K-3 scratches solved - light leaks unsloved: ideas welcome

Christian Schonberger · October 30, 2016

Hello group,

Solving the (hopefully) last problems with my S 16 K-3. Looking good so far. No emulsion scratches (after a lot of very careful polishing the gate in the right areas - loop formers removed) and just found the cause for the occasional base/backing scratch (exactly where the regular 16mm frame would end opposite pulldown claw. It's caused by the plastic part that leads the film out of (top) and back into (bottom) the sprocket/roller assembly. The part has sharp edges/burrs on both sides: top and bottom side. Too difficult to remove the part, so I'll tape off the rollers and some light wet (always fine machine oil, not water) sanding with 1000 and 2000 grade should solve the base/backing scratches once and forever.

Now those nasty orange-red light leaks (sprocket hole side). I see these - looking exactly the same - on a lot of K-3 footage on YouTube and Vimeo. I went through the footage frame by frame ( "," and "." keys on YouTube). These occur roughly along 3-4 frames (with some light spill) 26 to 30 frames before and less frames after a new shot (the white flash frame). Checked with scrap film: this locates the leakage exactly at the back side of the spools - and the emulsion is inside black "daylight" spools (???) Can't come from the footage counter: sealed it off with gaffer tape. It's clearly light that finds its way slowly to these areas when the camera is not running but exposed to bright light. If I don't expose the camera to a lot of light, or only have a short break, between shots: no light leaks there. The fact that the baffle plate is a silver-gray with a dot pattern (as opposed to matte black - the way it should be)) certainly doesn't help matters. Door and lock are always sealed tight with black camera tape.

This seems to remain a mystery for many a K-3 user. Painting any parts inside matte black is out of the question (I think): it can chip and probably cause chemical reactions.

Any ideas and tips highly appreciated.

Thanks in advance,

Christian

Edited October 30, 2016 by Christian Schonberger

Tyler Purcell · October 31, 2016

Can you post some samples?

I plugged the holes that remain after you remove the loop formers. That's one area light could get into the exposing area. The other way is through the silly footage counter. Someone recently had a similar problem to yours and all of their foam protector for the footage counter was missing. The foam goes bad and when you re-build the camera, it can simply fall off. That leaves a pretty gaping hole for light to get in. One solution is to cover the footage counter with a piece of black tape, another is to build your own seal for that area.

Christian Schonberger · October 31, 2016

Can you post some samples?

I plugged the holes that remain after you remove the loop formers. That's one area light could get into the exposing area. The other way is through the silly footage counter. Someone recently had a similar problem to yours and all of their foam protector for the footage counter was missing. The foam goes bad and when you re-build the camera, it can simply fall off. That leaves a pretty gaping hole for light to get in. One solution is to cover the footage counter with a piece of black tape, another is to build your own seal for that area.

Tyler:

Thanks for your reply.

Already covered the holes from the removed loop formers with black gaffer tape, I seal the entire "door" all around and the lock. I also sealed the footage counter completely from the inside with black gaffer tape. The light leakage were much worse - the typical defined streaks on both edges - before that. There is a clear pattern: as I stated: around 26-30 frames after the flash frame (burned-in when I don't cover the lens immediately) and a few less before. That places them at the back of both spools - upper loop is a few sprockets smaller). It takes some time for the light leaks to appear. BTW: solved the base scratch (as described in my OP). Here is my latest K-3 test footage:

Thanks again,

Christian

Edited October 31, 2016 by Christian Schonberger

Tyler Purcell · October 31, 2016

My camera always stops with the shutter closed, does yours?

Christian Schonberger · October 31, 2016

Yes. mine too. Pulldown claw always out in the exact same position. Only when the spring winds completely down is the position random. A short twist on the winder (or what's it called) counterclockwise: and all clicks into place again. Never lost a loop (five spools as of yet). There are a lot of reflecting "silver" materials inside the camera, but that is not the cause. If all fails, I'll make a cover of dense black cloth when the camera is not running.

It takes time until light seeps through the closed shutter - which obviously is at a distance from the gate. The pressure plate seales that off. The light leaks occur at the back of the camera. A mystery.... see the exact same light leaks on almost all unedited K-3 footage uploaded (and worse!).

BTW: this is my first footage with the Zenitar 16. All hand held. Need to get used to the barrel distortion. I only have the standard viewfinder. I almost have centering an image down. Leveling is harder with the curvature. It's all counter-intuitive eyeballing without a correct S 16 viewfinder. Having that replaced would cost me a fortune. I'll keep that money for a better camera - one day hopefully....

Thanks,

Christian

Edited October 31, 2016 by Christian Schonberger