![]() The corners are still not great here at large apertures but the results are very sharp from f/5.6 onward till diffraction impacts the quality beyond f/11. The border/corner issue is slightly improved at 35mm and, more so, at 50mm which is the sweet spot in the zoom range. On the positive side, the quality is pretty good between f/5.6 and f/8 here. At 24mm f/2.8, the worst spot of the lens, there isn't much in it at the borders/corners. ![]() this trend didn't hold in the outer image region. That's throughout the zoom range and quite an achievement in this lens class. Let start with the positives - the broader center zone is very good at f/2.8 and excellent at medium aperture settings. Note: 50mp are still a killer for most lenses. At 50mp, it gave us a wild ride from the deepest depth of our quality scale up to the near maximum. Well, you can't state that the Sigma 24-70mm f/2.8 HSM DG OS ART didn't entertain us regarding its resolution characteristic. The vignetting is substantially reduced at f/4 and pretty much gone from f/5.6 here. The light falloff increases again at the far end with a max. Vignetting is a lesser issue in the middle range. Even so, you will still be able to spot traces of vignetting in critical scenes. Stopping down to f/4 helps but it's more acceptable from f/5.6 onward. The light falloff is worst at 2.5 EV (f-stops) at the 24mm setting - this is clearly visible. Tamron’s lenses are already matching or besting some of their Canon and Nikon counterparts with their best copies, so this is excellent news.The vignetting analysis didn't reveal any special surprises. Tamron has also emphasized their new quality-control testing machinery (with Modular Transfer Function testing) and high manufacturing standards that aim to reduce variation between lenses to a bare minimum and produce consistent, high quality for modern high-megapixel sensors. The new model is compatible with the Tamron TAP-in console so that firmware can be updated and focus adjusted. It’s about 80g heavier than its predecessor, though. However, the basics measurements remain unchanged, with an 82mm filter ring, and a physical length and width of 4.4 x 3.5 inches (with minor variations depending on the mount). Both Tamron lenses have a minimum focusing distance of 15 inches, so the magnification ratio will remain the same, and both lenses have nine circular-blade diaphragms for aperture control.Īs expected, the exterior of the lens matches the existing lenses in the company’s new “SP” line, with a warm silver ring around the lens mount and simply-ribbed focus and zoom rings. The lens formula and glass-types remain the same as the first generation, both with 17 elements in 12 groups, containing three low-dispersion elements, three glass-molded aspherical elements, two XR glass elements, and one hybrid-aspherical element. The optics in the new lens have been treated with Tamron’s latest eBAND coating, which improves contrast and reduces flare. Not to scale, the Tamron and Sigma 24-70 lenses are both stabilized and attractive lenses. ![]() The auto-focus MPU has built-in digital signal processing blocks, so focus is expected to be responsive and precise, with particular improvements in difficult AF situations like low-light. While the company did not specify a stop rating for their first generation lens (it was probably around 3 stops), they are now claiming 5 stops of stabilization with their G2. In the second generation lens, Tamron has concentrated on improving image-stabilization and autofocus performance by providing the lens with dual micro-processor units (MPU), one dedicated to focus and one to VC. However, while Canon has still failed to release a stabilized competitor in the intervening years, Sigma has announced an ART series lens, Nikon has a VR model, and as of this morning, Tamron has announced the second generation of their stabilized lens: the Tamron SP 24-70 mm f/2.8 Di VC USD G2. ![]() ![]() Five years ago, Tamron was the first manufacturer to release a stabilized 24-70 f/2.8, and our initial tests showed that it performed very well against the subsequently released (non-stabilized) Canon 24-70 f/2.8L II, though the Canon was measurably sharper. ![]()
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