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05-17-2007, 08:01 PM   #16
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you make a good point...

05-18-2007, 10:38 AM   #17
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Vivitar ftw! lol

Hey, how are the Matched Vivitar Teleconvertors for the 75-205 and the 70-150? I also have the 75-205 lens and was wondering about picking up the matched teleconvertor.
05-26-2007, 03:13 AM   #18
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Hi!
I have good tele Vivitar 70-150mm 1:3.8 MC, with the matched converter (with the inscription: Vivitar 70-150mm 2X matched multiplier), have bought it together (about twenty years ago). The IQ is good, even with digital camera (*istD). I am afraid, that it will be difficult to find matched multiplier for 75-105. Now I am searching for 1.4 or 1.5 converter Kenko or Tamron, but I live in Poland and in Europe Union Pentax mount isn't popular, most are for Canon or Nikon. Buying in USA is expensive, there are taxes and customs, and sending is expensive too. My payments in foreign currencies I make with PayPal only and not all sellers accept it.
05-26-2007, 09:27 AM   #19
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QuoteOriginally posted by tipentax38 Quote
hi mediaslinky
as my english is very poor,i prefer to show you what a cheap tc can do than talk about it.
made your own opinion

it's a vivitar tcmacro *2 with a 50mm pentax, anda 200mm pentax
I love that 1st photo tipentax38, does it have any post processing?

cheers

05-28-2007, 07:48 AM   #20
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I own three teleconverters.

The Tamron AF 1.4x is the best of the lot and also the cheapest. It works with any of my lenses, maintains AF, and doesn't degrade the image much. It is small enough (about the size of a DA 21mm pancake) to always carry it. I picked this up for $25 on KEH about 3 years ago.

The Pentax A-2XS works nicely with most of my lenses except for the Sigma EX 70-200/2.8. It doesn't work with the Sigma due to Sigma not properly implementing the A protocol on the lens, so it reports itself as a F1.4 lens. The A-2XS doesn't pass through the FA digital contact. I bought this one for $25 at a camera store in their used case about 8 years ago.

The Sigma EX 2X works decently with the Sigma EX 70-200/2.8, but doesn't work with any of my other lenses due to the protruding front element. Build quality is poor and it takes a bit of fangaling to mount it onto the lens and to have everything function properly. This one was about $100 on KEH 3 years ago.

A couple of years ago I did 200mm lens tests (newspaper shots) with all three of these teleconverters. You can find them here:
http://phred.org/~alex/pictures/pentax/lens-tests/200mm/

Sigma 70-200/2.8 @ f5.6 @ 200mm:


With Tamron 1.4x: (Lens at f5.6, so really f8)


With Sigma EX 2X: (Lens at f5.6, so really f11)


With Pentax A2X-S: (Lens at f5.6, so really f11)


Finally this image shows the three teleconverters side by side. You can see the protruding lens on the Sigma that prevents it from working with most other lenses.
05-30-2007, 12:49 PM   #21
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can you use a TC on a DA 50-200mm ??
05-30-2007, 12:59 PM   #22
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QuoteOriginally posted by awetmore Quote
I own three teleconverters.

The Tamron AF 1.4x is the best of the lot and also the cheapest. It works with any of my lenses, maintains AF, and doesn't degrade the image much. It is small enough (about the size of a DA 21mm pancake) to always carry it. I picked this up for $25 on KEH about 3 years ago.

The Pentax A-2XS works nicely with most of my lenses except for the Sigma EX 70-200/2.8. It doesn't work with the Sigma due to Sigma not properly implementing the A protocol on the lens, so it reports itself as a F1.4 lens. The A-2XS doesn't pass through the FA digital contact. I bought this one for $25 at a camera store in their used case about 8 years ago.

The Sigma EX 2X works decently with the Sigma EX 70-200/2.8, but doesn't work with any of my other lenses due to the protruding front element. Build quality is poor and it takes a bit of fangaling to mount it onto the lens and to have everything function properly. This one was about $100 on KEH 3 years ago.

A couple of years ago I did 200mm lens tests (newspaper shots) with all three of these teleconverters. You can find them here:
http://phred.org/~alex/pictures/pentax/lens-tests/200mm/

Sigma 70-200/2.8 @ f5.6 @ 200mm:


With Tamron 1.4x: (Lens at f5.6, so really f8)


With Sigma EX 2X: (Lens at f5.6, so really f11)


With Pentax A2X-S: (Lens at f5.6, so really f11)
What happened there with the 2x-S? That shot looks worse than what my long-gone soligor TC could produce...

