3 of 3 people found the following review helpful
on 8 December 2012
I've got the DA35 macro but often I would end up using the kit 18-55 at its wide end instead. The DA21 seemed like the ideal answer.
The DA21 is small and the clever lens hood hardly adds to its length. On a K-7 it looks positively diminutive. As with all the limiteds, the design and build exude that certain satisfying precision feel. The lens hood design is unconventional but effective. The lens cap is a solid piece of felt lined aluminium, in keeping with the look and feel of the lens, but a bit impracticable and probably expensive to replace. Fortunately a standard old Pentax slip-on 51mm plastic lens cap fits perfectly.
The 21mm focal length is just right on an APS sensor camera, such as my K-7. It is just wide enough to make a difference but not too wide to give that somewhat boring stretched effect of ultra-wides. Autofocus is accurate, quiet and quick - there isn't a great deal of mass to spin around with this lens.
Optically, this lens is sharp enough to allow some cropping without a great loss of quality. It is quite sharp even wide open and gets better stopped down. The sweet spot seems to be somewhere between f/4 and f/5.6. There is a fair amount of barrel distortion and some CA, both easily correctable in post-processing. Contrast and colour rendering are excellent. Flare resistance is good, although when shooting into the sun at a certain orientation it is possible to provoke a 'green blob' flare, probably a sensor reflection.
I can see this lens staying on my camera a lot of the time. It is inconspicuous enough for street photography and sharp and wide enough for my landscape and architectural shots.
1 of 1 people found the following review helpful
on 2 September 2013
I had wanted a small, wide-angle prime for my DSLR for some time, and options are very few indeed. Outside of Pentax and Fuji, even fewer.
I decided on the 21mm as less expensive and a better all-round focal length than the 15mm. 21mm is a good focal length - not so wide as to cause distortion or leave subjects looking very small, but wide enough to capture a whole scene. It may not be wide enough as a travel lens where you want to capture wide scenes in streets with limited space to back up.
The lens is very small, extremely well constructed in metal and a pleasure to use. Image quality is very good - it could be sharper at f/3.2 but is very useable. It can sometime produce yellow_green flare when pointing at the sun. There is some barrel distortion which is visible when taking photos of buildings or other structures with straight lines, but it's easily corrected later (some cameras can do it automatically). However, I'm happy with the IQ it produces, it's certainly better than the 18-55mm kit lens. I wish it were a little faster (f/2.8 or better), but I suppose this would mean it had to be larger.
3 of 5 people found the following review helpful
on 30 September 2012
When I first got this lens I was a little bit disapointed. I own a few other limited lenses, and they blew me away the second I attached them to my camera. With the 21mm, the first shots were a little bland, and didn't really do it for me. Fast forward a year or so, and now it's probably my most used lens, although I still think it's the weakest of all the DA limiteds. In general I'm not the impressed by landscape pictures taken with this lens (the 15mm & 40mm are better in that regard). I also often find myself looking at a picture taken with the 21mm, and wishing I'd used the 40mm instead (which has a much smoother bokeh, and better subject isolation).
The focussing is fast, and generally accurate. Low light performance is a mixed bag. The focussing in low light is usually fairly accurate, however the smaller aperture isn't able to cope with anything that moves too quickly. It's too slow to capture drunken shenanigans in a pub after dark, but it's fast enough to capture a group sitting down to dinner. I'd probably advise using a tripod for the best reults.
The bokeh can be good, or it can be a bit busy. I've never really figured out how to predict this. It's just a bit hit and miss.
So having been somewhat negative about it, why is it my most used DA limited? When everything clicks into place, the pictures it produces are absolutely spectacular! It's also a FOV that suits the pictures I like to take. Sadly however, you'll need to invest a lot of time learning what does, and doesn't work, before you'll be able to get the most from it. It excels in street photograpy (especially in very colourful scenes), but for everything else, it's not much better than the camera on the iPhone4 (That may sound harsh, but actually the closest experience to using the DA21mm I've had, is the camera on the iPhone4s - although the DA21mm is sharper, and has more depth of field to play with). For landscapes, look to the 15mm.
All in all, if you need something in the 20mm range, it's by far the best option for Pentax (miles better than the 16-45mm DA zoom). It is a very good lens, it's gets a lot of use, but I often find myself wishing it was able to deliver just that little bit more. If it was f2.8 with the same 9 bladed aperture found in the DA40mm, then I doubt I'd be able to find any negatives. Without those, I feel it's slightly hampered, and so it doesn't really offer the same level of versatility you get with the other DA limiteds. It's brilliant, but slightly annoying at the same time.
5 of 9 people found the following review helpful
on 25 November 2010
I wish I had bought this lens sooner, I use it more than any other lens that I have, it is wonderful for every and any occasion.