What's the deal with C-mount?

Discussion in 'Adapted Lenses' started by agentlossing, Oct 31, 2013.

  1. agentlossing

    agentlossing Mu-43 Hall of Famer

    Jun 26, 2013
    Real Name:
    Andrew Lossing
    I've run across a few discussions of using C-mount and CCTV lenses on m4/3, but I really don't know much of anything about these lenses. I started browsing on eBay (never a good idea) and found some pretty awesome-looking legacy movie camera lenses. What sort of things can I expect from these things, if I go absolutely nuts and picked one up along with an adapter?
  2. AceAceBaby

    AceAceBaby Mu-43 Veteran

    Jan 21, 2013
    They can be very sharp, particularly in the centre, when stopped down, they're relatively cheap, often have "interesting" out of focus areas when wide open (swirly bokeh). There may be problems with some lenses in achieving infinity focus, possibly depending on the adapter.

    Of the ones I have:
    25mm f/1.4 - Very swirly bokeh wide open, and sharp stopped down
    35mm f/1.7 - Really nice colours, but prone to flaring
    50mm f/1.? - Sharp, but colours seem muted, and mine won't focus to infinity. I understand that people can/do shim these somehow to get them working.

    All of them have continuous aperture, no clicks, and you may have to mark your adapter or get used to where the max-min are. I rate the 35mm as the best of them, and it's nice to use for about $30 all in.

    I took this with the 35mm:
    P3230052 by Ace Ace Baby, on Flickr

    P3170035 by Ace Ace Baby, on Flickr
  3. kadamnation

    kadamnation Mu-43 Regular

    Feb 13, 2013
    Boston, MA
    The "deal," as I understand it, is that mid-length CCTV lenses work pretty darn well on m43 cameras with a <$10 adaptor, and can often be found for significantly less than other manual primes. Because they're manual and, generally, don't have aperture ring steps, they can be fun for bokeh-heavy video use or for general still shooting. I have a 35mm c-mount, and it's fun -- it will focus a little past infinity and due to a slightly shaky adapter I have to hunt back and forth a little to get the right focus, but it's a great lens for more casual shooting and I've used it successfully indoors and at parties given the fairly wide aperture. They do vignette a little depending on the focal length, and I've never tried a wide or tele c-mount lens, but the SLR Magic 17mm CINE lens is basically a 17mm c-mount lens so I assume anything between 17mm and maybe 100mm or so would work fine.

    For some further reading, the Phoblographer posted about a couple recommended high-quality C-mount lenses a while back, and video blogger Blunty left a review of a 35mm c-mount lens similar to the one I have: https://www.youtube.com/watch?v=3AWkiZjHmmM
  4. edwardconde

    edwardconde Mu-43 All-Pro

    Nov 8, 2012
    Los Angeles, CA