LensTip.com

Lens review

Pentax smc FA 77 mm f/1.8 Limited

22 September 2009
Arkadiusz Olech

7. Coma and astigmatism



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

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

The frame edges near the maximum aperture were not the best so we were curious whether the coma had a hand in that result. Looking at the crops below it can be clearly seen that it did. Its influence on the deformation of the circular diode is perhaps not very strong but it is certainly visible and it keeps the same, perceptible level even on stopping down by one stop. The Pentax visibly gives in to a Zeiss 1.4/85 which is faster so more difficult to correct. The lens also comes out poorly when compared to a Nikkor 1.8/85, which performance in this category is splendid or a Canon 1.8/85 – both of them corrected the coma better.

Pentax smc FA 77 mm f/1.8 Limited - Coma and astigmatism

The competitors from Canon and Nikon corrected astigmatism very well too – in their case this aberration remained at the level of 5-6%. Luckily here the Pentax doesn’t stand out from its rivals and reaches practically the same result of 5%.