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01-22-2010, 12:40 PM   #106
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QuoteOriginally posted by snostorm Quote
Hi Jacques,

Thanks!

Tamron also apparently made a very small run of the AF version of this lens in K mount. I've seen pictures and a few testimonials, but have never seen one actually offered, nor have I tried one, so I can't say anything about how the lens handles or shoots.

Scott
You missed 7 of them......
ONE Tamron for Pentax 1.4X Pz-AF MC4 Teleconverter LN - eBay (item 110469105510 end time Jan-10-10 15:14:38 PST)
Long out of production Pentax Autofocus Tamron-F 1.4X Pz-AF MC4 Teleconverter. Has dual powerzoom/SDM contacts.

One I bought like new "used" early last year and later last year when the local proshop closed I bought their brand new, never sold 6 TC's. Instructions dated from January 2000.
PLEASE NOTE,
These 7 teleconverters are listed separately for $234.95 a piece.
There are:
Six Brand New in the box with instructions, case, caps, one like new in the box "used" with same packaging except box is a bit tattered.

Please Remember, Price is $234.95 USA delivered for each ONE Teleconverter.


01-22-2010, 02:44 PM   #107
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QuoteOriginally posted by jeffkrol Quote
You missed 7 of them......
ONE Tamron for Pentax 1.4X Pz-AF MC4 Teleconverter LN - eBay (item 110469105510 end time Jan-10-10 15:14:38 PST)
Long out of production Pentax Autofocus Tamron-F 1.4X Pz-AF MC4 Teleconverter. Has dual powerzoom/SDM contacts.

One I bought like new "used" early last year and later last year when the local proshop closed I bought their brand new, never sold 6 TC's. Instructions dated from January 2000.
PLEASE NOTE,
These 7 teleconverters are listed separately for $234.95 a piece.
There are:
Six Brand New in the box with instructions, case, caps, one like new in the box "used" with same packaging except box is a bit tattered.

Please Remember, Price is $234.95 USA delivered for each ONE Teleconverter.
Hi Jeff,

I was referring to the AF version of the Tamron SP 300/2.8 LD (IF). It's very rare.

Concerning the Tamron AF 1.4x TCs, at this price, these are even more relatively expensive than the Pentax 1.7x AFA, I think. I bought mine new for $69 USD, which was the going price from B&H @ 4 years ago.

Scott
01-22-2010, 03:50 PM   #108
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QuoteOriginally posted by snostorm Quote
Hi Jeff,

I was referring to the AF version of the Tamron SP 300/2.8 LD (IF). It's very rare.

Concerning the Tamron AF 1.4x TCs, at this price, these are even more relatively expensive than the Pentax 1.7x AFA, I think. I bought mine new for $69 USD, which was the going price from B&H @ 4 years ago.

Scott
Opp's to the lens thingy...
Actually the current made in Vietnam Pentax AF TC's are $399+ USD
SMC PENTAX F AF 1.7X ADAPTER K20D K200D K100D K10D K110 - eBay (item 200284488123 end time Jan-29-10 01:15:07 PST)
Used ones are pretty close if not more...... go figure..
The Tamrons were a deal compared to them. Same Tamron AF TC for other brands $100+/- used.....new "old style" not much more. New style $199
http://www.amazon.com/Tamron-Teleconverter-Canon-Mount-Lenses/dp/B000068ODT
Crazy stuff...
01-23-2010, 07:41 AM   #109
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Tamrons 1.4x in Pentax AF SDM mount have no competition

Tamrons 1.4x in Pentax AF SDM mount have no competition.

Their power zoom contacts serve to make the newer technology SDM function.

Pentax never made this type of teleconverter, whereas Canon and Nikon made their own TC's and made their own TC's for years now.

The Original Tamron 1.4x was long ago discontinued.

Well long ago discontinued being prior to 2002 before the istD* hit the marketplace.

The Tamron MC4 Pentax 1.4x TC I've used with my slow 80-320mm 5.6 lens does exceptionally well in bright daylight. It doesn't add harsh chromatic aberations into my images.

