Pentax SMCP-A 50 mm F/2.0 Lens

The Pentax-A SMC 50mm F2 prime lens is an amazing value. You can find them for anywhere between $20 to $40. Partly because a lot of 50mm f2's were produced as high-end kit lenses for 35mm film cameras.

The Pentax-A means the lens has an automatic aperture -- meaning, the camera can control/adjust the aperture. However, you still need to manually focus. Don't consider this a bad thing. Manually focusing these lenses is easy. If you record video, then this lens is amazing and manually focusing is preferred. You can adjust the aperture manually but it's better to use Av (aperture priority) mode on the camera.

The 50mm is a wonderful focal length, even for cropped digital SLR sensors. I've noticed most of my shots are done between 40-60mm so 50 is wonderful. It's a small lens, but at f2.0, it lets in a lot of light. So this lens is perfect for low light conditions and when flash is not possible/preferable.

The SMC multi-coating is well established, and this f2.0 will outperform 2nd-rate f1.7 lenses which will typically need to go to higher apertures to get sharper shots.

In terms of quality, prime lenses are designed to excel at a single focal length. There is little if any distortion. The bokeh (the blurring pattern in the out-of-focus background) is very desirable.

Overall, price-per-performance, you can't beat this prime lens. Going below f2, the price goes crazy. Auto-focus versions are ridiculously expensive. You may f1.4 or f1.7 Pentax-M, but those will require you play with the aperture ring while focusing.

Summary: A highly recommended wonderful quality prime lens!
Tested: Pentax K-x, usually in Av-mode, 1600 ISO in low light, usually adjust aperture until shutter speed is at least 1/15s.

These older "prime lenses" are pretty cheap used and work fine on new Pentax DSLR cameras. They offer the professional look of a shallow depth of field, attractive bokeh, and the clarity that a simpler lens offers over the zoom stuff. In addition to that - it captures more light thanks to a f2.0. That means more detail and less noise in lower light.

it's my first prime lens but it's easy to use. Just set your f stop and focus manually. The results are instantaneous, rewarding and build confidence.

In case you didn't already know, the "A" designation on this lens, means it will work with all modes/settings on newer fully auto Pentax fim, and DSLR's. Only without auto focus, which in reality, with such a short focal length, is greatly prefered for it's accuracy on my part anyway.

Also of importance is tha fact these older lenses are made from all metal construction, so you get a better sense of quality not found in alot of the newer glass made.

Pentax-A 50mm 1:2 – As disclosed by seller, minor corrosion were present around aperture blades which do not affect lens’ mechanical or optical performance. Image quality is much higher versus an 18-55mm kit lens (at 50mm).

I really enjoy photography and I'm always trying to experience something new, this time I tried a 55mm prime lens with pentax k mount, its a really great lens, I am really enjoying it. It is a full manual lens and it has a really great defenition on photo. I'm really happy with it