hello all, well i'm looking to finally break down and get a new lens but to be honest i have not a clue what means what. i've been looking on ritz and calumet's web sites and am thoroughly confused. the lens i have now is 18-70mm (the stadard D70 outfit lens) so i'm trying to find one out of that focal range for more variety. one of the questions i have is about a 50mm "normal" lens, would that be the same as the 50mm setting on my existing lens (told you not to laugh)? also i see on these two sites lenses with similare focal ranges but one would be like 100 bucks or so and the other would be in the 300+ range, i notice the f/numbers to be different but what exactly does that mean? i know that's the aperture settings but does the f/number really make that much of a difference to drive the price up that high? and my final question, what's the advantage/disadvantage of a mirror lens? i saw a 500mm mirror in my price range, i don't think i need something that big but i was just curious is all. thanks in advance for any assistance!!! eb

Q: "50mm "normal" lens, would that be the same as the 50mm setting on my existing lens" Yes Q: "i notice the f/numbers to be different but what exactly does that mean?" The f/# is the maximum aperture. The lower the number the faster the lens is considered to be, and the more expensive they become. If you are looking at zooms you will often see two f/#'s listed, this means that the maximum aperture value changes depending on the focal length you are working with. There are zooms that have fixed maximum apertures, these also make the price go up. Q: "does the f/number really make that much of a difference to drive the price up that high?" It depends on who you talk to.... for the serious amatuer or professional, yes it's important, and yes it's worth the extra money. For myself...... f/2.8 and fixed maximum aperture is all that I will buy. If that means saving for a year, so be it. Q: "what's the advantage/disadvantage of a mirror lens?" Fun lens.... cheap.... I don't have one but would like one, mostly as a toy to play around with. But really not considered to be a good lens for serious photography. Most have a maximum aperture of f/8..... that is a serious detriment when considering how slow your shutter speeds would need to be in most lighting situations. Hand holding is impossible. Also in certain lighting situations you will see the typical ring effect in images. It literally looks like little ring shaped halos... some hate it, some find it charming. Advantages..... hmmm.... other than the extreme focal length.... and price.... can't think of anything.

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'chelle types faster than me! Of course we won't laugh. But a trip for you to the library may be in order. The focal length of the lens determines perspective. And yes, the 50mm of a "normal" lens should provide the same perspective as your 10-70mm zoom set at 50. However, a fixed focal lens, sometimes called a "prime", may offer some advantages over using the zoom. It may provide sharper results, or the lens may focus closer, or take in more light (f-number smaller). What lens you use really depends on the type of photography you want to do. The 18-70mm offers a pretty nice range for general photography. [The D70 is a digital, right?] If you lean more towards wildlife or sports, a longer lens, maybe a 200mm, or one of the zooms that go out this far, may be an interesting choice. If you do more people/street photography, a wider lens, maybe a bit faster, is suggested. [Though at 18 with your present zoom you are already pretty wide. The smaller the f-number the "faster" the lens, or the better it is for photographing in low light levels. The smaller the f-number, the bigger diameter of the lens. So it is heavier and costs more. Most of the time really fast lenses aren't needed, but in dim light they can be the only way to make the shot. For general use, around F/2 to 3.5 for medium to short telephoto is usually cost effective. For a 200mm, f/4 to 5.6 is pretty reasonable. A 500mm mirror lens is kind of a special purpose beast. They tend to be quite slow, f/8. I use mine occasionally, but not more than once or twice a year. Considering what you already have, I'd bet that one of the newer not-terribly-pricy 70-300mm f/4 to 5.6 compact zooms would be a good bet. As in most things in life, you do get what you pay for. You can find a pricier lens which is perhaps "better", but these are darn nice! Generally you can fond comparative reviews of lenses in the photography magazines, or by Googling.

thank you both for the invaluable information!!! i greatly appreciate it!!! believe it or not i've been trying to figure this stuff out for a while now but never bothered to ask as i didn't have the money to do anything just yet. i had no idea what to look for or how to phrase it for googleing!!! honestly i did try before asking:)!! again, thank you both for the assistance, it really helps a ton!!! eb

One other issue to consider is the marked focal length on the lens is based on usage on a conventional 35 mm film camera. Used on a digital camera with most companies using a sensor smaller than the 35 mm film format the effective focal length of the lens is increased, i.e. a 17 mm lens will give the approx field of view as a 24 mm lens on a film camera.

that's something i never would have thought of MG! wish i had the money for that 8 thousand dollar cannon that's true 35mm format. that sucks that digital does that with the lenses!!! thank you for that tip, as i said, i never would have thought about that!!! eb