Light Aberration on 16mm Bolex Footage - is it the lens or the camera?

[Jack Wormell]

Hi

 

On my last few 16mm Bolex H16 reels I've been getting this light aberration (examples in the attached photos). It seems to happen when there is a slightly overexposed part of the frame, and is particularly pronounced when it's contrasted next to a much darker part. I'm shooting with a Kern Palliard 25mm lens, but it hasn't always had this problem. I'd like to know if people think it's a problem with the camera or the lens?

 

Many thanks

 

Jack

[John Salim]

This is a classic example of the shutter being out of phase !
( the film has started to be pulled down before the shutter closed )

John S ?

[Tyler Purcell]

Do you have a moving shot? If the camera did work before and suddenly doesn't, I doubt it's the shutter. Usually an out of time shutter will have a streak in a portion of the frame, not the entire frame as pictured above. If the frame line jitters as well, then it's the loop size being too small. I would hedge my bets on that over a mechanical failure, but don't rule out the shutter timing quite yet. Need to see it in motion first. 

[Dom Jaeger]

I would agree with John, it looks like the shutter timing may have slipped. I have done enough Bolex repairs where the shutter gear set screws came loose and allowed the shutter to slip not to rule it out, though usually it's the result of someone taking the front off and not knowing how to set the shutter timing again.

It could potentially be a loop issue, though it seems unlikely for the same loading mistake to be made repeatedly on separate rolls. If you're using the auto loop-formers to load you can check that the loop is being correctly formed and held with some dummy film.

Shutter timing is also easy enough to check. Mark the emulsion side of some dummy film with a sharpie, a long wiggle that covers a foot or so. Load as normal until the wiggle mark is in the gate. Then disengage the motor (turn the MOT-O lever to O), lock the run release all the way to the left and use the rewind lever to manually inch the mechanism forward. With the lens removed, look through the lens port at the gate while inching the film through. You should never see the film move (the sharpie mark helps to tell). If the film moves at all before or after the shutter covers the gate, then the timing needs to be re-set. 

[Simon Wyss]

Claw-shutter mistiming. Claw late, shutter already opening while film coming to halt. Images are upside down and left-right inversed on film. Technician needed. Where is the camera from?

[Jack Wormell]

Hi Everyone, thanks for the replies. It does sound like a shutter mistiming issue. But here's a link to some shot's I've plonked together from the reel, for Tyler to look at: 

 

I'm assuming it is fixable if it's a shutter issue?

 

Huge thanks

 

Jack

[Tyler Purcell]

Yea I agree, it's a shutter. Easy to fix, just need someone who knows what they're doing. 

[Jack Wormell]

Great! Thanks for your help everyone.