Using an SLR lens on a Bolex H16 Non-Reflex

[Owen Felton]

I have a Bolex H16 Non-Reflex that came with two lenses. Both of these lenses are extremely difficult to adjust settings on because they seem to need lubrication. I recently had my camera CLA'd, but did not get the lenses repaired. Instead, I bought a C-mount lens adapater and attached my 35mm camera SLR lens to the Bolex. It is a Vivitar 52mm Skylight 1A lens. This attached perfectly, but when I look in the opening of the eye-level viewfinder to adjust focus settings before switching the turret to the correct position, I cannot get anything to focus properly.

I'm not sure if there is something wrong with the viewfinder in my camera, or if I simply cannot use this lens to shoot. I understand from what I've read about using SLR lenses on a Bolex that you have to be really careful and specific about adjusting focus and aperture, but this just doesn't seem to work from my initial test. I would prefer to avoid having to get my lenses repaired or buying a new Bolex lens, but if necessary, I would appreciate some recommendations on where to go from here. Alternatively, does anyone know any specific SLR lenses that would work well for a Non-Reflex Bolex? Any suggestions would help! 

[Dom Jaeger]

It's a non-reflex Bolex, so there's nothing in the camera that would make a lens "work well" or not, if it's a good lens it will work well. 

The only thing you need for SLR lenses is a decent adapter that seats the lens at the right flange depth, and a manual aperture lens. The main problem with using 35mm stills lenses is that you'll struggle to find the sort of focal lengths that are commonly used on 16mm. A typical wide angle would be 10mm or less, and a normal lens around 20- 25mm. Your 52mm Vivitar is essentially a telephoto lens on 16mm format. 

If the Vivitar isn't focusing it could be a few things.

We'll assume the lens itself is OK.

The adapter could be out (although usually a small flange depth error will just shift the focus scale a little, you should still be able to form an image).

Alternately maybe the adapter is not screwing all the way in, so check nothing is obstructing it. That issue would make the lens only focus on close objects.

If you have some C mounts, you can check if the top viewfinder works for them to rule that out. Presumably you have read the manual and know to adjust the viewfinder focus for your eye. 

 

[Simon Wyss]

7 hours ago, Owen Felton said:

Both of these lenses are extremely difficult to adjust settings on because they seem to need lubrication.

I would prefer to avoid having to get my lenses repaired

That tells everything. It had to be a Paillard-Bolex camera but you don’t let live the lenses you have.

The camera is made for C-mount optics. As Dom said, the adapter may be inferior or, my presumption, the focusing prism not seated correctly. I have encountered this many times with those cameras.

CLA can mean plenty of things. The A stands for adjustment and I doubt that the focusing finder got worked on. I even doubt that the mechanism of your camera was disassembled and gone through thoroughly.

Else the stills photo lens by its weight or you yourself may pull on the turret plate manipulating it, lift it off slightly, enough to make focusing impossible.

[Mark Dunn]

13 hours ago, Owen Felton said:

52mm Skylight 1A

This designation is for a UV filter, not the lens. 52mm. is the diameter of the filter thread.. The lens details will be inscribed on the front, behind the filter, but it's likely to be a 50mm, a so-called "standard" lens.

Edited March 5 by Mark Dunn

[Owen Felton]

8 hours ago, Simon Wyss said:

That tells everything. It had to be a Paillard-Bolex camera but you don’t let live the lenses you have.

The camera is made for C-mount optics. As Dom said, the adapter may be inferior or, my presumption, the focusing prism not seated correctly. I have encountered this many times with those cameras.

CLA can mean plenty of things. The A stands for adjustment and I doubt that the focusing finder got worked on. I even doubt that the mechanism of your camera was disassembled and gone through thoroughly.

Else the stills photo lens by its weight or you yourself may pull on the turret plate manipulating it, lift it off slightly, enough to make focusing impossible.

Why do you "doubt that the mechanism was disassembled and gone through thoroughly"? I had it repaired through Dr. Bolex, which is one of the only people I could find to do it in the country. Is he not trustworthy? Before I had my camera repaired, the motor barely even worked, and now it runs perfectly at all speeds. That seems pretty good to me, but I'm an amateur obviously. I am starting to think the viewfinder simply may not be working though, because even with my actual C-mount lenses, it doesn't look very good. 

[Simon Wyss]

2 hours ago, Owen Felton said:

Why do you doubt?

I am starting to think the viewfinder simply may not be working though, because even with my actual C-mount lenses, it doesn't look very good. 

That’s why, you are giving the answer.

Had Dr. Bolex done his work properly you could use the critical focuser. A crisp, clean view of the scene is possible by which you can choose the field of sharpness at will.

I know how much work it takes to clean an entire H.