Lens review

Pentax smc DA 35 mm f/2.4 AL

5 April 2011
Arkadiusz Olech

4. Image resolution

The resolution test of the tested lens was based on RAW files from the Pentax K-5 reflex camera. In its case the best fixed-focal lenses can reach the level of 51-53 lpmm and the decency level is situated near 34-35 lpmm. Let’s check how the Pentax smc DA 35 mm f/2.4 AL compares here.

Pentax smc DA 35 mm f/2.4 AL - Image resolution

Already at the maximum relative aperture the lens has a very good result in the frame centre - about 43 lpmm. On stopping down its achievements even improve and the peak of 50 lpmm is reached by f/5.6. These results don’t break any records but I suppose nobody expected them to do so in the case of a cheap, plastic, not very fast “prime”.

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The lens can be praised for the edge of the frame too – even by f/2.4 it gets results of 37 lpmm so safely above the decency level. The resolution increase on stopping down is slight, though, so the lens at no point exceeds 40 lpmm. Overall the results are decent but nothing more. Once again, taking into account the price and the target group of this lens, we shouldn’t complain at all.

How do these achievements compare with those of other lenses of this class? You can try a comparison with the Nikkor 1.8/35, tested on the Nikon D200 which gives MTFs about 4-5 lpmm lower than the K-5. The Nikkor fares somehow slightly better in the frame centre as it features f/1.8 aperture and can provide useful images even wide open. Stopped down to f/2.4 it reaches the level near 40 lpmm which, after considering the conversion factor, gives 44-45 lpmm so a bit more than the Pentax. What’s interesting, both lenses perform on the edge of the frame is a similar way. The Nikkor is not useful near f/1.8 but by f/2.4 it is already so and then the resolution increases very slowly – it is a significant disproportion between the performance in the frame centre and on its borders.

At the end we would like to present our testing chart crops taken from the centre; we used not sharpened JPEG files which were saved along RAW files.

Pentax smc DA 35 mm f/2.4 AL - Image resolution