Cinematography Mailing List - CML

Lens Mount


I'm wondering if someone could point me in the right direction to information regarding the different types of lens mounts and adapters, specifically for the S16 format (if that plays a big difference). I'm interested in the designs and attributes, differences and histories if at all possible.

Thank you in advance.

Matthew Smith

A lens mount has nothing specifically to do with a film format, but here's some basic info. I swear I wrote this all up before, but perhaps it wasn't on the CML. I'm going to skip some ancient and obscure mounts.

Arriflex -

Arri started with their standard mount, which was a ring with a small tab inside. This was common on the 35mm Arri 2c (and variants) and the 16mm Arri S. Later they developed the Arri Bayonet mount, which was the same sized ring with two outer "wings" that locked the alignment of the lens and provided a stronger mount. Standard mount lenses could be used in Bayonet mounts but not the reverse. This mount was common on later Arri 2c, S, M, 16BL, SR 1, SR 2, 35BL1, 35BL2, early 35BL3, 3c and early 3 cameras. This very popular mount was replaced by the Arri PL (Positive Lock) mount, which features a large four-point flange on the lens and a clamping disk on the camera for a very strong and stable mount. With adapters, Arri Standard and Bayonet lenses can be used. This is the most popular mount available today, standard on such cameras as later Arri BL3, BL4, BL4s, 535a, 535b, later Arri 3 models, 435, Moviecam Super, Compact, SL, later Aaton 16 & 35 cameras, ArriCam ST and LT models.

C-mount -

A threaded, screw-in lens mount of a rather small size. Generally only good for small primes and lightweight zooms and used primarily for small 16mm and industrial video applications. Cameras include Bolex, Beaulieu, secondary mounts on the Eclair NPR and ACL, and numerous industrial video cameras. The C-mount has a very short depth, which means that adapters mounts which put the lens further out can be made for numerous types. I've seen adapters for C-mount cameras to take all the Arri mounts, plus just about any still camera or other cine or video lens mount one can think of. There's still the issue of the fairly weak thread design, but some adapters get permanently installed and hard mounted to the frame of the camera body.

Eclair -

Eclair developed the CA-1 mount for their cameras when introduced in the late fifties. This mount uses a two-prong flange like the PL but is much smaller, about the size of the Arri Bayonet. This mount was available for the 35/16 Cameflex (CM-3), some high speed cameras and the 16mm NPR and ACL. The ACL also offered adapters for other mounts including Nikon and the smaller Arriflex mounts. Today these cameras can also be retrofitted to PL mounts.

Aaton -

The Aaton mount is a three-prong flange that is about the same size as the Arri Bayonet mount, but it's great advantage it it's relatively shallow depth. This allows it to accept various adapters for Nikon, Leica, and the smaller Arri mounts. This mount was standard on the Aaton LTR-7, LTR-54, and early XTR models, and was an option (instead of PL) with the XTR-plus and XTR-prod. The Aaton mount is almost identical to the Cinema Products mount (CP-16 and CP-GSMO cameras) and with slight modification any CP camera can accept Aaton mount lenses.

There are other mounts out there such as BNCR, Panavision, plus the standard (and not so standard) video lens mounts but I think this answers the spirit of your question.

Mitch Gross

Thanks Mitch.

I tried a search but was unable to find the exact info I was looking for.

Your information is greatly appreciated.

Matthew Smith

In his comments on lens mounts, Mitch Gross wrote, "with slight modification any CP camera can accept Aaton mount lenses."

I recently purchased a 15-150mm Angenieux zoom in an Aaton mount from an outfit in Florida with the intention of having the mount changed so that I could use it on my CP16R camera. I wanted this lens specifically because it covers Super-16, and the price was right. When it arrived at my place in California I was struck by how much the Aaton mount resembled the CP mount.

My intention was to have the mount changed to an Arriflex bayonet and to mount it to my CP with an adapter. The idea here was to make the lens usable on the CP and other cameras too, as I might want to use it on an ACL or SR some day. However, it seems that the cost of switching mounts from Aaton to Arri bayonet (at least according to the quote Century Optics provided) is more than I can afford. I was so discouraged by Century's quote that I put the lens on the shelf and haven't pursued the matter until now.

However, it sounds like Mitch is saying that it's possible to modify the CP to accept the Aaton mount-lens directly (as opposed to modifying the lens). This might be the affordable solution I'm looking for. I'd like to get more information - can anyone recommend a technician who can do this?

Any ideas about the cost? Is this process reversible? Would it preclude the use of my other, CP mounted lenses? Any information would be GREATLY
appreciated. Thanks.

Ian Marks

>However, it sounds like Mitch is saying that it's possible to modify the CP >to accept the Aaton mount-lens directly

Ken at Whitehouse AV in Burbank would be the guy to talk to.

Sam Wells

>Ken at Whitehouse AV in Burbank would be the guy to talk to.

I believe the CP-16 specialist who worked at Whitehouse is now with Visual Products in Ohio. If you can't get info at one then I suggest you try the other.

Mitch Gross

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