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01-01-2010, 12:30 PM   #31
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QuoteOriginally posted by tcom Quote
I ordered it from a seller from China (on ebay)
Sweet, now I just need to save up $380

01-01-2010, 03:48 PM - 1 Like   #32
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I'll add some comments, but I'm an unashamed F 1.7x AFA fanboy, so take that into account, and excuse the long writeup. . .

The 1.7x AFA is my most used Pentax product. I currently have 3, and would feel handicapped if I only had one. All of mine were purchased used, and are from the original production, so I can't comment on the new ones, but the 4 that I have owned performed identically , so if the new ones have been made from NOS components (the comment about not marketing in EU for environmental reasons points to this), they should perform consistently. The last one I purchased was the most expensive -- an EX condition for $228 shipped from KEH, about 6 weeks ago, so if one looks hard enough, and has a bit of luck (I'm sure I just lucked into logging on within minutes of this one being posted), these don't have to be prohibitively expensive.

At least one member here feels that this TC is inferior optically, but from his comments, he's never used one, so I have to question his motivation in saying this.
He also criticizes the AFA from the perspective that it can only be used to advantage with MF lenses, and that using it with an AF lens is silly and wasteful. Here, lack of experience also shows -- An AF version of a lens usually has a shorter rotational throw from lock to lock than an MF version, and AF lenses have less dampened focus ring action (considered a liability to MF technique). Since the MF component is only used to get the focus somewhat close, and only a rough adjustment is necessary. AF lenses are actually preferable for use with the AFA.

This member also finds the very quick AF speed to lock, the focus limiting (which I see as a feature, not a liability), and the fact that any lens with the AFA turns into a Quick Shift lens as "minute" advantages. I disagree. . . I find all of these considerable advantages in use.

There are two more advantages to the AFA's design. AFAIK, it's the only K-mount AF TC that does NOT pass through lens ID or FL info for AF lenses. This necessitates entering a FL to calibrate SR. This is less of an advantage on zooms than primes, but I haven't found that many zooms that I'd use TCs with (the 70-200/2.8s and Sig 100-300/4 are the most notable exceptions), but IMO, being able to approximate FL as a choice is better than the alternative of being forced to use the SR with a 1.4x, 1.7x, or 2x error, or not at all. The second, is that the AFA is (again AFAIK) the only AF TC that automatically converts the effective Av considering the 1.7x magnification. This is a minor point, but might be advantageous to P-TTL flash use.

Pentax is the only mfg to successfully implement this idea. Nikon produced the TC16a, which mirrors the intent, but a web search for this item quickly showed me its many flaws and limitations. The Pentax AFA is the only adapter that will work as intended, allowing AF critical focusing for any K-mount lens with any KAF body.

The disadvantages the AFA has are generally shared with other TCs. You lose light -- the physics of the situation dictates that the effective Av is directly proportional to the FL, so there is @a 1 1/2 stop penalty in light gathering. There is the inevitable degradation of IQ from adding optical elements not matched to the original design of the lens. I've only noticed this in the quality of the bokeh for relatively close BG and FG objects (they might get slightly more frantic), and the inevitable magnification of CA/PF faults from the lens. If one desires better CA/PF performance, your only real choice is to use the TC with a better lens in this regard. In my experience, any losses in apparent sharpness and ability to capture fine detail are offset by the added magnification which allows finer critical focusing and better metering. This probably helps me more than others as I like to shoot "closeups" of small birds. The last disadvantage is that it might be considered fiddly to use -- a claim that I have already answered. The AFA also restricts you to center point focusing, but can use any of the metering pattern options.

Some of my not-as-apparent uses for the AFA are with lenses like the FA 50/1.4 and D FA 100/2.8 macro. With the 50, it makes a pretty nice, compact 85/2.4 portrait lens with appropriately shallow DOF. With the 100 macro, I get a 170/4.8 that can both give me greater than 1:1, and will give me significantly more working distance at 1:1.

Ultimately, it's most used for birding. I'm a bit physically challenged by age, small stature, and a heart condition, so I just can't physically handle the best of the long tele primes (notably the Sigma EX 500/4.5, Pentax A*400/2.8, FA*600/4, and FA*250-600), nor do I have sufficient support for these lenses. I use an Amvona ATA 104T with a Wimberley clamp modified Manfrotto 468MG, and Wimberley Sidekick (which would probably work with the Sigma, but the other 3 would be quite a bit too much weight for any of these components). With the AFA and other TCs and two lenses (FA*300/4.5 and FA*300/2.8), I have the versatility of using 300/4.5, 300/2.8, 420/6.3, 420/3.9, 510/7.7, 510/4.8, 600/5.6, 714/6.7, 867/8.1 -- all with the convenience of AF and AE. I'm able to carry these pretty easily, including the support stuff, in addition to a couple of other smaller lenses for a reasonably long distance. There is no way I could carry any two of the larger primes like this, so I'd never use them, except for somewhere very close to home, which would hardly be worth the entry price. . .

