Pentax SMC DA 12-24mm f/4 ED AL (IF) offers a wide zoom range, but is it any good? The What Digital Camera Pentax SMC DA 12-24mm f/4 ED AL (IF) lens review reveals...
The use of mixed red, green, blue and silver markings may reduce the Pentax 12-24mm’s stylistic appeal but beneath the skin this is a very attractive lens that is well specified and competitively priced.
The zoom ring occupies the centre half of the lens and benefits from a deeply ribbed grip that feels exceptionally secure. Rotation is smooth and feels very positive, causing the lens to shrink back then extend again as the zoom is moved from one end of the range to the other. There is minimal overall extension.
Focusing can be carried out manually, using a narrow collar that is located immediately behind the flange that carries the accessory mounting thread, or automatically with full-time manual intervention. The AF mechanism is not especially quiet and causes the manual-focusing ring to rotate so fingers have to be kept clear: the moment that it stops, however, the ring is instantly available to relay manual refinements to the optics inside.
The use of two aspherical-profile elements and another element made of low-dispersion glass is designed to ensure a high degree of optical correction, but high-magnification inspection of the test-chart images revealed significant colour fringing. That said, real-world pictures are very sharp and do not suffer from any obvious colour fringes.
There is a slight anomaly in that the 24mm curve drops below the others at the widest apertures, but even here the performance remains very solid. Minimum aperture should be avoided but, except for wide-open at 24mm, all other settings return MTF figures that stay above 0.25 cycles-per-pixel and peak resolution, around f/8, is comfortably in excess of 0.3 cycles-per-pixel (as are f/5.6 and f/4 at 12mm).
In use, Pentax’s lens has a reassuringly solid feel. The IF label might suggest that there will be no movement of the focusing ring when AF mode is selected but that is not the case. That disappointment and minor cosmetic considerations aside, this is a very nice lens indeed.