I am sure this has been asked many times before but what lenses would you recommend for a Bolex H16 Reflex (non super 16)? Currently I have a Kern-Paillard 25mm (no RX markings on it), but I was looking for something with a wider view angle. Maybe like a 10mm?
RX marked lenses should be used on Paillard-Bolex H Reflex cameras at focal lengths shorter than 50 mm and at apertures wider than f/3.3. Longer telephoto lenses and any C-mount lens stopped down to f/3.3 or more will work. So a wide-angle lens must be a RX corrected one or you won’t be able to use it iris open. The reflex double prism introduces a longitudinal aberration to the light running to the film and to the light deflected for the viewfinder. To complicate things further, the light towards the film leaves the prism glass while the finder light doesn’t and the path through glass is shorter for the film light than for the finder light. This leads to an error with short conjugates or in other words when you do very close macro work.
RX lenses were made by Kern-Paillard, Schneider, SOM Berthiot, Angénieux, and others.
Yes, I read at length the information on the RX vs non-RX lenses. It is crazy how the physics of optics play into this just by having the light passing though the prism. I found a decent Berthiot Cinor 10mm f/1.9 SOM H16 RX that will arrive in the mail on Monday. Read good stuff about it. There is just some minor flare and spherical abberation at the edges. Won't bother me at USD 160. I just wasn't ready to shell out >USD 500 for a Switar.
I really do hope the 10mm will give me a wider angle than the YVAR 25mm that I have on it now (which equates to a 50mm to what I understand).
Yeah the price of Switars is ridiculous, C mounts in general have gone up since mirrorless camera enthusiasts discovered them but Switars in particular can be ludicrously expensive. That Berthiot should be fine.
You don't need to hope that a 10mm will give you a wider angle than a 25mm, that's a given. The shorter the focal length, the wider the angle of view, as long as the format stays the same. Don't be confused by "crop factors" that equate the views of different focal lengths on different cameras. Unless you're a full frame stills photographer locked into thinking of certain focal lengths having particular view angles it's not really helpful. A 10mm lens on your Bolex will give you slightly more than double the angle of view of your 25mm. There are field of view calculators online if you really need to get a sense of it before investing in a lens, but the standard configuration on modern turret Bolexes was a 10mm wide, a 25mm standard and a 50 or 75mm long. You can do a lot with just those.
Oooh, too bad you picked the Cinor 10-1.9. It has diaphragm mechanics prone to derailment.
Yes, Som Berthot were usually the budget choice for Bolex cameras, but I've seen plenty of their lenses still working after all these years. In my experience the main cause of iris blade derailment is oil from the grease leaching into the iris and adding extra drag as the blades slide against each other. Even well-made iris blades can deform or develop loose pivots under those circumstances. Switars have their own weakness in the choice of lubricant Kern used that hardened over time, Angenieux primes are susceptible to corrosion under their chrome.
The biggest difference between Som Berthiot and Kern primes that I've noticed is the contrast - Kern Switars generally have better contrast than the Som Berthiot primes I've tested.
Very right you are. The point about the blades I’m showing is that they are hard to repair. I can push a needle through the opening as a trial to reerect the—burrs?—but after two or three attempts, also from the opposite side, in finding a fit I encounter danger of total outfall (hardening-breaking). A comrade of mine here in town spoke of a no-play fit between the dome-shaped crowns and the grooves. Please see picture. As I understand it today that was never intended, the risk of blade slip-away is too big.
Blades, leaves, which is the right term?
We should team for a press, punches, and dies to make fresh leaves with solid pivots. Lens Mechanics or so