LensTip.com

Lens review

Tamron 17-50 mm f/4 Di III VXD

13 March 2024
Maciej Lata││o

7. Coma, astigmatism and bokeh

The Tamron 17–50ámm f/4 DiáIIIáVXD doesn't show any noticeable coma problems. In case of the smaller APS-C sensor this aberration is corrected perfectly well but in the corners of full frame you can notice some deformations of point-like images of a diode. Fortunately this effect is not huge so we can consider the performance to be at least good.

Center, 17ámm, f/4.0 Corner APS-C, 17ámm, f/4.0 Corner FF, 17ámm, f/4.0
Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh
Center, 33ámm, f/4.0 Corner APS-C, 33ámm, f/4.0 Corner FF, 33ámm, f/4.0
Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh
Center, 50ámm, f/4.0 Corner APS-C, 50ámm, f/4.0 Corner FF, 50ámm, f/4.0
Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh


Astigmatism, understood as an average difference between vertical and horizontal MTF50 function values, amounted to 10.2%, a value considered by us to be a medium level. Still there are distinct differences between particular focal lengths. At 17 mm astigmatism is negligible, reaching just 3.3%, but in the 33-50 mm range it increases noticeably, approaching from time to time high levels.


Please Support Us

If you enjoy our reviews and articles, and you want us to continue our work please, support our website by donating through PayPal. The funds are going to be used for paying our editorial team, renting servers, and equipping our testing studio; only that way we will be able to continue providing you interesting content for free.

- - - - - - - - - - - - - - - - - advertisement - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

The appearance of defocused circles of light is sensible. Taking into account the fact that you deal here with a lens of moderately fast aperture that, additionally, is a wide angle instrument for the majority of its range, you shouldn't complain about these images too much. Of course you can mention concentric circles that most likely stem from the presence of aspherical elements in the system. It is also a nice surprise that the influence of mechanical vignetting is noticeable only at the maximum relative aperture and disappears practically completely on stopping down the aperture by 1 EV.

Center, 50ámm, f/4.0 Corner APS-C, 50ámm, f/4.0 Corner FF, 50ámm, f/4.0
Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh
Center, 50ámm, f/5.6 Corner APS-C, 50ámm, f/5.6 Corner FF, 50ámm, f/5.6
Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh
Center, 50ámm, f/8.0 Corner APS-C, 50ámm, f/8.0 Corner FF, 50ámm, f/8.0
Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh Tamron 17-50 mm f/4 Di III VXD - Coma, astigmatism and bokeh