GH2 Canon FDn 15f2.8, 20f2.8, and 24f2.8 on a GH camera?

Good to know. I have several of the older breech lock FDs and look to be getting a Speed booster soon. I have been using one of the original SLR Magic 12mm f1.6, but would like another wider FD to complete my set (24 f2.8, 35 f2.0 50 f1.4, 85 f1.8).

If you get a chance, please post some pics or clips with that 15mm when you get it - thanks.

Danny

Greg_E said:
Not really. I have a Zeiss Touit 12mm for my Fuji camera (1.5x crop), it also should be a fisheye, but it is simply an extreme wide on that camera. Since they sample only the central portion, you only get the light rays that follow that central portion, you could tape off a big hunk of the front lens and never know the difference on a crop sensor (and it might not be a bad idea to tape it off to prevent flair). This is overly simplified, but gives the proper idea.

That said there may still be some curvature, but I don't expect it to be worse than an old style 30mm on a 135 film camera, or worse than a 20mm on the same film camera when I have it mounted to the speed booster (if said speed booster ever ships) and the GH2. Video mode on the GH2 is said to be around a 1.86 crop so 15mm*1.86*.72=20mm equivalent to 135 film, not sure what the real viewing angle will be but you can look it up if interested. I'll almost certainly cut a plastic plug to attach to the front with a cutout large enough to clear with the speed booster to help prevent flair, once I figure out the opening size needed.
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You might want to look at the Rokinon lenses in EF mount and just dedicate an adapter to that lens. But yes I'll get some stuff once it arrives and before I change the mount to EF. Probably shoot some stills on my Fuji and some 1080 video on my GH2 for comparison. I can shoot video on the Fuji, but it suffers from moire really badly, the 60p modes are completely unusable (in my opinion).

Too bad no one makes EF mount conversions for the older breach lock, they are much more solid lenses and if you get the S.S.C versions are basically the same glass and coatings (from what I've read).
 
Lenses arrived... 15mm looks like it will be a really good lens, need to get some pictures/video with it, but I think it will be very good.

The 24mm looks like it will be a good lens, if I get one that is worth keeping! The focus ring on this one has some play in it, enough that I can't keep it. Have to send it back for refund.

It's surprising just how much more solid these lenses feel compared to the 50mm f1.8 or the even cheaper 50f2 that I have. The wider lenses don't feel like plastic blobs like both of these 50's feel.
 
Greg_E, any chance you can throw up some pics (or clips) with that 15mm?

Greg_E said:
Lenses arrived... 15mm looks like it will be a really good lens, need to get some pictures/video with it, but I think it will be very good.

The 24mm looks like it will be a good lens, if I get one that is worth keeping! The focus ring on this one has some play in it, enough that I can't keep it. Have to send it back for refund.

It's surprising just how much more solid these lenses feel compared to the 50mm f1.8 or the even cheaper 50f2 that I have. The wider lenses don't feel like plastic blobs like both of these 50's feel.
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Yeah, been a busy few weeks at work, but I took next week off and should have some time to fool with this rig. Need to get an EF mount for it too, my lens Turbo should be here today or Monday.

One problem that I can foresee is the focus, it goes from 10 feet to infinity in about 10 degrees of rotation. Pretty typical for still lenses, but something to consider if using it without a speed booster (wide normal viewing angle).

The 24mm went back to KEH, haven't purchased a replacement yet.
 
Guess I should have ordered the EF mount for that lens last week, the lens Turbo is here. Also got the plastic needed to cut gears, waiting on the cutter and something to create a disk holder to let me cut the gears. Should have enough plastic to cut gears in three sizes for most of my lenses, at least enough for a couple after the failures that I'm certain to produce. I'm kind of thinking that I want to put two sizes of gears on each lens so I can have two different rotation speeds. Since I'm making my own this is something I can accomplish that other people may not do. Trying to decide on the value vs. time aspect. The 4 inch diameter stuff (120 teeth or 97.6mm) is going to be difficult to work on with my small milling machine. Most of my lenses won't take anything smaller than a 78.4mm gear so I was going to machine 78 and 97 and stack them next to each other on the lenses that have enough room for both, that could give me a 6 speed choice from about 1:1.5 to 1:4 ratios (lens rotation : follow focus rotation). nFD lenses are about 170 degrees stop to stop, or at least the ones I've had are this way. Mamiya 645 lenses are about 180 degrees.
 
So I've been kind of waiting for my FDn to EF mount to arrive before doing much with the 15f2.8 lens, and the weather has been mostly raining too. But the mount is here and now I'll be able to test on both plain adapter and on Lens Turbo. This is the manufacturer's video for changing the mount, just happens to be the same lens I'm converting.

https://youtu.be/CTpxtnQJDXo

Note he shows the older brass, mine is the newer aluminum.

Here is the only problem with doing this... In order to guarantee infinity focus, he cuts the mount slightly short. Normally this isn't a huge issue if you are using this on an EF mount camera. But since this will be used on a mirrorless camera, there is a slight problem. Pretty much all the adapter makers also cut the adapters slightly short to once again guarantee infinity, this starts adding up to a lot of error. For the moment I'll just live with it, but in the long run both the adapter and lens mount will need to be shimmed.
 
Big setback... The 15mm rear element hit the Lens Turbo front element just before the 5 foot mark on the scale... Pretty much renders this lens useless. I say useless because a 24mm lens with booster is going to be almost the same angle of view (17.2mm eqv.) I can probably gain a small amount back by shimming the lens mount, but I doubt it needs the thickness that will allow clearance. Looking like a need 6 thousandths for clearance, and I'm betting the mount is only 1 or 2 thousandths difference.

For those playing along, 6 thousandths is about 2-3 sheets of paper in thickness, that's how small the movement is on the long end from 4.5 feet to infinity. Sometimes hard to conceive of these things until you try to watch it move when you turn the ring those 15 degrees.
 
Some of you may have known this, but I didn't... Apparently these focal reducers don't come set up for the lenses and cameras they are built for. And if you stick any lens spaced approximately correctly in front of them, they work. What I needed to do was loosen the screw in the camera end of the mount. Ñow spin the optics closer to the sensor and test. Best to do this on a tripod, and measure from focal plane to your target so you know what to hit. Since this adjustment is all internal, it's a game of on camera off camera until you are satisfied. It is close now and no more physical interference.

Marty at fdtoef.com told me that 0.001 inch shim is about the most I should try on the lens mount. With a distance this small I may not bother. There are bigger errors to fix with the other adapters that need attention first. And gears to make, and spacers to build, etc.
 
I haven't forgotten about this sample video. I did just stick this on my rig with matte box and follow focus (had to wait for the FF to arrive) and noticed that with the Lens Turbo, the 15mm was vignetting in the corners from the matte box. Looks like I won't be able to use the rotating filter when using this lens and lens turbo because I need to push it that far into the box. Also look like I need to make a new lens gear because the thumbscrew holding the output gear on the FF hits the matte box and I have almost no gear mesh at closest focus.
 
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