Pentax Q 8.5mm f/1.9 Lens Review


Pentax Q 01 Prime 8.5mm f/1.9 Performance

So is the lens any good? Coupled with the 12MP Q system bodies performance will be slightly better with the larger sensors of the Q7 and Q-S1 bodies and in fact sharpness is impressive.

At the centre, sharpness is excellent from f/1.9 to f/4 and very good from f/5.6 to f/8. The peak is f/2.8 and there is a massive amount of depth of field even at this wide aperture.

The edges are very good from f/1.9 to f/5.6 and still good at f/5.6 and f/8.  

How to read our MTF charts

The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.

The scale on the left side is an indication of actual image resolution as LW/PH and is described in detail above. The taller the column, the better the lens performance.

For this review, the lens was tested on a Pentax Q-S1 using Imatest.


CA (Chromatic Aberration) is very low at the centre and still well controlled at most apertures at the edges. Some fringing can be seen at the edges, but it can be tackled in software.

How to read our CA charts

Chromatic aberration (CA) is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.

Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimise the problem, hence they usually cost more.

For this review, the lens was tested on a Pentax Q-S1 using Imatest.

 

The drawing of the lens is very good, showing just +0.18% of pincushion distortion with correction turned on, but with definite barrel distortion when turned off. Flare is also well controlled, with no problems shooting against the light in terms of artefacts, but a slight loss of contrast in the worst cases.

The sample images were shot with the Pentax Q and Pentax Q-S1 bodies.
 


Value For Money

Prices for the 01 lens on its own can be surprisingly high and also surprisingly variable. It is excellent VFM at £85, but not very good at £181. That is the sort of variation found. When included with a Q series body the value is fine and if possible that would be the way to buy the lens.

For more options have a look at the Top 10 Best Pentax Lenses.

 

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