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

Handling and Features
Performance
Verdict
Specification



This ultra-wide angle zoom lens provides an angle of view equivalent to an 18-36mm lens on a 35mm format, when mounted on a Pentax Digital SLR. It sports a constant aperture of f/4 throughout the zoom range and costs around £730.

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

This lens is one of the premium offerings from Pentax, as denoted by the metallic green ring around the lens. Consequently, build quality is very solid indeed with a metal lens mount and a mixture of high quality plastics and metal used for the construction of the lens barrel. The lens weighs around 430g and balances well with the Pentax K-5 IIs body used for testing.

Focusing is performed internally, so the lens barrel does not extend during focusing, although the front section of the lens extends by a few millimetres at either end of the zoom range. As a result the filter ring does not rotate, which makes it perfect for use with polarising and graduated filters. A petal shaped hood clips bayonet fitting on the front of the lens and it has a removable section to provide access for adjusting a polarising filter while it is attached.



The manual focusing ring rotates during auto-focus, so care may need to be taken to it catching your fingers as it moves back and forth. Manual focusing action is smooth although there is very little damping on the focus ring, which can make applying fine adjustments tricky. The Pentax 'Quick Shift' focusing system has been implemented on this lens, which means manual adjustments can be applied once the lens has focused automatically. Auto focus is screw-driven, so it generates more noise than newer silent focusing lenses do. Even so, it locks onto subjects very quickly.

The minimum focus distance of 30cm is typical for a lens of this type and it is close enough to pose no issues when shooting in claustrophobic environments, or for exploiting the distorted perspective produced by wide angle lenses used close up.

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.

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

Value For Money

Being priced at around £730, this lens commands a similar amount of money as top of the line wide angle zooms for APS-C format do on other camera systems.

Sigma produce a 12-24mm wide angle zoom, which can also be used on full frame cameras, which costs around £560, although it has a slower variable aperture of f/4.5-5.6 and a bulbous front element means filters cannot be easily attached. Sigma also produce a 10-20mm f/3.5mm lens which sports silent internal focusing, a slightly faster maximum aperture and only costs around £390.

Tamron also produce a 10-24mm f/3.4-4.5mm lens for Pentax, which costs around £350. This lens provides a similarly wide 10mm focal length to the Sigma lens, but has a variable maximum aperture.

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

Overall, this is a fantastic quality wide angle lens, which delivers sharpness that will satisfy even the most demanding photographers. The lens is well built, and priced similarly to equivalent lenses from other camera manufacturers. It's a shame CA levels are quite high towards the edges of the frame, and that the distortion pattern has a slight wave to it, but these flaws can easily be overlooked by most who value clarity above all else.

	The Pentax SMC P-DA 12-24mm lens is a fantastic quality wide angle lens, which delivers sharpness that will satisfy even the most demanding photographers.

Pentax SMC P-DA 12-24mm f/4.0 ED/AL Pros

Outstanding sharpness
Very good build
Fast focusing
Hood included

Pentax SMC P-DA 12-24mm f/4.0 ED/AL Cons

Slightly wavy distortion may be difficult to correct properly
High CA levels towards edges of the frame

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
VERDICT

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

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