Zoom in to focus technique?

[greg_8mm]

Hi there y'all..

I've been using this technique ever since i started shooting super8. First with a Canon 814E, now with a B4008 ZMII.

The footage i got back with the 814E always came out sharp. But some of the footage ive been getting back from my Beaulieu came out soft. Some shots really a lot out of focus.. Totally unusable that is..

So, i guess most of you know what I mean with the "zoom in to focus" technique but here goes anyways: I zoom in on the subject i want to have in focus, adjust the focus ring so that it's sharp on the ground glass and then zoom out again to get the proper framing.

I use the 6-66 Schneider Optivaron lens. Usually the shots at which im entirely zoomed in come out sharp. Some of the shots where I zoomed out again come out soft.

Could it be that the lens doesn't hold focus when i zoom out? Or should it work well using this technique but am I doing something wrong?

The strange thing is that its not consistent. I have the feeling sometimes when I zoom out again it does keep focus, sometimes not..

[BK]

The back focus of your lens is out, you need to have it re-colliminated.

Bill

[richard p. t.]

You may be accidently bumping the macro leaver on the lens as you zoom back out.
rt

[greg_8mm]

Nah the macro lever stays solid in its position.. I think the lens needs recollimination, the one thing I was dreading..

Oh well, anyone suggestions on where to have it done, and how expensive it would be?

thanks

[BK]

A good reference on Beaulieu lens recollimination is Martin Baumgarten's site:

http://lavender.fortunecity.com/lavende ... ation.html

Unfortunately I don't know any good lens tech that I recommend or the cost of such a service.

Bill

[beaunizo]

A test for infinity is simply done by putting the camera on a tripod. Zoom in and focus on an object with thin lines (380kV electricity mast) in a far distance. Expose a bit of film and check this with a loupe or microscope. After having it processed.

Like this, of course, you can test the other focal lengths too

[beaunizo]

double posted, somehow :?:

[Maurizio Di Cintio]

Hi, Greg.
I think there is a problem with collimation, too. The fact that sometimes it doesn't happen might depend on depth of field: sometimes it is some great that it compensates the problem, I think.

Last year I had my Beaulieu serviced by Bjiorn Andersen at Filmkonsult: he is skilled and really kind plus his rates are quite reasonable.

Here is his email address:
info@beaulieu-service.com

Best of luck

[Davideo]

Alan Gordon Enterprises of Hollywood does lens collimination:

<http://www.alangordon.com/service.home.htm>

[Rick Palidwor]

Just in case... before you send it for servicing, are you sure you had the diopter set right?
Rick

[greg_8mm]

Yes. I always check my diopter before a shoot.

It's just a few shots that are out of focus.. Its just that they're REALLY out of focus, not just a little bit soft.. So that makes me think something must be wrong with the lens.

What is collimation gonna set me back do you guys think?

[Rick Palidwor]

It's just a few shots that are out of focus..

If the lens needs to be collimated wouldn't all the shots be out of focus, not just a few?

Rick

[Will2]

If the lens needs to be collimated wouldn't all the shots be out of focus, not just a few?

Would probably depend on what zoom point you're at. Shoots that are really wide might appear more in focus than close ups or zoomed in shots.

Bjorn is definitely the way to go. He's passionate about getting the best results and he corrected some bad repairs I had done at another shop.

I'm thinking good proper collimation will be less than $200, and he may throw in some general servicing as well. It would be better than factory specs when you're done.

[Marco P]

If the lens needs to be collimated wouldn't all the shots be out of focus, not just a few?

Would probably depend on what zoom point you're at. Shoots that are really wide might appear more in focus than close ups or zoomed in shots.

Sorry, but the opposite is true: For short focal lengths' the required precision has to be significantly higher than for longer. Therefore, a collimation problem will show up with short focal lengths first.

Marco