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July 4th, 2006, 02:00 PM | #1 |
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Canon FD lens Actually working on HD100
I've been working on this project since NAB, and finally got a prototype working. This is NOT gaffer tape engineering, but a real mount. The lens will focus to infinity, and the iris works correctly. So first, here are some pics of a mounted Canon 50mm F1.8 FD on the hd100
http://71.98.60.159/50mm/index.html and a link to some images from the glass on the camera http://71.98.60.159/50mm/sample_images.html So the bad news is its not an adaptor you can put onto the lens yourself, then mount to the camera. I actually had to fabricate a 1/3" lens mount, and connect the canon lens to it. The clearances are such between the canon and the JVC that making a reliable & interchangeable adaptor is not likely. The outer part of the back of the canon is almost exactly the same size as the whole in the JVC lens flange. Even in stainless steel, I would not count on a realiable adaptor that would go JVC flange->short tube->canon body mount. Compounding the problem is that the locking lever on the JVC mount is above the locking collar of the body, meaning you would have to also work around that, its that close. I also had to perform some extensive mods inside the lens in order to remove the click stops, and to make the iris work correctly - as you move the iris ring, the iris moves as expected without the lens being in the "mounted" postion. Normally, a canon lens won't do this without having both the lens mount in the mounted position and one of the rear lever pins pushed over. In attaching the mount, I had to remove both of those levers. So like I said, it required some extensive mods to make work, and this glass will never work on a SLR again although I don't think that is an issue here. This should really be considered a conversion rather than adaptor. All of that said, the lens works nicely. The common plain 50mm F1.8 will focus to just under 2ft (.66m) continously from infinity. While this isn't a true macro, its close. Note that I can nearly fill about 1/3 the frame with the end of my finger. The lens wide open has a soft, diffused look. this could be do to some shinyness on the adaptor, but once the lens is closed down to f4, its much sharper and the flare seems to be gone. It overall looks nice. At F2.8, there is some flare/diffusion, but sharper than wide open. Another upside, no breathing. You can rack focus from 2ft to 20ft and nothing moves. This is nice. Chromatic Aberation does exist with this lens, but its a soft pleasing circular pattern that goes evenly around the point rather than the stock lens's up/down pattern. So I have a 50mm 1.4 that is next to mod. Its an older breech mount, which I think will prove much easier to mod because its not the FD mount with its built in rotation of the mount. I'm also in the look out for a 20mm and 85 1.8 as possible other candidates. Q1: Will I mod your lens ? at this time no but its certainly a consideration in the future.This will have to wait until I can fabricate a 1/3" mount I am satisfied with, and in small volumes. The next part of this answer will be, can I do it for a price that makes sense, which again depends on fabricating mounts, and the lens in question. Some glass like a 200 2.8, 300 2.8 are prime canidates for modding, and have been for other formats like PL or Arri mount. The price to mod a lens in the $300-$1200 range will look a lot different than the same price to mod a $15 lens. I might consider simply stocking & selling modded 50mm F1.8's too. Many options here. The bottom line for me is that if I get enough interest from people who are really willing to pay for the work, then I can invest in what I need to do this and produce a quality product for a reasonable price. Q2: Will I sell the 1/3" lens mount by itself ? no. even if I am able to make 1/3" lens mounts I'm happy with, there is still extensive modifications to be made to the lens in order for it to work. This is not a matter of just putting the flange onto the back of the canon and off you go. There are even differences in the canon lens mounts that may require the 1/3 mount to be modified depending on the glass you are mounting to. Q3: How does the focal length work out ? The focal length of the lens is unchanged. a still lens at 50mm will have the same angle of view that the stock lens has at 50mm. There is no glass added in the mod, nor is this a shoot off a ground glass project like RedRock Q4: How does the iris work ? the iris functions as expected, it opens and closes as you turn the iris ring without the quirks the FD mount normally has - ie if the lens is unmounted, it moves to midposition and locks there. Mounted it normally sits wide open. The click stop has been removed so that the iris ring turns continuously. Q5: Is the image flipped or upside down ? No. the image appears normal and correct So there you have it. It can be done, but not simply. its great to have an option available to mount FD glass, as I've always liked its look. Steve Oakley http://www.practicali.com |
July 4th, 2006, 02:13 PM | #2 |
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modding
Quick question - I ordered some FD glass, but won't have it for a week or 2. How tricky is the mod to remove the aperature click-stops? I'm fairly handy and I've ripped lenses apart and put them back so I'm not shy about it, just curious (without having looked inside yet) what it'll take. Thanks!
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July 4th, 2006, 02:20 PM | #3 |
Obstreperous Rex
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Wow, that's amazing Steve. Would you mind if I attached your photos directly into your post? Or would you prefer that folks just hit your site. Well done,
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July 4th, 2006, 02:27 PM | #4 |
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Hi, as far as removing the click stop, its a peice of plastic buried in the lens. You have to remove the back of the lens past the iris ring to get at it. once there, its two screws and its gone. Putting it back together is the challange since there are several springs and interlocking parts to make the FD lens mount work. I've worked on some other lenses, and the FD mount is more complicated than most.
If some one wants to post the pics to the board feel free as long as the moderators are ok with the bandwidth. Steve Oakley www.practicali.com |
July 4th, 2006, 02:35 PM | #5 |
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Thanks!
Steve, thanks for the quick and detailed reply!
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July 4th, 2006, 04:59 PM | #6 | |
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July 4th, 2006, 05:01 PM | #7 | |
Obstreperous Rex
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Quote:
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July 5th, 2006, 10:39 AM | #8 | |
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Quote:
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July 9th, 2006, 12:15 AM | #9 |
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New Images from lens
Ok shot some more stuff, labeled them in PS as to apeture
http://71.98.60.159/50mm/index.html http://71.98.60.159/50mm/index.html Wide open, the lens diffuses with this soft filter effect. nice if you want it, otherwise you need to shoot it at around F4 for it to look normal. Also I saw some funky red flares on the bottom of the image sometimes - this is similar I think to another user with a nikon adaptor. although I'll try some black paint, it almost appears that the flare is a reflection from the from of the optical block, which means not solvable easily. also keep in mind, with something like a 6X magnification factor, the 50mm lens is equal to 300mm in 35mm still camera lens terms, so those people are a good 300-400ft away in the full length shots.Amazing this short lens has so much reach. Steve Oakley |
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