[nitehntr]

i am wanting to get a 2X converter to use with an old 500mm f4.5 SMC manual focus lens. it will be used on my K5 and hopefully in the near future a K3. would i be better off with a manual focus converter or a newer one that would also work with my DA* lenses ? any recommendations or advice would be greatly appreciated.

[thazooo]

I'll give a thumbs up for both Pentax 1.4x s a and the Pentax 2x s a converters. Both have contacts and good glass. At one time I had the Tamron 1.4x with the screw drive. Wasn't happy with how well it focused a Sigma 170-500 lens. Appeared to bind.
The Pentax converters have an 'L' version also. It's for specific lenses because it protrudes into the lens.

Hope this helps.

[Stone G.]

I concur with thazooo regarding Pentax Rear Converter A types. But it appears that the Rear Converter A 2X-S may cause vignetting with your 500mm lens and that you might want the A 2X-L? Be careful though, there is a protruding element that your lens must be able to accomodate.


I have posted the Rear Converter A manual - where you can find recommended lens-converter combinations - here:

http://www.gyes.eu/documents/pentax_rear-converter-a_operating-manual(1990).pdf

For my DA* 200mm f/2.8, I use the A SX-S converter with very decent results:

Pentax Rear Converter A 2X-S and scm Pentax DA* 200mm f/2.8

[nitehntr]

thanks for the answers you were both a huge help i did not know that there were lens specific versions of converters. i have never used one and just want to get one now since acquiring the 500mm. i like wildlife and this should help a lot. thanks again

[Stone G.]

i did not know that there were lens specific versions of converters

And that's probably one major reason why teleconverters have got such a bad reputation nowadays.

One can easily understand that adding a TC of mediocre quality to any lens will have to produce mediocre or worse results. But all quality lenses are carefully optimized designs and it is not granted that any "quality" TC of any brand will have an optical design that will MATCH the optical design a particular lens.

In particular, when it comes to zooms or primes with internal focusing, both types having lens groups moving relative to one another, the reults from mis-match can be very dissapointing.

[thazooo]

Something to remember when shooting a 500mm with a 2x converter, Vibrations . Have a sturdy tripod, nerves of steel help too
Up to about 600mm you can shoot with just a little tweaking of your technique. After that you really have to watch what you're doing.
I've always used the 2 second timer or burst mode to get clear shots. Watch the wind, at 1000mm a strong wind can set off vibrations too.
Have fun.

[nitehntr]

yepper i use a tripod even with my 300 and a lot with the 60-250. get way sharper shots that way. the mirror lock up helps a lot too.