Pictured below from left to right are the Pentax DA 40mm f2.8, the DA 70mm f2.4 (shown twice with its supplied lens hood retracted and extended), and the DA 18-55mm f3.5-5.6 kit lens. Even with the kit lens adjusted to its 35mm focal length where the barrel is at its shortest, you can see straightaway how much smaller the pair of Limited Edition lenses are.

Measuring 63mm wide and just 15mm long (when focused at infinity), the Pentax DA 40mm f2.8 Limited is one of the smallest standard DSLR lenses in the world. Weighing 90g without its supplied lens hood, it’s also very light. Mount this on any Pentax DSLR and you’ll hardly even notice it; indeed it’s barely larger than a DSLR body cap. It’s easy to understand how it’s nicknamed a ‘pancake’ lens.

The Pentax DA 70mm f2.4 Limited lens is clearly larger than the 40mm, but still highly compact at 63mm wide and 26mm long (when focused at infinity). It weighs 130g without the supplied lens hood. We’ve pictured it above with its lens hood attached and in its retracted and extended positions – see below for details.

Both lenses are so short, there’s very little to hold onto, and you’re also likely to brush your fingers against the focusing ring when it turns during autofocus. But there is a slim ridge right by the mounts you can safely grip and both lenses are so light they need little ‘under-barrel’ support anyway. The K10D body also has a ridge on its left side which acts as a small grip for your left hand – see our Pentax K10D review.

Both lenses are supplied with lens hoods, but neither are the common petal designs. The DA 40mm f2.8 Limited has a very slim metal screw-on lens hood which adds just 7mm to the total length and could easily be mistaken for a lens cap. The lens cap itself is actually a smaller diameter metal disc which screws into the hood. The filter thread into which the hood also screws, measures 49mm in diameter.

The Pentax DA 40mm f2.8 and 70mm f2.4 Limited lenses have effective focal lengths of 60 and 105mm respectively when mounted on a Pentax DSLR. This gives them almost standard and short telephoto coverage respectively.

To illustrate their coverage in practice, we shot the same scene with each lens within a few moments of each other from a tripod to ensure a consistent position. To show how their coverage compares to the standard kit lens, we’ve also included samples from the DA 18-55mm f3.5-5.6. So below from left to right are the Pentax DA 18-55mm at 18mm, followed by the DA 40mm f2.8 Limited, the DA 18-55mm zoomed-into 55mm and finally the DA 70mm f2.4.

Pentax DA 18-55mm at 18mm		Pentax DA 40mm f2.8		Pentax DA 18-55mm at 55mm		Pentax DA 70mm f2.4
18-55mm at 18mm (27mm equiv)		40mm (60mm equiv)		18-55mm at 55mm (83mm equiv)		70mm (105mm equiv)

The samples above have no surprises: the DA 40mm f2.8 Limited delivers roughly the same coverage as mid-way through the kit lens range, while the DA 70mm f2.4 Limited is slightly more powerful. The DA 40mm is just a little longer than a standard lens in practice, while the DA 70mm offers short telephoto capabilities. See our Gallery page for portrait and landscape samples.

Pentax DA 40 and 70mm Limited lens aperture

The DA 40 and 70mm Limited lenses have maximum focal ratios of f2.8 and f2.4 respectively. Both provide a bright view when composing, decent flexibility in low light and the potential to create very small depth-of-fields. The DA 70mm is particularly good in this regard and makes an ideal portraiture lens – see our Gallery for examples.

Pentax Shake Reduction with the K10D and DA 70mm Limited

The DA 40 and 70mm Limited lenses don’t feature optical stabilisation, but mount them on either the K10D or K100D bodies and their built-in Shake Reduction systems will extend the range of shutter speeds you’ll safely be able to handhold. For a full report on how the Pentax Shake Reduction system works, see our Pentax K10D review, but in the meantime, here’s an excerpt with examples taken using the DA 70mm lens.

In use we found the K10D’s Shake Reduction system certainly allowed us to handhold longer exposures than normal, but we rarely achieved more than two stops of compensation. During numerous tests, the biggest difference between an image taken with and without Shake Reduction can be seen below. Both images were taken moments apart using the K10D fitted with the DA 70mm Limited Edition lens, thereby working at an effective focal length of 105mm.

With the aperture closed to f22 at 100 ISO, the shutter speed was 1/8 of a second. We cropped an area from each image measuring 564×272 pixels, then reduced it to 282×136 pixels for reproduction here; you’re therefore viewing the images at 50%.

Pentax DA 70mm with K10D Shake Reduction OFF		Pentax DA 70mm wit K10D Shake Reduction ON
70mm (105mm equiv), 1/8, f22, 100 ISO		70mm (105mm equiv), 1/8, f22, 100 ISO

The image above right with Shake Reduction enabled may not be 100% sharp (even when viewed at 50%), but it does show a great improvement over the image above left. When we increased the shutter speed to the point where both images were 100% sharp though, there were only two stops difference. Like all anti-shake systems though, the effectiveness varies between people and situations. The bottom line is the K10D’s Shake Reduction system certainly made a difference, but not as much as experienced with other image stabilisation systems.

Pentax DA 40mm f2.8 Limited Using Pentax K10D		Pentax DA 18-55mm at 55mm Using Pentax K10D		Pentax DA 70mm f2.4 Limited Using Pentax K10D
1/350, f8, 100 ISO		1/350, f8, 100 ISO		1/350, f8, 100 ISO
1/350, f8, 100 ISO		1/350, f8, 100 ISO		1/350, f8, 100 ISO
1/350, f8, 100 ISO		1/350, f8, 100 ISO		1/350, f8, 100 ISO

To compare real-life performance we shot the same scene with the Pentax 40mm, 18-55mm and 70mm lenses within moments of each other using a Pentax K10D in Aperture Priority mode. The 18-55mm was zoomed to 55mm for this test and all lens apertures set to f8.

Clearly the three lenses tested here have different focal lengths and therefore different fields of view. As such the actual crops can’t be directly compared in terms of detail, but they do give an indication of how each handles the same subject matter.

The image left was taken with the Pentax K10D using the DA 40mm Limited Edition lens at f8; the original JPEG measured 3.29MB. The crops below are presented here at 100%.

Pentax DA 40 and 70mm lens results continued…

Outdoor / Resolution / Corner sharpness / Fringe and macro / Geometry / Vignetting

Pentax DA 18-55mm f3.5-5.6 AL Pentax DA 40mm f2.8 Limited Pentax DA 70mm f2.4 Limited DA 18-55mm at 18mm f3.5 DA 18-55mm at 55mm f5.6 DA 40mm at f2.8 DA 70mm at f2.4

Pentax DA 40 and 70mm lens macro comparison, tested with Pentax K10D

Pentax DA 18-55mm f3.5-5.6 AL at 55mm		Pentax DA 40mm f2.8 Limited		Pentax DA 70mm f2.4 Limited
DA 18-55mm at 55mm f8 Max area of 66x44mm		DA 40mm at f8 Max area of 184x124mm		DA 70mm at f8 Max area of 194x130mm