Lens Mod FAQ

I receive dozens of emails everyday and I want to respond to them all but sometimes it just isn’t possible. I’m not a trade secret kind of guy. I like to spread knowledge and educate as many people as I can. So here is a quick little FAQ in regards to lens modification and a few other common questions I am asked… Frequently.

1) What lenses work well for motion picture?

2) I have a bunch of still lenses. Can they be converted to work for cinema?

3) What is a Cine-Mod?

4) Can my lens be Cine-Modded?

5) What lenses are well suited for a Cine-Mod?

6) Can the mount on my lens be changed?

7) I have Nikon lenses. Can the focus be reversed?

8] The focus throw of my still lenses is short, can it be expanded?

9) Can lens breathing be corrected?

10) Can my lens be re-housed for cinema use? What is the cost?

11) Can my lens be converted to PL mount?

1) What lenses work well for motion picture? Obviously cine lenses work best for motion picture. The glass used in still lenses works well, but isn’t always suited for motion. Still lenses tend to breathe, the image is not stable and “jumps” when focused or zoomed. There are some still lenses that work well such as full manual lenses like Nikon AIS, Leica R, or Zeiss ZF. These lenses are built very well and eliminate some of the flaws of modern auto focus lenses. There are many other characteristics to consider. Like, does the lens telescope when you zoom? This can create problems with a mattebox. Internal focus lenses are a much better option. Most auto focus lenses lack a hard stop at the end of focus travel and will not work well for marking distances with a follow focus.

2) I have a bunch of still lenses. Can they be converted to work for cinema? There are certain measures that can be taken to help still lenses get close to cinema lenses. It all boils down to usability. You can modify your lenses with a Cine-Mod and it will help quite a bit. Simple add-ons and minor modifications can go a long way.

3) What is a Cine-Mod? A Cine-Mod is a procedure that Duclos Lenses performs. The standard cine-mod consists of a three part process including a solid, seamless delrin focus gear, de-clicking the aperture for smooth movement, and an 80mm step up ring for clamp on accessories, all of which are customizable to suit the users needs. It makes still photo lenses more suitable for motion picture use.

4) Can my lens be Cine-Modded? Most still lenses can receive the Cine-Mod. As long as there is a surface to attach the focus gear, and a threaded front ring, it is usually possible. Some modern lenses do not have a manual aperture ring and cannot be de-clicked.

5) What lenses are well suited for a Cine-Mod? The lenses that benefit most from the Cine-Mod are full manual lenses with longer focus throw and metal housings such as Nikon Ais, Leica R, and Zeiss ZF. Auto focus lenses will still have a relatively short focus throw and possibly no aperture ring.

6) Can the mount on my lens be changed? Certain lens mounts can be easily adapted. Over the years people have made adaptors for many styles of mounts. Nikon to Canon. B to PL. Etc. But some lenses cannot be easily changed. For example, Putting a hard PL mount on a Nikon lens is very difficult and usually requires re-engineering most of the lens to accommodate a PL mount usually costing more than a PL mount lens in the first place. Another common lens conversion would be the Russian OCT 19 to PL. People love the look of the old Russian Lomo lenses. These can usually be converted easily but the cost is high and the build quality of Lomo lenses is not advantageous.

7) I have Nikon lenses. Can the focus be reversed? Not really… Reversing the focus direction requires hours and hours of design and engineering. It basically requires designing and building a new focus mechanism. In short, yes it can be done… But to 99% of shooters, the cost is prohibitive. The simplest solution is a focus reversing gear that goes between the lens and a follow focus or simply a follow focus that allows for reversed travel.

8] The focus throw of my still lenses is short, can it be expanded? Sometimes this can be done by using specific gears on a follow focus unit. But extending the travel within the lens would again require re-engineering the focus mechanics. This also is cost prohibitive. It would be cheaper to simply purchase a proper cine lens with the appropriate focus travel.

9) Can lens breathing be corrected? No. Breathing is a characteristic that is considered when the lens is designed. Most still lenses breath simply because it doesn’t matter since you don’t focus as you take a still photo. Cine lens designs take this into consideration and compensate for it. This is a major part of the cost difference between still and cine lenses.

10) Can my lens be rehoused for cinema use? What is the cost? Re-housing lenses is a very long, expensive, and involved process. Duclos Lenses spends months and months on a single design in order to achieve a lens that works as well as it can for cinema use. While there are many still lenses that are great for shooting stills, most are just not suitable for a complete re-house. Duclos Lenses tries to accommodate users with lens features such as focal length, max aperture, size and weight, that are not available from other manufacturers. There is a very specific set of criteria that must be met in order to consider a lens for re-housing. Very few lenses meet this criteria. It’s almost always more expensive to rehouse a single still photo lens for cinema use than it is to purchase a new cinema lens.

11) Can my lens be converted to PL mount? Changing the mount on a lens is a very involved process. Specific measurements that are critical to optical performance must be maintained. The distance from a PL mount flange to the sensor is 52mm. This means that within that distance, the glass itself must be placed at the given distance from the manufacturer. For example, a Nikon mount lens has a flange depth of 46.5mm. This distance can’t be changed because it is relative to the optical design. So the glass must stay in the same place while giving the PL mount 52mm of distance to the sensor. This can usually be accomplished by rehousing a lens and designing the rear housing from scratch with this goal in mind. If you’re thinking about re-housing your lens, read the previous question (10).



