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Old Aug 25, 2009, 5:41 PM   #1
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Default Got One At Last - Pentax 1.7X AF Adapter

I had tried bidding on ebay several times when they came up but could not get myself to bid over $400 that the bidding went to. After researching past activity I decided to try a Chinese store on ebay that has Buy it Now for $348 plus $19.95 shipping. Sent question first if he had in stock, replied promptly no and two customers are in front of you. I ordered on August 3rd and received it yesterday. Pentax must still be making these but not marketing in the US. Box came with all pamplets including "Notification Of Change in Company Name" due to merger with Hoya. Tested it at home yesterday with DA* 300mm and DA* 50 135mm. Interestingly it gives you the actual aperture with the allowance for the adapter. Biggest aperture with the DA* 300mm was f6.7 and the 50 135mm was f4.5. I was hoping this would act as a focus limiter for BIF's (Wish the lenses had a limiter). It does but is more restrictive then I would like. It focuses down from infinity (if you manually set lens there) and gives a little range there, but not much range on the short end. It does focus fast if you are within it's range. It will take some practice, I need to decide if I want to keep it or sell on ebay, should be able to get at least my money back or more from what I experienced. Will work with it for a while. Took it to Loxahatchee today with the DA* 300mm for effective 510mm. Tried BIF, Wading Birds and macros - samples attached. IF ANYONE THAT HAS USED THESE HAS ANY INFORMATION ON HOW TO GET BEST FROM THEM PLEASE LET ME KNOW.

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Old Aug 25, 2009, 5:52 PM   #2
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It looks like you're well on your way to me! Does this actually autofocus with an SDM lens? Who is the seller on ebay?
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Old Aug 25, 2009, 6:03 PM   #3
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Originally Posted by jnanpentaxfan View Post
It looks like you're well on your way to me! Does this actually autofocus with an SDM lens? Who is the seller on ebay?
It does not focus with SDM, the adapter has a limited focus range. Was made to use with manual focus lenses. When I turn on the camera I have to put in the lens focal length as 500mm. This is better the when I use the Kenko 1.5x, it focuses in SDM, but slow, and sees the lens as 300mm still.

Just serch on ebay for Pentax 1.7x, there is only one dealer with a buy it now. They communicated very well with me.

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Old Aug 25, 2009, 10:38 PM   #4
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Ed, I've owned two and sold one to a friend in exchange for some nice new gear...

It's a tricky TC to work with, but in the right lighting and solid technique it's amazingly good. Technique is one of the most important factors in getting those sharp images, especially with a moderate aperture lens. I can post a few with the 1.7x AF TC + FA* 300/2.8 if you need them? Larger images of course.

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“The camera is only a tool: the image is the product of your mind and vision.”
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Old Aug 25, 2009, 11:15 PM   #5
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It does have a limiting factor and the longer the lens the bigger this issue becomes, but then it was designed to make MF lenses AF. I originally purchased mine for use with my A*85mm 1.4 during the film days and with that lens it is simply great.

Once you get use to it the TC becomes more user friendly although it will never work with the full focus range of longer lenses without some adjusting from the photographer.

I find it to be far sharper with good glass, and the sharper the lens it is used on, the less degradation of the image will be visible.

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Old Aug 26, 2009, 3:08 PM   #6
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Hi Ed,

I’m a big fan of the AFA, and have two that I will most likely take to my grave.

You’ve obviously noticed that the aperture value is automatically converted and that you have to manually choose a FL for the SR system – both nice touches, and this is how I’d like to see all TCs work with Pentax bodies.

Another feature that’s not apparent at first is that the AFA is recognized as a unique lens by both the SR and FL adjustment systems on bodies that have them. IOW, regardless of the lens used with the TC, the camera will remember the last SR FL set with the AFA mounted, and the same is true of any focus correction setting, so you have to keep this in mind to prevent some problems.

The best advice I can give is to try to use the AFA until the manual focus part becomes almost second nature. Some people apparently hate this aspect and dismiss this TC before they give it a fair trial. The versatility the AFA offers in extending the capabilities of long teles is, IMO, pretty amazing.

I’ve also found the relatively narrow focus range a limitation for BIF with a 300+AFA, but my problem has more to do with my lack of technique in acquiring a fast moving subject in the VF with the FOV of a 510mm. I’ve found that a lens of @ 200mm or under +AFA is much better for me for this purpose, though I really don't do a lot of this type of shooting since I have very few opportunities to shoot interesting species in flight.

I have found myself choosing to use the AFA BECAUSE of the focus limiting aspect though. My eyesight is a bit variable because of meds, and with the narrow DOF of fast teles, I do a lot of refocusing with slight changes of focus point to try to get the best detail. This has to be done quickly, since the birds usually don't cooperate, and the AFA really helps here. It's usually a lot more decisive about locking focus, and usually just makes almost instantaneous micro adjustments. Even with the focus limiter on the FA*300/2.8 (there are 3 stages -- 2-4m, 4-15m, and 15m-∞), the lens tends to do more full hunts within the range than with the AFA, and that can be frustrating.

Here’s a list of lenses that I have that work well with the AFA. As Tom suggested, top quality lenses show little IQ degradation, and are the best to use with this, or any high quality TC.