The Tamron for Pentax FA SDM mount are pretty rare if you think about it. Discontinued in 2002, made for a 3rd place or lessor camera maker (Pentax) I would assume far less were made for pentax mount. I see far more available in Minolta Alpha mount than I do in Pentax Mount. Canon and Nikon mounts of the Tamron 1.4x Version 1 in black paint are always abundant.




QuoteOriginally posted by jeffkrol Quote
Opp's to the lens thingy...
Actually the current made in Vietnam Pentax AF TC's are $399+ USD
SMC PENTAX F AF 1.7X ADAPTER K20D K200D K100D K10D K110 - eBay (item 200284488123 end time Jan-29-10 01:15:07 PST)
Used ones are pretty close if not more...... go figure..
The Tamrons were a deal compared to them. Same Tamron AF TC for other brands $100+/- used.....new "old style" not much more. New style $199
Amazon.com: Tamron AF 1.4x Teleconverter for Canon Mount Lenses: Camera & Photo
Crazy stuff...


01-23-2010, 08:03 AM   #110
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Another thing I noticed over the past couple years...

Another thing I noticed over the past couple years is I've seen some open bidding auctioned off Pentax mount Tamron MC4 1.4x TC sell/hammer above $300 plus delivery.

I don't think $300 plus is crazy money for a Pentax owner to pay if they want a Tamron made for Pentax Autofocusing & SDM & Powerzoom mount TeleConverter as both Canon and Nikon sell their TC's above $300 thesedays too.
01-23-2010, 12:26 PM   #111
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QuoteOriginally posted by Samsungian Quote
Another thing I noticed over the past couple years is I've seen some open bidding auctioned off Pentax mount Tamron MC4 1.4x TC sell/hammer above $300 plus delivery.

I don't think $300 plus is crazy money for a Pentax owner to pay if they want a Tamron made for Pentax Autofocusing & SDM & Powerzoom mount TeleConverter as both Canon and Nikon sell their TC's above $300 thesedays too.
Hi Samsungian,

I'll disagree about the crazy money thing. . . $300 is not unreasonable for a pro quality TC (ala Canon and Nikon), but the Tamron F 1.4x AF PZ MC4, although a very good TC optically, doesn't have nearly the same build quality, and this has to be a factor when comparing prices, IMO. The greatly inflated prices for the Tamron TC are due to market perception (availability/demand), not its intrinsic value. As I mentioned in a previous post, they commonly sold for $69 brand new until stock levels dropped and demand started to exceed supply, maybe 2-3 years ago. At this price, they were considered a great deal -- very good optics at a bargain price. . .

Also, my Tamron TC does not play well with my DA*50-135 as it hunts and quits after 3 tries. It only can get an accurate lock if the initial focus plane the lens is set to is within a fraction of an inch of the desired one -- and I've heard others who have had the same experience. I don't really have a use for this combo as I have 3 other lenses that cover the range nicely, but I wanted to see if it would work -- and AFAIC, it doesn't. The tests I've done were in bright sunlight, and on multiple occasions.

Because of this experience, I would not flatly state that either the Tamron or the Kenko PZ TCs are SDM compatible -- they may work well with your particular SDM lens, or possibly with with certain models of SDM/HSM lenses, but if they don't work reliably with all SDM lenses (by "reliably", I mean just mount the TC and it will focus as well as without the TC, with due consideration to the light loss), they should not be touted as being "compatible". "Potentially compatible" or "SDM contact compatible" is as close as I'd put them, and I'd consider these marketing euphemisms. I can easily state that they are truly compatible with screw drive lenses with appropriate max apertures though. . .

I think you do a disservice in your post to both the C/N TCs and to SDM/HSM lens owners looking for a truly compatible TC.

Scott
01-23-2010, 12:54 PM   #112
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I keep missing the offers on eBay and here on this forum!!
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01-23-2010, 01:47 PM   #113
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Tamron1.4x is as good as it gets. Pentax dropped the ball

Tamron1.4x is as good as it gets. Pentax dropped the ball in not ever offering a full autofocusing Teleconverter. Yes they roadmapped one and then failed to deliver it. Wait a few years longer and maybe Pentax will roadmap it again and this time actually offer it for sale??? Its only been what some 23 years since pentax first offered autofocus glass and still no 1.4x AF TC...

