is there a back focus adjustment ?

[cur-sed_neil]

i just came off a live shoot for a band and discovered my back focus is out...
anyone else experienced this?
before owning a dvx, i was a canon xl-1 user - I know, I know, sorry - anyhow, the canon backfocus could be adjusted when it went out... but it appears you cannot adjust the backfocus of the dvx.
very frustrating... i looked like an amateur with the footage!

here are the conditions of the shoot as i experienced the problem:
24pa, shutter off, f-stop 2, gain L, manual zoom and manual focus, no nd's.
i zoomed in tight on the singer and got my focus, then zoomed out about halfway. as i zoomed out, i could see the focus starting to soften, so i stopped zooming and changed the focus so the singer was in focus again, then when i zoom back in again, i had to refocus again...
grrr...

i NEVER had this problem with my canon!

it made manual "punching in and out" shots impossible to achieve because the focus was out!!! wtf?!

any suggestions?

thanks in advanced.

[JBN]

Any back focus problem on a camera such as this is going to be an electronic problem unfortunately (no manual adjustment). I wasn't aware that you could adjust the back focus on a Canon XL1. They are notorious for back focus problems.

[cur-sed_neil]

CRAPPY!

yeah, the canon manual lans has a little back focus adjustment screw that you can loosen and fine adjust the focus ring - it's awesome!

too bad the dvx doesn't have this...

:-/

[theos]

How would you tell the back focous is out?

[EvanG]

Good question. Also, I've read that the standard XL1 lens, while it has no manual adjustme for back focus, can be adjusted. Is it done in an auto setting function? Anyone know?

EvanG

[kplo]

You'll need to send your camera in for service. Pana authorized service centers have the computer program/setup to do a "software alignment" which can correct your issue if the lens assembly itself is not physically damaged.
Try doing a reset first (check your manual) to see if that helps.
Here in Los Angeles, I trust Digitronics (Eric) to do that kind of work. Had my DVX100a in for that last year (they also do a proper cleaning as part of that service).
Cost about $200 as it was, indeed, a software alignment problem.

Hope this helps,
Ken

[EvanG]

I'm shopping a couple Canon 14x manual lenses. They appear to have a backfocus adjustment, whereas the stock lens does not. They also appear to have better optics, and real manual focus and zoom rings instead of servo operated ones.

To my understanding Back focus refers to the "focal flange length". This is the distance between the rear lens element and the CCD. If you find that your focus is sharp when you are zoomed in but soft when zoomed out, your back focus needs adjusting. This normally only happens to cameras with detachable lenses — consumer-level camera users shouldn't have to worry about it.

EvanG

[EvanG]

433332_2.jpg

This is the lens I went with. Canon 14X Manual Zoom XL 5.7-80mm f/1.6-1.7 Macro. Reviews I've read are good for this lens. Better manual control and better optics. Anyone with experience with one?

EvanG