Lens for DSLR

[Nicole]

Originally Posted by OsmosisStudios

Y
3: Build. The 55-200 is a consumer-grade lens and, as such, has a plastic mount and is entirely plastic. Controls arent the greatest. The 70-300 is a pro-sumer-grade lens and, as such, is much more solid and has a metal lens mount. It's also heavier, so that may be a drawback.

Although this depends on which version of the 70-300 you're talking about. The 70-300mm G lens (which is the one I have ) is plastic and only about $150. Whereas the VR one is $560 on amazon (and I'm guessing that's the one with the metal mount you're referring to).

[inkista]

Originally Posted by SJRosa

I don't know anything about aperture yet, Would u mind helping me understand that?

ummm.. That's what the link I put into my post was for. Here it is again:

What is maximum aperture and why is it so important?

Basically, the aperture setting on your camera is how large the shutter opening in the lens is going to be set when you take the picture. The larger it is, the more light comes in at once, and the smaller it is, the less light comes in at once. It's one of the three basic exposure controls you have on a dSLR: aperture, shutter speed, and iso.

Aperture are given by f/#. What's confusing here for most newbies is that the range of numbers isn't linear and the smaller the f-number, the larger the aperture is. This is because the f-number is a ratio, so just as 1/8 is smaller than 1/2, f/8 is smaller than f/2.

Now, a lens is always described by its focal length and maximum aperture. E.g.,

• 70-300mm f/4-f/5.6
• 50mm f/1.8

On a zoom lens, the maximum aperture is often given as two numbers: one for each end of the focal length range. So, the 70-300 described above would have a maximum aperture of f/4 a the 70mm (wide) end of the zoom, and f/5.6 at the 300mm (telephoto) end of the zoom range.

The main thing to know is that f/4-5.6 is NOT the aperture range of the lens. Your camera can probably stop any lens down to f/22.

The main cut-off point to remember is that available light shooting (i.e., indoors without a flash) usually requires f/2.8 or larger to attain shutter speeds fast enough to prevent motion blur (without stabilization). Larger max. apertures tend to make a lens bigger and more expensive.