I’m not sure the exact size you would need (I know my Pentax lenses use 1mm to 1.2mm), but at a dollar a pack you could just pickup one of each size and be covered.

Providing the selenium cell still functions at the same speed it was designed at you would be best using 3200 film. You could also shoot 800, 1600, etc and push process to 3200. The selenium cell is calibrated to operate the shutter based on ISO 3000 sensitivity, but since it’s old its probably a bit slower now. I would think you could test the sensitivity by doing a test similar to the one I used to get my shutter speeds, only in this case you would need a digital camera too. You could aim both cameras at the same light source and capture data from the J66. That would give you a definite shutter speed for a given light source and you could adjust the ISO on your digital until you had a similar shutter speed with correct exposure. You should then have a pretty good idea of the actual sensitivity of your J66 cell.

I believe by default the shutter goes to the slowest speed possible. From what I understand the selenium cell voltage drives the needle which directly controls air flow from the pneumatic piston. As the voltage climbs the shutter speed increases proportionately.

Its made for 3000 Film, how can it works with 100 or 400 film? Should i use Delta 3200? Thank you, Joe

From the research I’ve done prior to purchasing my set of 44m’s I would guess there is little difference. The spring controlling the aperture mechanism should be safe to remove as long as you put it back later. If you can’t access it from the rear of the lens it may be necessary to do so from the front. You may even have to remove the ‘guts’ from the lens housing.

If I can get my hands on a model 44M-4 I’ll give it a go.

thanks!

We’ve also shot and developed C41 color in the J610, but would not recommend it to someone that isn’t familiar with the traditional B&W process. It requires very precise control of the development temperature (in the neighborhood of 105F within a few degrees), or the results can be less than desirable.