QuoteOriginally posted by rdrum76 Quote
can you use a TC on a DA 50-200mm ??
Yes, but it'll be pretty slow at 200mm with a 2x TC

Adam
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05-30-2007, 08:51 PM   #23
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I have a number of EX Sigmas lens and was looking at TC's, should I stick to the EX TC or look for some other brand?

05-30-2007, 09:15 PM   #24
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QuoteOriginally posted by RussellW Quote
I have a number of EX Sigmas lens and was looking at TC's, should I stick to the EX TC or look for some other brand?
Check the list of compatible lenses for the APO tele-converter EX. If your lens is on the list, then that converter will probably give better results than anything else. Also, the 1.4X converter will degrade the image much less than the 2X converter.
05-31-2007, 05:14 AM   #25
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QuoteOriginally posted by GaryML Quote
Check the list of compatible lenses for the APO tele-converter EX. If your lens is on the list, then that converter will probably give better results than anything else. Also, the 1.4X converter will degrade the image much less than the 2X converter.
I know conventional wisdom says that but I'm not quite sure that in the case of the matched Sigma lenses with Sigma TC's. I have a Sigma 70-200EX f2.8 (not the DG) and I use a Sigma 2xTC with it and the IQ difference with the TC on or off is pretty minute. I can't see ow the 1.4x would give better results since there is so little difference with the 2X.

Of course I have no idea how the TC's fair on other EX glass and for a 2xTC you really need a constant f2.8 lens.

Here are a couple of shots from my birds gallery in my pbase account, a lot of the photos there (up to the most recent ones) where taken with the Sigma lens/TC combo.





07-21-2007, 09:10 AM   #26
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Great thread. I have to go back and read more fully. I have some experience to share and one question related to it, and the 1.7x Pentax TC.

I have the Bower 2x. It's [ahem] 'ok'. While great that it retains auto focus, it doesn't change the focal length advertised to the camers. So my 28-75 f/2.8 Tamron remains as such in the camera when I take shots with the 2x multiplier; and shake reduction is comprimised. So the shots were pretty soft. I turned shake reduction off. From in-camera preview it seemed I had a better 'save' ratio, but not great. However, as I'm going on Safari and was hoping to use it with a 200mm or 300mm zoom or prime, I surely don't want to give up the Shake Reduction I have in the camera that factored into me buying it.

Edit: I forgot to mention ... weird AF reaction from the lens pointing to a tree trunk about 30 meters away, with the background full of trees much further away; all ambient light. The AF was "pulsing" at over 5 steps a second, creeping up to the in-focus point over the course of several seconds. Never saw anything like that. Back & forth hunting yes, but never that creep. AF is normal in direct sunlight and pretty quick.

That leads to my question about the Pentax 1.7x TC. Particularly pictures Mo posted using it a few months back with the FA* 80-200mm f/2.8. I see in Exif some of the pictures are 300mm. So just to confirm, was that automatically set correctly, or does the zoom setting + TC multiplier have to be manually set by the "keep TC on, take lens off, turn camera on, set focal length at the prompt" tom-foolery?

Thanx all

Last edited by m8o; 07-21-2007 at 11:08 PM.
07-21-2007, 10:15 AM   #27
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The vivitar Macro TC is not to be compared with the cheap vivitar TC(s, its a wanted Item over here.

The Pentax 1.7 has also great possibillities for macro.

I Use the Sigma 1.4 APO EX on my F* 300/4.5 and on my F 100/2.8 macro. The results are that good that I'm thinking about a Sigma 2X APO DG.

The AF from F 100/2.8 macro is slow anyway but the F* 300/4.5 is Good but slows down with the 1.4 tc. On a sunny day the AF resulkts are better.

The Sigma 1.4 and 2 x converter do not fit any lens.


Guido
07-21-2007, 10:39 AM   #28
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This is a picture with The Pentax F* 300/4.5 and the Sigma 1.4 APO EX
In fact I was to close (2meters) to make a decent picture.
Be aware that you need a good tripod becuse:
300*1.4 = 420 * 1.5 (cropfactor)=630mm

Guido


07-21-2007, 11:21 AM   #29
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Thank you Geyst. I'm wondering, what focal length gets reported to the camera through the 1.4x? 300mm or 420mm? I took a look at the pic, but exif wasn't in the image after the down-sampling.
07-21-2007, 11:48 AM   #30
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My Ist Ds does not see the TC. The TC just passes data true tp the body.

No real problem for me biut with shake reduction you need to set your focal lenght manual. No problem with a prime, but not a good idea with a zoom.

Guido
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