Which tele zoom lens to buy?

Getting to grips with my K100D/18-55mm kit lens, I am seeking advice on buying a telezoom lens to complement my kit, with quality to match without blowing the budget.

I have been looking at the Sigma 70 - 300 mm, which seems a good alternative at a reasonable price. The Sigma 55-200 mm may also be an alternative, but does not seem to have the macro facility.

Specifically, can anybody explain the difference between the Sigma 70-300mm f4-5.6 APO DG Macro and the Sigma 70-300mm f4-5.6 Macro Super II? They seem to have identical spec, but the price differs a lot.

The APO version has an apochromatic element (see http://en.wikipedia.org/wiki/Apochromat for the technical stuff) which makes it a sharper, but more expensive, lens. I have the earlier (Non DG) version of it and its is indeed a very decent lens.

You might want to consider the Pentax 50-200 or its Samsung equivalent, and others say the Tamron 70-300 is a good lens that can be had for relatively little money. The other option is to try to pick up a Pentax SMCF 70-210 ED lens secondhand. They have a very good reputation (which means you will be paying similar money to some of the new lenses I have mentioned).

The Macro function is useful - but as it only reaches 1:2 at 300mm you need a good tripod or a very steady hand! The Pentax/samsung, while not Macro, manages about 1:4, which is pretty good (fills the frame with something 4 inches wide)

There is little point in a macro function on a zoom lens. It will not make the lens anywhere near as good as a proper macro lens, and it's easy enough to use a couple of extension rings if you need to focus closer.

Extension rings should be in everybody's bag, in my view.

G

While what G says is true, the macro function is useful, but not anywhere near as good as a dedicated macro lens...

I have an old Sigma 70-300 Apo Macro, and the APO versions do have a very good reputation, much better than the non-APO version, letter APOs are better still I think... I've moved up to the EX 100-300 and D-FA 100

I hear good things about the DA 50-200, F70-210 and the Tamron..

But to answer your question, it is worth paying the extra for the APO Sigma over the non-APO. Comparing the Sigma APO lens with the others is a subjective matter which I can't answer

Peter

Tony,

Thanks for the info! Most enlightening. Unfortunately, the second-hand market here in Norway is rather limited. However, I found some acceptable prices for Sigma lenses (APO), so I expect that is what I will go for. Pentax original is rather expensive here.

George,

Appreciate the words on macro extension rings. Since there is obiously no optics in the rings, I suppose it doesn't really matter which brand to buy.

Thanks for the advice, gentlemen.

You can also wait for the new Pentax DA 55-300, who seems to come out soon, at a very reasonable price. About the 260 GBP mark, here in the Netherlands.
Martin.