Pentax Camera Lens Review: Cosmicar-A 28mm f2.8 - Pentax Wide-Angle Lens

My purpose with this Pentax lens review, and later camera lens reviews is to give readers a no-nonsense personal opinion of lenses for Pentax. If you're looking for a wide-angle prime lens, and don't need autofocus, then you should give this non-SMC Cosmicar lens a look. A digital camera lens these days can easily put you back a few hundred dollars, and that's why I personally like trying out older Pentax manual lenses. For under $100, you can buy older K-mount lenses that have comparable optical quality to modern "budget" lenses. Don't get me wrong, I also own DA lenses, and I love them for their good points.

Before I go on, let me say that the K-X, K10D, K20D, or whatever K-mount camera you own will work with this Pentax Cosmicar 28mm lens. My favorite feature of my Pentax digital SLR is that it is backwards-compatible with older bayonet lenses. I personally use this lens on my K100D.
The non-SMC designation of this Cosmicar lens means simply that it does not have super-multi-coating. The optics of this lens, however, is essentially the same as the Pentax-A lens, just without the Pentax SMC added. If you're not too concerned with this fact, I think it is something that can be overlooked.

Being an "A" series lens, it supports automatic aperture modes on Pentax cameras. I like this feature, because I can shoot in Tv mode and change the settings quickly on the menu without touching the lens. Of course, you will still need to manually focus on your subject, but for someone like me who shoots a lot in semi-auto modes, this is a nice feature.

Since this is a manual lens, it is limited in what subjects it can handle. Of course, with practice one can shoot more dynamic subjects. At this moment I use it mainly for landscape, architecture, and other static photography. I think it is very good for what I use it for. A quick side-note; If you ever have a choice (usually comes down to money), using a prime lens vs. a zoom lens is preferable as the former renders better image quality. In my experience, stopping the lens down past f4 is where it does very well. I'm pleased with the sharpness, but I won't say for a minute it's in the class of a DA star or limited lens. For it's price and other things considered, I'm very happy with the sharpness of this 28mm lens.

For what I've said about the limitations of a manual lens, I think there are some positives as well. For one thing, you can use selective focus on your subject. Also, you can use hyperfocal distance quite a bit in landscape photography, as it is easy to calculate the distance on the lens at which everything in frame will be in focus. Being an f2.8 camera lens, you can get very shallow depth of field, and I have to say the bokeh on this lens is decent. Also, with the ability to go wide-open at f2.8, you can get pretty good low-light performance. I'm not going to go over every Pentax camera's noise-handling capabilities, but it's safe to say that if you keep the ISO under 800 on the K100D with this lens, you should be satisfied.

Pentax lenses have been around for a loooong time, and the "old" ones are still being used today. There's one reason, and it's the optical quality. Now, you have to remember that the Pentax Cosmicar-A f2.8 28mm lens was manufactured from the start as a "budget" lens. This means that the optical quality won't be as good as higher-priced lenses. Lenses for Pentax range in price from a couple hundred dollars to thousands - typical of any camera manufacturer. However, reports from various sources agree that this prime lens is sharper than other similar "budget" priced zooms. The bottom line is, if you're looking for an inexpensive wide-angle manual lens, I recommend trying out this one out. Thanks for reading this Pentax lens review!