FA 50/1.4 – makes a pretty nice 85/2.4 portrait lens – a little soft wide open, but tack sharp stopped down.
F 50/1.7 – same, except at f2.9

D FA 100/2.8 macro – The 1.7x magnification allows 1:1 shooting at a longer working distance, giving the critters more room and me a bit more versatility in using an external flash. I’m sure that it would work well with any macro lens. The focus limiting effect really makes this lens more useful as an AF tele lens as full lock to lock hunts can be very frustrating (and all too common) with the ultra long focusing throw of a macro lens.

A 70-210/4 – a bit slow at f6.8, but the IQ of this bargain zoom is one of the few that really holds up to TC use.

Tamron SP 80-200/2.8 LD Adaptall 2 – IMO, the best of the MF zooms in this class. 136-340/4.8 is a pretty good stand in for a Sigma 100-300/4, and a half stop bump in ISO to match performance isn’t very painful. I even like the push-pull zoom, especially with the lens tripod mounted – it’s just faster and less confusing considering the MF component of shooting this combo. I was hoping that this lens might stand up to stacked TCs, but didn't like the results. I guess that's asking too much from a zoom. . .

Tamron SP 180/2.5 LD (IF) Adaptall 2 – makes for a nice, compact 306/4.3, but I’d rather use my FA* 300/4.5.

A* 200/2.8 ED – IMO, a better lens than the SP 180, despite the commonly quoted comments that the Tamron is almost too sharp. This lens gives great results with the AFA, but for me, I’d rather use an AF lens because of the shorter MF focus ring throw.

FA* 300/4.5 – my most used lens with this TC. A bit slow at 6.7, but if you consider that the Bigma is about the same speed, but considerably longer extended to 500mm, and over a lb more in weight, it works well as a 510mm hand held lens, which is how I always use mine.

Tamron SP 300/2.8 LD (IF) – I have the 60B (the green one). This lens shines with the AFA. A pro-spec lens commonly available for $300-800 USD. Mine came bundled with an SP 140F 1.4x Adaptall 2 TC which is excellent.

With just the AFA, a very good AF 510/4.8. About 5 lbs, a bit over 9” without the hood, with a Minimum Focusing Distance of about 8 ft, and possibly available at under $1000 total, this is a very attractive package, IMO.

AFAIK, the only competition in FL and speed are the K 500/4.5 at 7.5 lbs, 17”, with an MFD of 33 ft(!!!)

and the Sigma EX 500/4.5 APO DG, at 7 lbs, @13”, with an MFD of @ 13 ft.

Add the 1.4x TC, and it becomes a very competent 714/6.7, IMO. The center sharpness remains very good, and for me that’s about all that matters. I usually just shoot the subject in the center, then crop for composition in PP. The biggest negative effect the TCs have is that they make the bokeh busy if the background is fairly close.

I can get away with handholding this combo at short distances in very good light, but for shots longer than @ 20ft, I find a very steady tripod setup is easily the best way to go, and the shorter shots benefit from a steady base, allowing a significantly higher % of keepers.

I also have and use a Sigma EX 300/2.8 APO and an FA*300/2.8 ED (IF) that I use with the AFA. The 300/2.8 class is about the largest lens that I can handle carrying and using because of my physical limitations. Both of these outperform the Tamron in sharpness and CA/PF control, but the Sigma usually goes for $1500-2000 used, and the Pentax is usually about twice as much as the Sigma. It's a long story why I have all three of these 300/2.8s, and I won't bore you with the details.

If you search through the threads I’ve started, you’ll find a lot of examples, since I use the AFA extensively.

Cograts on your new acquisition. I hope that you find it as useful as I have.

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Old Aug 28, 2009, 9:06 PM   #7
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Default AFA w/M42 Lenses

I actually got the AFA so as to be able to sort of autofocus M42 lenses. (I'm actually embarassed at how little I paid.) It's fantastic to be able to auto-focus a screw-mount 200mm 2.8 on a DSLR. The end result being the equivalent of a 540mm lens is out of sight.

And now the but - even with the body on shake reduction, I really can't hand hold this lens below 1/250th and am only comfortable at 1/500th and up.

However, it was a great way to bring new life to my old Spotmatic lenses.

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Old Sep 7, 2010, 10:58 PM   #8
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Doh! he shot his price up to 450 BIN, and its pretty much the only place ive found that has em listed, been looking all day

thats just a tad too much for me, Ill hafto keep looking.

darn monopolizer!
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Old Sep 8, 2010, 1:33 AM   #9
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Originally Posted by NMRecording View Post
Doh! he shot his price up to 450 BIN, and its pretty much the only place ive found that has em listed, been looking all day

thats just a tad too much for me, Ill hafto keep looking.

darn monopolizer!
A quick search found two - one in the USA (£323.85+£19.43) and one in Czech Rep. (£421.01+19.43). Note those are GBP not US$ !
Pentax : 15 Ltd, 77 Ltd, 43/1.9 Ltd, Cosina 55/1.2, DA*300/4, Contax Zeiss Distagon 28/2.8, Raynox 150/250, AFA x1.7, Metz 50 af1.

Nikon : D800, D600, Sigma 500/4.5, Sigma 120-300/2.8, Zeiss Distagon ZF2 - 21/2.8, Zeiss Distagon ZF2 - 35/2.0, Nikkor 85/1.8G, Sigma 50/1.4. Nikon x1.4 TC, Sigma x2.0 TC
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Old Sep 8, 2010, 5:43 PM   #10
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Congratulations Ed!
you should have fun with that baby for quite some time.

Life's a breeze on a Goldwing...
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