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08-20-2011, 07:27 PM   #16
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What are the possible definitions of Automatic when used with extension tubes? Does it always mean automatic aperture or is there a different automatic feature on film cameras that it could mean?

I'm asking about these tubes in particular because they were included in an auction I won and I want to know if I should be happy to have them or mildly excited.

Vivitar Automatic Extension Tube AT-22 36mm with a 20mm & 12mm attached to that

08-20-2011, 10:41 PM   #17
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There are a few kinds of "automatic" tubes. What you have, the Vivitar AT-22, uses a KM mount with mechanical aperture linkage. I'm not sure with your K200D, but on my K20D I would put the camera in M(anual) mode and use the Green button to meter and shoot. With any PK-bayonet mount lens and those tubes, this stops-down the iris. These tubes force you to set the aperture manually on the lens; it's the stopping-down that's automatic. Someone shooting a camera that supports TTL flash will have flash automation too.

Another kind of PK 'automatic' tubes are A-type, with electrical contacts as well as the mechanical linkage. A-type tubes and lenses let you control the aperture from the camera, whether in an auto-exposure mode or by twisting an e-dial. They also support p-TTL. AF tubes are A-type with an AF drive shaft also; but AF isn't real useful in macro work. Then there are M42 'automatic' tubes, also with a mechanical linkage somewhat similar to your Vivitar tubes but only for M42 cameras. Such tubes support no automation on PK SLRs.

Let's see, should you feel wildly happy, or mildly excited, or depressed? [/me spins the wheel] That depends on how much they cost. Yours are better than the el-cheapo non-auto tubes that go for under US$10 per set, shipped from Shanghai. Yours don't provide A-type control nor AF linkage, which cost (much) extra. I just checked eBay sales; I'd say yours are probably worth around US$25-35 or so. If you're shooting in ambient light or don't mind fiddling with flash to get exposures right, I'd say you can be pretty happy!
08-21-2011, 06:04 PM   #18
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I would say meets expectations. The term automatic gets confusing and I was hoping that automatic meant something more. But it's not a big deal since I only own a few lenses with auto aperture. Although it would have been nice to use my A50 with a short tube at an aquarium last weekend. And not use the green button when I'm chasing the fish and manually focusing. Catch in focus = lifesaver.
08-21-2011, 06:56 PM   #19
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Hey RioRico do you anything about a Vivitar A 2x teleconverter? I just bought one. Is it easy to take the glass out?

08-21-2011, 07:25 PM   #20
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QuoteOriginally posted by krp Quote
Hey RioRico do you anything about a Vivitar A 2x teleconverter? I just bought one. Is it easy to take the glass out?
with a hammer it is
08-21-2011, 07:25 PM - 1 Like   #21
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QuoteOriginally posted by abacus07 Quote
I would say meets expectations. The term automatic gets confusing and I was hoping that automatic meant something more.
It would be cynical to think that 'automatic' means whatever a maker wants it to mean, eh? But with tubes and TC's, it usually means just the mechanical linkage.

QuoteOriginally posted by krp Quote
Hey RioRico do you anything about a Vivitar A 2x teleconverter? I just bought one. Is it easy to take the glass out?
Sure, once you get the blowtorch and carborundum drill, it's easy as cake, a piece of pie.

Actually it helps to have a lens spanner, but you can probably get away with just a measuring compass, anything with a couple points that can be secured into place. Or you might not even need such, just a good pair of pliers. The glass in a TC is set in an inner tube (not the rubber tire kind!), sometimes with notches for a lens spanner, sometimes extending just beyond the support structure. If the glass holder is sticking out, grab it with pliers; if it has notches, use the lens spanner or compass. Twist until it's unscrewed. Presto!

If yours is an actual A-type, it has contacts on its base. The base might be painted or not. If unpainted, no problem. If painted, you should probably sand the paint from the TC's bayonet so it makes good contact with the camera mount. And be sure those contacts are clean; I use a Teflon eraser for that.

