Originally posted by lovemehate how good is the
50-200mm f/4-5.6 SMCP-DA ED Zoom Lens
for low light, taking peoples photos? Is It telephoto lens? I hear some people saying I need a telephoto lens....
There are a few things that you need to understand (please remember that I am also a newbie, so I'm just sharing the understanding I have of things):
one: Aperture
if you're talking about low light, you need a larger aperture. That's the "f" portion of the lens specs. The smaller the number, the bigger it opens up to let light in.
here's a visual example:
[IMG]file:///tmp/moz-screenshot.jpg[/IMG]
So you need a lens that will give you more light. So the "f" portion must be a smaller number.
In my opinion, any lens with more than f:3.5 will be struggling indoors without a flash. Sure, it'll work, but you'll have to use the flash...otherwise it'll have to stay open for longer to get all the light it needs. Then both yourself and the subject have to be VERY stable to take a second-long or more exposure and come out sharp.
Your idea of using a lens of f4-5.6 at it's biggest aperture for low-light isn't a good one.
two: Focal lenght:
I can't explain the technical aspect of it, but here's my own understanding. The longer the lens, the more telescopic effect you'll have. An example would be to use a magnifying glass (which in itself is a simple lens). If you hold a magnifying glass very close to something, there's no magnifying effect. if you move it further, then it'll look bigger, but you'll have to move the distance between your eye (and in your camera's case, the sensor) and the magnifying glass accordingly to be in focus. That's for the zoom part, and why zoom lenses seem to change size significantly.
Another thing is how wide you'll go. if you take a tube a look though it against your eye, if the tube is short (let's say a 2cm or 1inch tube) you'll have a wider visual image. If you take a longer tube (such as looking through a 30 cm or 1ft tube) you'll see a lot less wide. you have to get closer to a window to see the sides after all.
Some people also use their hands and fingers. Spread both your hands with your arms outstretched, make the thumbs touch each other, and whatever spread you hands cover is approximately 50mm. One spread hand would be 100mm. your closed fingers would be 200mm. I still have to test these out myself against what I see in the viewfinder on my K-x, maybe I'm a bit off. But whatever the case may be, if you experiment, you'll find out and be able to use this to evaluate the width that your image wil have.
Now, camera lenses have multiple pieces of glass permitting you to adjust so the image is in focus on the camera's sensor and doesn't have the tube effect (Called vignetting), while keeping everything you've selected in view.
So your idea of using a 50-200mm lens for indoor people photography isn't a good one unless the room you're in is really big. In my living room: 100mm will be the face only, 50mm will be the face and torso. If I wish to photograph multiple people, I'm on the wider end (shorter lenght) on my zoom.
three: depth of field
I won't go deep into depth of field. Just know that the bigger the aperture, the less depth your focus zone will have (focal length also has an effect on depth of field, but I still don't understand it fully). People that have a lens of extreme aperture such as the A f1.2 and use it wide-open (at f1.2) might have people who's eyes are in focus, but the tip of the nose (in front) and the ears (in back) are out of focus. Using the same lens at f2.8 makes the person in focus but the background wall (or other people in the background) out of focus. Using that same lens at f8 makes the subject and the wall behind then become in focus.
But having zones out of focus is often a desired effect. It makes whatever you have in focus "pop out" more, and removes clutter on your picture.
In summary:
if you want low-light, indoor photography, the 50-200mm f/4-5.6 SMCP-DA ED Zoom Lens will not be suitable.
Sorry for the lengthy post. I hope this helps!