Wide angle lens and accessory Sunpak 144 flash unit questions

I just bought a Pentax K100 kit with the included FA 18-55 and a FA 80-200/f4.7 second lens. (I can't believe I paid $60 for the latter lens!)

I'd like some suggestions on a dedicated, smaller wide angle lens. Probably at leasst 75% of my shots in the past with both film and digital cameras have been landscape shots. I typically take two overlapping shots, then merge them together using Photoshop. I'd rather NOT have to continue doing that! I'm not anywhere near a professional/expert photographer, but I do consider myself a dedicated hobbyist.

Anyway, I am confused over what type lenses I can/should use. I'd like to get something smaller and lighter than the 18-55 kit lens, and hopefully something a little wider and faster. I'm perfectly happy with a non-zoom, and I don't care much about the brand. Even auto-focus is not a requirement, but AE would be nice. I don't want to mess with adapters, etc. I'm looking in the $200 or less category. I don't care if the lens is new or used.

On the focal length issue, I am confused. The kit lens is a 18-55. I always considered an 18mm lens on a film SLR to be VERY wide. But the stock lens doesn't seem all that wide to me. Probably wider than my other non-slr digitals, but not as wide as I'd like. What's the story here? I think I read somewhere the 18mm is not really 18mm, but 1.5 times that, or 27mm. I'm confused obviously. What lens is wider than that?

Also, I have an older Sunpak Auto 144 Thyristor flash unit. I know not all units will work with all cameras, but I did determine, after hours of research, that this flash does work with another digital camera I have, A Panasonic Lumin DMC-FZ20 camera. I seem to recall that there might be some voltage issues? I'd rather not fry the Pentax without doing some research......but I don't know where to start....any ideas?

Thanks

Your lenses do behave differently on an APS size sensor such as used on Pentax dSLRs. For one thing, the sensor intercepts only the middle part of the projected image. To achieve a "wide angle view" effect on the sensor, you therefore need a lens that would be considered "super-wide angle" on a film camera. Correspondingly, to achieve a long telephoto effect, you only need a moderate telephoto lens.

The factor to achieve an equivalent angle (degree of wideangle/telephoto coverage) is as you say 1.5.

Lenses are conventionally expressed in 35mm equivalent focal lengths, meaning a designed-for-APS-digital DA14mm prime lens is 14 x 1.5 = 21mm equivalent = approximately as "wide" as a 21mm lens mounted on a 35mm film camera.

A designed-for-digital 200mm lens is 200 x 1.5 = 350mm equivalent = approximately as "long" as a 350mm lens mounted on a 35mm film camera.

There are other differences involved, but this is an indication.

RP

About the only thing that meets most of your requirements is the Manual focus/exposure Zenitar 16mm f/2.8 fisheye. Should come in at less than $200 and is smaller/lighter than the 18-55mm. Anything else W-I-D-E is $$$$$$$$$$ (unfortunately). If you want to go nuts, here are the currently available new Ultra-wide angle lenses for Pentax -
Sigma 10-20mm f/4-5.6 (I own this lens and LOVE it!)
Pentax 12-24mm f/4
Sigma 12-24mm f/? (I think it's f/4-5.6)
Pentax 14mm f/2.8

The above are rectilinear, Pentax also has a 10-17mm fisheye which alot of folks here like. All are $500 and more though, so start saving!

Then there's the 16-45mm f/4 and 16-50mm f/2.8, but those aren't exactly ultra-wide (although a bit wider than your 18-55mm)

Like the other post said, the sensor is 1.5x smaller than 35mm film, so the AOV is narrower for a given focal length. You'll just have to get used to it Now 28mm is "normal".

Good luck!

Thanks for the reply. That's about what I thought.

So I ought be be looking for a really low number, like 12-15mm wide angle to better the 18-55 zoom on there now? On the other hand, should I expect significantly better quality shots from a fixed power , say 15-28mm wide angle lens?

"...About the only thing that meets most of your requirements is the Manual focus/exposure Zenitar 16mm f/2.8 fisheye. Should come in at less than $200 and is smaller/lighter than the 18-55mm...."

Sounds like that's why I will have to do. I've seen a little on that lens; now I'll do additional research. At least that lens is a bit faster and marginally wider than the kit 18-55 I have now.