What to do with the glass you've removed: I keep mine. Never know when it'll come in handy. And there's a trick you can play with TC's: remove the glass, flip it around, and put it back, reversed! Now you have a focal expander. Theoretically, it works just the opposite of a TC, reducing the focal length and increasing the speed of whatever lens is mounted on it. Does this actually work? I dunno, I haven't tried it yet. Maybe next week.
08-22-2011, 09:56 AM   #22
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RioRico - thanks again for the help (you've helped me a couple times in the past as I've been getting going with this stuff). my 50 is an M lens not an A, but I think I will follow the general advise of doing work with these types of altered setups in a controlled studio setting with a tripod as opposed to out in the field. cheers!
08-22-2011, 10:25 AM   #23
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QuoteOriginally posted by yeatzee Quote
with a hammer it is


08-22-2011, 10:27 AM - 1 Like   #24
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QuoteOriginally posted by pentaxk1000denver Quote
RioRico - thanks again for the help (you've helped me a couple times in the past as I've been getting going with this stuff).
Shall I beg for a thumbs-up somewhere? Naw, I won't beg...

QuoteQuote:
my 50 is an M lens not an A, but I think I will follow the general advise of doing work with these types of altered setups in a controlled studio setting with a tripod as opposed to out in the field. cheers!
Yes, that M50 reversed definitely calls for studio work. Put it non-reversed on short cheap tubes and it'll do fine for close (not macro) field work. I just now put my M50/1.7 on the thinnest PK macro, about 12mm thick; working distance is 14-24cm / 5.5-9in at ~1:3 magnification, which should do for many floral etc shots. If I add a thin 7mm tube section, working distance becomes 12-17cm / 4.75-6.75in at almost 1:2 magnification, good for many bug shots.

And note that 1:2 mag only eats about 1 stop of light. I'm using bits from one set of cheap PK tubes here, the kind that sell for under US$10 shipped from Shanghai. This is a real cheap and easy way to work close with an existing lens.

QuoteOriginally posted by yeatzee Quote
with a hammer it is
I prefer a .22 LR round, carefully administered.

Last edited by RioRico; 08-22-2011 at 12:01 PM.
08-22-2011, 10:28 AM   #25
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There are some TC's out there wherein you can easily remove the lens or it was designed so you can remove the lens.
I know that I got one but kinda forgot what it was.
It was an LBA buy, when I saw it listed and found out that the lens was designed to be easily removable.
It is an old TC and not the new ones.
08-22-2011, 12:49 PM   #26
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QuoteOriginally posted by GerryL Quote
There are some TC's out there wherein you can easily remove the lens or it was designed so you can remove the lens.
I remember seeing one listed a few weeks ago, called a Vari-Macro or something like that. I've been looking for a variable-focusing TC to gut, to use as a focusing helicoid for EL's. But that one just goes from TC to tube.

My humble comments on TC's:

* For converting to tubes, non-auto TC's without even a mechanical linkage aren't worth de-glassing IMHO because cheap tubes are cheaper.

* Simple auto TC's can be worth de-glassing IMHO because similar tubes that I've seen are rarer and costlier. And see my proposed trick below.

* A-type TC's are worth de-glassing. Be sure the contacts are clean, and if the base is painted, you may need to sand off paint for good electrical contact.

* A trick I haven't tried yet: pull the TC's elements and re-install backwards. Now it's a focus expander, with shorter focal length and wider aperture. Right.

I save the glass I've pulled from TC's. Who knows, I may figure out some tricks with them eventually. Of course, I save all sorts of old camera junk. Surprising things can be done with optical detritus stuffed into bellows, eh?
08-22-2011, 10:31 PM   #27
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QuoteOriginally posted by RioRico Quote


I prefer a .22 LR round, carefully administered.




My CZ USA 452 w/ 4x32 scope would have no issue with that task. If I didn't live in the 'burbs i'd give it a shot!

(no pun intended)
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