Pentax SMC 35mm F2.4 AL Lens

Pros:
Cost
Optical Performance

Cons:
Plastic build
No included hood or bag
Smaller aperture vs competition for same price

Bottom Line:
Buy one.

The Pentax 35mm is a great lens that complements any standard zoom. The aperture is large enough to be advantageous. It offers at least a half stop over an f/2.8 zoom, and in reality probably closer to an f/stop given the fewer lens elements. The lens is bright at f/2.4, where most zoom lenses lose significant contrast wide open. Focus is fast and accurate (one of the faster lenses I have used), taking only a fraction of a second to lock in most cases, min to infinity to min is about 1 second or less.

The lens has moderate to low distortion (-0.8% barrel) and minimal CA on the K-5, not much over 1 pixel at the corners. The lens is very good across the frame from f/2.4 to f/2.8 and excellent from f/4 to f/8. It really performs well optically.

Although the construction is all plastic, it is a well built lens. I wouldn't let this be a deciding factor in purchasing this lens or not. If this lens had metal construction, everyone would think it were a Limited. However, it does lack quick shift focus.

This lens performs nearly as well as lenses costing much more, and I see why Pentax limited the aperture to f/2.4. They wouldn't want to compete with their other products. The price is fine, and so is the lens. I recommend this lens to anyone looking at the Pentax system. It is great for people of all experience levels. It should be called the Pentax DA 35mm f/2.4 AL [un]limited.

The free shipping was fast as usually, thanks to Amazon.com!

You can read all other reviews for its pros and cons. I'm just telling you why I've picked up this lens.

I went to a kid's party about two weeks ago, I took my K-x with the 18-55mm kit lens on it. I set ISO to 1600 (sometimes 3200) auto. I didn't use flash at all. Most of time, the indoor light were sufficient for a decent photo. However, kids moved a lot and fast, the shutter speed was simply not enough to capture those actions...so a faster lens is obviously necessary for this situation. I have a M 50mm f1.7 lens, I got the decent speed, but with manual focus, it's almost impossible to get focus quickly enough. So my conclusion is that I need a faster lens with AF!

I've been thinking to get FA 50mm f/1.4, but for indoors with limited space, its FOV seems too narrow, although its price is acceptable, I doubt its usefulness for indoor application (when I shot with 18-55mm lens, I seldom used any FL higher than 50mm, most of the time, 18-35mm).

The next thing I've been considering is this lens. Its price is right, it has f/2.4 aperture, it's lightweighted, it looks nice on my K-x (see those pictures I shot with my cell phone). I tested it as soon as I got it. Indoors, no lights on, only tv is on, so it's pretty dim, I set ISO to 1600 auto, lens wide open (f/2.4), AF worked well, pretty fast, no hunting, the picture came out bright, sharp, the color looks very good to me. I further tested in a restaurant (see those photos I uploaded). With K-x's low-light performance, this lens is a perfect companion! I would think it's more than enough for a kid's party (light condition is much better than restaurant). I cannot wait to put it in real test for the next kid's party coming soon...

Usefulness: although it can be used for anything, I would think it's most useful for indoors (specially for moving subjects that require decent shutter speed). For other situations, like outdoors, in good light condition, I still prefer using my 55-300mm (a very sharp, versatile lens to me), or the 18-55mm kit lens (I don't have any other expensive lenses).

Lens hood: it doesn't come with hood, I don't think you need a hood for indoors. I bought a lens hood on ebay for the old 50mm f/1.7 lens, but doesn't fit well. I put the hood on this lens, perfect fit! I can put the cap on the hood, too.

Thank you for your time, and hope this helps.

UPDATES:

After attending two birthday parties (one at school, the other at a friend's house), I would say this lens is sufficient for this purpose, although sometimes I only wish I got wider FOV (I killed FA 50mm F1.4 for this reason). Other than that, with aperture wide open, the picture is sharp, bright, color rendering is good, WB is accurate (more natural compare to my M 50mm F1.7 lens which gives me warmer tone). At both parties, I set my K-x to ISO1600 auto, at school I often got ISO800 at 1/60sec, in the house (in the afternoon, all natural light through windows except in the basement), I can get ISO-200 sometimes at 1/60sec, most of the time, I got 400-800, because of this, I switched my 55-300mm lens on for the second half for some candid photos.

I'm both very pleased with this lens and a little disappointed. On the plus side, the lens produces beautiful photos. It's sharp from f-2.4 on. It focuses very quickly and is very light. It's the last point that leads into my disappointment. The lens is light because it's built of plastic including the lens mount and filter threads. I find myself in the odd situation of wishing the lens cost more. Because it's such a sharp lens and such a useful focal length, the APS equivalent of a 50mm, I'm sure that I'll be using it a lot. That means putting it on and taking it off my camera. How long will the plastic K-mount last? Hopefully, with care a long time, but I'd happily pay a quarter to a third more to get a unit with a metal mount.

I'm actually happy with the build quality. Everything seems tight and built to tight specifications, just what I've come to expect from Pentax lenses. And for the price I really shouldn't complain. It's easily the best lens for the price I've seen. While I don't have one of these cameras, I expect that it would make a great low weight compliment to the Kx or Kr camera bodies. Even with a heavier body the light weight is appreciated.