Computar TEC-55 55mm Telecentric Macro Lens

• jb7

  Participant

  May 31, 2012 at 12:11 pm

  I bought this lens for a particular project, making a DSLR film scanner- you can read about the first version of it here… http://www.largeformatphotography.info/forum/showthread.php?88697-DSLR-SCANNER-No-7″ onclick=”window.open(this.href);return false;

  However, it turned out not to be suitable on a full frame sensor.
  It’s a telecentric macro lens, here’s the specification – http://computarganz.com/product_view.cfm?product_id=561″ onclick=”window.open(this.href);return false;

  This guy on flickr can give a much better description of it’s capabilities, (and his pictures speak for themselves) but in digest, it’s a very capable lens for focus stacking, since the magnification of the background doesn’t change as you focus through your subject. It has very low distortion, and extremely high resolution. http://www.flickr.com/photos/johnhallmen/5927446282/” onclick=”window.open(this.href);return false;

  It has a c mount, 25.4mm threads, but I was able to mount it using a couple of step rings, attached to a reversing ring. A dedicated C-mount adapter would be better, but the 25mm ring has enough bite to make it secure. The 28-25mm step ring, and the 49-28mm ring is included in the sale. It can also be mounted to a set of macro bellows, of course. Reversing ring is not included.

  Its image circle is only 11mm at infinity, as stated in the specifications, but at 1:1 and above, it’s very capable on crop frame sensors, with a 22mm image circle at 1:1.It doesn’t cut off sharply, it just loses resolution. Using the setup I described above, with the reversing rings, I’m getting from 1x to 1.5x magnification on a Nikon. Flange focal distance will determine the range of magnification available on your camera.

  I hardly ever sell anything, but since I replaced this one with a Micro Nikkor, I have no further use for it, and it will just waste away. I’m sure somebody else could put it to better use than I could. Condition is good, with excellent optics, but some paint loss.

  Looking for €70,or best offer. I’m in Dublin. Drop me a line at jb7photos (at) me.com

  

  This picture shows items for sale- lens, and two step rings.

  

  This one shows the method I used to mount to a camera, via a reversing ring (not included)