Which would be a better lens + TC combination?

*woodworm* · 10-06-2008, 11:38 AM

Hi everyone

I have done a search of the forum so apologies if this has been asked before and I missed it ...

I'm going on Safari next year (woohoo!) and I'd pretty much decided that the Sigma 100-300mm f4 + 1.4xTC would be an ideal lens/TC combination.

But I have been wondering if one of the recent 70-200mm f2.8 + 2xTC would be a better option. 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 that the 100-300mm + 1.4TC will be a 140-420mm f5.6 and the 70-200mm + 2xTC will become 140-400mm f5.6.

Although I'd be losing 20mm at the long end, I would gain an extra stop at the short end (when not using the TC) and have a lighter weight lens when using hand held (no TC). But would the image quality suffer too much with a 2xTC?

Thanks for your help

Malo1961 · 10-06-2008, 11:52 AM

Going on safari means probably a high risk of dust, getting into your camera.
Therefore I would choose for the lens, that gets the most action, without changing or placing converters. IMO that would mean the 4.0/100-300 Sigma. I reckon if wildlife is your aim (from open vehicles)using the 4.0/100-300 probably covers 75 % of your photo's. And because you have the best chance at dawn and dusk, you will have to cope with low light levels. The 2.8/70-200 with 2x converter means 5.6 to begin with. So you lose a full stop. And I am pretty sure the quality wide open from the 4.0/100-300 is a lot better than the 2.8/70-200 with the 2x converter.

HIH,
Martin.

PS, And I know that using the 2x TC would mean: Losing AF on the 70-200. ( It did also in the former version) So check that out first, before you decide anything.

Photomaximum · 10-06-2008, 12:40 PM

You loose two stops with a 2X but only one with a 1.4X.

You will get inferior focus results with a 2X as compared with a 1.4X. The loss of image quality is less with the 1.4X as well.

I only use tele extenders when its a "must." A lot of folks leave them on their camera because they bought one and they "look cool."

Buy the best lens you can afford and then the 1.4X is my vote...

*woodworm* · 10-06-2008, 12:55 PM

Thanks for the replies.

I had pretty much decided on the Sigma 100-300mm but just wanted run the idea past someone more knowledgeable than me!

Arpe · 10-06-2008, 05:22 PM

Originally Posted by Malo1961

PS, And I know that using the 2x TC would mean: Losing AF on the 70-200. ( It did also in the former version) So check that out first, before you decide anything.

My 2x EX autofocusses on my Sigma 70-200.

*palmor* · 10-06-2008, 10:11 PM

Originally Posted by Arpe

My 2x EX autofocusses on my Sigma 70-200.

Ditto, the 70-200EX will focus just fine with the Sigma 2xTC. That being said I think I'd go for the 100-300 plus 1.4x TC just because you can get to 300mm without the TC at f/4 which might be a nice option.

Kind of off topic but a small suggestion. If you can swing it try to pick up a cheap used istDS or something and keep your wide angle lens on it. You won't want to be switching lenses all that often and you may miss some shots if you want to go from landscape to wildlife in a hurry. I did this on a trip to Alaska (I already had the istDS) and it was invaluable

John

Malo1961 · 10-06-2008, 10:48 PM

Originally Posted by Arpe

My 2x EX autofocusses on my Sigma 70-200.

My Bad.

The loss of AF only counts for the 2x TC and the 4.0/100-300 EX APO DG
Sorry for the wrong information.

Lowell Goudge · 10-09-2008, 02:52 PM

I would go for an older sigma APO 70-200 F2.8 EX. and the 1.4 and 2X TCs.

I have had excellent results with these combinations and have posted the results before.

http://www.pentaxforums.com/forums/187646-post19.html

http://www.pentaxforums.com/forums/208249-post1.html

Both shots with 2X TC.

*nobbsie* · 10-09-2008, 04:45 PM

It all depends on whether you need f/2.8 or not. If you don't then the 100-300 would probably be a better choice. However I've gotten great results with the old version of the Sigma 70-200 and the Kenko MC7 2xTC.

Shot with the K20D @ f/5.6, resized and sharpened a little.

104317683 photo - nobbsie photos at pbase.com

104317732 photo - nobbsie photos at pbase.com

*woodworm* · 10-10-2008, 03:06 AM

Hi and thank you for the replies.

Both sets of images are very impressive - regardless of which lens combo I eventually go for I will be exceptionally happy if I get something as sharp as those!

If I hadn't very recently had to replace the roof on the back of my house, I would have already bought the Sigma and would be out playing with it - but now I've had extra time to think about it I'm getting all indecisive ... I'm terrible at making decisions!