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Old Sep 30, 2006, 10:11 AM   #11
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Very interesting, thanks for sharing.
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Old Sep 30, 2006, 1:48 PM   #12
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Thank you elduderino. I hope a further kit lens vs. sigma lens vs. S70 comparison won't exhaust you
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Old Sep 30, 2006, 2:02 PM   #13
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bahadir wrote:
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Anyway, I'm considering to make another comparison butwith the sigma 28-300 lens this time...
Just keep in mind that it's a *very* low quality lens (one of the lowest quality lenses you can buy, with poor optical quality ratings from users, even stopped down to smaller apertures, especially on it's long end.

Users rate it's optical quality at 1.9 on a scale of 1 to 5 in the lens surveys at http://www.photozone.de when used on a DSLR with an APS-C size sensor (which is only using the "sweet spot" of the lens, since the sensor is smaller than 35mm film. and only the sharper center portion of the lens is used). On a 35mm film camera, it only rates a 0.92 on a scale that is supposed to run from 1 to 5. It doesn't get much worse than that. Out of hundreds of lenses available for this camera, only a few rate that bad.

It's MTF charts (scientific tests versus user opinions) aren't much better. It's a low quality lens.

If you're going to compare cameras, don't use low quality lenses if you want to see how well a camera can perform. Otherwise, you'll see the limitations of the lens versus the camera.

Yes, a lighter weight, lower cost 28-300mm lens is convenient and easy on the wallet. But, a lot of design compromises go into a lens like that. As a general rule, the greater the difference between wide and long (especially with a lens that's not very bright, like this Sigma), the more compromises that are made.

Is this kind of lens useful? It depends on your intended purpose for the images. It's not a very high quality lens. If you're not making larger prints, the design compromises may be worth it to you, in return for low cost and light weight in a lens with a relatively useful focal range.

Also, most DSLR models don't have things like sharpening, saturation and contrast bumped up as much as the in camera processing from non-DSLR models. So, keep in mind that a little post processing may be needed for a fairer comparison if you want to see what a camera is capable of.

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Old Sep 30, 2006, 3:02 PM   #14
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Also, most DSLR models don't have things like sharpening, saturation and contrast bumped up as much as the in camera processing from non-DSLR models. So, keep in mind that a little post processing may be needed for a fairer comparison if you want to see what a camera is capable of.
Exactly... its called P&S for a reason. There is alot of in camera enhancement going on. They are set up this way because they target a different market, usually those that just want to shoot, print out a 4x6 and go. The DSLR is going to be set less agressive giving more control to the photographer. You can bump up saturation and contrast in the DSLR and get the same results. I would also compare full size images or 100% crops and different ISO settings.
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Old Sep 30, 2006, 3:38 PM   #15
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Hopefully, my comments won't offend your friend. Many users like a general purpose "walk around" lens like that Sigma.

It's convenient with a very useful focal range, and it can produce pleasing images at the print sizes most users would need.

But, if you're going to "pixel peep" (comparing images to see what a camera is capable of capturing), almost any lens would be a better performer compared to that one.

Any lens choice is a compromise (size, weight, optical quality, brightness, focal range, ergonomics, flare resistance, color, contrast, sharpness, chromatic aberrations, distortion, Autofocus Speed, cost, etc.), and no one lens is "just right" for all users in all conditions.

If I want the best quality images possible, I use a good prime. If I want something that's lighter as a walk around, I use a mid quality zoom (just not one with that much difference between the widest and longest focal lengths). But, each user is going to have different requirements for a lens, and different uses for the images it produces.


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Old Sep 30, 2006, 3:47 PM   #16
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Thanks for yor expert feedback, Jim. Much appreciated! I am too aware of the importance of the lens, sensor andimage processorfactors on the final image quality. As I said, I just intend toget a budget dslr with the least investment (who doesn't!)So, I could even persuade my friend to upgrade to the 400d making a small contribution to his purchase by buying his 300d )
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It's MTF charts aren't much better. I wouldn't buy one, and if I had one, I probably wouldn't use it as a door stop either (it's not heavy enough for that purpose). lol
:lol:...fortunately it is free to try for me. I hope you can, at least, bearseeing comparable imagestaken withthe kit lens and the sigma on 300d.Just required an interval of lens changing time, about one minute.. Both at 1/500; f/7.1; iso 100@ 35 mm.and in M mode.

First the Sigma 28-300...
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Old Sep 30, 2006, 3:48 PM   #17
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and the kit...much difference?
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Old Sep 30, 2006, 4:05 PM   #18
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I edited out the door stop comment after reflecting on it. It was a bit harsh.

But, I see that it was noticed and you made the quote before my edit. :-) Oh well....

Actually, the Sigma looks better to my eyes between those two shots. But, they aren't being taken in controlled conditions and even a slight change in lighting or focus point can make a big difference.

The Sigma really doesn't look *that* bad on it's wide end stopped down some from what the MTF charts indicate (although on the long end, it would not be my lens of choice for sure). The user performance surveys are a little less forgiving compared to the charts. lol

Again, if you're not "pixel peeping", a lens like the Sigma can produce pleasing images. But, if you want to start comparing detail captured with other cameras, there are much better lenses around. Ditto for the "kit" lens. These are not the highest quality lenses, as lens quality goes. They're designed to be light weight for their focal range, with a budget price.

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Old Sep 30, 2006, 4:18 PM   #19
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style="BACKGROUND-COLOR: #000000"@ widowmaker and Jim: I am so pleased to read your valuable comments which I couldonly see after having sent these two images

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I edited out the door stop comment after reflecting on it. It was a bit harsh.
Harsh enough for the Sigma company to sue you???:G
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Old Sep 30, 2006, 4:22 PM   #20
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As the old saying goes (at least in my part of the world), "you can't squeeze blood out of a turnip" :-)

Also, I'd have lots of users on my side (the user performance surveys rate it poorly compared to other lenses). In addition, Sigma might not want the comparisons with a higher quality lens to be shown in court.

P.S.

It's only my personal opinion anyway. Just because I wouldn't want to use one doesn't mean that you wouldn't want to use one. lol

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