Backfocus problems with XL2?
 

Just contacted my source in Ottawa and he said my XL2 wasn't avail. yet because he had to ship all four back - he's convinced after the first one was tested out of the box that there's a backfocus issue with his batch - he checked all 4 and said the cams performed nothing at all like when the Canon rep was demo'ing with a unit in the store a few weeks back - anybody else hear this? I wanted to ask him more on the phone - he's 4 hrs. away - but he said he was pretty p.o.'d and he'd call me back when he calmed down...

eek!

Mark,

I was messing with my XL2 last night and noticed that zooming in, setting focus, then zooming out that the focus was shifting slightly. Maybe I need to send mine back as well.

Thanks for this info and please keep us updated on what your Ottawa source finds out.

=gb=

Time for more tests. I think we should all check our cameras for this. I did a search on backfocus problems and apparently the XL1 started out with this problem and the haloing that has been mentioned.

When the XL1 first came out, a friend of mine bought one. It had a bad back focus issue. He sent it in and they got it calibrated and back within a week. Too bad they don't have external back focus adjustment on the lenses. I'd guess it's a problem of the lenses not all meeting standards. Anyway, apparently the back focus is adjustable; but not by a mere mortal, only by a service tech.

The 16x and 14x manual lenses both have adjustable back-focuses you do yourself.

True, but you lose the optical stabilization when using manual lenses, don't you? That sort of defeates the purpose in a small hand held camera, for me anyway. There are lots of times I switch from our DSR500 to the DSR250 for hand held stuff simply because the 250 is lighter and has the optical steadyshot that lets me get much steadier stuff than I can with the 500.

I remember when the VX1000 first came out, it also had back focus issues. You couldn't zoom in, get critical focus, then zoom out to a wide shot and expect the camera to stay in focus. But that issue went away with the VX2000 and subsequent upgrades. I've had no issue at all with the 250. I was hoping it wouldn't show up on the XL2, because I have an interest in the camera. Still, once the lens is properly calibrated, it should be OK. Thing is, you'd think they would do that at the factory.

I shot a focus chart and could not detect any back focus problems.

For anyone who cares to do it, power the camera on to any program mode other than "Green Box." Turn image stabilisation off. Set the lens to manual focus. Zoom all the way in to the most distant object in sight. Set focus. Zoom all the way back out. Everything should still be in focus.

I have noticed this same problem with my GL-2. I set focus to manual, come in tight on the subject, adjust focus accordingly, and when going wide the image loses some clarity. If I then push the button returning to auto-focus, the image sharpens.
To further compound this problem I notice that if I do all the above (all the while in manual settings) then return to a medium or close shot after a wide shot (still in manual) that the image is not sharp. What gives?
Tom Markos

In my previous post I left out an important question I needed to ask. If I choose to use the manual setting, is it imperitive that I use use the focus ring to adjust focus during initial setup when I am fully zoomed in on a subject or can I zoom in, press the auto focus button until sharpness is established, then return to manual setting?
When I use the latter technique the image remains crisp despite changing range.
Tom Markos

That would be a classic back focus problem. Since there is no external back focus adjustment on fixed lens cameras, you need to send it in to a service center.

Bill,

Is it possible that the manual focus problems only occur in low-light situations? I haven't had the opportunity to test this theory.

Tom Markos

If there is a back focus problem, it would be the same, but it would show up more in low light because there would be less depth of field and any focus miss would be more pronounced.
You can use the auto focus button, which is what I do most of the time with those kinds of lenses. It is usually about as fast and accurate as doing it with the focus ring, which really isn't a mechanical ring at all. As mentioned, you zoom in, push the button, release it and you're there.