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04-22-2009, 09:17 PM   #16
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QuoteOriginally posted by HermanLee Quote
Wow, cool!

Will this method work with any TC, ex: Tamron 1.4x, or Vivitar Macro 2x TC ?

Now, how is the photo looks like without the glass element? Will it be the same or even better?

Thanks again.
The Vivitar 2x Macro Focusing Teleconverter is constructed so that removing the glass is much more difficult. I have read about people simply breaking the elements but you risk offending the lens gods.

04-23-2009, 04:36 AM   #17
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All I can say is what a waste of a good teleconvertor...
Probably cheaper to buy something like the Kenko AF extension tube.
I can't bear to do this to my gear, especially if it is in good working condition.
04-23-2009, 05:24 AM   #18
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QuoteOriginally posted by pcarfan Quote
Dave

Thanks. Where do I get these sticky-back aluminum foils ?
I don't think it matters much what you use. I'd try regular (maybe heavy duty) kitchen foil first.

Iowa Dave
04-23-2009, 09:46 AM   #19
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QuoteOriginally posted by SOldBear Quote
Not exactly.

If you combine your FA 50mm macro/2.8 with an unmodified 2X TC, you'll have a 100mm macro/5.6 with 2:1 magnification ratio. IQ will suffer, however.

If you combine your FA 50mm macro/2.8 with the modified 2X TC, you'll have a 50mm macro/2.8 with about 1.5:1 magnification ratio. IQ remains more or less the same.
Why is only 1.5:1 mag ratio with modified 2xTC ?

04-23-2009, 11:08 AM   #20
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great

Great. This is what I was looking for a long time.

@pcarfan - the instruction pics are very useful. So the actual optics is in a holder in those TCs? If the black piece holding the optics is screwed onto the lens the way you showed, I believe I can take it out from a TC. I lack precision and mechanical skills, so always afraid to unscrew lens or any other delicate object.

@newarts and pcarfan - i have a DA 50-135. I want to use it for macro. Now if I modify the TC in this way, the lens/TC combo will work right? I do not care about autofocus. I will do manual focus. All I need is some apertue control i.e. the lens should be wide open so that I can see through the viewfinder and focus. DA does not have aperture ring. And this has been my problem. My PK extension tubes make the DA keep its aperture at its smallest opening. As a result I can not see and focus properly. Very little light passes through it. Now you guys are saying that this modified TC / extension tube will keep the DA at f2.8, right? I do not need further stop down for greater DOF. I will be happy with f2.8.
04-23-2009, 01:03 PM   #21
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QuoteOriginally posted by HermanLee Quote
QuoteOriginally posted by SOldBear Quote
If you combine your FA 50mm macro/2.8 with the modified 2X TC, you'll have a 50mm macro/2.8 with about 1.5:1 magnification ratio.
Why is only 1.5:1 mag ratio with modified 2xTC ?
Because you need about 50mm more to bring the magnification from 1:1 to 2:1. The TC (now an extension tube) is only about half that long, or less.

Also, at 1:1, the max aperture of the 50mm macro/2.8 is actually 5.6. At 1.5:1, it is 6.3. Focusing will be difficult.
04-23-2009, 01:14 PM   #22
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QuoteOriginally posted by creampuff Quote
All I can say is what a waste of a good teleconvertor...
Probably cheaper to buy something like the Kenko AF extension tube.
I can't bear to do this to my gear, especially if it is in good working condition.
Maybe....

But what if the teleconver is not good , and it comes for free....

I somehow end up with 7 TCs as part of package deals:

- a 1.4X AF and a 2X AF Tamron, which I keep.

- a good PK-mount 2X, which I keep, but modify to use with Nikkor lenses.

- 2 PK-mount 2X and 2 PKA-mount 2X with no good optics. They are now extension tubes.
04-23-2009, 02:59 PM   #23
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QuoteOriginally posted by kibipod Quote
Great. This is what I was looking for a long time.

@pcarfan - the instruction pics are very useful. So the actual optics is in a holder in those TCs? If the black piece holding the optics is screwed onto the lens the way you showed, I believe I can take it out from a TC. I lack precision and mechanical skills, so always afraid to unscrew lens or any other delicate object.