Agree or disagree if you will, but the F 1.7x AFA has my vote for the most versatile and enabling accessory for Pentax long tele shooters by quite a margin.

To make a long post even longer, I'll include some samples . . . You can see that each was shot with a different body. All final focusing decisions were made by the respective AF system, and the flash shot was a totally brainless P-TTL exposure (attach the flash, turn it on, and shoot).

K100DS, FA*300/4.5, 1.7x AFA


K-7, FA* 300/2.8, 1.7x AFA


K10, Tamron SP 300/2.8, Tamron SP 140E 1.4x TC, 1.7x AFA, AF 540FGZ in P-TTL


DS, Tamron SP300/2.8, Tamron 140E 1.4x TC, 1.7x AFA


K20, FA*300/2.8, Sigma EX 1.4x APO AF TC, 1.7x AFA


Scott
01-01-2010, 06:45 PM   #33
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Interesting thread. I'm interested in hearing people's opinions of using this TC for sports with a Tamron or Sigma 70-200 2.8, or the Sigma 100-300 f4.
01-01-2010, 08:02 PM   #34
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QuoteOriginally posted by jake14mw Quote
Interesting thread. I'm interested in hearing people's opinions of using this TC for sports with a Tamron or Sigma 70-200 2.8, or the Sigma 100-300 f4.
I had the sigma 100-300mm f4 and for some reason (took me a while to figure it out) the lens iris wasn't closing to the proper position as set on the camera with the 1.7x afa. I discovered this looking in the lens and hitting depth of field preview and judging how closed down it was, so I used the aperture ring and that was better. I used a kenko 1.5x mostly with that one though. I'm not sure if it was my lens only or a sigma incompatibility thing.

01-01-2010, 11:02 PM   #35
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QuoteOriginally posted by koper Quote
i would like to know if the teleconverter work with

Pentax smc P-DA 300mm F4 ED (IF) SDM ??????
It works with my M 400/5.6 so it should work with your 300/4. BUT - take note - the AF in the converter is only a fine tune device, it will not make large focusing adjustments. It also does not work on the 400/5.6 in anything but bright contrasty situations. As a 1.7X TC, it is very, very good optically, and turns my M 400/5.6 MF lens into a 680mm f/9.5 sitting bird MF lens. That's a lot of lens, and needs ISO 400 to do anything much, but I cannot afford the FA* 600/4.
01-02-2010, 03:56 AM - 1 Like   #36
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I do use my 1.7x TC for closeup photography and for wildlife.

For wildlife, I use the TC mainly on the DA*300 to get the extra reach.





I do also use it for closeup photography, on the Voigtlander 125, especially for insects. The TC gives the extra range to remain at a distance to avoid the insects fly away. It does also speed up the focusing, I set a coarse focus on the lens, the TC doing the fine tune, and this is both fast and accurate.



01-02-2010, 04:47 AM   #37
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QuoteOriginally posted by borno Quote
I had the sigma 100-300mm f4 and for some reason (took me a while to figure it out) the lens iris wasn't closing to the proper position as set on the camera with the 1.7x afa. I discovered this looking in the lens and hitting depth of field preview and judging how closed down it was, so I used the aperture ring and that was better. I used a kenko 1.5x mostly with that one though. I'm not sure if it was my lens only or a sigma incompatibility thing.
I just ordered one of these from a guy in China. Do you think it will work on the Sigma 120-400?

Thanks!
01-02-2010, 05:10 AM   #38
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QuoteOriginally posted by stanleyk Quote
I just ordered one of these from a guy in China. Do you think it will work on the Sigma 120-400?

Thanks!
I'm not Borno, but I'll try to answer.

The manual for the AFA is concervativ. It says it needs f:4 or faster lens to focus. I have tested it on a K-500/4,5, works fine under good light conditions, but I don't like the results of the combo.

Sigma 120-400 is f:5,6 at the long end. So I'll say it is to stretch thing a bit to far. It may work, in high contrast light, but I would not trust on it.

