Sigma 50-150 f2.8... Adding a 2x converter?

I have a Sigma 50-150 f2.8 EX DC II which I use a lot and works very well for almost everything I shoot.

However, every now and then I get dragged out with birding friends, and 150mm is kind of short for even the most friendly duck.... I don't really do this enough to buy a dedicated lens for this purpose, but I would like to have something.

Would I be crazy to get a used Sigma 2x teleconverter to use for the odd bird shoot? It would give me 300mm at f5.6, but would the quality be really bad?

Has anyone used a combo like this?

Yes, quality would really be bad. Only to be used for emergencies if you ask me.

Zoom lenses suffer much more from IQ degradation when used with converters/extenders than primes, generally speaking, and beyond 1.4X it tends to get really atrocious.

I'd suggest you'd rather buy an older MF lens, 400 F/5.6, 300 F/5.6, and use an adapter with that. Ok, it is manual focus, but you are likely to get much better results possibly at lower cost than the price of the converter.

Kind regards, Wim

wimg wrote in post #7815028
Yes, quality would really be bad. Only to be used for emergencies if you ask me.

Zoom lenses suffer much more from IQ degradation when used with converters/extenders than primes, generally speaking, and beyond 1.4X it tends to get really atrocious.

I'd suggest you'd rather buy an older MF lens, 400 F/5.6, 300 F/5.6, and use an adapter with that. Ok, it is manual focus, but you are likely to get much better results possibly at lower cost than the price of the converter.

Kind regards, Wim

No the quality isn't really bad. Really, it's not as bad as one is always lead to think. It surprised me. The Af is not as fast, just stop it down a little and it will give you some keepers. But 300mm is still a little short for birds, unless your in a blind.

CountryBoy wrote in post #7815280
No the quality isn't really bad.

Well, I think it is. I sold mine as a result, as I knew I wouldn't use it again.

Seeing is believing.

Yes, me too, in a negative way.

Yes, 1 in about 200, and you need to shoot fairly close, stop down at least 2 stops, and preferably 3 if that is possible without getting into the diffraction zone. To me that is not a little.

True, but if you try to keep things inexpensive, that is where you end.

IME, it is better to stack two 1.4X t-cons, or a 1.4X tcon plus a 1.4X extender, than use a single 2X extender or tcon.

IMO, a 2X extender or tcon is an absolute emergency solution only, but then, that is my opinion.

Kind regards, Wim

I haven't used my Sigma 50-150mm F/2.8 with a 2X TC but I occasionally use the 50-150mm with my Tamron SP AF 1.4X TC when I need that extra reach.. I find the results excellent with very little image degradation..

If I were you I'd either borrow or rent a Sigma 2X TC and do some tests..

wimg wrote in post #7819724
Well, I think it is. I sold mine as a result, as I knew I wouldn't use it again. Seeing is believing. Yes, me too, in a negative way. Yes, 1 in about 200, and you need to shoot fairly close, stop down at least 2 stops, and preferably 3 if that is possible without getting into the diffraction zone. To me that is not a little. True, but if you try to keep things inexpensive, that is where you end.

IME, it is better to stack two 1.4X t-cons, or a 1.4X tcon plus a 1.4X extender, than use a single 2X extender or tcon.

IMO, a 2X extender or tcon is an absolute emergency solution only, but then, that is my opinion.

Kind regards, Wim

I'm thinking user error !

yogestee wrote in post #7821841
I haven't used my Sigma 50-150mm F/2.8 with a 2X TC but I occasionally use the 50-150mm with my Tamron SP AF 1.4X TC when I need that extra reach.. I find the results excellent with very little image degradation..

If I were you I'd either borrow or rent a Sigma 2X TC and do some tests..

That's the one I have and used, the Sigma 2x. The 50-150mm does handle the 1.4 very well. Not a lot of loss in Af speed either.

You can try the 2x, or maybe try to find a good used 50-500mm, and a good tripod.

I think when making comments on the picture quality with a TC you have to take in consideration if its going to be used with a crop or FF body.

To the OP, the 2x converter will produce quite acceptable pics.

Here is a sample (70-200 + Tamron 2x). You decide if it is acceptable or not. But imo, to say that it would be "really bad" is just not true.

What people are saying here pretty much mirrors everything I've read... Some people love 'em, some hate 'em.

I've seen them for sale used for $150ish, which is cheap enough to give it a try... And if it doesn't work out, back on the market it goes!

Thanks to everyone, even conflicting opinions are helpful!