General discussion

Lens questions...

While reading about the new Canon XT I came across this line:
Canon's EF-S f/3.5 to f/3.6, 18- to 55-mm lens

1. Do the numbers 3.5 and 3.6 describe the max aperture at the ends of the zoom range? That is, when the lens is not zoomed the aperture is 3.5 and when zoomed it is 3.6?

2. How does one compare the "18 to 55 mm" zoom to the zoom of a 35mm camera? With my 35 mm camera 18 mm would be a fish eye lens and 55 mm would be a "normal" lens. That must not be true with a digital lens?

3. Can these be converted to an ?X? number like 4X?

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Canon XT lens

That lens description must be a misprint.
If you look at the photo of the XT, it is printed on the lens : f3.5 to f5.6 18-55mm

1. It would be f3.5 at no zoom and f5.6 when zoomed.

2. That is where that multiplier of 1.6 comes in.
multiply both numbers by 1.6 and you get 28.8 to 88 mm and you get the 35 mm equivalent.

3. Divide 55 by 18 and you get the zoom ability.
Which is 3.05X
So in terms of a non DSLR camera the equivalent would be 28.8 mm lens with 3X zoom.
And in that world, 28.8 is considered a wide-angle lens.
The wide angle Canon S70 lens is 28mm.
But it has a 3.5 X zoom


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Thanks again

The misprint was in PC Magazine:
"Canon's EF-S f/3.5 to f/3.6, 18- to 55-mm lens will cost just $1,000."

I guess I would like a lens that had a little more zoom than 3x. And costs less than the camera body! Is there a good descriptive list of Canon lens on line somewhere?

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Canon Lens

It is my understanding that the new canon Rebel will sell for $1,000 including the f/3.5 to f/5.6, 18-55-mm lens.

If Canon is making a lens as you describe, it might sell for $1,000 but I wouldn't buy one at that price.

One of the handiest lenses for the Rebels is the tried and true f/1.8, 50mm lens. It is bright and inexpensive ($80).

Here is a link to all Canon's current lenses:


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