How do I know what aperature to set my camera to?

Question

I have a minolta x-700 i think.
im in a photography class at school. when i look in my view finder, i dont know how high to set my aperature??

all my friends camera's have this little thing where you keep turning your aperature, and try to balance a needle in a spectrum.

http://tinypic.com/view.php?pic=2vbk2uu&s=2

that is what mine looks like, and as i turn the aperature, the red slash moves up or down. how do i know what aperature to use?!! i know that it has to correspond to the shutter speed, but why doesnt mine have a needle to balance, and what do i have instead of that?

thanks in advanced

Answer 1

its actually more of an aesthetic decision than anything, but if you have your camera set in automatic mode, that is aperture priority or shutter priorty the camera uses its small brain to make these decisions giving you less control of your image making. As you know aperture will control the depth in your image which is especially more noticeable with longer focal length lenses.
If you don't understand the concept of the aperture try this. If you wear glasses take them off, obviously the world is going to get really blurry, take a piece of paper and cut out a small pinhole into the paper. Place the paper close to your eye as if were a pair of glasses, you will notice that the once blurry world is somewhat sharp, and you should be able to make out details. You will also notice that things are a bit dark because not much light is being allowed through that pinhole. Well if you were a camera this would mean that your shutter would have to stay open longer.
So when to use a small aperture such as f22 or f16? Lets imagine a hypothetical situation. You are a photographing a flower, the flower itself is quite sharp, but the background is somewhat blurry, and you want the background to be in focus. In this case use a small aperture, but what about the shutter speed? That little graph with all the numbers you see in the viewfinder represent your shutter speeds, for example right now it says 1/125 of a second. At the bottom there is a plus and minus sign. If the plus is flashing or highlighted then it means the image is overexposed, meaning the shutter speed is too long and your image will be too light. Vice versa if it is underexposed it will be a bit dark. So what I am suggesting is that you put your camera in full manual mode. You will first select your aperture, that is how much depth or shall I say sharpness you want in your image, in particular the parts you are not able to focus in to make sharp. Then you will choose your shutter speed until that little side arrow doesnt highlight or flash either the plus or minus guide. If the camera says the correct shutter speed is below 1/60th of a second represented by the number 60, for example 1/30th, put the camera on a tripod, most people in particular beginners cant seem to shoot a sharp picture below the threshold of 1/60th. Anyhow I hope this helps you out a bit.

Answer 2

As an owner of 3 Minolta X-700 cameras I know you are in Auto Mode, aka Aperture Preferred. As you select an aperture the camera selects a shutter speed to insure correct exposure. You have to watch where the shutter speed indicator light is to avoid too slow of a shutter speed. Your shutter speed should always be a reciprocal of the lens length - when using a 100mm lens set an aperture that gives you a shutter speed of 1/125 minimum.

You select an aperture to control Depth of Field (DOF). If you select f11 you'll have more DOF than you will if you select f2.8. Just watch where the shutter speed indicator is.

Answer 3

You sound like you are in aperture priority mode. What that means is that when you adjust the aperture, and the camera automatically adjust the shutter to expose CORRECTLY.

Your friends are in manual mode, where they set the shutter (and leave it there) and then adjusting the F stop until the meter says the exposure is correct.

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In your case no matter what aperture you set, the camera is making sure the exposure is correct (by counter correcting the shutter). The exception is if the situation is too bright or too dark and the shutter is out of range.

Good Luck.