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10-04-2009, 07:17 PM   #1
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Fallingwater's Avatar

Join Date: Oct 2009
Location: Trieste, Italy
Posts: 24
Go-anywhere lens: Sigma 18-200 f3.5-6.3 vs 28-135 f3.8-5.6 vs 28-105 f2.8-4

I'm looking for a zoom lens that I can leave permanently attached to my K20D when not needing specific performance, or when I can't carry much gear with me; the 18-55 kit lens just doesn't cut it.
My past experience with a long-zoom prosumer (a "10x" Kodak Z612) has taught me that all the zoom is nice to have, but the times I've used full zoom on it for actual pictures (as opposed to "let's see how big I can make that house" silly shots) in the three years I've owned it can be counted on the fingers of two hands. Hell, maybe even on one; I almost never go past the half-zoom setting.

The 18-200 has great versatility going for it, with its useful-once-in-a-blue-moon ton of zoom and relatively serious wide-angle.
The 28-135 is less versatile in both tele and wide, but I'm fairly sure I wouldn't find myself missing the additional zoom and wideangle very often; it's also marginally darker than the 18-200 in full wide, but 0.3 f should be barely noticeable. It's a macro lens, too. And then it's also pleasantly cheaper, at half the price (110, vs 220 for the 18-200).
The 28-105 is less versatile again, but it's quite a bit brighter. At 150mm effective though I'm thinking it might leave me wanting for more zoom - and it's not a macro lens. Then again, brightness! (and it too is cheap!)

The big question, and the reason for this post, is image quality. I've been told countless times that ultrazooms can't help but be optically lousy (relatively speaking), and I believe it; by this logic, the 28-135 ought to give me considerably better quality than the 18-200, and the 28-105 should be better again. Is that in fact the case? If yes, how much better, exactly? Is it visibly noticeable, or is it one of those things you only see when magnifying pictures like the CSI guys (except without the magic resolution)?

Any ideas will be very appreciated.


Last edited by Fallingwater; 10-04-2009 at 07:56 PM.
10-04-2009, 08:06 PM   #2
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Stratman's Avatar

Join Date: Mar 2007
Location: St Louis, Missouri U S A
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Posts: 2,464
I bought a Sigma 28-200 zoom recently, and although it is not DA* quality, for what I paid, I can't complain. the model is : 28-200 F3.5-5.6 DL Hyper Zoom Macro. Here are a few shots with it mounted on my K110D from a recent fishing


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