01-02-2010, 05:49 AM   #39
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Here's a question I thought of while I was sleeping

Since the 1.7x TC is AF, does that mean that Catch-In Focus (aka Focus Trap) would not work? I thought Catch-In Focus required a manual focus lens (or a lens/TC with its own MF switch).
01-02-2010, 10:38 AM   #40
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QuoteOriginally posted by GoremanX Quote
Here's a question I thought of while I was sleeping

Since the 1.7x TC is AF, does that mean that Catch-In Focus (aka Focus Trap) would not work? I thought Catch-In Focus required a manual focus lens (or a lens/TC with its own MF switch).
Goreman,
You are suffering from PRSS , "Pentax-related-sleeplessness-syndrome"
Remedy: get one of those TC's!
01-02-2010, 10:47 AM   #41
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QuoteOriginally posted by snostorm Quote
I'll add some comments, but I'm an unashamed F 1.7x AFA fanboy, so take that into account, and excuse the long writeup. . .

The 1.7x AFA is my most used Pentax product. I currently have 3, and would feel handicapped if I only had one. All of mine were purchased used, and are from the original production, so I can't comment on the new ones, but the 4 that I have owned performed identically , so if the new ones have been made from NOS components (the comment about not marketing in EU for environmental reasons points to this), they should perform consistently. The last one I purchased was the most expensive -- an EX condition for $228 shipped from KEH, about 6 weeks ago, so if one looks hard enough, and has a bit of luck (I'm sure I just lucked into logging on within minutes of this one being posted), these don't have to be prohibitively expensive.

At least one member here feels that this TC is inferior optically, but from his comments, he's never used one, so I have to question his motivation in saying this.
He also criticizes the AFA from the perspective that it can only be used to advantage with MF lenses, and that using it with an AF lens is silly and wasteful. Here, lack of experience also shows -- An AF version of a lens usually has a shorter rotational throw from lock to lock than an MF version, and AF lenses have less dampened focus ring action (considered a liability to MF technique). Since the MF component is only used to get the focus somewhat close, and only a rough adjustment is necessary. AF lenses are actually preferable for use with the AFA.

This member also finds the very quick AF speed to lock, the focus limiting (which I see as a feature, not a liability), and the fact that any lens with the AFA turns into a Quick Shift lens as "minute" advantages. I disagree. . . I find all of these considerable advantages in use.

There are two more advantages to the AFA's design. AFAIK, it's the only K-mount AF TC that does NOT pass through lens ID or FL info for AF lenses. This necessitates entering a FL to calibrate SR. This is less of an advantage on zooms than primes, but I haven't found that many zooms that I'd use TCs with (the 70-200/2.8s and Sig 100-300/4 are the most notable exceptions), but IMO, being able to approximate FL as a choice is better than the alternative of being forced to use the SR with a 1.4x, 1.7x, or 2x error, or not at all. The second, is that the AFA is (again AFAIK) the only AF TC that automatically converts the effective Av considering the 1.7x magnification. This is a minor point, but might be advantageous to P-TTL flash use.

Pentax is the only mfg to successfully implement this idea. Nikon produced the TC16a, which mirrors the intent, but a web search for this item quickly showed me its many flaws and limitations. The Pentax AFA is the only adapter that will work as intended, allowing AF critical focusing for any K-mount lens with any KAF body.

The disadvantages the AFA has are generally shared with other TCs. You lose light -- the physics of the situation dictates that the effective Av is directly proportional to the FL, so there is @a 1 1/2 stop penalty in light gathering. There is the inevitable degradation of IQ from adding optical elements not matched to the original design of the lens. I've only noticed this in the quality of the bokeh for relatively close BG and FG objects (they might get slightly more frantic), and the inevitable magnification of CA/PF faults from the lens. If one desires better CA/PF performance, your only real choice is to use the TC with a better lens in this regard. In my experience, any losses in apparent sharpness and ability to capture fine detail are offset by the added magnification which allows finer critical focusing and better metering. This probably helps me more than others as I like to shoot "closeups" of small birds. The last disadvantage is that it might be considered fiddly to use -- a claim that I have already answered. The AFA also restricts you to center point focusing, but can use any of the metering pattern options.

Some of my not-as-apparent uses for the AFA are with lenses like the FA 50/1.4 and D FA 100/2.8 macro. With the 50, it makes a pretty nice, compact 85/2.4 portrait lens with appropriately shallow DOF. With the 100 macro, I get a 170/4.8 that can both give me greater than 1:1, and will give me significantly more working distance at 1:1.

Ultimately, it's most used for birding. I'm a bit physically challenged by age, small stature, and a heart condition, so I just can't physically handle the best of the long tele primes (notably the Sigma EX 500/4.5, Pentax A*400/2.8, FA*600/4, and FA*250-600), nor do I have sufficient support for these lenses. I use an Amvona ATA 104T with a Wimberley clamp modified Manfrotto 468MG, and Wimberley Sidekick (which would probably work with the Sigma, but the other 3 would be quite a bit too much weight for any of these components). With the AFA and other TCs and two lenses (FA*300/4.5 and FA*300/2.8), I have the versatility of using 300/4.5, 300/2.8, 420/6.3, 420/3.9, 510/7.7, 510/4.8, 600/5.6, 714/6.7, 867/8.1 -- all with the convenience of AF and AE. I'm able to carry these pretty easily, including the support stuff, in addition to a couple of other smaller lenses for a reasonably long distance. There is no way I could carry any two of the larger primes like this, so I'd never use them, except for somewhere very close to home, which would hardly be worth the entry price. . .

