Canon EF to PL, Is It Possible?

 

Yes. But not really.

For the Canon CN-E Primes PL Conversion, click here.

The PL mount is an excellent standard that Arri gave us several decades ago and has been the industry standard alternative to Panavision’s camera mount ever since. The PL (Positive Locking) mount is large enough to accommodate sizable rear elements and strong enough to support the largest of professional cinema lenses (with proper support of course). More and more cinema is moving over to Nikon F, Canon EF, and even the Micro 4/3 standard. So why is everyone trying to slam a PL mount on their grandfathers old set of Nikon AIS lenses? It’s simple. All three of the still photo mounts I mentioned have their limitations that can really disrupt a cinematographers flow. For example, Nikon, Canon, and M34 all have a locking pin that keeps the lens set in it’s place and you push the little button to release the pin. Most of those camera mounts have a very weak leaf spring that keeps a bit of pressure on the lens mount to stabilize the lens. Certainly not as much pressure as PL mount fully tightened. Still photo mounts usually have one position that the lens attaches to the camera in and that’s it. you can’t rotate the lens relative to the camera whereas PL mount, depending on the lens manufacturer, can have up to four mounting positions, each 90 degrees apart. Not a deal breaker but still just another reason PL is superior for cinema. I can go on all day about the benefits of PL mount over Canon or Nikon mounts but that wouldn’t help many people. I receive more and more emails and phone calls from people asking if we can convert their Leica R or Zeiss ZF lenses to PL mount. Here’s the important part of this post… Sure, it’s possible. But it’s also possible to put a Ferrari motor into a Hyundai. I guarantee it would be cheaper, quicker, more reliable, and all around easier to simply purchase a brand new Ferrari than it would be to custom install a Ferrari motor into a little Hyundai. The same goes for PL mounts on still lenses. I can see the appeal of putting a PL mount on your favorite “rare” Leica lens but it’s probably not what you had in mind. This sort of conversion would take a lot of design time and prototyping which any engineer can tell you is very expensive. In engineering and machining, its always cheaper to order large quantities than it is to order a single part. When prototyping, ordering thousands isn’t possible since you don’t know if it will work. That’s the whole point of prototyping. This means that a prototype design and fabrication can cost 5-10 times more than the actual end product. Panvision did this a while ago with a bunch of Leica R lenses branded under the Dalsa Digital Cinema name. The company went under shortly after so there are only a few sets of rehoused Leica R lenses floating around the cinema world. To get a bit more in-depth of why simply adding a PL mount requires so much design and engineering, here is a quick little sketch I made that illustrates the flange depth issue behind PL mounting still lenses. A bit more of the technical stuff. The problem with changing from  a still photo mount to PL is all in the dimensions. Particularly flange depth and back focus. The two different specifications are critical when combined. Any error in either measurement can be devastating. Any given lens is designed and set to a specific back focus, the distance from the rear element to the sensor. This measurement is extremely critical to within .0005″ or 12.7 microns. Changing the distance from the rear element to the sensor will result in the inability to obtain infinity focus or accurately adjust focus according to the scale on the lens. So that’s that. You cannot change the distance from the rear element to the sensor. Period. In my illustration I’ve use a standard lens originally designed for a Canon EF mount which you can see at the top. The distance from the rear element to the sensor is represented by the blue dotted line which, as we already covered, cannot change. The red dotted line is the flange depth. Flange depth is a manufacture specific dimension. It’s the measurement from the surface of the mount on the camera to the sensor. Canon EF mount has a flange depth of 44mm. The flange depth of the camera is critical to the lens because the lens is seated on the camera mount. Which means that the distance from the rear surface of the lens mount to the sensor is also 44mm. PL mount is 52mm, represented by the lower illustration with a red line as well. The distance from the surface of the PL mount to the sensor is 52mm on all PL mount cameras. The flange depth is essentially just empty space. A blank distance that gives the lens area to focus the light onto the sensor. So when we have a still photo lens that is designed to have only 44mm of empty space and we apply the same dimensions to a 55mm empty space you have problems. Remember, the distance from the rear element to the sensor cannot change which means that you have to move the mount but not the glass. In the illustration above, take a look at the PL mount on the lower graphic. It’s place much farther forward on the lens barrel. This shows exactly what the problem is in most cases. the difference of the 44mm Canon EF mount and the 52mm PL  mount is a mere 8mm but those 8mm make a huge difference. You essentially have to remove 8mm of material from the back of the lens to accommodate a PL mount. In this case that could mean cutting into critical components such as aperture linkages, focus mechanisms, and anything else that is located at the rear of the lens. This is where the expensive part comes in. All of these components can’t just be thrown away. They have to be re-engineered and repositioned to fit in a space that will be 8mm shorter than it was before. This isn’t always the case as some lenses are smaller or constructed differently. For example, telephoto lenses traditionally have a large empty space from the rear element to the mount which leaves a lot of empty space to work with. There are usually still a lot of mechanical components that have to be addressed, but they just aren’t crammed in like most other lenses. So some lenses would be easier to work with than others, but it’s always going to be a custom one off job until someone decides to take a nice new large supply of still lenses and rehouse them to accommodate a PL mount all while repositioning components to function properly. Oh wait… Zeiss already did that with the ZF.2 and CP.2 lenses.