Categories: Tutorial

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17 replies

  1. Hello,
    I am looking into buying the Zeiss primes, should I buy the ZE or ZF series, for the cinema modification?
    Secondly, can you put on PL mounts on these lenses? I will not be using them on a still camera.
    Third, I have a Tokina 11-17 2.8, can I send this lens in for your modification? If so, how much would it be?
    Great work.
    Jim Bridges
    Type A Media
    http://www.typeamedia.com
    404-630-6433

  2. Hi, I have an Angenieux P2 135mm F2.5 T.V. Lens and wondered what it would cost to be able to use it on my Nikon cameras? Thanx, Jake.

  3. Thanks for this informative FAQ. I just started collecting old Nikons for use with my 7D and you answered my question about lens breathing–although it wasn’t the answer I was hoping for ;)

  4. Your services seems realy great! Is it possible to put a iris ring on a lens that originaly has internal aperture there are so many nice lenses (Canon L series lenses) that would be great in cine use if that could be done on them.

  5. I notice that you do not mention Contax Zeiss MF lenses (predecessors to the ZE and ZF, which I think are ideal candidates (more so than Nikons) because of their build quality and long focus throws. The other reason I like them is mechanical apertures (compared to ZE) which makes them more stop motion/time-lapse friendly. Any reason why you’re not modding them?

    • The Zeiss/Contax lenses work very well. I don’t mention them very often because it’s becoming more and more difficult to find good quality, well cared for lenses since you can only buy them second hand these days. However, with their fully manual function and the nice focus throw they make great candidates for the Cine-Mod and motion picture use.

  6. What are in your experience the best candidates, optically speaking, for cine work on Canon 5DmkII and 7D amongst the Nikon AIs? Also as mentioned previously why are none of the older Contax Zeiis MF ever mentioned for this purpose (cine use)
    Thanks for your reply

    • Optically, the best candidates for motion picture use is really up to the user and what “look” they are going for. Some may say it’s best to start with the most accurate image and alter in post from there. I would say the Zeiss ZF.2 lenses would accomplish this the best. Others would say the most cinematic, dreamy look would be the best. For this, I would say the Leica R lenses would be very well suited for such shooting. It’s really up to the user and what sort of results they are looking for. The Zeiss/Contax lenses work well for motion picture use since they are fully manual and can easily be Cine-Modded. One downside to the Contax lenses is their housing can be a bit small making accessories a bit difficult to cram into one rig. For example, if your lens is only two inches long, your mattebox is going to be two inches away from your camera and now you have to figure out a way to cram a follow focus into that small space as well. It can get difficult.

  7. Matt: I just won a Zeiss 50 mm F1.5 ZE lens from Vince Laforet’s workshop. Can you modify the ZE lens or should I request the ZF mount if it is available. I ultimately want to use this lens on the Panasonic AF100 which I hope to purchase later this year.

    Thanks

  8. It is great that you offer a complete “cine mod”. Very cool. Would you be able to “cine mod” C-mount lenses? (Navitar .95 50mm, 25mm, 17mm for example?) I was thinking of using these with a GH2, but they would be most useful obviously with a focus gear and possibly even a permanent mount adaptation to M43. I realize you can’t tell me really unless you have the lenses, but I just thought I’d ask, in case for whatever reason you know it is simply not feasible.

    Thanks.

  9. Matt, I own 3 Leica-R lenses: Elmarit-R 1:2,8/28mm; Summicron-R 1:2/50mm; and a Macro-Elmar-R 1:4/100mm. All are adapted for Canon with Leitax adapters. I’ve shot some great video with these but would love to mod them.

    Can these lenses be Cine-modded specifically focus rings and iris de-click? Don’t need the step adapt on the front ring though since I’ll use matte box. Please advise.

    Also the 100mm is pretty stiff on the focus ring; unlike the other 2. Can anything be done about that?

    Thank you!

    Jon

    • Sure! The Leica R lenses are very well suited for the Duclos Cine-Mod. In fact, they work very well for motion picture use. There used to be a Leica specialty repair shop but I believe they are no longer in business. Not sure where you could send the lens to have some service done to it.

      -M

  10. hi matthew,
    i will be getting a panasonic ag-af102 soon and for lens i was thinking of the zeiss zf series. i was wondering would it be possible to convert the lens mount to a micro 4/3 without the use of an adaptor?
    regards,
    ed liew

    http://www.visualline.com.my

  11. Hi,

    I was wondering if you have had any success modifying the lower end 14mm 2.8 Rokinon/Vivitar, and the corresponding 35mm 1.4 or 85mm 1.4 by the same manufacturer. The glass I have seen is fairly good and they are a good deal less expensive than the Zeiss lenses.

  12. Do you think the Rokinon 85mm, 35mm and 24mm are worth rehousing in a pl mount casing?

Trackbacks

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  2. Zeiss ZF.2 Cine-Mod Set « Matthew Duclos' Circle of Confusion

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