Design and build quality

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 DA 70mm f2.4 Limited is also supplied with a screw-on metal lens hood, and while much larger than the previous model, is still very small. It’s a push-pull design which measures 16mm in length when retracted, or 24mm when extended. You’ll probably leave it fitted for most of the time as the classy velvet-lined lens cap is designed to slip over the hood and not the bare lens itself. Like the 40mm Limited, the filter thread measures 49mm. Both lenses are also supplied with carrying pouches.

While both lenses are small and light, they have superb build quality with all-metal construction, featuring high-grade aluminium barrels, hoods and caps. The focusing rings are also very smooth in operation, complete with distance markings on both, and additional depth-of-field guides on the 70mm; the 40mm barrel simply isn’t long enough to squeeze them on.

Both lenses are quite audible when focusing on the K10D, and as mentioned earlier your fingers may get a small surprise as the focusing rings turn during autofocus. While the end section of each lenses also extends during focusing, they at least don’t rotate which will come as some relief to users of polarising filters.

The DA 40mm f2.8 Limited lens focuses faster, additionally improved by a shorter angular range from infinity to its closest focusing distance of 40cm. The DA 70mm f2.5 Limited feels noticeably slower when focusing, and must turn almost twice the angle from infinity to its closest focusing distance of 70cm.