). Anyway, maybe I'm not crazy after all and it can even be fixed?
TIA,
Randy

I don't think anyone lost interest, you said it was fixed. However, back focus usually is not an intermittent problem. Once the back focus is out of adjustment, it doesn't fix itself, so the problem should be repeatable. It would be like front end of your car going in and out of alignment. I've never heard of that happening. Try several of the tests we've suggested and see if you can get the problem to occur.

Does Canon check for any back focus problems when you send it for their recommended yearly check-up?

Yes, they give the camera a thorough once over.

Thanks Jeff,
Actually, I didn't mean to imply the problem was fixed, just not noticable outside at that time when I checked it. I subsequently did the suggested test and it did indeed lose focus. It's still under warranty so I suppose I'll be sending it in.
Thanks again everyone,
Randy

Thanks for everyone’s advice. I’ve talked to Canon again and they are going to service the camera. I will let people know how it turns out.