Hi Terry,

Good question! “135,” like “120” and indeed all other signifiers, are of course arbitrary. Someone coins them, and by convention we come to understand their meaning. Given that multiple terms can signify the same thing, the question is, “what are the pros and cons of ‘135’ vs. ’35mm’.” Here’s why I greatly prefer “135” as a format name: First, given that the two most widely used film formats are X and “120,” it makes the most sense to me to pair “120” with “135,” both Kodak identifiers, rather than to utilize different provenances when comparing apples to apples. Second, I like to avoid the ambiguity of focal length vs. film format. For example, “I shot this on 35.” Does that refer to a lens or a film format? For Mercury Works, which specializes in producing a universal camera system that can shoot almost all popular film formats, with nearly any lens from any system, such distinctions actually become very important. We do everything we can to reduce confusion, given that we are dealing with inherently confusing (to many folks) and complex permutations of lenses and formats. Admittedly, this confusion would be lessened in the context of a standard camera system that shoots only one format, and uses only one series of lenses. But in our case, ambiguity is a real issue! It’s really unfortunate that “35mm” is an extremely common focal length across a variety of formats. Kodak, in an era when they were producing lenses, cameras, and film, likely coined these terms for similar reasons. Finally, “35mm” contains a second ambiguity: does it refer to the width of the film or the width of the exposed image–film or format? The 645 format exposes an image nominally 35mm (36mm) wide/long on 120 film. Similarly, our 135 Pano backs expose an image 24mm x 67mm. There is no 35mm dimension at all. It seems to make much more sense to refer to the film, then, by an arbitrary designator that cannot be confused with any measurement. Those are my reasons, but I completely accept “35mm” as another name for the same film, and respect your preference. Thanks for bringing up this somewhat irreverent (and fun) topic!

You wrote, “The newly re-titled “Compatible Lenses” page now contains greatly updated information about compatible view lenses, medium format system lenses, hybrid lenses, and 135 SLR system lenses.”

Do you not know that “135” was simply a Kodak inventory naming number just like “120” or “828” or “116” or “122” was and has little to nothing to do with the film itself?

Seeing that you folks are all about film and formats, why would you not simply say “35mm” instead?

Yes, I am a nit picker. It is a lonely life but someone has to do it…

Terry Thomas…
the photographer
Atlanta, Georgia USA