Best Tele-Converter for use with Pentax 100mm Macro Lens


Link Posted 25/05/2012 - 11:32
Thanks Mike,
I have a fairly large garden which is rather over run with weeds and I know where to look for the bugs. They generally stay put in various places when they've found a source of food and shelter.
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Link Posted 25/05/2012 - 11:39
Crucial point by Ken on the focusing distance. A teleconverter will allow you to photograph a skittish butterly, tubes will allow you to photograph a dead one in greater magnification. So the answer is you need both of course.

Thanks Mike, I can't do flash like you experts, I just wait for a cloud.
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Link Posted 25/05/2012 - 11:43
Thank you all for your advice.

The disappointing spider image was taken whilst using the Pentax Ring Flash, exposure was 1/180th second. Although I was not using a tripod I was resting the lens barrel in my hand against the work surface with the camera tipped so that the ring flash lamp housing was just kissing the work surface. I believe that the camera shake function was on, it's usually on by default with me! I also used the ring flash modelling light which I find helps me with critical focusing. The lens was wound out to closest focus and I moved camera back and forth towards the subject to achieve best focus point.

The images that you have posted here in response are magnificent; they are exactly what I am trying to achieve! What is this Pentax 1.7 and is it still in production?

My preference for converter use, as opposed to extension tubes is to maintain greater subject distance thus less chance of subject spooking.
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Link Posted 25/05/2012 - 15:35
On my wish list now too, Charlotte.

Thanks for the clarification on TC vs tubes. Of course, you need both. Will start with the tubes as they are cheap!
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Link Posted 25/05/2012 - 17:01
The Pentax-F 1.7x is called an AF adapter not a TC although it
sometimes gets advertised as a TC.... If it looks like a duck,
quacks like a duck..... it is a duck etc.

The Manual can be downloaded from:

It's quite a bit out of date 1987 I think

I've got two of these and if anyone wants the spare one
I'd be willing to sell if for 250 + post at cost.
Excellent condition, but no case, although I can
find one off another make of TC.

I've also got a spare Pentax Rear Converter-A 2X-S
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Pentax K-1 + K-5 and some other stuff

Last Edited by Algernon on 25/05/2012 - 17:04



Link Posted 25/05/2012 - 21:01
Many thanks for all the help, from so many, in such a short time. However, in view of the overwhelming advice and wondrous images, I had snapped up a Pentax SMC F AF 1.7X Teleconverter Tele/ Converter Adapter from e-bay, prior to receiving the 'Algernon' offer. In fact, my wife did it for me! Can't complain about that, can I? I just have to await it's arrival now!
Thanks again to all of you for the help. Appologies if this is becoming garbled, I feel my Blood sugar is dropping now.
Regards Photon/Colin
All five minute jobs take a minimum of eight hours!


Link Posted 02/06/2012 - 01:54
Thanks to Charlotte's 'link' to 'e-bay',I received my 1.7x converter by Saturday morning 26 May. By Saturday afternoon I had used it to photograph a few spiders really close up. I am really pleased with the device and the resultant images. The nameplate/Label on the device, in six lines of text, states: 'PENTAX, SMC, PENTAX-F, 1.7 X, AF, ADAPTER'. The comas don't appear on the label, of course, I've used them here to serve as line separators!

This all proves the usefulness and effectiveness of the 'Pentax Forum'; within 36 hours of asking for help I had lots of advice and the necessary equipment to get on with the job! Thank you all very much.

Regards Photon/Colin
All five minute jobs take a minimum of eight hours!


Link Posted 02/06/2012 - 13:27
Glad you got sorted .. we will expect to see pictures soon

Interestingly I tried the adapter on my Series 1 Vivitar 105mm f2.5 macro and the IQ was average at best.
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Link Posted 03/06/2012 - 00:27
I've been using 68mm of tubes on my Sigma 105mm F2.8 macro as I don't want to lose IQ by sticking a 2xTeleconverter on it. I find that if I am careful and creep in very slowly, I don't usually 'spook' the insects into flying away, and this includes even skittish ones like flies and Damselflies.

Having said this, I did use the Sigma 50mm Macro last year on some occasions with the TC and the results were not bad at all - very little loss of IQ. I might give it a try on the 105.

A reasonable 2x TC can be bought second hand for reasonable cost (my 7 element Teleplus was 30 and it has the auto contacts so maintains auto aperture capability) so you won't risk much by buying one and trying it.


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Some cameras, some lenses, some bits 'n' bobs


Link Posted 05/06/2012 - 09:57
I use the Pentax 1.4X-S converter with catch-in-focus, works a treat


Link Posted 15/06/2012 - 15:39
I saw a rumour a while ago (on the USsite) that Pentax would be releasing a new TC/AF-adaptor this year to replace the FA version...

I've either missed the annoucement from Pentax or it hasn't happened yet(?)

I'm too poor right now to go for the FA-1.7/1.4-AF adaptor but deffo struggling with bug-shots with just the 100mm macro lens, keep spooking them off by going in to close!
Pentax K5- Vivitar 19mm 3.8; FA35mm f2; D-Xenon 100mm macro f2.8; DA50-200mm WR...
Yongnuo YN-560; Vivitar 285HV; Cactus V4 triggers...
Pentax-MX & M50mm f1.4; Spottie & 55mm f1.8; MG & M40mm 2.8...


Link Posted 16/06/2012 - 12:14
[quote:3496ace15f="DaveHolmes"]I saw a rumour a while ago (on the USsite) that Pentax would be releasing a new TC/AF-adaptor this year to replace the FA version...

I've either missed the annoucement from Pentax or it hasn't happened yet(?)

Probably was just a rumour


Link Posted 16/06/2012 - 13:52
I know there was a 1.4X TC on the lens roadmap a few years ago, which then disappeared. I seem to remember seeing it back on the roadmap again when they announced the new lenses, such as the 560mm.

Only time will tell.


Link Posted 16/06/2012 - 14:11
One final question, without wishing to start a new thread:
How do I correct my inattentively stupid spelling of the word 'Converer' which obviously should have read 'Converter' in the Thread title?

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