Pentax F 1.7x AF converter

[tcom]

Strange thing...

I am having a Pentax F 1.7x AF converter since quite a few years. It came with me on quite some trips, South Africa, Namibia, Zambia, Botswana, Madagaskar, Costa Rica,... After all these trips, the TC begins unfortunately to show some weaknesses. Not really surprising giving the kind of conditions I was using it.

I had a look around, especially at ebay, to look for alternatives. I found a guy selling new 1.7x AF converter. I jumped on the occasion and ordered it.

It arrived today, and I am quite surprised.

The old one is made in Japan (Ser no 10009xxx),  the new one looks really brand new and is assembled in Vietnam (Ser no 1056xxx). I am also surprised by the papers coming with the converter. There is the usual "Notification of Change in Company Name" which is included in all new equipment since Hoya took over Pentax. There is also the user manual, while showing an older Pentax SFX SLR on the pictures, states at the end "Copyright Hoya Corp 2008".

Can it be that this teleconverter is still in production for selling on certain markets?

[JIMBO]

I have been looking for this one too after trying Daacons. [dave] It worked really well on my 70-200. Good luck. JIM

[spyglass]

Dominique,

If you don't mind me asking, do you have a link to the source / seller of the teleconverter? And what price range would one expect to pay.


Thanks,

Spyglass

[tcom]

Spyglass: search on ebay for a seller called "jinfinance". The price is around USD 370.

[calsan]

The manual is available on Pentax USA website.
However, it's just a black and white scan - the quality is quite low, but shows the Pentax SFX camera, as Dom said, although it has the old Asahi logo:

http://www.pentaximaging....F_ADAPTER_1%5B1%5D.7X.pdf

Also, listed as discontinued on Japanese website:
http://www.pentax.jp/engl...index35_list.html#adapter
 

It's possible that the Vietnamese factory still has access to the tools to make these.  Might be happening without official pentax blessing.  I also just looked on a few Japanese camera shops online and wasn't able to find it being sold new.

[tcom]

For those interested, I tried to compare the "old" Made in Japan version with the "new" Assembled in Vietnam version.

As the weather is pretty dull outside, I tried it on flowers, ie. closeups.

I set the K-7 on a tripod, set the camera to manual focusing and tried my best to set the focusing point to the same spot which is particular sensitive on closeups. I used Liveview in 8x mag to check the focusing.

Here is the result:

K-7, Voigtlander 125, f/8, 10s, 100iso


K-7, DA*300, f/7.1, 3s, 100iso


On the left side is the "old" made in Japan version, on the right side, the "new" assembled in Vietnam version.

By clicking on the image, you get to the full resolution photo.

[racort]

Here's a link to those :

http://cgi.ebay.com/SMC-P...enses?hash=item2ea1e2c1bb

[braver]

I'm interested in this converter.  Can you guys who use it extensively, especially @tcom, comment on what lenses you use it with and how?  Does the AF work with all of them?  What about vignetting, not playing well with any particular Pentax lenses?  Is it safe to use it with all Pentax lenses, including those made after it was discontinued (if it was ever)?

[tcom]

First of all, this Pentax F 1.7x AF converter does not pass the AF to the lens, neither traditional, nor SDM. You do need to focus manually the lens. This focusing does not need to be very precise. When you then half press the shutter, the camera will focus precisely thank to the moving lens in the teleconverter. The good thing about it is that this works on really all lenses you can mount on your camera, be it one of the latest DA* lenses or a K lens, and the AF is really fast.

Basically, you can use this converter on all lenses you can mount on a Pentax camera, but the results will vary. The teleconverter does always have an impact on the resulting image quality. As a general rule, the impact is really heavy on most consumer zooms, with a huge loss of contrast and details. But on higher grades zooms (such as the DA*60-250) or on primes, this teleconverter does really perform well.

I mostly use this teleconverter on the Voigtlander 125/2.5, Pentax DA*300/4, Zeiss 100/2 and Pentax DA*60-250.

[Oggy]

I have to admit I am really tempted by one of these. They seem to be the only TCs that get near producing an acceptable result. Tcom - how do they get on focusing on a moving subject?

[tcom]

Getting a moving subject with this 1.7x AF converter is rather difficult and needs a lot of practice.

As long as the moving subject remains within the range the AF converter can adjust, there is no problem, but if the distance to the subject moves too much, then you do need to try to following the subject by manually focusing the lens.

[Oggy]

Thanks Tcom. Sounds as if my Sigtma is safe for the time being.