I am wondering whether anyone has ever found computer-controllable focusing lenses.
I am looking for a lens that can be focused in the same way the commercially available DSLR lenses can be focused. However, couldn’t find any data sheet for Nikkor or Canon lenses, either because they are not publicly available or because I’m not using the proper keywords.
Of course, other suppliers besides mainstream consumer ones are also appreciated.
P.S.: I don’t need auto-focus, that I’ll implement myself, I just need a lens that adjust its focus keeping the image plane at a fixed position.
Apologies, but it isn’t clear what you are looking for. You want to use a DSLR lens? Or any solution? In my experience DSLR lens are driven by electronics in the camera body so you would have to duplicate those electronics if you didn’t plan on also using the camera body. Another option might be a lens on a motorized translation stage.
-Hazen
It would be great to use a DSLR lens, but I can’t find the specifications of the communication protocol. I won’t use a DSLR body, hence the need for the protocol.
I assume there are other lenses that allow focusing without being for a DSLR. I wanted to avoid the motorized stage approach if there is a lens with the built-in capabilities.
I was able to find this for Canon ES lens:
http://web.media.mit.edu/~bandy/invariant/move_lens.pdf
Also this:
I searched for “external drive for canon dslr lens”, FWIW.
-Hazen
Thanks for the links! It is indeed quite interesting what is going on, the one from MIT (by Bando) explicitly says:
We are asked not to disclose the commands in public.Please contact me to get the values shown as ??
The second, from Stanford, cite a work by Bando in which they don’t say anything about the commands sent to the lens (just that they are SPI commands).
I wonder if other manufacturers (Fuji, Nikon, Leica, Sigma?) are so secretive about their lenses…
Strange, hard to imagine why Canon feels the need to be so secretive about this. If you can’t get the commands from Bando then you could probably intercept them pretty easily by adding wires to the pins and then using a library like gphoto to send focus commands to a USB tethered camera. For the Canon lens there are only a few commands, 3 I think for each focus direction.
There are also motorized c-mount lenses like this available:
No idea if they are any easier to interface with.
-Hazen
This site has a lot of information about Nikon lens, though no clear explanation of how to specifically drive the focus motor, at least that I could see.
https://nikonhacker.com/wiki/Main_Page
I’d guess that Sigma lenses might be the easiest since they are designed to work with other manufacturers cameras. Following that idea led me to these pages:
- http://www.martinmelchior.be/2013/04/conversion-of-old-sigma-lens-to-work.html
- http://www.butterflybikers.cz/index.php/cz/elektronika/item/1-canon-eos-protocol-convertor-for-old-sigma-lens
-
https://www.dslr-forum.de/showthread.php?t=649529 (in German, which you can maybe read?).
Where they seem to document some of the Canon SPI protocol, see in particular (2) above. Looks like you might even be able to buy a chip for this from the author?
-Hazen
The only reason I can imagine is that they want to keep control of who can make lenses for their cameras. It is not only Canon, I’ve quickly checked other manufacturers to no avail. It would be interesting to know whether Sigma (or any Chinese lens manufacturer) has actually a spec sheet or just reverse engineer the commands.
I also found the Theia lenses. For example this, at 257€+tax is a bit more expensive that a Nikkor, but has, apparently, motorized iris, focus, and focal length.
Building on the links you shared, fount this company that provides an interface for canon lenses, and they actually use a Basler camera, exactly what I have on my setup. And this guy (translated from Russian) who started digging into the protocol of Canon (the blog post is from 2011 I believe, but it keeps getting comments.
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