Focus goes in and out

[D_Odell]

Hi,

Anybody experienced that focus differs with Beaulieu models durring a shot with the same settings?

As you can see on these two stills from a shoot, the focus has gone from overly sharp to quite unfocused. And since almost the whole shot consisted of the unfocused type I wonder if anybody know why there can be such difference?

Focus: http://img836.imageshack.us/img836/6307/fokusc.jpg
Unfocus: http://img839.imageshack.us/img839/5581/ofokus.jpg

Camera: Beaulieu ZMII with Angenieux 6-80 lens.
Technically the camera was on tripod al the time and the focus barrel never changed during the shot.

Best,
David

[Will2]

How was it transferred?

[D_Odell]

Flashscan HD from Uppsala bildteknik, Kents company.

Best,
David

[Angus]

Not a Beaulieu I know....but with my Elmo Super 110 over the first second of a shot the film obviously breathes in the gate. The first 6 frames or so are in focus, then about 10 or so are out of focus, befor ethe film gradually returns to focus...thereafter the shot is in focus - assuming I set the focus correctly to begin with!

So it is possible something similar is happening with your Beaulieu...but even the grain dots seem out of focus in the 2nd jpeg. As if the transfer wasn't correct.

[D_Odell]

Yeah I think your right about the film grain being diffuser in the blurry one. How come a transfer can change it's focus?

[Blue Audio Visual]

I'm pretty sure the grain is the same in the two pictures, and that the problem lies with the camera rather than the transfer.

Here's a picture showing the same section of the image blown up, with both transfers side by side.

You'll have to right-click and view the image to see it full size (or equivalent on a Mac).

Which is which?

[D_Odell]

Yes it's hard to see. I have sent an mail to a Beaulieu technician I send my cameras for service. I'll respond if you gives any info.

Here is the compare with 200% crop:



It's exported as tif then jpeg and jpeg so not so much to expect in keeping the sharpness.

Further I can say that I uses Plus-x for this shot. And this kind of in and out focus haven't occurred in other stocks. Maybe an solution, but hopefully not.

[ekoe]

Hello David. It's ekoehler7 here.
I recently noticed something on a Schneider-Kreuznach 6-70 that may explain what happened. I was using the lens for a test, set it at 10' and started to frame a focus chart... I happened to look at the lens barrel and was suprised to see it rotating on it's own, apparently due to the action of the damping grease on the helicoid. I tried to replicate it but I couldn't get it to do it again.
Maybe your Angenieux 6-80 did the same thing?
My other thought would be condensation on the front element. Is that possible?
Hope that helps.

[D_Odell]

Hi ekoehler,

That sounds like a possible explanation. So it shouldn't have anything with the stock or anything like that, as for the electronics inside the camera.

Thanks,
David

[ekoe]

It wouldn't have anything to do with the electronics unless the camera were autofocus.
It could be to do with the stock... for instance, if you had stored your film in a refrigerator or freezer and did not allow it to acclimate to room temperature. If the temperature inside the S8 cassette were significantly lower than room temperature at the time of filming, condensation could form on the film as it was exposed, causing diffusion of the image.