I'm just going on what I read, people here and elsewhere say 1.4x Tamron is compatible with their SDM lenses. Your experience with Tamron and SDM is duly noted. Have you tried several 1.4x Tamrons or just one to draw your conclusion from ???

You should do a search of others who found Tamron 1.4x works with their SDM glass and convince them otherwise and convince them to now retract their statements ???

One person I can think of who owns Tamron 1.4x is Javier.

So why not Start with Javier G ???

He's the Pentaxian who popularized the 1.4x MC4 Tamron TC, get him to retract his old multipage thread posted here somewhere concerning his observations using the Tamron MC4 1.4x TC.

By the way, list price on Tamron 1.4x in black is $179 from 2002 till supply was exhausted. What you paid was a remainders price, likely sold at a loss by Tamron to B&H to clear out standing inventory before the next white version 1.4x TC launched. The newer white version 1.4x was never offered in Pentax mount.

Good luck buying any more brand new 1.4x Tamrons in Pentax autofocus mount for $69 anywhere, including B&H.

And I'll safely guess that, if you offer your 1.4x tamron for $69 you'll have a long list of eager buyers...





QuoteOriginally posted by snostorm Quote
Hi Samsungian,

I'll disagree about the crazy money thing. . . $300 is not unreasonable for a pro quality TC (ala Canon and Nikon), but the Tamron F 1.4x AF PZ MC4, although a very good TC optically, doesn't have nearly the same build quality, and this has to be a factor when comparing prices, IMO. The greatly inflated prices for the Tamron TC are due to market perception (availability/demand), not its intrinsic value. As I mentioned in a previous post, they commonly sold for $69 brand new until stock levels dropped and demand started to exceed supply, maybe 2-3 years ago. At this price, they were considered a great deal -- very good optics at a bargain price. . .

Also, my Tamron TC does not play well with my DA*50-135 as it hunts and quits after 3 tries. It only can get an accurate lock if the initial focus plane the lens is set to is within a fraction of an inch of the desired one -- and I've heard others who have had the same experience. I don't really have a use for this combo as I have 3 other lenses that cover the range nicely, but I wanted to see if it would work -- and AFAIC, it doesn't. The tests I've done were in bright sunlight, and on multiple occasions.

Because of this experience, I would not flatly state that either the Tamron or the Kenko PZ TCs are SDM compatible -- they may work well with your particular SDM lens, or possibly with with certain models of SDM/HSM lenses, but if they don't work reliably with all SDM lenses (by "reliably", I mean just mount the TC and it will focus as well as without the TC, with due consideration to the light loss), they should not be touted as being "compatible". "Potentially compatible" or "SDM contact compatible" is as close as I'd put them, and I'd consider these marketing euphemisms. I can easily state that they are truly compatible with screw drive lenses with appropriate max apertures though. . .

I think you do a disservice in your post to both the C/N TCs and to SDM/HSM lens owners looking for a truly compatible TC.

Scott



Last edited by Samsungian; 01-23-2010 at 02:02 PM.
01-23-2010, 02:16 PM   #114
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Here's Javier's TWO YEAR old Tamron 1.4x TC thread

Here's Javier's Tamron 1.4x TC TWO YEAR old thread at Pentaxforums



https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/19694-tamron-t...rter-pics.html
01-23-2010, 04:55 PM   #115
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I have one SDM lens & one HSM lens. The Tamron 1.4x TC works reliably with both.
01-23-2010, 04:57 PM   #116
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QuoteOriginally posted by Samsungian Quote
Tamron1.4x is as good as it gets. Pentax dropped the ball in not ever offering a full autofocusing Teleconverter. Yes they roadmapped one and then failed to deliver it. Wait a few years longer and maybe Pentax will roadmap it again and this time actually offer it for sale??? Its only been what some 23 years since pentax first offered autofocus glass and still no 1.4x AF TC...