Like I said before: Yes, putting a PL mount on just about any lens is possible. It’s just not going to be quick, cheap, or easy. 



Categories: Tutorial

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27 replies

  1. Great article. Well ilustrated.

    Thanks for sharing

    • Recently I found a mount made by KCW™ technica , that is supposed a Pl to EOS mount adaptor…. hope that their dimension is a working one for the back flange sensor distance.

      Henry Chung
      HKSC

      • I went to their offices and checked out their adapter and basically it doesnt work.
        Every lens that we tried only worked on a few distances, there is no way you can pull focus, it does not hold the focus, basically every lens will hold focus at different distances, for example, a 50mm will hold focus at 5 feet, and that is it., and 35mm will hold focus at 7 feet and thats it – and you cant rack & keep focus.

      • I’ve seen this same issue with quite a few KCW adapters. There are a few PL to EF adapters out there that work properly. One of my favorites is the TLS PL to EF adapter. It maintains proper flange depth. The only catch is that it’s limited to very few lenses because of physical dimension restrictions.

  2. How about the opposite… Is it possible to add a click-on PL mount to an EF mount camera, in order to use PL mount lenses? I would think the mount would need support, either from the rods or the baseplate. The obvious camera I have in mind is the Canon C300.

    Scott

  3. In the professional world, the mounts are not moving toward Nikon, Canon, etc. Still PL… all the time.

  4. I would like to be able to use my Arri Ultra Primes on the Nikon D800 and it seems there is an adapter for this following this link.

    http://www.angenieux.com/zoom-lenses/index.php?txt=11

    Looking into it myself.

  5. NinoLeitner: “Believe it or not – an EF to PL adapter for the C300 by Panavision, @rodneykiwi brought it from LA! My unicorn http://propic.com/n24Bu

  6. I’ve read everything on the site but my question remains. CONTAX (CY) to a perminant PL mount for 28mm, 35mm and 50mm. Can it be done? Re-housed very nice, if available and approximate cost quote.

    • Robert, As this post explains, yes it’s possible… But the cost would be substantial. IN the case of a Contax lens, you’re looking at re-engineering the entire rear of the lens including the aperture movement and optics housing. It would likely cost more than some modern PL mount lenses.

  7. i got that kcw techica too, tried it on my canon 6D and Red lenses. It had a macro effect, theres also a problem with back focus so will have to adjust. they said zoom lenses work fine. I hope you can test as well on this kcw technica.

    • In that vein, I am curious to know if I can go PL MOUNT on CONTAX CY (Zeiss) lenses. Seems a guy in Korea is doing some with great results but prefer a USA company. Willing to spend money, but can’t do many thousands for each lens. Please advise.

  8. I have the Duclos 11-16 in PL as well as the Red 17-50. I would love to use these on a EF mount C300.

    • Hey
      I got c500 with PL mount, but now only one lens pl mounted. And I got lots of lenses to my 5d mark II. Is possible to buy an adapter to mount EF lenses in c500 with PL mount. My budget now dont let me to buy more expensive cinema glasses.

      • Unfortunately there aren’t any simple Canon EF to PL mount adapters available. This post covers the issue in regards to flange depth and explains why it simply isn’t possible. I would recommend looking for some used lenses to get a feel for what kind of glass you’re looking for.

  9. PL flange is longer than EF. yeah I cnow. Im looking now for used glasses. But i have last questions – is posible to change mount in camera. I got PL mount and go to service for changing on EF.

    • This is the same scenario as changing the mount on the lens. Any camera mount can be changed but there usually isn’t room with Canon cameras. They are filled with mechanics (mirror box) and electronics that would all have to be moved or removed in order to make room for the PL mount. It’s not too difficult and has been done by several companies. One of the best ones I’ve seen so far comes from Hot Rod Cameras

  10. Admiring the dedication you put into your site and in depth information you offer.

    It’s awesome to come across a blog every once in a while that isn’t the same unwanted rehashed information.

    Fantastic read! I’ve saved your site and I’m including
    your RSS feeds to my Google account.

  11. Can you give us any insight into the design of the Canon Cine Primes? Based on the existing construction will it be possible to mod the EF lenses to PL? Or another way of looking at it, would it be a major redesign for Canon to build PL mount versions?
    The Cine Primes are great lenses, but I really don’t want to spend that much cash on a set of EF mount lenses!
    (If you tell me you can mod them, I might buy a set now!)

  12. From what I can see, the only still lens that should “easily” convert to PL would be T-Mount/YS-Mount lenses, which have a flange distance of 55mm vs. PL mount’s 52mm. Any experience with this sort of conversion? Being a screw mount, would a simple screw on adapter work?

  13. Dear Mr. Duclos, Hi. Your write up was really very informative and practical. I really appreciate. Great. Take care. SAEED RIZVI

Trackbacks

  1. Matthew Duclos’ Circle of Confusion: Can a Still Mount Lens Be Changed to a PL Mount Lens? | Kelly On A Tangent
  2. Canon EF to PL | CineTechNews

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