Originally posted by arthur pappas the kit lens for my K100D Super is 18 - 55mm. I'm looking to buy a wide angle lens & found one that's 24mm. Does this mean my kit lens at <24mm is 'wider' than the 'wide angle' lens?
Arthur,
18 < 24, so yes, the kit lens can go wider than the "wide angle" lens you've found.
But note that 24 isn't
very wide these days. Have you read yet about what is commonly called "crop factor"? The sensor in cameras like the Pentax digital slrs (all of them, including the K10D) is smaller than the sensitive area of an old 35mm film camera and this makes a difference to the EFOV ("effective field of view"). A 24mm lens on an old film SLR (or on a full-frame digital SLR like the Canon 5D or the Nikon D3) is fairly wide. But the same lens, when used on a Pentax K10D or K100D or similar camera, has an effective field of view equivalent to the EFOV of a 32mm lens on a film SLR, which is to say, wideish, but not what I'd call very wide. To give you a concrete example, say, you're photographing a house from the street out front. The 24mm lens on a Pentax K10D might let you see the entire width of the house, from the left side to the right side. But the same lens on a film SLR would let you see a good bit more, the yard on the sides of the house both on the left and right. So if you're using a Pentax digital SLR with a 1.5x "crop factor" and you are thinking of photographing, oh, wide buildings, or large groups of people, or the Grand Canyon, you'll probably want to do better than 24mm. When I need to go wider than that I put on my Sigma 10-20, which on my K10D is an honest-to-gosh wide angle.
As for lens hoods, they serve two purposes. They help prevent "flare" in your photos, which can occur when stray light hits the mouth of the lens from the side rather than from more or less directly ahead of you. And as Matt and others have noted, the lens hood provides quite effective protection of the lens in many instances, particularly protection from knocks. Many people use a neutral density filter for protection, but I think it's less effective than a lens hood. Last year I took a nasty spill while hiking with my K10D. AS I was going down, I did my best to protect the camera, but it took a bang on the rocks nonetheless. If I'd had only a filter on the camera, the business end of the lens would have taken the hit directly. But I had a lens hood on, and it took the hit instead of the lens. The hood got a nasty scratch from the rocks, but otherwise, no harm done. Well, I limped for a week, but the camera was fine.
Will