I'm just going on what I read, people here and elsewhere say 1.4x Tamron is compatible with their SDM lenses. Your experience with Tamron and SDM is duly noted. Have you tried several 1.4x Tamrons or just one to draw your conclusion from ???

You should do a search of others who found Tamron 1.4x works with their SDM glass and convince them otherwise and convince them to now retract their statements ???

One person I can think of who owns Tamron 1.4x is Javier.

So why not Start with Javier G ???

He's the Pentaxian who popularized the 1.4x MC4 Tamron TC, get him to retract his old multipage thread posted here somewhere concerning his observations using the Tamron MC4 1.4x TC.

By the way, list price on Tamron 1.4x in black is $179 from 2002 till supply was exhausted. What you paid was a remainders price, likely sold at a loss by Tamron to B&H to clear out standing inventory before the next white version 1.4x TC launched. The newer white version 1.4x was never offered in Pentax mount.

Good luck buying any more brand new 1.4x Tamrons in Pentax autofocus mount for $69 anywhere, including B&H.

And I'll safely guess that, if you offer your 1.4x tamron for $69 you'll have a long list of eager buyers...
QuoteOriginally posted by Samsungian Quote
Here's Javier's Tamron 1.4x TC TWO YEAR old thread at Pentaxforums



https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/19694-tamron-t...rter-pics.html
Hi Samsungian,

I made no absolute claims, unlike your post, and I did read the thread when it was current. AFAIK, the thread only confirmed that the Tamron F 1.4x and Kenko 1.5x can work with some lenses, but that doesn't confirm "compatibility", IMO. Others found that either of the TCs didn't work for them acceptably from an AF standpoint. I don't dispute those who state it works for them, and suggesting I ask for a retraction is just silly. It's just that the Tamron or Kenko PZ TCs for SDM/HSM lenses are not something that I'd recommend without significant reservations above and beyond the normal caveat emptor. You seem to believe differently. . . from what you've read. . .so be it. I'll stand with my reservations based on personal experience.

The fact that Pentax has not produced an AF TC other than the 1.7x AFA is irrelevant to my post, except that it brings up more questions. I'd think that Kenko or Tamron would revive production to fill a market void if they knew that their TCs would be the only game in town for SDM. Not doing so makes sense if they knew that they couldn't reliably claim SDM compatibility. They still list both the standard 4 element for Canon and the 5 element SP for Canon and Nikon. It probably wouldn't take much to slap K mount plates on both ends and make the appropriate electrical connections, and they'd have the SDM TC market all to themselves. . .but they haven't, and apparently don't have plans to. . . and you have to ask yourself why the SDM TC from Pentax is still vaporware. . . maybe reliable SDM compatibility is a bit more involved than just supplying pass through PZ contacts?

I have not confirmed the functional limitations of the Tamron either with other SDM lenses nor with other TCs, but I don't think that the other posters that you seem to base your statements on have either, so you have as much reason to doubt their results as you have to doubt mine. Have you asked them to confirm their results??? . . . or maybe you could ask them to enter this thread with their experiences and we could have another gazzilion post thread that comes to no real concrete conclusion.

I can't recall seeing a post by anyone who can attest to reliable, usable SDM compatibility with any PZ TC and more than one SDM model (Edit: -- now I've seen one -- Thanks Dave), but as I previously stated, it's possible that some models/examples offer better compatibility. I have also read where others have had the same experience as I with either the Tamron or Kenko and an SDM lens. One poster here disputed my Tamron/SDM experience in another thread, strongly stating that his combo worked well, then in a different and later thread stated that he had to manually prefocus his DA*300/4 to get the Tamron to lock reliably with it, but that was okay with him . . . I can accept this with the 1.7x AFA as it is a known limitation of the design, but not with a fixed focus TC that uses the lens' focus mechanism. The combo should be functionally seamless other than the magnification and considerations for light loss. Anything less is unacceptable for me. YMMV. . .

