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Old Apr 22, 2006, 6:44 AM   #1
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I am wondering whether to buya 18-55 and50-200 pentax lens set, or a Sigma 18-200mm, or a Sigma 28-300mm lens, and am not sure what would be best.

I take images of all kinds and at all distances, and am rather impatient, and would not really want to keep changing lenses all of the time.However I don't want to spend money on a lens that might be rubbish.

Can anyone advise or comment on the quality of the Sigma lenses (18-200, 28-200, and the 28-300mm)and advise me on what they think I should do?

I look forward to your replies, with many thanks.




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Old Apr 25, 2006, 8:34 PM   #2
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The two Pentax lenses are better optically than the single 18-200mm Sigma. However with the single lens you don't have the hassle of lens swapping (and far less risk of sensor dust). It depends on what you want. For ultimate quality both of these choices are a compromise, the Pentax 18-55mm and 50-200mm lenses are better than the 18-200mm Sigma since they are not faced with the wide to tele issue (lenses wider than 35mm and lenses longer than 80mm have very different requirements so any lens that spans that range will either be expensive and heavy or will have made some optical compromises that other lenses may avoid).

Having said all that I should note that in most cases you will probably not be able to tell the images from the two lens choices apart. The Sigma will probably produce images that are sharp enough to produce 8" X 10" images that are quite impressive. Only when pushed to their limits will you notice any difference and even then it may be small. The Sigma coatings may not be up to Pentax SMC standards but they will probably perform just as well 90% of the time.

Glad I could help by clouding this issue even more:?, good luck deciding. If it is any consolation, I use both Pentax lenses and a Sigma 24-135mm seehttp://www.stevesforums.com/forums/v...=80&page=2 . I have found no reason to see the Sigma as anything but a quality lens, and the Sigma 70-300mm and 75-300mm tele zooms are very popular with people on this forum.

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Old Apr 25, 2006, 9:30 PM   #3
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Ira

I see you have received your Sigma 24-135 Lens, how have you found it?

Also did you know that Sigma lenses are manufactured by Pentax :shock:

My Pentax guy repairs lenses and said when you open them up, the optics etc are marked Pentax Asahi Optics Coy. Believe it or not!!:-?
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Old Apr 29, 2006, 7:04 AM   #4
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Crashman, the 24-135mm is quite nice, I am getting some decent results and hope to try it out this weekend. I find it very heavy but with a confidence inspiring solid feel. So Asahi Optical makes the glass for Sigma, interesting. The camera and lens industry has become like the automotive industry, each new item has components that may be from competing manufacturers.

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Old Apr 29, 2006, 3:42 PM   #5
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Monza76 wrote:
Quote:
Having said all that I should note that in most cases you will probably not be able to tell the images from the two lens choices apart. The Sigma will probably produce images that are sharp enough to produce 8" X 10" images that are quite impressive. Only when pushed to their limits will you notice any difference and even then it may be small.
The Sigma 18-200mm is known for it's focus issues beyond 135mm i.e. it doesn't unless you focus lock at 135mm and then zoom out to 200mm.

Given that limitation I would comment that you would see the difference at any resolution when using this lens beyond 135mm.

See thread: http://www.stevesforums.com/forums/v...mp;forum_id=80for other responses.
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Old Apr 29, 2006, 7:10 PM   #6
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Oops, that kind of test data is pretty clear. Wonder if anyone has tested the 24-135mm f2.8-4.5 Sigma? I have read in the Popular Photography test that it has some distortion issues but is generally a pretty good lens (it is replacing the FA 28-80mm f3.5-5.6, a not very impressive lens to begin with).

I apologize for my uninformed comments, I retract any endorsement of the 18-200mm Sigma until further information is available.

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Old Apr 30, 2006, 3:44 AM   #7
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The review that I refered to in an earlier post is at:

http://www.epinions.com/content_185158569604

which to fair was for against the Canon version BUT my own personal experience testing the Sigma 18-200mm on my *istDS confirmed that it was also a problem with that lens.

Another review can be found here:

http://www.photozone.de/8Reviews/len...3563/index.htm
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Old May 21, 2006, 8:03 PM   #8
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I am thinking on purchasing this lens myself and wonder how fast the auto focus is.
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