Zoom Lens + TC - which combination?

Hi people

I recently posted on here asking about which zoom lens would be most suitable for a safari and after the advice and other research I'd pretty much decided that the Sigma 100-300mm f4 + 1.4xTC would be most suitable.

But I have been wondering if one of the recent 70-200mm f2.8 + 2xTC would be a better option (not sure about Tamron or Sigma yet). I can't imagine anyone has had both of these combinations, but are there any obvious advantages or drawbacks that I may be missing?

I believe (and may be wrong) that the 100-300mm + 1.4TC will be a 140-420mm f5.6 and the 70-200mm + 2xTC will become 140-400mm f5.6. These are very similar, but the 70-200mm f2.8 (without TC) may be more useful with low light, etc.

When on safari my aim is to not be changing lenses too often, so when in the jeep I will be using the TC, but when out walking I will remove the TC.

Thank you.

If you go down the 70-200 route, be aware that there aren't any teleconverters yet that work satisfactorily with the Sigma 70-200 f2.8 HSMII.

The Kenko 1.5x (but not the 2x version) and Tamron 1.4x work up to a point, as they have 'SDM/HSM/Power Zoom' contacts in the body, but autofocus on C-AF is a bit hit and miss and my lens never seemed to settle on a focus point with the converter attached. S-AF was more successful however, but I think it still throws the results off, as with any converter really. Manual was ok with both those converters.

The Sigma APO converters don't work at all with the 70-200 HSMII, even in manual mode, although I keep reading that Sigma are bringing out a new Pentax version that is compatible although nobody knows when that will be.

My particular Sigma 70-200 HSMII wasn't sharp at f2.8, but excellent from f4 onwards, which kind of negates the advantages of the wider aperture. In my case, I would have had a 140-400mm f8, although as I say it's academic as no 2x converter works with the Sigma! It did weigh a lot less than the 100-300 f4 though!

So, the Tamron is your only option at the moment if you decide to go down this particular road.

The 100-300 already has the same 35mm equivelant field of view as a 150-450. Multiply that by the 1.4 that the T/C will provide and you have a massive 210-630mm. You'll have trouble keeping it still enough at the long end.

Hi, thanks for your replies.

Mannesty, I only plan to use the TC when I am able to use a monopod / tripod (for either lens).

Which reserves will your safari be in ? If it's one where your driver/guide can go off road ,then you will be able to get very close to the wildlife.A tripod/monopod is not easy to use in the confines of a safari landrover especially with the engine running.Hope you have a great trip ,
Mike

Hi Mikenya, we will be in South Luangwa / Lower Zambezi national park. I had a monopod recommended to me as the type of vehicle are low sided jeeps and it would be awkward to use a bean bag. We're not going until next year - but making my christmas list now!

From the tests that I have seen on the internet I woul recommend a 1.4, 1.5 or 1.7 TC at most.

The 2+ TC's just take too much on image quality, mostly sharpness.

Matej

Hi pikipoki - welcome to the forum and thank you for the reply. My plan is still to go with the Sigma 100-300mm + 1.4TC (if required).

Looking at the price of the 100-300mm f4 Sigma new I dont think it is going to be far off the DA* 60-250mm f4 is it?
I know you will lose 50mm on the top but will gain 40mm at the bottom plus you get weather sealing, sdm and from what I have seen of the test shots pretty good IQ.

I know this lens is 'imminent' - but I'm not convinced it will be available before my trip next June!

Anyway, I'm hoping that someone will upgrade to the Pentax and sell me their Sigma cheap!

Well SRS are taking orders for next month and I believe they are pretty on the ball when it comes to Pentax gear.