Monday, September 6, 2010

First Taste of "Noctilust" - Canon FL 55mm f/1.2 - A Canon FD to Nikon F Conversion

I find it incredible how I often wander into "new" territory completely unexpectedly. Though some may argue my activities automatically disqualify any notion of "chance". Essentially, my constant perusing of eBay and the local shops and flea markets hardly allows me any room to claim mere good fortune as a factor. I suppose I put myself in the position to "come across" things...This is all beside the point.

I hadn't heard the term "Noctilust" until just the other day but I have certainly become quite familiar with it now. I have always read about fast lenses and even used a couple here and there. But I don't know that I have ever really desired one just because I think I have been more after what I need and can use everyday. Sometimes, though, decisions get made for you.

While exploring the local flea market this past weekend, I came across an old Canon FT. Despite having no real need for film camera, I tend to always check them out because I am still a hardware nut above all. What first caught my eye, and what my attention was now transfixed upon in a closer inspection was the 55mm f/1.2 lens sitting on the front. In all practicality, as a Nikon user, the Canon FL and FD mount lenses are quite useless to me. Because save for a complete re-engineering of the lens mount, I cannot do much in adapting the lens. I figured it was a cool piece but I would pass it up since it would prove some work to use. Then the gentleman told me the price. Sold! That was quick...

Canon FL and FD to Nikon F

If you are looking to adapt either of these archaic Canon mounts to the new Nikon F for use on the digital bodies consider this:

- Canon FL and FD focal flange distance is 42mm while Nikon's is 46.5mm. This means you need to figure out how to reduce the Canon lens' mount by 4.5mm.

- Adapters that contain no optics but merely mate an FD or FL lens to a Nikon body cannot possibly retain focus at infinity. So with this means, you will turn every lens into something of a macro lens.

- Adapters do exist with optics to compensate for the differing focal flange distance however, these typically have a multiplication factor associated with them as well as an inherent reduction of light. So your lens will be slightly more telephoto (often 1.6x or so) and your lens speed will be reduced by the added optics. Not only that, the optics currently in use with these adapters, by most accounts, is inferior and degrades image quality.

My thoughts: No sense in using a straight optic-less adapter since I do not need another macro lens. This lens was made for portraits! Adapters that use optics are also out since what's the use of an f/1.2 lens if it just gets knocked back down to a slower stop. Also, it makes no sense to use all sorts of round-a-bouts like adapters only to wind up with a mediocre image in relation to what that lens may be truly capable of. I just would rather not be limited by some cheap adapter.

A DIY Project - Photographic Blasphemy!

OK, an admittedly exaggerated title considering I know many photographers who shoot Canon and use Nikon glass on their Canon bodies. But it was funny when The Girl asked in a whisper-like voice, "Is that a Canon lens?...on your Nikon?" I have taught her well. Actually I'm quite non-partisan though I do like to continue to egg on the whole Canon/Nikon battle in jest.

I decided the only way to really make this lens worth my while was to convert it to an F-mount. So I first removed the FD mount from the lens via three simple screws located just inside the Breech/Lock mechanism. This exposed some threading, as well as the A/M ring which switches the lens from Auto to Manual stop-down mode. Since this lenses aperture ring is up front by the filter ring, it would prove tough to easily make this lens index with a Nikon so I will most likely be using this in stop-down mode. Considering I bought this lens for its f/1.2 aperture, I don't believe I will need to worry about auto-indexing. As I said before, for this lens to focus to infinity the rear element would actually need to recess back inside the Nikon mount of the camera. Since at this point I'm not prepared to physically alter the lens in any permanent manor that would prohibit it from being returned to its original FD mount, I have chosen to drill a spare F-mount I have to fit the original 3 screw holes used for the FD mount.

So I ended up with that. The rear element protrudes ever so slightly beyond the Nikon F mount but not nearly enough for infinity focus. The most common concern with converting these older f/1.2 lenses is that, typically you run into some tight if not simply unmanageable tolerances between the rear element and the mirror of present-day DSLRs. After some measuring and working out the numbers, this lens, in theory, could achieve infinity focus through a full mount conversion (milling down the rear portion of the lens to the correct length, and then attaching the Nikon F mount). But the numbers of where the rear element must be inside the camera in conjunction with where the mirror swings are nearly dead on. In reality, it's probably too close for safe operation. I actually even found one of these FL 55mm f/1.2 lenses on eBay converted for Nikon. I messaged the seller with some questions but still have not received a response. My guess is infinity focus is not achievable.

Despite that somewhat discouraging information, I managed to get an F mount on the rear of the lens and give it a whirl! I have about 4 feet to work with. Honestly, I am thinking a few more feet may be all I need. This lens, for me, will be a beautiful portrait lens. I am interested in the soft ethereal qualities of the shallow DoF. I most likely would never even need more than 10 feet or so. For now, I will tinker with my 4 ft.


