The Pentax DA 40mm f2.8 Limited Lens Review

*Note* This post was featured in my old blog which I have now closed, since I do not use a Pentax anymore. But still useful for anyone who plan to buy this little pancake. :)

The DA40 Limited. I was very fond of this lens and it was almost always on my Pentax camera, but I sold it to get a Tamron 17-50mm f2.8 as I wanted the range of the Tamron.

You can find the technical bits of this lens here at the Photozone Review.

Here's my personal story. I am a father of a toddler and as any father will know, toddlers love to be carried. Now, as much as would love to carry a DA*16-50 and a DA*50-135 everywhere I go, this is never going to be my fate. After going through much review sites and through the forums, I have decided I had to buy this lens. Why?

1. AF speed. It is said to be the fastest focusing lens in Pentax-land. Children move very fast, so I need something really good at focusing. I would agree with what I have tested this is indeed the fastest
2. Weight. Nothing beats this. It almost makes my Pentax k-x an EVIL camera.
3. IQ. Has 9 aperture blades and great technical reviews. No distortion, no CA, consistent sharpness from center to corners and sharp wide open.
4. Quite close focusing. Since it's already so tiny, it seems like I get to go quite close to the subject. Also not as intimidating as bigger lenses.
5. Quick shift. Great for videos where you can auto focus first, then manual focus later.

The focal length of 40mm is very decent as a standard lens in my opinion. I found it much easier to use than a 50mm on an APS-C sensor.

Using the Lens

I absolutely love the size of the lens. This is one of the only lens I had which I can comfortably take good photos with one hand while carrying my 10kg daughter on the other. It is also very solidly built, as I have dropped the lens on the floor (non-concrete, that is) twice and there was hardly a scratch. AF is also very quick and I can focus faster than say using a FA31 or Tamron 17-50mm f2.8. The Quick Shift function is definitely a bonus especially taking videos (no need to change to manual focus mode first). One silly thing about the lens is the lens cap, which looks nice, but totally not practical. So what you can do is simply buy a USD1 plastic lens cap from eBay to replace it.

Image Quality

The DA40 lives up to it's reputation of being a sharp lens open wide (see photos below). And it sharpens to it's optimum at around f4 or f5.6. I have found however, the sharpness of this lens cannot match my Pentax-A 50mm f1.7 at f8 or Pentax FA43 at f2.8. The M50 and FA43 is just crazy sharp when you pixel peep compared to the DA40.

Girl who just had a big mouthful of cake. DA40 @ f2.8 ISO1000. Resized only.

Here's a very quick and dirty comparison of sharpness and bokeh of DA40 vs FA31 @ f2.8. Sorry for the underexposure. Like I said, quick and dirty!

DA40 @ f2.8

FA31 @ f2.8

You may notice that the bokeh of the FA31 is better (of course for a lens 3 times the price, it better be!), but you can notice some CA from the FA31 but none on the DA40. Colors are nice and bright as seen in the photo below:

DA40 @ f2.8 ISO400. Resized only.

Here are some other photos for your reference:

Peekaboo! Cropped, resized and touched up. DA40 @ f2.8

Wedding rings. Resized and touched up. DA40 @ f2.8

Do not enter!

Summary:
The DA40 is a good lens. If you want to take photos with ONE hand, nobody beats this baby. It is not the sharpest lens in town, but it is very sharp nonetheless. There is effectively no distortion or CA in this lens, which is really nice (saves you the hassle of post-processing)! Compared to Tamron 17-50mm @ 40mm f2.8 however, I found that both lenses are quite equally matched in terms of IQ (this is purely based on experience, since I bought the Tamron after I sold the DA40).