Pentax SMC P-DA 12-24mm f/4.0 ED/AL (IF) Lens Review

Pentax SMC P-DA 12-24mm f/4.0 ED/AL (IF) Performance

At 12mm, sharpness is already outstanding across the frame at 12mm and stopping down is of little benefit, other than for increased depth of field. At 18mm, the lens performs similarly as far as sharpness is concerned, although there is a slight reduction in sharpness towards the edges of the frame, with clarity falling just short of excellent levels here. Stopping down to f/8 results in the highest levels of sharpness for this focal length. Finally, at 24mm, sharpness in the centre of the frame remains extremely high at maximum aperture, although the clarity towards the edges of the frame takes quite a hit, just scraping below good levels of sharpness. Again, stopping down to f/8 results in outstanding sharpness across the frame.

MTF@12mm

MTF@18mm

MTF@24mm

How to read our charts The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Pentax K-5 IIs using Imatest.

Chromatic aberrations are a little on the high side, exceeding 1.25 pixel width towards the edges of the frame at 12mm, 18mm and maximum aperture. This level of fringing may become visible in large prints or in harsh crops from the edges of the frame along high contrast edges.

CA@12mm

CA@18mm

CA@24mm

How to read our charts Chromatic aberration 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 minimize the problem, hence they usually cost more. For this review, the lens was tested on a Pentax K-5 IIs using Imatest.

Falloff of illumination is well controlled for a wide angle zoom lens. At 12mm the corners of the frame are 1.27 stops darker than the image centre and at 24mm the corners are 0.56 stops darker. Visually uniform illumination is achieved with the lens stopped down to f/5.6 or beyond throughout the zoom range.

Distortion is very well controlled for a lens of this type. Imatest detected 3.81% barrel distortion at 12mm and 0.32% barrel distortion at 24mm. unfortunately the distortion pattern isn't uniform across the frame, having a slight wave to it, which is more pronounced at 24mm and should make it more difficult to apply corrections in image editing software afterwards.

During testing, this lens proved itself very resistant to flare and contrast levels are good, even when shooting into the light. The petal-shaped hood does a reasonable job of shielding the lens from extraneous light that may cause issues.

Add your message