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View Full Version : Sigma & Tamron 18-200mm Zoom Lens



WightWalker
02-01-2006, 12:15 PM
18mm Test

For those that read Steve's Digicam forum, this will look familiar but I thought it worth posting here as well for anyone considering either of these lens.

Here's the Sigma 18-200mm & Tamron 18-200mm compared against the Pentax 18-55mm - unfortunately, I ommitted to save the Pentax RAW format.

Sigma wins over the Tamron, close to Pentax in JPG - better in RAW.

WightWalker
02-01-2006, 12:21 PM
55mm Test

Here's the Sigma 18-200mm & Tamron 18-200mm compared against the Pentax 18-55mm - unfortunately, I ommitted to save the Pentax RAW format.

Sigma still wins over the Tamron, close to Pentax in JPG - better in RAW.

WightWalker
02-01-2006, 12:23 PM
135mm Test

Here's the Sigma 18-200mm compared against the Tamron 18-200mm.

Sigma still wins over the Tamron - better in RAW.

WightWalker
02-01-2006, 12:24 PM
200mm Test

Here's the Sigma 18-200mm compared against the Tamron 18-200mm.

Overall, the Tamron wins over the Sigma - better in RAW.

WightWalker
02-01-2006, 12:25 PM
200mm Test
Here's another Sigma 18-200mm compared against the Tamron 18-200mm.

This one clearly shows how much better focused the Tamron is over the Sigma; this decided me against the Sigma as it wos poor above 135mm & the Tamron which is poor below 135mm.

Conclusion
Overall, the results are in keeping with the review here:

Sigma - http://www.epinions.com/content_185158569604
Optically good, despite vast range. But at 200mm, I have to either manually focus, or use a parfocal technique (i.e. focus at 135mm, shoot at 200mm).

Tamron - http://www.epinions.com/content_192627838596
More optical shortcomings than its Sigma counterpart, but my copy focuses better. Despite optical shortcomings, I can still make decent 8.5"x11" prints.

The Sigma is useful in the range 18-55mm & out to 135mm but given the restrictions on 200mm focusing, it's not for me.

The Tamron quality falls short of the Sigma except at 200mm, again it's not for me.

For the time being I'm sticking with the Pentax 18-55mm kit lens & will purchase the Pentax 50-200mm to extend the range - OK it will not be as convenient as using a 18-200mm single zoom BUT I'm not prepared to accept the limitation of either the Sigma or Tamron.

astro
02-01-2006, 11:20 PM
Great tests. I'm quite surprised that the Sigma/Tamron superzooms look better than the kit lens.
BTW do you have higher quality versions? The test images have a lot of JPG artifacts. I can host them for you if you need a host.

WightWalker
02-02-2006, 01:47 AM
Full size comparison images can be viewed here:

18mm - http://www.catbells.plus.com/ImageComparison/18mmComparison1.jpg

18mm - http://www.catbells.plus.com/ImageComparison/18mmComparison2.jpg

55mm - http://www.catbells.plus.com/ImageComparison/55mmComparison.jpg

135mm - http://www.catbells.plus.com/ImageComparison/135mmComparison.jpg

200mm - http://www.catbells.plus.com/ImageComparison/200mmComparison1.jpg

200mm - http://www.catbells.plus.com/ImageComparison/200mmComparison2.jpg

The Pentax Kit Lens shots were taken somewhat before the Sigma followed by the Tamron resulting in some lighting differences.

The Point of focus for the Pentax was to the left of centre whereas the Sigma & Tamron were at the centre.

I omitted to take a set of RAW images with the Pentax but having previously compared the Pentax against the Tamron I was more interested in concentrating on the Sigma compared against the Tamron.

Both lens appear to run out of zoom at 135mm i.e. there is very little apparent lens movement as you zoom from 135mm to 200mm.

I would agree that there is very little to choose from between the Pentax & Sigma, & then the Tamron. Had the overall performance across the range been as good, particulary from 135mm to 200mm, then I would have gone for the Sigma.

WightWalker
02-05-2006, 11:31 AM
Well, if ever there was any doubt as to whether my decision to scrap plans to purchase either the Sigma or Tamron 18-200mm was the right thing to have done, results that I've just got from the Pentax 50-200mm remove any of that doubt. OK, we are not comparing like with like BUT the quality of the Pentax is, perhaps as you would expect, superior to either of the independants between 50mm & 200mm.

This is the first of 2 shots

WightWalker
02-05-2006, 11:32 AM
And the second - just look at the difference in clarity

WightWalker
02-06-2006, 09:01 AM
This shot concentrates on the junction boxes, wiring & labelling on one of the boxes.

The Sigma just does not work as it's clearly out of focus.
The Tamron is a considerable improvement.
The Pentax is a clear winner.