LensTip.com

Lens review

Tokina AT-X PRO DX 11-20 mm f/2.8

8 September 2015
Arkadiusz Olech

7. Coma, astigmatism and bokeh

The thumbnails below show clearly that the tested lens has no noticeable problems with the coma correction. That aberration is not corrected in a perfect way because images of the diode in the frame corners are a bit deformed but it is not a reason for serious carping.

50D, 11 mm, f/2.8, center 50D, 11 mm, f/2.8, corner
Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh
50D, 16 mm, f/2.8, center 50D, 16 mm, f/2.8, corner
Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh
50D, 20 mm, f/2.8, center 50D, 20 mm, f/2.8, corner
Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh


The astigmatism, understood as an average difference between vertical and horizontal MTF50 function values, amounted here to 4.5% which we consider to be a low value. It’s worth mentioning here that its level was the highest at the 11 mm focal length and the lowest at 20 mm but the differences weren’t that pronounced.


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

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

When it comes to the appearance of defocused images there is nothing impressive there. The circles of light in the centre are noticeably darker (and it is connected to spherical aberration, mentioned earlier) and in the corners of the frame they are deformed, with lighter rims. Still it should be mentioned that their shape is oval but not truncated which means that the vignetting is caused mainly by the optics, not mechanical obstacles.

As you see there are no serious reasons to complain especially that in this type of instruments it is difficult to get wide areas of nicely emphasized blur.

50D, 20 mm, f/2.8, center 50D, 20 mm, f/2.8, corner
Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh
50D, 20 mm, f/4.0, center 50D, 20 mm, f/4.0, corner
Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh
50D, 20 mm, f/5.6, center 50D, 20 mm, f/5.6, corner
Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh Tokina AT-X PRO DX 11-20 mm f/2.8 - Coma, astigmatism and bokeh