Just finished converting the FD 85L f/1.2L. Lots of work but worth it for a <$300 lens.

It is lighter than EF 85L, has fantastic manual focus, real easy to use w/ Live View (5D MkII) and surprisingly sharp at f/1.2.

See for yourself (f/1.2):

It is a portrait lens, so here is one. Again ... I just had to try it.

f/1.2:

Convert one more and I'll buy it.

Shuko wrote:
Convert one more and I'll buy it.

Not everybody is OK with a lens not focusing to infinity ... Mine focuses up to ~10m or so because I choose to keep the same lens configuration as in the FD setup. It might be possible to adjust for infinity focus (i.e. Rokkor method), I just don't know how yet.

Best is to do it yourself (not really difficult and very self rewarding); if I have time I will post a how-to.

congratulations on your project!

I would love to see a how-to post also.

Great work. I would also love to see a how-to.

Oooh, nice!
I'd like one, but the cost to convert dissuades me.

norrad wrote:
congratulations on your project!

I would love to see a how-to post also.

+11111111

congrats

I'd love to see a proper comparison between this lens (FD 85 1.2 SSC or 'L') and either the EF 85 1.2L or maybe EF 85 1.2L II.

I had the FD 85 1.2 SSC and EF 85 1.2L and found no real optical difference between them but I never did compare them directly in a methodical way and I suspect this is the only way to show up minor differences.

I suppose I'm questioning if there is really any point in doing the conversion other than possibly saving some money. I don't mean to be critical, just qurious.

JJ

JohnJ wrote:
I suppose I'm questioning if there is really any point in doing the conversion other than possibly saving some money. I don't mean to be critical, just qurious.
JJ

Since it is a time consuming conversion, this is a very valid question. My motivation was:

Weight: EF = 1,025g (2.3lb) ; FD = 680g (1.5lb)
Compactness: EF = 84mm ; FD = 71mm
Manual Focus of FD is great
Cost: EF ~$1,000 / $1,500 ; FD = $300 for an E+ copy

Alex,

You've mentioned that the conversion isn't difficult but still a lot of work and a time consuming process. What part of the process has been the most difficult? The most time consuming?

I wasn't as lucky as you, so I purchased my 85/1.2 SSC a bit on the high side. As a result, I want to make certain that I understand the conversion process thoroughly lest my ineptitude destroy the lens.

I haven't seen any fd 85/1.2's go for $300. Not saying there haven't been any, but it seems as though the going price is a little higher. If I am wrong please point me in the direction of some $300 FD 85L's, I want one.

I've seen them go for $450-$500, but not in E+ condition.

Alt lens conversion is an idea I keep toying around with. I do currently have one FD lens and have considered and passed on others. This and the rokkors show the potential, I guess I'm still worried about the problems with clearances and focusing. What conversion kit did you use for your 85L? Any mirror problems?

hdan wrote:
You've mentioned that the conversion isn't difficult but still a lot of work and a time consuming process. What part of the process has been the most difficult? The most time consuming?


Most difficult: none really. I was just careful not to damage the rear element when resizing it and removing all the mechanical guts. Plastic/tape protection helped.

Most time consuming: figuring out how the aperture works, and measuring everything to keep the original FD configuration. Then, resizing rings/spacers with a file. I wanted to go slow to avoid big mistakes.

Here are some critical measurements (85L, not SSC) I made:

ewadler wrote:
I haven't seen any fd 85/1.2's go for $300. Not saying there haven't been any, but it seems as though the going price is a little higher. If I am wrong please point me in the direction of some $300 FD 85L's, I want one.

E-bay isn't always the best place to shop. I am lucky enough to live in Tokyo, so I go to fly market and used gear photo shops. $300 ~ $350 is quite common for a 85L.

dancam wrote:
Alt lens conversion is an idea I keep toying around with. I do currently have one FD lens and have considered and passed on others. This and the rokkors show the potential, I guess I'm still worried about the problems with clearances and focusing. What conversion kit did you use for your 85L? Any mirror problems?

This not a kit, this is pure DIY.

If you want infinity focus and original FD configuration, the rear element needs to be at 1.7mm above EF mount. Typically up to 1.2 ~ 1.5mm is OK before getting in Mirror issues. Mine is set at 0.7mm to avoid any problem. Next step is either to understand if we can adjust the lens infinity (a la Rokkor) or remove another 0.5mm to gain focus up to 15m.

