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07-19-2008, 09:21 PM   #1
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Pondering between a FA 28-105mm 3.2-4.5 & Sigma 24-135mm 2.8-4.5 for K20d.

Let me preface this by saying that I usually shoot portraits, but otherwise consider myself a general photoenthusiast. My current all-rounder lens for my K20d is the Sigma 17-70mm F2.8-4.5 DG. While it's a good performer, it does weigh a good bit and doesn't have as much length to it as I'd like, as I find myself shooting zoomed-in a lot. I thought about grabbing the Sigma 24-135mm F2.8-4.5 asp; it would offer almost double my current focal length of my current all-rounder while keeping similar aperture, but at the cost of more weight, (maybe) slightly less IQ, and slower auto-focus (more glass to move). The FA lens, on the other hand, is almost half the weight of my 17-70mm (and less than half the weight of the 24-135mm), which is good as I find myself just taking my K20d with me in my duffel bag more times than not. It isn't quite as fast at the wide end, nor quite as wide (or as varied) an FOV, nor quite as long as the Sigma 24-135mm, but I'd imagine it would auto-focus faster, as there's less glass to move. I'm not particularly concerned about shooting wide, but rather trying to find a good balance between overall image quality (with a bit of emphasis on sharpness), travel weight/bulk, & more zoom length. I can't afford to buy both lenses, but I'd keep my current Siggy in either case, as it has served me well and would be useful for when I'd have to put more emphasis on wide-angle shots and better IQ-I believe that either choice I'm looking at would have slightly less IQ than my current lens, but I'm looking at other factors now. Right now I'm kinda leaning towards the FA because of its lower weight/bulk, but I'm feeling that the Sigma would probably be better in the long-run due to its FOV of 36-202mm verses the 42-155mm the FA would offer me. Whaddaya guys think?

07-20-2008, 05:37 AM   #2
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I haven't used either one of these lenses myself, but I checked pbase for sample pics and here's what I found:

Pentax smc P-FA 28-105mm F3.2-4.5 AL IF Lens Sample Photos and Specifications
Sigma 24-135mm f/2.8-4.5 Lens Sample Photos and Specifications

I've given this some thought myself, as I'm also in the same boat with the Sigma 17-70. I'm planning on buying the DA12-24 in the next month or so and since there's a good bit of overlap between the 12-24 and 17-70, I've given some thought to getting something with less overlap.

Instead of doing that, I've also given some thought to eventually getting a DA*50-135/2.8 for those times I need a faster telezoom. As long as I'm not planning on shooting wildlife or anything too distant, the 50-135 would work nicely with the 12-24 and DA35 macro. In the meantime, I'll try the same combination with the DA55-300 that I already have.

07-21-2008, 09:31 AM   #3
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It does, hwblanks. More samples are always good. Looks like the IQ from the samples I've studied look good for both, although I have to say the Sigma looks a tad softer. I just wish I can make up my mind which one would be better-zoom length, or weight. Days like this I wish my car was solar-powered Sherman tank-no gas & no insurance to worry over.
07-21-2008, 10:19 AM   #4
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QuoteOriginally posted by Grimlock Quote
although I have to say the Sigma looks a tad softer.
Sigma 24-135/2.8-4.5 is soft, yes... I have purchased one back when Cameta Camera was unloading 'em for < USD $100 apiece on ebay... you generally need
to close it down 2+ stops to get anything acceptable (= f6.7+)

07-21-2008, 12:07 PM   #5
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I personally have owned Pentax FA 28-105mm f/3.2-4.5. I almost bought a Sigma 24-135 f/2.8-4.0 but find the lens too bulky for walk around and found it soft in testing shots.

The Pentax FA 28-105 f/3.2-4.5 is not the sharpest at wide open aperture, but it is great for walk around purposes as it is really lightweight and small, it is not much bigger than the kit's lens. I have done some night shooting with the lens and found it reasonably good and I love the lens for its color, and it is very compact and light.

Pentax SMC FA 28-105 f/3.2-4.5 Test Shots - Hin's Tech Corner

And I find the lens more outstanding in film camera with Pentax PZ-1

Pentax PZ-1 & SMC FA 28-105 f/3.2-4.5 - Hin's Tech Corner


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