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 p.48 #4 · p.48 #4 · Official: Tamron 35-150mm F/2-2.8 Di III VXD (Model A058) | |
Sorry, this is going to be a rather lengthy post. I spent some time looking at my copy of Tamron 35-150 against the Sony 35 GM, 16-35 GM, 24-105 G, 100-400 GM, and Sigma 105 mm F2.8 DG DN Macro. Three series of images were collected at 35 mm, 100 – 105 mm, and 150 mm; all with 100 ISO, wide-open except the 35 GM at F2. All in-camera corrections and DRO were turned off. The camera (A1) was on a tripod. A remote shutter control was used, with a 10 s delay for the image acquisition. For each focal length, a total of 8 images were collected; of these, 4 were with the camera stabilization turned off. The best of the eight images was selected and used for the following comparisons.
The target was somewhat primitive (see the image below), but it served its purpose for what I wanted to learn. The camera was ca. 2 m away from the target at 35 mm, near 5 m at 100 mm, and near 7 m at 150 mm. Thus, all images of the target filled the frame of the sensor similarly.
The objective of this testing was three-fold: (1) to learn how the Tamron fared in comparison to the Sony lenses, (2) to see whether there could be some pronounced decentering, strong filed curvature, or some other quality problem with my copy of the Tamron, and (3) separately, to compare the Tamron wide-open to one-stop closed (F2 vs 2.8 and 2.8 vs 4) at 35, 100, and 150 mm.
In all cases, the images for comparisons were generated from the RAW files in DxO Photolab using Cobalt Standard color profile with no corrections applied, except some WB adjustments. Note that these should look quite different from the out-of-camera JPGs, or images post-processed by other means, with the sharpening, contrast, vignetting corrections, etc. applied.
Here are my findings for question 1. The lenses are listed below in the order of apparent loss of quality in the corners of the images, starting from the best one. “>” means better, “~” means hard to distinguish. The central chart looked indistinguishable in all images; thus, the lenses used here produce practically the same quality in the center. For the corners:
At 35 mm:
Top left: Tamron ~ 35 GM > 24-105 G > 16-35 GM
Top right: 35 GM ~ Tamron > 24-105 G > 16-35 GM
Bottom right: 35 GM > Tamron > 24-105 G > 16-35 GM
Bottom left: 35 GM > Tamron > 24-105 G > 16-35 GM.
Summary: The Tamron comes shockingly close to Sony 35 GM (both at F2) in the corners. Tamron is better than the 24-105 G at 35 mm despite the 2-stop F difference. The 16-35 GM is softer at F2.8 than the 24-105 G at F4, but only marginally so – this difference is most likely of no practical concern.
At 100 mm (Tamron and 100-400 GM) – 105 mm (24-105 and the Sigma):
Top left: Tamron > 100-400 GM > 105 DG DN > 24-105 G
Top right: Tamron ~ 105 DG DN > 100-400 GM > 24-105 G
Bottom right: Tamron > 105 DG DN > 100-400 GM > 24-105 G
Bottom left: 105 DG DN > 100-400 > Tamron > 24-105
Summary: Overall, Tamron is excellent at 100 mm F2.8; there is some drop in IQ in one corner, of no practical concern. Tamron seems overall better than the other two zooms, however, I don’t mean to exaggerate the differences. In real life, all four lenses can be expected to produce good image quality.
At 150 mm:
The 100-400 GM at F5 seems marginally better than the Tamron at F2.8 in three corners, except the bottom left where the Tamron is better. The differences are probably insignificant in practice.
Conclusion: (a) If the 35-150 mm lens had been produced by Sony, I believe it would have merited the GMaster designation, (b) Replacing the 24-105 mm F4 G lens by Tamron 35-150 F2-2.8 paired with the 16-35 F2.8 GM seems right to me, however this is certainly one of those personal choices where opinions might differ.
Here are the findings for questions 2 and 3, asked earlier in this post. For 2, I seem to have a good copy of the Tamron lens – no reason to complain whatsoever. For 3, when comparing the images at 35 mm F2 vs F2.8, also at 100 and 150 mm at F2.8 vs F4, the major effect of stopping is the significantly reduced vignette. The image quality is marginally improved as well, but the improvement is very minor. Other than the pronounced vignetting, shooting the Tamron wide open is of no practical concern. This indeed suggest that Tamron might be a lens of choice for event shooting indoors, as has been already noted by others.
the overall setup of the target
at 35 mm, from the upper left corner
at 35 mm, from the upper right corner
at 35 mm, from the bottom right corner
at 35 mm, from the bottom left corner
at 100-105 mm, from the upper left corner
at 100-105 mm, from the upper right corner
at 100-105 mm, from the bottom right corner
at 100-105 mm, from the bottom left corner
at 150 mm, from the upper left corner
at 150 mm, from the upper right corner
at 150 mm, from the bottom right corner
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