Essai du Tamron 20-40 mm f/2,8 Di III VXD sur Sony Alpha 7R III par Arkadiusz Olech (traduit par Maciej Latałło) pour LensTip.com :Tamron 20-40 mm f/2.8 Di III VXD review - LensTip.com
Points forts :
- très bonne qualité d'image au centre sur toute la plage de focales
- qualité d'image raisonnable sur les bords du format APS-C
- pas de problème sérieux d'aberration chromatique longitudinale
- aberration chromatique latérale négligeable
- faible aberration sphérique
- astigmatisme modéré
- autofocus silencieux, rapide et précis,
- léger vignetage sur capteur APS-C
- performances raisonnables en contre-jour
- focus breathing
Points faibles :
- vignetage important sur capteur 24x36
- distorsion notable à la focale la plus courte.
Our expectations we voiced at the beginning, that the limited focal range of 20-40 mm might allow Tamron to construct a handy, lightweight lens which would be also optically very efficient, proved to be right. Our list of pros is very long and includes very significant positions. The list of cons, for a change, is nicely short and it includes just completely predictable issues which, additionally, can be corrected by appropriate software. In case of distortion, for example, it was made easy by the producers as they offered you some field of view to spare.
The current price of the Tamron 20-40 mm f/2.8 Di III VXD reaches $700 and it's rather high, being $100-$200 lower than the price of such models as the Sigma C 16-28 mm f/2.8 DG DN or the Tamron 17-28 mm f/2.8 DI III RXD that are more difficult to construct. We would complain about this fact a lot more if only the tested lens fared poorly in our tests. As its results are very good you just have to sigh and get over it. Perhaps, after all, it is well adjusted to the parameters and performance, offered by this lens.