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03-23-2010, 06:59 PM   #1
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Teleconverters: Dollars vs. Quality

Can ayone tell me if the optics (and/or other features) in a $200+ sigma tc is noticeably better than a $75 Kenko or Vivitar, etc. Also, if I am going to invest the money into a 70-200 f2.8 sigma w/HSM, should I just accept the fact that it will only work properly with a Sigma tc (and not with a "fourth party" tc)?

03-23-2010, 07:46 PM   #2
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If I may help re-ask your question; what TCs work well with the Sigma 70-200/2.8 HSM? I'm sure some members have that combo they are happy with. Also I recommend you start by reading the reviews on 3rd party TCs in the Lense Review section of the Forum for general likes/dislikes on the TCs you might be looking at.

Hope that helps.
03-24-2010, 04:09 AM   #3
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QuoteOriginally posted by sbluems Quote
Can ayone tell me if the optics (and/or other features) in a $200+ sigma tc is noticeably better than a $75 Kenko or Vivitar, etc. Also, if I am going to invest the money into a 70-200 f2.8 sigma w/HSM, should I just accept the fact that it will only work properly with a Sigma tc (and not with a "fourth party" tc)?
If you want to use the tc with the Sigma 70-200/2.8 mainly, you should buy the original Sigma tcs. With the Sigma Apo 1.4x tc you will not see any loss in image quality with that lens. It is just awesome. Even the Apo 2.0x tc is a good combination with that lens. Thi combo is great and offers also great versatility. No other tc will give you that quality on that lens.

But I would wait, as Sigma will sooner or later release an HSM/SDM version of these tcs. Or you buy and older screwdriver AF 70-200/2.8 and the matching tcs…

Ben
03-24-2010, 04:45 AM   #4
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Note that at present the sigma TCs do not support HSM and you will be stuck with manual focus

Also note that sigma TCs will NOT fit on many lenses due to the protruding front element. which requires a 35mm diameter 12mm deep recess in the ack of the lens.

I use both 1.4x and 2x sigma TCs on my APO 70-200F2.8 EX (Non GD Non Macro Non HSM) and they perform very well, with virtually no loss of IQ.

If sigma comes out with similar TCs for their HSM line I would recommend them, if you are considering using TCs only with the 70-200, in my opinion you may be better off getting a used non HSM version., The screw drive versions focus just fine based upon my experience.

I can;'t comment about differing IQ between the 4 later versions of the lens since I bought mine, but I have never had any cause to want a better lens.

03-24-2010, 04:48 AM   #5
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According to Sigmas website the APO tc's will not AF with the 70-200 f2.8 II APO EX DG HSM macro on a Pentax body. They state that you can on MF.
It was one of the reasons i decided to but the tamron 70-200 f2.8 instead.
Maybe someone with that combination could verify or deny that.
03-24-2010, 04:29 PM   #6
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QuoteOriginally posted by Ivor K Ecks Quote
According to Sigmas website the APO tc's will not AF with the 70-200 f2.8 II APO EX DG HSM macro on a Pentax body. They state that you can on MF.
It was one of the reasons i decided to but the tamron 70-200 f2.8 instead.
Maybe someone with that combination could verify or deny that.
See my post above. Perhaps I was not clear enough.

the present sigma 2x TC in pentax mount is a KAF mount not KAF2 mount, meaning it is missing the power contacts for the motor in the lens. Therefore there is no HSM function due to no power. The HSM lens, I believe does not have screw drive.
03-24-2010, 06:12 PM   #7
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If I did go with the Tamron would I have enough AF speed to photograph sports?
What options would I then have as far as tcs?
03-24-2010, 06:57 PM   #8
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QuoteOriginally posted by sbluems Quote
If I did go with the Tamron would I have enough AF speed to photograph sports?
What options would I then have as far as tcs?
Sorry I cant really help further.

There are a couple of third party TC's from the 1990's made for pentax Power Zoom lenses, which function. I think the most reliable is the tamron, but all are somewhat rare.

This has been one lacking thing in pentax's line up, a TC for a long time

by the way, I have the sigma APO 70-200 F2.8 EX and both 1.4 and 2x TCs, You might want to look at used market they work great.

03-30-2010, 02:37 AM   #9
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Tele converters with a 70-200

I was starrting to feel a little worried reading this column as I have just bought a Sigma 70 - 200mm f2.8 EX DG HSM. straight to the destructions. It states "The lens can be used with Sigmas 1.4x Ex DG Apo or 2x EX DG Apo Tele converters". It then goes on to say, "The Pentax mount Tele converter is not compatible with this particular lense."

Looks like I'll be taking my lens and camera in to try out the teleconverter first.

James
03-30-2010, 04:34 AM   #10
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QuoteOriginally posted by James also Quote
I was starrting to feel a little worried reading this column as I have just bought a Sigma 70 - 200mm f2.8 EX DG HSM. straight to the destructions. It states "The lens can be used with Sigmas 1.4x Ex DG Apo or 2x EX DG Apo Tele converters". It then goes on to say, "The Pentax mount Tele converter is not compatible with this particular lense."

Looks like I'll be taking my lens and camera in to try out the teleconverter first.

James
You'll be hard pressed to find a matching SDM-compatible tc in the shops right now. YOur best bets are the old Tamron 1.4x tcs and Kenko 1.5x tcs. Butz do a in-depth search in this forum first (there is a very long Tamron tc thread, which contains a lot of useful info), because only certain model versions will work with SDM.

Sooner or later, Sigma will surely release SDM compatible Apo tcs.

Ben
03-30-2010, 06:39 PM   #11
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It's very confusing how the compatibility info is presented on the Sigma site.

If you go to the Sigma site and look at the 70-200mm F2.8 II EX DG MACRO HSM, then click on accessories, it will list both TCs as options:
70-200mm F2.8 EX DG APOMacro HSM II - Telephoto Zoom Lenses - SigmaPhoto.com

According to the TC Compatibility Chart, the 70-200mm F2.8 II EX DG MACRO HSM is supported with AF.
Lens - Teleconverter Compatability Chart

If you look at the fine print below the chart, it clearly states that for Pentax, only MF is available.

However, if you dig even deeper, you will find out that the TCs are not compatible at all with HSM lenses on Pentax mounts:
Notice to customers using Sigma Tele Converters for Pentax mount | sigmaphoto.com

I know this because I spent hours digging around researching the 50-150 and 70-200 HSM lenses (including their new OS line) only to find out that no TC is compatible with these HSM lenses, manual or otherwise. Very disappointing to say the least.
03-31-2010, 06:16 PM   #12
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How do you find the AF speed? I will be shooting wildlife and sports. I realize that the Sigma HSM is faster thanTamron's screw drive, but in your opinion is the Tamron that terribly slow?
03-31-2010, 06:18 PM   #13
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Let me know what you find out. Unfortunately, I dont think they'll work w/HSM.
03-31-2010, 06:29 PM   #14
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In owned the Sigma 70-200mm F2.8 II EX DG MACRO HSM and their 1.4x tc, Kenko 1.5x tc and Kenko 2x tc would not auto focus
03-31-2010, 07:45 PM   #15
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Still on the hunt - just found the Bower TC while scanning the offerings at B&H Photo.

Bower | SX4PK 2x Telextender | SX4PK | B&H Photo Video

Though they claim it will provide AF capabilities, information on the specs seems somewhat contradictory.
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