Both B&H and Adorama had the Tamron F 1.4x AF PZ MC4 priced at $69 for years. I bought mine in 2004-5, and the price remained the same for at least a couple of years. This wasn't a closeout deal, or even a specially priced sale, it was the "street price" for the TC. If you seriously think that MSRP on lenses (especially 3rd party mfgs) means anything, then I have quite a few lenses I'd love to sell to you. . . A while ago, maybe a year or two, as available stock levels dwindled, and relative demand increased, the B&H price on the Tamron went up to over $100 until new stock was completely depleted.

I've no doubt that I couldn't buy another for the same price. The comment that I made was that the relative current market price was possibly less reasonable than even the 1.7x AFA, and I even added "I think". . .

You failed to address the build quality difference between the Tamron and C/N TCs and it relationship to price/value. . .

Scott

Last edited by snostorm; 01-23-2010 at 05:40 PM.
01-23-2010, 07:56 PM   #117
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OK, I guess I misunderstood this sentence

OK, I guess I misunderstood this sentence ???

QuoteOriginally posted by snostorm Quote
Hi Samsungian,

I think you do a disservice in your post to both the C/N TCs and to SDM/HSM lens owners looking for a truly compatible TC.

Scott

Ever considered either your 50-135mm SDM is defective or your Tamron is defective?

Seems to me others here and elsewhere are happy with theirs, and as Pentax offers no AF 1.4x of their own, what 1.4x AF options are available for Pentax owners thesedays? You know other than waiting 23 years and counting for Pentax to provide a simple true autofocus function 1.4x TC ?

SDM is what just 3 years old now? What kept Pentax hands tied during prior 20 years in failing to offer their own 1.4x AF TC???

I like my Tamron MC4 1.4x Teleconverter. YES, My 1.4xII TC Canon Eos is superior to Tamron 1.4x TC, but Canon's made their 1.4x available for 20 years now and its even had a design improvement so Canon Eos System has had two decade long head start. Canon's USM autofocus is superior micro motor based SDM Pentax lenses too. But if you want to own only Pentax System then what do Pentaxians do? Wait wait wait... or buy the best available product? Tamron 1.4x TC is it.

I wonder what keeps Pentax from making a simple Full Autofocus 1.4x available for sale ? Nikon sells their autofocus function TC for $420 thesedays, which for me is alot of money. Thats a hair more than what both of my brand new Canon 1.4xII and 2xII TC cost me together in 2008. So a two for one money kinda deal for me in comparing Eos to Nikon TC pricing.

Nikon 1.4x Autofocus TC at $420 linky:

http://www.bhphotovideo.com/c/product/228165-USA/Nikon_2129_TC_14E_II_1_4x_Teleconverter.html

edit, added $420 link

Last edited by Samsungian; 01-23-2010 at 08:28 PM.
01-23-2010, 10:51 PM   #118
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QuoteOriginally posted by Samsungian Quote
OK, I guess I misunderstood this sentence ???




Ever considered either your 50-135mm SDM is defective or your Tamron is defective?

Seems to me others here and elsewhere are happy with theirs, and as Pentax offers no AF 1.4x of their own, what 1.4x AF options are available for Pentax owners thesedays? You know other than waiting 23 years and counting for Pentax to provide a simple true autofocus function 1.4x TC ?

SDM is what just 3 years old now? What kept Pentax hands tied during prior 20 years in failing to offer their own 1.4x AF TC???

I like my Tamron MC4 1.4x Teleconverter. YES, My 1.4xII TC Canon Eos is superior to Tamron 1.4x TC, but Canon's made their 1.4x available for 20 years now and its even had a design improvement so Canon Eos System has had two decade long head start. Canon's USM autofocus is superior micro motor based SDM Pentax lenses too. But if you want to own only Pentax System then what do Pentaxians do? Wait wait wait... or buy the best available product? Tamron 1.4x TC is it.

I wonder what keeps Pentax from making a simple Full Autofocus 1.4x available for sale ? Nikon sells their autofocus function TC for $420 thesedays, which for me is alot of money. Thats a hair more than what both of my brand new Canon 1.4xII and 2xII TC cost me together in 2008. So a two for one money kinda deal for me in comparing Eos to Nikon TC pricing.

