Web Analytics RiceHigh's Pentax Blog: Latest Pentax Reviews: DA18-135 and K-5 Vs 7D

Saturday, June 04, 2011

Latest Pentax Reviews: DA18-135 and K-5 Vs 7D

1. New DA 18-135 Review @ ePhotozine:-

http://www.ephotozine.com/article/smc-pentax-da-18-135mm-f-3-5-5-6-ed-al--if--dc-wr-lens-review-16544

I think the above test is of good reference value. But nevertheless the tester/reviewer/editor has been conceptually wrong about the meaning of MTF, in particular MTF20 is NOT about the "resolution of coarse details" and neither for MTF50 is NOT about the resolving power of "fine details". All in all, the resolving power is measured as either lp/mm (line-pairs per millimetre) traditionally or now lw/ph (line-widths per picture height). The MTF percentage means only the difference between that original totally dark against completely bright test chart patterns, which 100% is the highest possible figure and Zero means that the lens can resolve nothing at all. At MTF 20(%), the dark to white difference is already rather minimal and the contrast is really low, resulting in ambiguity/blur in real life.

2. K-5 Vs Canon 7D Shootout Review @ PF:-

http://www.pentaxforums.com/reviews/Canon_7D_vs_Pentax_K5.php

I think the test is nicely done in general but do bear in mind the primitively biased stance of the PF in favour of the Pentax gear, i.e., when shortcoming is not a shortcoming anymore but yet additional feature *option* of the Canon is a shortcoming instead! :-o E.g., *on-demand* AF possibility during video recording! ;-)