Optical effect to identify - Vintage Cooke Zoom

[Alec Lemonde]

Hi all,

Came across an intense flaring/ghosting (not really sure what's happening here) phenomenon using a Cooke S16 Varokinetal 10.4mm-52mm. It has been serviced by Visual Products 2 months ago.

The stills come from footage on a RED GEMINI in 2K crop mode, with standard OLPF and no filter or mattebox on. It is present across the aperture (toned down past T5.6) and zoom range (seems to zoom in the effect). Can provide examples in other lighting situation. In a lot of scenes the light source, even a window with ambient daylight, will appear as a blue ghost/flare. The effect was noticed on ARRI mini LF too and potentially on ARRI SR2 (though not as evident on the 16mm footage shot yet, as the source was ambiant overcast daylight).

I find this interesting as I tested a lot of vintage S16 zooms before from Angénieux, Canon and Zeiss and never came across this to my memory.

Anyone has insight or guesses on this? Trying to gather information from other users too.

 

Thanks,

Alec

[Alec Lemonde]

Note: Some of it was also noticeable with full mattebox, matte and flags on when shooting tests inside a controlled room with one window as only source.

Edited June 16, 2024 by Alec Lemonde

[Dom Jaeger]

If you’re seeing image highlights doubled it’s due to reflections on internal glass surfaces. Sometimes it can be from sensor cover glass reflections or from filters. Odd flaring is more likely to be shiny surfaces inside, or oily iris blades. 

First step would be try it on a different camera. 

Did you ask VP?

[Alec Lemonde]

Problem was solved after a check up: small amount of lubricant had found its way onto an internal element.