Nikon D700 with Canon FL 55mm f/1.2
ISO 200 1/320 @ f/1.2

Just off-center Crop

I have to say, judging from my first few test shots, I love this! Noctilust here I come. I didn't think a fast normal lens was up my alley but it truly is a thing of beauty. No one shoots an f/1.2 lens that I know of for sharpness and it is clear why. This lens is not sharp wide open. But then again, I don't believe perfect sharpness was necessarily what the designers were striving for. This optic possess a unique ability to render subjects softly and in a way that is almost boastful. I find myself completely unconcerned with sharpness which is entirely uncharacteristic of me.

The Girl defeated by her Pizza
ISO 1600 1/80 @ f/1.2

Contrast with this lens is great and I don't see a whole lot of CA actually. I do notice this lens is prone to flare. This originally had a uniquely designed hood that I just may pick up since I believe I will be using this lens a lot more in the future.

I can't say a whole lot more on performance at this time save for continue posting more images as I use it. I plan on eventually milling down the back some more and getting as much as I can out of this lens. And I'm sure in the future I will end up with another fast lens to compare it to!



  1. Wow great post and you absolutely told the right story, the disadvantage of consversion, they don't fit properly. I recently bought Canon FD 105mm f/1.8 for $80 and thought I can convert easily, but not so lucky. It is completely manual focus !
    This is a good post, I will try to write my story too. Thanks

  2. I have never tried converting FD lens to Nikon but I have converted some Minolta Rokkor to EOS.
    For some of them, the infinity focus can be adjusted not only by decreasing the distance of the rear element to sensor. Some of them have a infinity adjustment screws inside which works by adjusting the distance of the rear and front elements. If the canon FD has it, that should be able to fix your problem (:

  3. That is great news about the infinity adjustment. There may be hope yet! I will have to open 'er up again and take another look. Thanks for the info!

  4. Hi David,

    i ve done this conversion 3 times over with infinity focus before. twice with this exact lens, and once with the SSC version of this lens.

    infinity focus is possible but ONLY WITH DX. if you mount it on nikon fullframe, it hits the mirror box and i cracked the last element of one of these lenses by putting it on a Nikon FA. its completely workable with canon fullframe though.

    you need to remove and shave/grind the piece that you screwed the nikon mount into. i used a soft grind stone and water for this. sand paper is ok, but takes a very long time.

    you will also need to grind down the lip around the last element at the 2-5 o'clock position so that you don't hit the aperture tab in the camera too.

    as for performance, the non-ssc version is not really as sharp as the nikkor-s 55 1.2, but has nice,warm colours. the SSC version has very nice, punchy-yet-natural colours that were very real to life. SSC is better than the nikkor s 55 1.2.

    both of them fell short of the nikkor 50 1.2 AIS though. especially so for skin tone rendition.

    I like old lenses and I ve also played around with Minolta MC, Zuikos, Fujinons and M42 mount conversion. telephoto's are the easiest to convert and usually anything 50mm and above that isnt too fast can be converted.


  5. one more point. The infinity adjustment screw will help you by about 1/2 a meter or so.. you really need to grind the thing down by 2-3mm to get infinity focus. difference between nikon and FD register distance is 3.5mm.

    i also dd one to EOS. not as much to shave so its alot easier. but then the EOS mount is almost too wide to allow you to drill holes for the screws. i ended up having to use a very strong metal adhesive..

  6. I have this same lens, but I'm using a Canon FL-NIKON F converter ring on my nikon D7000, and when I open the aperture to 1.2 everything looks blurry, only look good from 2.0, can you explain to me whats happening ? , Thank you very much

  7. I believe your problem is that you are using an adapter. Think about this: Your Canon lens, when mounted to the native Canon camera sits a specific distance from the film plane, 42mm to be exact. This distance is called the Flange Focal Distance. Nikon systems have a Flange Focal Distance of 46.5mm. A difference of 4.5mm. This means if the Canon lens was placed in front of a Nikon camera, in order to focus correctly, the lens would need to be 4.5mm closer to the sensor that the Nikon lenses. Well that puts the lens INSIDE the mount (granted in most cases, lenses won't physically fit INSIDE the mount). The only solution for this would be to actually mill off some of the lens barrel and refit it with a Nikon mount. Even then you run the risk of the rear optics interfering with the mirror. NOT recommended if this is new territory for you unless you don't mind risking your gear.

    So when you put a mount adapter on a Nikon camera, to use FD lenses, you have actually ADDED distance between the lens and the film plane/digital sensor. The effect of doing this is the same as placing extension tubes on a lens. As your lens is moved beyond its designed Flange Focal Distance, a.k.a further away from the sensor, you will lose infinity focus and ability to focus on objects even a few feet away, or inches, depending on how far the lens is. Granted, with an adapter, you won't have added that much distance but it only takes a 1mm or two to lose focus even within 20 feet depending on the optic.

    My guess about your focus issue is as you stop down, your depth of field is greater so you may appear to have some focus but not much I would imagine. Are you able to focus on objects far in the distance? Theoretically, you shouldn't be able to.

  8. Hello! Do you have some photos shot at f/1.4, 1.8, 2?