Hi,

i have to decide between Sigma 10-20 and Tamron 10-24.

About the Tamron I did't find to much about how it works on Pentax. There are some reviews and tests, but most of them are on different cameras so it's hard to compare.

Although the tests are really different, they all have in common that the Tamron is not sharp wide open especially at the boarders. So I was almost about to get the Sigma, but then I read the review on dpreview for both lenses.

The verdict is, that the Sigma is better at the boarders but overall quality the Tamron is at least as good as the Sigma, especially when stopped down a little bit

dpreview

I'm especially looking at the overall conclusion and the sentence that starts: "Compared to other...."

If the Tamron is just a little bit less sharp than the Sigma I Would prefer the Tamron because the 20-24 range that if offers compared to the Sigma would make 5-10% of my pictures. But if it is significant less sharp I would prefer the Sigma.

I'm not a pixelpeeper, but IQ is important to me (but not looking at it at 100%.

Thanks in advance for any suggestions
Richie

[forensicscientist]

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/72317-i-love-m...y-10-24-a.html


mark

[Knurled Knob]

Richie -- Until yesterday I was had been trying to make the same decision as you for several weeks. I really wanted the extra zoom range of the Tamron, but was concerned that it rendered a lower quality image than the Sigma as earlier reviews of the Tamron indicated. The more I researched, however, the less concerned I became. I found the dpreview you mentioned to be helpful. Another was at photocrati, and there were some others as well that I'm blanking on right now. Probably most helpful to me was reading the discussions and reviewing images like Mark's on flickr at the Tamron 10-24mm group.

Most important to me were the reports that the Tamron was sharper in the center and at a greater range of focal lengths and apertures, and probably produced better colors. I rarely print photos and never print greater than 8x10, so the issues reported by pixel peeping 100% crops at the edges aren't as important to me. To me, ultrawide lens photography is about producing images that draw the viewer into the scene. In my view, having a sharp center is vital ... a slightly lower IQ at the edges is not a big deal. If I look at something in the room I am sitting in, only the center of the image I see is sharp ... outside 30* angle of view everything is a blur. Having a relatively sharp image across a 109* angle of view (whether from a Tamron, Sigma, Pentax or other lens) is an amazing achievement!

So for me, the faster, greater zoom range, center sharpness, color and 6 year warranty of the Tamron was the choice, although it was still a close call to make.

Scott

[Pentaxor]

the Tamron's advantage here is the extra 4mm focal length and warmer color.
the Sigma on the otherhand is the sharpness.

I don't really rely on the dpreview reviews too much as they seem to be inconsistent or sometimes have the opposite results compared to other reviews and even to real world results coming from users. the better center sharpness alone is debatable as the Sigma has an already excellent center sharpness. if you are shooting landscape or architecture that needed sharpness in the borders and extreme corners, the DA 12-24 is the best one, though quite pricey. if you can't have a DA 12-24, the Sigma would be the better alternative to it, IMO.

[MattGunn]

I also was trying to make this decision a couple of weeks ago. In the end I decided to get the Tamron and I have no regrets. I can't really comment on its performance yet as I am undoubtedly the limiting factor. I have only had it a week and a half and haven't had the chance to play with it as much as I would have liked yet but already I'm glad I have the extra 4mm over the sigma.