teleconverters

I've done quite a bit of reading lately and I realise with a TC I'm going to lose at least 1 stop of light, fine, but I'm also concerned that I retain autofocus function and don't lose too much image quality.

I've read recently that I should really consider the sigma 1.4 EX DG if I'm using a sigma lens as they are designed to be matched together.

alternatively, the Tamron PZ-AF MC 1.4 and the Kenko PZ-AF 1.5 are talked about quite highly, however, the Tamron appears to be double the price of the Kenko but I have no idea if it justifies that price difference?

I did read one review that raved about the Tamron and said it lost no quality at all which I just don't believe. I realise there are lots of Teleconverters and you really do get what you pay for, but retention of autofocus is a big plus for me and I don't want to go beyond 1.4-1.5 as far increase in mm goes.

can people comment on the Kenko and tamron at all? is the tamron worth £130 notes more in price?

What lens do you want to use it with?

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at the moment I have the DA L 55-300 but I'm also casting around for a faster 300 tele if I can find one at a reasonable price.

The 55-300mm is a great lens, but it doesn't take to teleconverters too well. I really wouldn't bother with that path.

You'd be much better served with the Pentax 300mm and TC.

The 55-300mm works very well with a TC.
This was at about 280mm + TC Handheld K-5 200ISO




Edit: Just noticed you have the 55-300mm that hasn't
got Quickshift, in which case I would change the lens
first for the more expensive version otherwise it
huns for focus quite a bit. It's better to set the focus
at infinity before using AF

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Not with mine it didn't, which one was that Algi?

Jessop 1.7x TC also works well with the Sigma 150-500mm.

That shot was straight from a JPG although I took RAW as well.

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Good to know, many thanks!

It also allows you to get in close, although this was the 55-300mm at
120mm + TC




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so what is the name of the pentax 55-300 with quickshift because that is my one gripe with my existing DA L 55-300 ED, it hunts......a lot.

for airshows I want a fast 300 lens to get round that, sometimes the 55-300 I have just hunts and I have to zoom right back to 55 to re-acquire and have it lock in.

the jessops 1.7 TC sounds good. is there more to the model number I should be looking for than just jessops 1.7 tc?

I had been considering the kenko 1.5 pz-af or the tamron pz-af 1.4 but am struggling to see why the tamron is double the price of the kenko.

what sort of figure should I be seeing the jessops priced at?

do you shoot moving action with your 55-300 + TC setup? because that is my main use, action ie air shows, ie fast moving aircraft.

SMC Pentax-DA 55-300m has QuickShift, SMC Pentax-DA L doesn't.

According to this thread that is all down to user error and not the lens.

Using a teleconverter on the 55-300mm will make the AF a whole lot worse for airshows.

great, thanks for that.

if I can source one of these I think that will make me a lot happier, get a good TC to go with it and then sell my existing 55-300.

The Jessops converter is (as far as I can tell) exactly the same as the Teleplus version I currently have advertised in the sales section.

well as long as it works in AF mode with the modern lenses I don't mind.

I was just leery of some teleconverters because a lot of older ones won't do AF and I 've seen some threads advising people to get a teleconverter that is marked PZ-AF to address that issue.