[Iksobarg]

Seem so much more expensive (crazy spencive!) than 2x converters?
I have some ideas but want to hear from the salty guys here.
Thanks

[Adam]

I don't think your statement about the pricing is necessarily correct. Regardless, the stronger the tc the more it worsens your image quality, so that's always something to keep in mind.

[jatrax]

How about an example?

There are lots of cheap manual 2x TC's out there but good ones with contacts and AF are rare and pricey same as the 1.4x ones. The Pentax AFA 1.7x is more than a TC if you are looking at that. It was designed to provide autofocus to older manual lenses when it was introduced. That it is still sought after and pricey is a testament to it's design, and the fact that Pentax has no modern TC available.

[vonBaloney]

Yes, the Pentax 1.7x AF is a special thing that allows you to autofocus manual lenses, and it pricey for that reason. And then you've got the Tamron-F 1.4x AF-Pz and the Kenko version of it which is labelled 1.5x, which I think are the only known TCs that allow autofocus pass-through with SDM/DC/HSM lenses, and so they are pricey for THAT reason. (And all of the above are pretty high quality optically as well.) And so there are no 2x TCs out there that have either of those features, plus most seem to agree that 2x TCs lose too much light and degrade the image too much, so they just aren't that popular. I have a pretty good 7-element Vivitar 2x TC -- works fine if the base lens is very sharp but does add some aberrations. And then I've got the 200F 2x Adaptall TC (only for Adaptall lenses), which *is* expensive and a cult item (and also very high quality).

[ElJamoquio]

vonB - I think there's a Tamron Pz 2x that has the pass-through for SDM (actually powerzoom) contacts. It's not expensive, in part, because it's not very good.

[vonBaloney]

vonB - I think there's a Tamron Pz 2x that has the pass-through for SDM (actually powerzoom) contacts. It's not expensive, in part, because it's not very good.

From what I've heard, those contacts can never be gotten to actually work on any SDM lens, even though they do on the 1.4x version.

[dadipentak]

There's also the light cost with the 2x TC's (rule of thumb is 2 stops) so AF can get dicey if the light isn't bright & contrasty.

[Iksobarg]

Well I hadn't read up on tcs as much as I should have. EBay gave me the price disparity. Anyway I wanted to add some range to my Revuenon 50/1.2, not necessarily 2x, but cost of the shorter tc pushed me for the time being into 2x-ville. It's maybe a fail approach. 85s are kinda pricey so I sought a shortcut. Now I think two things apply: you get what you pay for and short cuts are just that. I'm thankful nonetheless for you guys' feedback, hoohoo! BTW: can anyone tell me what model Tammy this is: http://m.ebay.com/itm/121206491995 ? Tyvm.

[Iksobarg]

I found this dpr thread helpful: Re: Your thoughts on a 2X TeleConverter?: Pentax SLR Talk Forum: Digital Photography Review

[Ponosby Britt]

Nobody is making a high quality TC for Pentax, including Pentax. I bought old stock, new in box from Japan a couple of years ago, Kenko 1.5 Pz AF that works well with my SDM DA 50-135 & screw drive Sigma 100-300/4. They are hard to find so they are expensive. If Pentax would make a good quality TC, people would buy them. Its been on their lens road map a long time.

This surf photo was made with the Kenko & 50-135, I didn't want to add the Sigma to my backpack on airplane. The B-52 concert photo was the Sigma 100-300/4 and the Kenko 1.5 TC.

Sigma does make good quality TCs but they have limited use on even Sigma lenses.

[ElJamoquio]

When I was trying out the Tamron 1.4TC with the DA* 300, I was much happier with cropped pics with the 300, for what it's worth.

Personally I'd keep the $250 and put it towards a K-3 or K-5IIs which would allow more cropping.

[pacerr]

For what you'd spend on a GOOD 1.4x TC you could find a DA or DA L 55-300 lens that would be MUCH more versatile, the IQ would be equal or better across most, if not all, of the focal length of that lens and you'd not be regretting the TC later.

Short of * lenses, the DA(L) 55-300 is a much more useable choice IMO. The optics are the same for those lenses -- only a degree of convenience between them.

The only down side is the difference in size and weight if that's a factor for you.

(And yes I've personally tried ALL the choices many times over through the years, including this opinion.)

H2