XL1 / XL1S focus hunting backfocus problems

[James Graham]

Precisely.

In this case, this is not a fault but a simple fact of optics.

Further testing (playing) confirms Don's elucidation upon my observations.

[John Locke]

James,

I'm having a similar problem with my 16x lens...except mine occurs at about 80% of full zoom. Adrian tells me that sending it in for service will do the trick.

[James Graham]

John,

What I'm getting at is the fact that what some people are calling 'XL1 focus problems' are in fact caused by some of the automatic features of the camera creating optical changes which will affect your focus.

I've noticed quite a bit of focus paranioa on these boards and it easy to create the impression that everything comes down to the fact that there is a fatal flaw with the XL1 stock lens.

I think that there are myriad of problems being dumped into the same pot. Some genuine back focus problems, some lens defects, some motor defects and others which are simply not actual problems at all. I have been able to replicate some of these problems when using the XL1s in full automatic and semi-auto modes.

When I have the camera mode set to (M), focus set to manual, the white balance set to one of the presets (ie. not Auto) and gain controls set manually I have found that the XL1 performs exactly as expected.

I suspect that the real culprit is Canon's automatic system(s) on the XL1s which are relatively poor compared to Sony offerings or even that of it's little brother the XM2 (GL2). The bottom line is that the XL1s needs to be controlled completely manually in order to produce it's best images. I am comfortable with this although I can understand there are many situations where this can be a real pain the proverbial.

In your case, you are obviously experienced and I trust your judgement if you believe that this is a genuine defect with the lens. If so, I would follow your original course of action and send it to Canon.

Jim.

By the way, nice website John!

[Sandy Kaye]

Maybe take a look at my "Replace the CCD" thread.... before you decide to take it in to Canon.

[Rob Lohman]

The mentioned thread can be found here

[John Locke]

Thanks for visiting my site, James.

It would depend on when you bought your lens (or actually when it was produced). Apparently, on older XL1/16x lens combos like mine...that has never been sent in for a checkup...there are certain back focus issues, firmware updates, and lens modifications needed.

I've been needing to send my camera into Canon for a long time for servicing but haven't had a chance. And to be honest, I've been able to work around the focus problem. Mine goes soft at one brief spot while zooming at about 80% of full zoom. Also, like you, it does tend to drift out of focus when the camera is in auto mode (green box) and the lens is in manual. So, I've just worked around that...I stay away from auto as much as possible and just adjust my zooming range. But it's about time to get these things taken care of.

One of the other wranglers, Adrian, said he sent his camera in for servicing and had those problems cleared up. So, I imagine that'll be the case with me, too.

I'd wait for a consensus here, though, and see what some of the others think. If you haven't had it serviced yet or in a long time, though...couldn't hurt.

By the way...your site is looking good, too. I'll check back later to see it when it's complete.

[Terry Pickford]

I am sure that there has already been an answer to my questions but I will ask them anyway.

Setting the lens to AF, I have noticed that when I zoom in, the object goes out of focus for a second or two. If I refocus at full zoom, then zoom back out and then zoom in once more, the same thing happens before the subject automatically sharpens once again. Is this normal and is it just a case of zooming too fast onto a subject?

I have also noticed that if I pan using the AF lens mode, depending upon the speed of pan, the subject and backgroung goes out of focus very easily. I have found that if I pan using MF mode, the situation does improve but on occation the background is still liable to loose focus or blur.

I am interested in capturing wildlife in flight, and I am finding that if I set the lens to AF it is almost impossible to keep my subject, usually small, in focus. The lens appears to hunt far too easily loosing sight of the subject all to often. I am therefore forced in most cased to use the lens in MF. But then the subject is very quickly out of focus anyway.

Any advice would be most welcome
Terry

[Don Palomaki]

Auto focus works based on contrast in the focus zone (center) of the image, and vertical edges make for the best contrast, auto focus wise. Moderatly rapid zooming and/or panning can result in significant changes to the contrast profile of an image, and can cause the autofocus to hunt for better focus. Using manual focus setting will help.

Birds in flight can be a very difficult if not almost impossible auto focus target.

Panning will cause blur in an image, especially if zoomed in, due to motion, just like camera shake with a still camera.

[Dylan Couper]

Yep, that's about it.

The best thing for you to do is to practice your manual focus skills. You will be able to outfocus the AF in no time!
Then of course you will start lusting after one of the true manual focus lenses. :)

[Jeff Donald]

I do a lot of flight shots and AF is just not possible for any type of close work. I use Canon EOS EF lenses and manual focus to obtain good, sharp, footage. AF just isn't fast enough and the birds get lost in the sky and as Don points out, lacks sufficent contrast for the AF to work.

[Don Berube]

A good way to build up your manual focus skills is to zoom in all the way on a car in moving traffic and maintain the focus on the moving vehicle as it drives by. If you want a real test of your focusing skills, do this at night!

- don

[Edwin Quan]

my xl1s focus is set on auto. whenever i am in close range to someone (approx. 4 or 5 feet away) and the lighting is low (i guess you can compare the lighting to the lighting in most restaurants) my xl1s just can't seem to focus properly. what happens is the xl1s will seem to catch the correct focus, then fail, then catch the correct focus again and so on. this goes on for the length of the shot. what am i doing wrong?

[Ken Tanaka]

Edwin,
The XL1s' difficulties with auto-focus are pretty well known. It's by no means alone. Most cameras in this class seem to have difficulty auto-focusing on scenes with dim light and low contrast.

It would be a good practice to begin learning to manage your focus manually, as most pro's and serious hobbyists do. First set your len to manual focus. Now target your primary subject, zoom-in close to set your focus (with the lens' focus ring or by pressing and holding the auto-focus button on the lens). Now pull the zoom back to frame the scene and shoot.

[Ken Tanaka]

One additional comment on your post. Note that the minimum fucusing distance for the XL1s' standard lens is about 1 meter at full-telephoto and 20 cm at full-wide.

[Don Palomaki]

The auto focus needs some light and contrast in the subject to work. In the case of the XL1 specs it needed 50 lux for reliable operation - not sure what the figure is for the XL1s.