Nikon 1.4x Autofocus TC at $420 linky:

Nikon | TC-14E II 1.4x Teleconverter for D-AF-S & | 2129

edit, added $420 link
Hi Samsungian,

I guess you did misunderstand.

You did a disservice to C/N TCs by comparing them by price only to the Tamron, and giving the impression that they are equivalent products. I would think that owning a Canon TC you could see the difference in build quality easily, but apparently that got by you. The only reason I mentioned what I paid for one was to illustrate the disparity in original price (which would indicate a difference in practical build quality, BTW) compared to the current market value.

You did a disservice to SDM lens owners looking for a TC that will AF with their lens by stating that the Tamron will work with it. Is it a lock that it actually will work as well as it one would expect with a screw drive lens? No, I think not. My experience coupled with the exact same experience from others says that compatibility might be an issue. This isn't the case with screw drive TCs (or the screw drive functionality of the Tamron) -- sure there are probably bad examples, but I've never experienced one, and don't recall any testimonials of this.

The actual or relative cost of the N/C TCs was never an issue. Neither is the fact that Pentax hasn't offered any AF TCs other than the AFA. Neither is AF speed, or any other difference in performance between brands. The fact that the Tamron TC is probably the best chance of getting a working TC for SDM is not the issue. I like my Tamron TC also, otherwise I wouldn't still own it and use it, but that's not the issue either. I stated that equating the Tamron with N/C TCs because of the price the market demands was not really reasonable because of differences in build quality. I stated that it was a great bargain for me because it offered very good optics at a very low price.

Yes, I've always felt that either the TC or my particular lens is at fault. I didn't and don't care which it is because I don't use them in combination and never intended to. It's probably not the body, as the lens TC combo acts the same with 4 different SDM capable bodies. But this wasn't the issue either. The fact that others have had exactly the same response from their combos leads me to believe that my situation is not unique, but a symptom of example variation where the PZ contacts in the TC allow the focusing motor in the lens to operate, but not to the precision needed to AF reliably. There's something amiss with the feedback system. Since the lens functions well alone on all the bodies, the most likely source of the problem is with the TC.

I was not and am not knocking the Tamron. It was designed as a PZ TC, for which purpose, it works fine. SDM uses similar contacts, but that doesn't guarantee that a TC designed and discontinued before SDM was ever offered would offer full functionality and precision of this feature. Tamron never stated that their PZ contacts would work with SDM, and neither has Pentax. The precision of an AF feedback loop is of a totally different nature than just supplying power to a motor to operate the zoom ring on the lens. You gave the overwhelming impression that they work with all SDM lenses. I gave a counterexample and argument that maybe this might not be the case. You respond with a sentence from a previous post, a rant about Pentax missing the ball on AF TCs, an unnecessary statement that I use faulty gear, and comparisons of Canon and Nikon TC prices. . .

Here, I'll make it simple. . .

1. Can you state with certainty that a Tamron F 1.4x AF PZ MC4 will allow full functionality with any SDM lens -- that it will focus as well as the bare lens with minor considerations for possible image degradation and light loss?

2. Can you state that the above mentioned Tamron TC is the equal to Canon and Nikon AF TCs in build quality, and therefore they are of the same intrinsic value as long as they function as expected? In other words, if you compared them physically, with no regard for optical quality, brand, or market influences (availability and demand), would you pay the same price for the Tamron considering only how the TCs look and feel?

Those were the issues I was talking about. If you can answer either or both of these questions affirmatively, then we'll have to disagree. I doubt that I could convince you, and you certainly haven't convinced me. If you answer negatively, then there is no disagreement here.

Scott
01-24-2010, 02:52 AM   #119
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Fine. You've convinced me.

Fine. You've convinced me. Your Tamron TC is crap, so you win.

I still like my Tamron TC, so I win too.

An advantage of Tamron TC over Canon and Nikon own TC's is the Tamron mounts on any lens, not just lenses with recessed rear lens elements. The snout on both Canon and Nikon TC's limits their teleconverters use.