Agree or disagree if you will, but the F 1.7x AFA has my vote for the most versatile and enabling accessory for Pentax long tele shooters by quite a margin.

To make a long post even longer, I'll include some samples . . . You can see that each was shot with a different body. All final focusing decisions were made by the respective AF system, and the flash shot was a totally brainless P-TTL exposure (attach the flash, turn it on, and shoot).

Scott
Scott,
First, your photos are stunning.
So, please stop posting them here because I am becoming rather jealous!

Seriously: I see that you have "stacked" two TC's for some of your pics. Granted, you have some fast glass and I would assume this "stacking" would only be possible with fast lenses, right? ... but I wonder if that there is a remote possibility to achieve similar (if not quite as good as those you have) results with slower lenses, i.e.: F4 such as the DA*300.
I am soon getting this Tamron 70-200 f2.8 and I already have a Tamron 1.5x TC. Do you think stacking another TC (such as your 1.7X) on top of it would work with?

Cheers.

JP
01-02-2010, 10:49 AM   #42
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So, I have browsed the Net and found a couple of places selling this TC:
$480 USD in "auction 1"
$529 USD in "auction 2" ... that was two days ago.
Went back to retrieve the info this afternoon: GONE! I mean, the ads have simply disappeared!
Anyway, the prices are way too steep for my present and nearly empty budget.

JP
01-02-2010, 11:14 AM   #43
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QuoteOriginally posted by jpzk Quote
So, I have browsed the Net and found a couple of places selling this TC:
$480 USD in "auction 1"
$529 USD in "auction 2" ... that was two days ago.
Went back to retrieve the info this afternoon: GONE! I mean, the ads have simply disappeared!
Anyway, the prices are way too steep for my present and nearly empty budget.

JP
But it is an auction, I am guessing it is from eBay? You must know that it's only expensive because they currently don't have them available anywhere except probably Japan. So the thing is when this TC actually becomes available here from a authorized dealer, the prices will significantly be cheaper than what you could find on eBay. But at the moment it's still quite rare and can be pricey, just wait it out and maybe it will retail for 250-350 when it appears on Amazon.
01-02-2010, 02:09 PM   #44
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QuoteOriginally posted by LeDave Quote
But it is an auction, I am guessing it is from eBay? You must know that it's only expensive because they currently don't have them available anywhere except probably Japan. So the thing is when this TC actually becomes available here from a authorized dealer, the prices will significantly be cheaper than what you could find on eBay. But at the moment it's still quite rare and can be pricey, just wait it out and maybe it will retail for 250-350 when it appears on Amazon.
That would make sense.
Of course, if the demand is high and the product rare ... !
Can't hardly wait to get me one of those, instead of LBA'-ing into a very expensive long, fast glass.
Thanks for the reply.

JP
01-02-2010, 02:17 PM   #45
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I've done biz with Rong Jin

I've done biz with Rong Jin a.k.a. "Jinfinance" over the past few years.

I've never bought a 1.7x Pentax mf>af from him but it looks like he's sold (((74))) of them.

Looks like $379 plus delivery from Shanghi China.

I too like mine, earlier Japan made model I bought years ago.

If you love Pentax its certainly an innovative adapter any fan should own.

However I find it can be a chromatic aberations monster with certain lenses I own.

With my 300mm 2.8 Adaptall 2 its a GEM.

1.7x, 300mm 2.8 and K20D abnd seven other lenses keep me owning my Pentax.

According to my pentax instructions sheet it costs you only one f stop,

so my 300mm 2.8 becomes a 510mm f4.

and then you aps-c croppers get added reach I suppose.

Handy item and smart of Pentax to re-make them once more.


SMC PENTAX F AF 1.7X ADAPTER K20D K200D K100D K10D K110 - eBay (item 200284488123 end time Jan-29-10 01:15:07 PST)



QuoteOriginally posted by jpzk Quote
So, I have browsed the Net and found a couple of places selling this TC:
$480 USD in "auction 1"
$529 USD in "auction 2" ... that was two days ago.
Went back to retrieve the info this afternoon: GONE! I mean, the ads have simply disappeared!
Anyway, the prices are way too steep for my present and nearly empty budget.

JP
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