Pentax Q Review

Distortion

The lenses exhibit a more pronounced distortion than we are used to see from APS-C and larger format lenses. This could very well be unavoidable given the small focal lengths of just a few millimeters (8.5mm for the standard prime) combined with the much larger distance from sensor to optical mid point (which we estimate to about 25mm).

We shall take a closer look at the distortion of the two "real" lenses, the 01 Standard Prime and the 02 Standard Zoom, for which the camera has built-in distortion correction. Correction is not available for the 04 Toy Lens Wide, and is largely a non-issue for the 05 Toy Lens Telephoto. The 03 Fish-eye lens distorts by design of course.

The camera can correct distortion for JPG images. To correct RAW images you can either "develop" the images into JPG in the camera, or use the included SilkyPix post-processing software.

We think it will become the rule rather than the exception in the future that optical flaws are corrected by firmware in the camera and that one when evaluating the optical performance of a system should look at the combined effect of lens and firmware correction.

What is really useful is that correction is applied to the live view image on the LCD monitor, so the image you see on the monitor when composing your shot is corrected for distortion! This makes it possible to frame your shot accurately since what you see on the monitor is what you get. The excellent in-camera correction made us prefer shooting in JPG for most subjects since no extra effort was then required during post-processing of the images.

01 Standard Prime Brick Wall Test

Uncorrected Corrected in camera
Uncorrected Corrected

The correction is perfect. The remaining misalignment is due to the shot being hand held.

02 Standard Zoom Real-world Image Test

Uncorrected Corrected in Camera
5mm uncorrected 5mm corrected
5mm 5mm
6mm uncorrected 6mm corrected
6mm 6mm
8mm uncorrected 8mm corrected
8mm 8mm
10mm uncorrected 10mm corrected
10mm 10mm
15mm uncorrected 15mm corrected
15mm 15mm

Very little correction is required from 10mm and up. Again, the correction is near perfect - straight lines become straight after the correction is applied.


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