I suspect you'll disagree with this statement too, so let me be the first to say

"Fine, you win"






QuoteOriginally posted by snostorm Quote
Hi Samsungian,

I guess you did misunderstand.

You did a disservice to C/N TCs by comparing them by price only to the Tamron, and giving the impression that they are equivalent products. I would think that owning a Canon TC you could see the difference in build quality easily, but apparently that got by you. The only reason I mentioned what I paid for one was to illustrate the disparity in original price (which would indicate a difference in practical build quality, BTW) compared to the current market value.

You did a disservice to SDM lens owners looking for a TC that will AF with their lens by stating that the Tamron will work with it. Is it a lock that it actually will work as well as it one would expect with a screw drive lens? No, I think not. My experience coupled with the exact same experience from others says that compatibility might be an issue. This isn't the case with screw drive TCs (or the screw drive functionality of the Tamron) -- sure there are probably bad examples, but I've never experienced one, and don't recall any testimonials of this.

The actual or relative cost of the N/C TCs was never an issue. Neither is the fact that Pentax hasn't offered any AF TCs other than the AFA. Neither is AF speed, or any other difference in performance between brands. The fact that the Tamron TC is probably the best chance of getting a working TC for SDM is not the issue. I like my Tamron TC also, otherwise I wouldn't still own it and use it, but that's not the issue either. I stated that equating the Tamron with N/C TCs because of the price the market demands was not really reasonable because of differences in build quality. I stated that it was a great bargain for me because it offered very good optics at a very low price.

Yes, I've always felt that either the TC or my particular lens is at fault. I didn't and don't care which it is because I don't use them in combination and never intended to. It's probably not the body, as the lens TC combo acts the same with 4 different SDM capable bodies. But this wasn't the issue either. The fact that others have had exactly the same response from their combos leads me to believe that my situation is not unique, but a symptom of example variation where the PZ contacts in the TC allow the focusing motor in the lens to operate, but not to the precision needed to AF reliably. There's something amiss with the feedback system. Since the lens functions well alone on all the bodies, the most likely source of the problem is with the TC.

I was not and am not knocking the Tamron. It was designed as a PZ TC, for which purpose, it works fine. SDM uses similar contacts, but that doesn't guarantee that a TC designed and discontinued before SDM was ever offered would offer full functionality and precision of this feature. Tamron never stated that their PZ contacts would work with SDM, and neither has Pentax. The precision of an AF feedback loop is of a totally different nature than just supplying power to a motor to operate the zoom ring on the lens. You gave the overwhelming impression that they work with all SDM lenses. I gave a counterexample and argument that maybe this might not be the case. You respond with a sentence from a previous post, a rant about Pentax missing the ball on AF TCs, an unnecessary statement that I use faulty gear, and comparisons of Canon and Nikon TC prices. . .

Here, I'll make it simple. . .

1. Can you state with certainty that a Tamron F 1.4x AF PZ MC4 will allow full functionality with any SDM lens -- that it will focus as well as the bare lens with minor considerations for possible image degradation and light loss?

2. Can you state that the above mentioned Tamron TC is the equal to Canon and Nikon AF TCs in build quality, and therefore they are of the same intrinsic value as long as they function as expected? In other words, if you compared them physically, with no regard for optical quality, brand, or market influences (availability and demand), would you pay the same price for the Tamron considering only how the TCs look and feel?

Those were the issues I was talking about. If you can answer either or both of these questions affirmatively, then we'll have to disagree. I doubt that I could convince you, and you certainly haven't convinced me. If you answer negatively, then there is no disagreement here.

Scott
01-24-2010, 06:44 AM   #120
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I tried a couple of kenko 1.5x pz-shq TC's with my da300mm and while it would focus with sdm, it would go back and forth some. I paid less than $40 for them (long time ago)and didn't want to pay a bunch of money for the tamron to find it did the same thing. I suspect people's idea of "working" is different. I think if pentax could make it work they would have given us the one they promised (and teased us with) I don't see how the tamron would be any different than the kenko as neither transmits any distance info to the camera or anything digitally. I would say the kenko worked too, just not to my liking.
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