Compact Zoom for Reflex Bolex

[Jordan Beard]

I recently picked up a Bolex SBM and I'm looking for a compact zoom lens for it. I passed on the Kern 16-100 because it seemed a bit too bulky for my setup. Could anyone recommend a smaller zoom lens in C-mount or Bolex Bayonet mount? Ideally looking for something that goes as wide as ~17mm. Has anyone had any experience with the Angenieux 17-68mm f/2.2 "Special P" lens?

[Todd Pinder]

I have both Vario Switar and Berthiot 17-85, not the fastest but very compact! 

[Ben Ericson]

It should be noted that the bigger Kern lenses' zoom functions are a lot smoother than the other options. You could try the compact Kern 17 - 85. The 18 - 86 is smaller than the 16 - 100 but it is still fairly large.

[Jordan Beard]

Thanks for those insights. The Vario Switars seem like the best option in terms of quality though they are quite large... I might need to just get over the size issue. Have you guys tried or heard much about the Angenieux 17-68mm f/2.2? It looks like a decently fast lens that's closer to the 17-85mm in size and even designed for the Bolex's reflex prism. Haven't found much about it aside from a couple tests on micro 4/3rds camera.

[Ben Ericson]

2 hours ago, Jordan Beard said:

Thanks for those insights. The Vario Switars seem like the best option in terms of quality though they are quite large... I might need to just get over the size issue. Have you guys tried or heard much about the Angenieux 17-68mm f/2.2? It looks like a decently fast lens that's closer to the 17-85mm in size and even designed for the Bolex's reflex prism. Haven't found much about it aside from a couple tests on micro 4/3rds camera.

I haven't used it. I would assume that any of those lenses will work for you. In my experience, the zooms are pretty similar optically. Using prime lenses like the Kern 26 1.1 is where you will see a huge difference in the quality of the glass. Even then, it's all 16mm.

[Dom Jaeger]

Angenieux’s 17-68 was their first 16mm zoom, designed back in the late 50s. It was actually one of the very first mechanically compensated zoom designs, along with one they made for 8mm, so historically quite an important lens, but understandably primitive in terms of the evolution of zoom lenses. Som Berthiot’s Pan Cinor design (which includes their 17-85) was even earlier, and used a more basic form of optical compensation that was made more or less obsolete by Angenieux’s innovation. They both still work OK of course, but a contemporary prime lens is noticeably better. 

The first Angenieux 17-68s were silver (Type L3 were for reflex Bolexes, sometimes labelled Special P), in the late 60s they were mechanically redesigned with black housings (4x17 C were for reflex Bolexes) and are a better mechanical design (the internal elements slide rather than rotate) and coatings were improved. 

The Kern Paillard range of lenses were groundbreaking for their superior contrast, so you’ll find their zooms can look sharper than contemporary Berthiots and Angenieuxs. Vario-Switars are probably the best zoom options for reflex Bolexes, and generally produce excellent images. Apart from the bulk, the one downside I find is that the ones with auto-aperture use two blade irises, which create diamond shaped bokeh, but if ease of use is important to you then it’s a handy feature. 

The other factor to consider is aperture speed. If you like to shoot in low light, the compact zoom options like Kern’s Compact 17-85 or Berthiot’s version are quite slow. Angenieux’s 17-68 is a lot faster at f/2.2 (T2.5), but still a long way from a Switar prime.

Your camera has a Bolex bayonet mount, which was designed specifically for heavy zooms, so if you can find a zoom in that mount it can help prevent the lens from developing back focus problems that might make your footage look soft or out of focus, especially at wide apertures and the wide end of the zoom range. A C mount is not that sturdy, particularly if you transport a camera with the zoom attached and it gets a bump. 

If a compact and lightweight form is really important to you, as well as image quality, I would suggest maybe trying primes. Otherwise probably a black Angenieux 17-68 or Kern’s Compact 17-85.

Of course perhaps the most important factor is the state of a lens - scratched coatings, fungus, worn mechanics, out of tolerance settings, dry lubricants, oil on iris blades etc can have a tremendous impact in the quality of the image. So make sure to ask lots of questions from sellers and be patient in your search, or be prepared to pay for an overhaul. I have found Berthiot’s zooms to be more prone to fungus for some reason.

[Todd Pinder]

I saw that JK camera can remove the auto iris of the 16-100 POE making it less bulky, but yes the 2 blade aperture is what kept me away the most from those lenses.

[Maxim Lequeux]

On 6/21/2020 at 4:35 AM, Dom Jaeger said:

The first Angenieux 17-68s were silver (Type L3 were for reflex Bolexes, sometimes labelled Special P), in the late 60s they were mechanically redesigned with black housings (4x17 C were for reflex Bolexes

Is there a big difference between the black 4x17C and 4x17B for reflex Bolexes?

[Dom Jaeger]

17 hours ago, Maxim Lequeux said:

Is there a big difference between the black 4x17C and 4x17B for reflex Bolexes?

The one for reflex Bolexes is 4x17C. It has a corrective element to compensate for the Bolex prism in the light path. It will introduce slight aberrations if used on a normal C mount camera at wide apertures. The exit pupil is fairly deep, so the Bolex prism has only minimal effect.