When selecting I've assumed that the images are shot as RAW and then developed with UFRaw, are being corrected with lensfun lens error. (The correction data for this lens are, since February 2013 release of lensfun contained and they are based on my copy ;-) When measuring the lens I have the imaging performance of course exactly considered)
The following lenses were alternatively in question:
- The Sigman 10-20 / 4-5.6 falls from a total average. It has less depth and less treble.
- The Sigma 10-20 / 3.5 ranks in a different price range. For the higher price you get more light, but this is paid for by weaker imaging performance. That reminds me, the light intensity at the focal length does not matter, there was no reason to draw closer this lens into consideration.
- The Sony 11-18 is optically identical to the old Tamron 11-18. It was eliminated because the design is outdated the higher price then no longer mattered.
- The lenses from wide angle specialist Tokina dropped out because they are not available with Sony connector are. The 11-16 / 2.8 would be eliminated because of poor performance in backlight without towards.
The strengths of the Tamron:
- Good performance in backlight. This is particularly important with wide angle lenses and not subsequently corrected
- With short focal length at f 5.6 an excellent sharpness in the center. This creates to correct the reserve to converging lines without much losing quality. (The argument against Sigma)
- Lighter than the alternatives. (The use of plastic is a Qualtätsnachteil is an Urban Legend. Until now, all damage to lenses that I have experienced and seen can be attributed to the failure of metal. What is logical, because the metals that are used for lenses are soft and brittle)
The Tamron is of course not without problems and I want to explain why I think they are great Abel.
- Like all wide angle lenses there are problems with color fringing (CA). This error is easily corrected retrospectively and the correction results in an appreciable gain in sharpness.
- At maximum aperture of local contrast is dull. Although fine details are there, but only weakly drawn. That's a shame, here helps stop down to 5.6.
- Loss of sharpness in the corners. Here, the Sigma is better. The problem diminishes when the CA's are corrected on the one hand. And must be corrected on the other hand with wide-angle shots often converging lines. The high resolution is in the middle of the application, are in any case at least two corners disappear from the image. The correction of barrel distortion shifts already the most problematic areas of the image.
- Decreasing image quality at longer focal lengths. The quality is a nice way for the focal lengths at the highest on whose behalf you buy a super wide angle at the short. Because where there also did that kit lens leaves after the performance.
- The AF is not just fast. Do not bother me with wide angle lenses.
In my copy I was overall pleased with the image quality, which is consistent with the experience of a friend who uses the same lens on his Pentax.
The performance was about what one might expect after the test results. In my copy, there is a slight problem with the centering, the outer right edge is worse. This area falls away in correcting converging lines usually.
By correcting the chromatic aberration (CA) is obtained in the corners noticeable sharpness.
Conclusion: Dreamlike images in a fantastic price.
A word about Full Frame: For a FF camera that thing do of course not make much sense. Since it would be the Tamron or Konika Minolta 17-35 / 2.8-4. But quite useless, it is then not, as long as you can do without at the edges on some sharpness. From about 12mm can be a horizontal strip of need in the middle as Panorame, from about 13mm a square cutout in the center, and from 15mm to give the image corners sky again useful, so you have virtually a shift lens.