@newarts and pcarfan - i have a DA 50-135. I want to use it for macro. Now if I modify the TC in this way, the lens/TC combo will work right? I do not care about autofocus. I will do manual focus. All I need is some apertue control i.e. the lens should be wide open so that I can see through the viewfinder and focus. DA does not have aperture ring. And this has been my problem. My PK extension tubes make the DA keep its aperture at its smallest opening. As a result I can not see and focus properly. Very little light passes through it. Now you guys are saying that this modified TC / extension tube will keep the DA at f2.8, right? I do not need further stop down for greater DOF. I will be happy with f2.8.
Ext. tube with A contacts ( the 6 electrical contacts/dimple), will keep the aperture open AND allow you to use the camera to control aperture. So, if the 50-135 doesn't have the aperture ring, then you need one of these. You can choose whatever aperture setting you want off of the camera, and the camera will keep the lens wide open so you can focus. Flash will work in P-TTL.

Extra explanation: You have two problems. One keeping the aperture open for focusing, and second in not having the aperture ring. Purchasing an 'auto' TC with no contacts will keep the aperture open for focusing even if the aperture ring is stopped down, however, as your lens doesn't have the aperture ring then you need the TC with 'A' contacts.

My lens has the aperture ring, however I want the A contacts to be able to use P-TTL flash and the camera body to change the aperture and not having to fiddle around with the aperture ring.

Hope this helps.

04-23-2009, 08:09 PM   #24
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I got it finally. Thanks.

All I need now is some A TCs showing up in the marketplace here
04-24-2009, 09:38 AM   #25
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QuoteOriginally posted by creampuff Quote
All I can say is what a waste of a good teleconvertor...
Probably cheaper to buy something like the Kenko AF extension tube.
I can't bear to do this to my gear, especially if it is in good working condition.
I would've thought so too, until I started looking for them! Kenko AF extension tubes are pretty rare around here and end up being pretty expensive if you find them new.

They also don't AF (which is fine, but weird that they call them AF tubes!).

Much easier to find old scratched up TC's going cheap... but then there's work involved

Thanks pcarfan!
04-24-2009, 05:01 PM   #26
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QuoteOriginally posted by kibipod Quote
I got it finally. Thanks.

All I need now is some A TCs showing up in the marketplace here
FYI: Even when I have the F4 sigma mounted, the aperture can be lowered to f1.2, so there is some issue with the aperture info. however, the lens+ext.tube combo works fine, P-TTL is acceptable.

Also, FWIW, the 540 flash with the diffuser pulled down works better in certain situations, as straight flash with the ext. tubes gives a faint circular glow against dark background when taken at a steep angle. Also, 2 TC for a total of 50mm works great, 4 for a total of 100mm has some faint light casts. So, i may put the other two in the marketplace.


@farfisa....you are welcome.


P.S: An un cropped image with the sigma 100-300 and ~100mm ext tube with 540 flash in P-TTL handheld. PP in CS2. I am still learning,....once I get the hang of it, it will get better.


Last edited by pcarfan; 04-24-2009 at 06:15 PM.
04-30-2009, 09:27 PM   #27
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pcarfan,

I am wondering if it is possible to do the conversion on this teleconverter?

The camera facing part does not have enough space for the plier to get a grip, but it does have those two slot on either side of the lens.



On this side of the tele, there is about 1-2mm of grip space, but that would mean the lens have to be remove in this direction?

04-30-2009, 11:15 PM   #28
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Buy a cheap dial caliper and use its claws in the slots to remove the retainer.

This is what I've been using to disassemble/assemble lenses. There is a retail Harborfreight store a few miles from my house; the caliper is on 50% off sale almost every other week.

05-01-2009, 04:15 AM   #29
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The caliper idea is excellent....

song_hm, that TC will keep the aperture open for focusing (auto TC), however it doesn't have the A contacts so you would have to set the aperture in the aperture ring, so your lens needs an aperture ring. P-TTL flash will not work....
05-01-2009, 08:20 PM   #30
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QuoteOriginally posted by SOldBear Quote
Buy a cheap dial caliper and use its claws in the slots to remove the retainer.

This is what I've been using to disassemble/assemble lenses.
Thanks for the tip. I'll be taking a trip to the hardware store. Based on your experience, this TC should disassemble toward the rear after removing the retainer?

QuoteOriginally posted by pcarfan Quote
song_hm, that TC will keep the aperture open for focusing (auto TC), however it doesn't have the A contacts so you would have to set the aperture in the aperture ring, so your lens needs an aperture ring. P-TTL flash will not work....
Understood. I was planning to use with it with my M lenses.
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