Bolex Pl mount with modern super35 lenses

[Scott Toler Collins]

I am a bit new to Bolex's still and was wondering about using a Bolex EBM adapted to PL mount. I am somewhat aware of the prism issues with wider lenses but has anyone tried putting wide angle s35 lenses on a reflex bolex? Like let's say a 14mm or 10mm prime with super 35 image circle. Or a wide angle zoom like the Tokina 11-20mm PL.

I own a lot of s35 lenses and would love to use them on a bolex if I buy one. I'm just curious what the result would be in terms of infinity focus or possible spherical aberration. Any insight is appreciated!

[Nicholas Kovats]

Les Bosher makes one of the best Bolex Bayonet/PL Mount adapters. Accurate and precise FFD. S35 lenses on a 16mm will have a magnifying effect. 

[Dom Jaeger]

If the adapter is good quality like the Bosher one Nick mentioned you’ll have no problem with infinity focus. 

The prism will affect some lenses when used at wide apertures, how much they are affected depends on the lens and the aperture. The more you stop down the less the prism will introduce aberrations, until maybe f/3.5 or f/4 where it becomes pretty minimal. I found that the exit pupil depth is an important factor - this is the image of the iris as seen from the rear of a lens. If the iris seems very shallow, less than say 10mm under the rear element, then the prism will have a pronounced affect, introducing spherical aberration and astigmatism at wide apertures. The deeper the exit pupil, the less affect the prism has. Longer focal lengths have deeper exit pupils, which is why they are not affected, and RX lenses were not made above 50mm. 

Whether you find the aberrations the prism introduces ugly or interesting is something you’d have to judge for yourself. 

[Scott Toler Collins]

So I assume a s35 lens would have less affect on the prism because the image circle is so much wider. Safe to assume? Of course I'll shoot tests but it sounds like the prism is mostly affected with smaller exit circles. 

[Dom Jaeger]

4 hours ago, Scott Toler Collins said:

So I assume a s35 lens would have less affect on the prism because the image circle is so much wider. Safe to assume? Of course I'll shoot tests but it sounds like the prism is mostly affected with smaller exit circles. 

No it has nothing to do with the size of the image circle. It’s the depth of the exit pupil and the aperture. More modern S35 lenses designed for digital sensors will often have deeper exit pupils, as they are designed to be more telecentric, so they will work better with the prism. But an old Cooke Speed Panchro for instance, with quite a shallow exit pupil, will be more affected, even though it covers a larger circle than 16mm format lenses.  Again, it’s only the wider angles.