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

The coronavirus crisis has been adversely affecting many businesses and, sad but true, ours is not an exception. Despite that difficult situation we would like to preserve continuity and high quality of publications available on all our websites. Still, we are now aware it might be impossible without additional financial help. That's why we would like to ask all those who visit, read, and care about Optyczne.pl, LensTip.com i Allbinos.com for support - it's enough you send us a small sum of money via PayPal. If a lot people decide to support our websites we think we'll stand a chance and survive next months without any lasting harm. We count on your support and understanding, stay safe and be healthy.

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