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02-02-2012, 10:34 AM   #1
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cheap 1.4x or 1.5x teleconverter in fd or md mount?

I'm wondering if anyone has any ideas for cheap 1.4x or 1.5x teleconverters in canon fd mount or minolta md mount. I'm looking for cheap because I plan on trashing it to make a pk - fd adapter and a pk - md adapter. The idea is to get better quality glass than your typical 30$ ebay adapter (which so far as I know is the best that is commercially available). I don't really want to trash a 100$ lens though. I am making my first attempt with a vivitar 2x in canon fd mount. I have had a lot of complications but it still seems like I have a chance of completing it successfully.

I did get a kiron 1.5x fd mount for 9$ from b&h but they seem to be somewhat rare (it was rated an 8 which is well worn so that my have contributed to the low price). There are not enough on ebay to get a good idea what one typically goes for should I find a md one or should I trash the fd one I have. I'm almost thinking I should give a few tries with cheap 2x ones before I attempt a more expensive or harder to find 1.5/1.4 one.

So does anyone have any ideas of ones that can be found cheap?

On a side note, the 2x I am working on will focus to about 10 feet at 28mm and about 30 feet at 70mm on a vivitar 28-70mm with self contained auto focus (I have no idea if this lens works right so that is another variable). On my vivitar 90mm 2.5 it focuses out to about 100 feet. I can still cut it further to try to get closer to infinity (I just got it to 100 feet last night, it was at about 30 feet on the 90mm). Also, when the lens would only focus to 30 feet on the 90mm, it would focus to infinity on a 300mm. I have to wonder if what range the teleconverter is optimized for is a variable too. As far as I know the kiron is optimized for two lenses that fall between 28mm and 150mm. I have no idea about the vivitar 2x but would like to know.

02-02-2012, 12:23 PM   #2
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After a little clean up and the use of a golf scope to judge distance, it looks like the 90mm focuses out to about 100 yards.
02-02-2012, 12:36 PM   #3
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i am not sure that they will be any better than the cheap adaptors that are already out there for $30.

having said that, you really don't care what Teleconverters you get, i.e. pentax canon etc, you need the following things \
-enough mounts to get the combinations you need,
- enough bodies to mount the lens and body mounts to (2 or 3 if you need a spair)
- enough elements to maje 2 functioning TCs
Mix and match and shim as needed
02-02-2012, 01:33 PM   #4
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With canon fd teleconverters (at least the 2 I have and as best as I can tell from online pictures, others), the rear mount is a single machined unit with the body. The only way to do it is to cut back the lens. I am there for just taking a canon teleconverter, cutting back the lens, and attaching a m42-pk adapter. Perhaps it has something to do with the easiest way to make the reverse bayonet type mount fd uses.

All my pk teleconverters have the front and rear mounts screwed on as a separate unit. I'm kind of hoping that is the way minolta is as it would be a lot easier to just switch stuff out and shim as you said. All the canon fd lenses I have converted have had screw on mounts so I haven't figured out why teleconverters are not that way.

I'm still lost with how teleconverters work so I am just going to experiment with 2x ones for now as they are cheap. For instance, with my quantaray auto focus k mount teleconverter, and the 18-55mm kit lens, at 55mm, it will only focus to about 25 feet (no infinity). With my sigma 28-200mm AF lens, it will focus to infinity throughout the range though? These are not modified, just regular k mount stuff. My vivitar MF 2x k mount does the same with these 2 lenses. It's hard to know how far you have to cut the mount and hard to know if you have infinity focus when proper equipment doesn't always focus to infinity. This is something I just discovered so I haven't really planned further. I assume that teleconverters being optimized for a particular focal length must play some part but what part escapes me.

I guess if I get lucky and get something to work with better image quality than Chinese glass then great, and if not, It didn't cost more than adapters so I have only wasted my time.

Are you saying that they will probably not be better than the Chinese ones because I am looking for cheap ones? I may be willing to spend more down the road if I get cheap ones to work well. I was also hoping the old manual glass can be cheap but good thing might help (though that seems to apply to 2x ones, not 1.4x ones which are still expensive).

02-02-2012, 02:00 PM   #5
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don't you have one of the Chinese adapters? I could swear you had posted about it one or twice. If yes, here are a couple of shots with the vivitar converter. They were taken when the 90mm lens would focus up to 30 feet or so. now it will focus to 100 yards. Regardless if you have an adapter or not, what is your opinion? Fyi I had issues taking sample pictures due to motion blur (using an ist-ds so no SR and hand held lens to the camera in lower light).
I'll set up for test shots when I get a mount attached (waiting on another m42-pk from ebay and maybe tools to drill and tap for screws).
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