AlexTokyo wrote:
This not a kit, this is pure DIY.

If you want infinity focus and original FD configuration, the rear element needs to be at 1.7mm above EF mount.

That sounds about right. My EOS/FD50L rear element is at about 2mm above the EF mount, and is pretty much exactly placed in relation to the main lens assembly at infinity.

JimBuchanan wrote:
That sounds about right. My EOS/FD50L rear element is at about 2mm above the EF mount, and is pretty much exactly placed in relation to the main lens assembly at infinity.

Here is where the 1.7mm comes from, given an EF mount total length at 6.67 mm, from mouth to ring base.

We want FD config, so according to the above diagram we want the rear element at 10.40mm "altitude" vs screw base. This gives:
- Screw base 0.00 mm
- Original spacer ring (after removing the little gouge) 2.00 mm
- EF mount total 6.67 mm
- Distance EF-RE X mm
- Rear Element 10.40 mm

=> Distance EF mouth / Rear Element X = 1.73mm

It will take me some time to go through all this. Thank you, for the detail. I printed off the drawing earlier, and its pretty close, if not exactly, my findings.

My "about 2mm" measurement includes the rear element mount frame, as thats the surface that gets hit by the mirror and what everyone is concerned about.

One qualification is the thickness of the EOS bayonet, one starts with. Mine are 8.23mm inward offset from the camera mount face, which may be different.

Another is where one assigns the 42mm register zero point in the FD lens. I think your right on it, according to my measurements, but who really knows?

My comments here are about the FD50L and maybe should be in the FD50L thread, but I think the method is the same as and related to the FD85L, given my supposition that the rear element in both lenses is the same distance from the sensor (to be confirmed). Matching the infinity sharpness and original spacings was a long iterative process. I made the rear element in a M42 thread frame, so as to be able to adjust the placement. If I threaded the rear element in (away from the sensor) far enough to have the 5D mirror clear it, the main lens group would be closer than original spacing and be close to touching the rear element. I push the rear element out toward the sensor, and the main group would need to be pushed out (away from the sensor) for an increased space from original. I always do initial conversions with 2 lenses, using one as a reference.

I think we are on the same track.

Thanks!

JimBuchanan wrote:
Another is where one assigns the 42mm register zero point in the FD lens. I think your right on it, according to my measurements, but who really knows?


A guy modified his 300D to accept FD lenses. He took his "Flange" base at the same point than the diagram above, and his body/lens combo is focusing to infinity correctly.

Overall, it makes sense: this is precisely where the body flange touches the lens mount. Done deal as far as I know.

Hope that helps,
Alex

PS: 42 is actually 42.14mm, and EF is 44.14mm. Still a 2mm difference :-)

I understand now. You start your measurments at the screw base of the lens body and get 10.4mm distance for the rear lens element. I get more than a millimeter more.

Besides the fact we are talking about 2 different lenses with a very similiar mechanical build, I just realized a big difference. You state your lens doesn't focus past 10 feet, neverless to infinity, and mine does. That would explain the different measurments we get. However, regardless of focus distance, the rear element placement never changes on the FD50L or FD85L.

JimBuchanan wrote:
You state your lens doesn't focus past 10 feet, neverless to infinity, and mine does.


My 85L focuses actually up to 10 meters (33 feet). Because: 1) I wanted to avoid mirror issues w/ the rear element and 2) wanted to keep the same original FD design (distance between rear element & last next group).

I saw in a different thread that adjusting the entire lens to gain infinity while not moving the rear element is actually a bad idea, since the last lens group could easily hit the rear element (convex/convex contact). What that means is to reach infinity w/ 85L one must either have a shaved mirror or to alter the original FD lens setup. I am not ready for either option yet.

JimBuchanan wrote:
That would explain the different measurments we get.

Not really. The 10.40mm is for proper infinity focus. The difference we get is because we are talking about 2 different lenses.

This might be the most interesting and treasured lens in my entire lineup, but it is definitely hurt by the mirror issue. As the rear lens position is not affected by moving the focus ring, I cannot even use the Live view mirror lock up trick on the 5d2 to counter the problem, as I can with the Rokkor. I can only hope one of you technically bright guys here eventually will have an epiphany...