I'm doing a project for school and i need to change the aperture for different photos. But my camera refuses to take the photo on any other aperture. Why is there an aperture adjuster if you can't use it. And how can i fix this??

This is a common problem. The metering and light balance are the reasons that you are having problems achieving good results with your photos.

All cameras on the auto cycle are calibrated for 18% gray. Another words a photo of all white results in 18% gray. A photo of black results in 18% gray. The camera adjusts the shutter speed and aperture to achieve an average light level of 18%. That is why photos of snow always appear gray. To compensate for this characteristic of the cameras an 18 % gray panel is held in front of the camera and than the settings are set.manually. The metering in the camera is now locked and using the same light levels objects will be in their natural level.

A second problem is the white balance. Using flash avoids some of these problems. Adjusting the camera for source lighting type will help the most. The light balance is the cause of discoloration of the objects in the photo. Usually the camera white balance can be set for auto, incandescent, fluorescent, outdoor or flash,

Use a manual setting if it is available on you camera, You need to adjust the settings until you get acceptable results. If the photo is dark add light by reducing the aperture number to a lower number allowing more light. After the aperture is open wide(lowest number) increase the exposure to longer time. With very low light levels a tripod may be necessary.. After doing this once record the numbers for next time.

You want the fastest shutter speed you can get and the largest aperture possible.
If you're close enough and it's allowed, use the flash. The flash will freeze the action. However, it's likely to give you a dark background instead of a blurry background.
If not, use the Aperture Priority mode. Open the lens to its maximum aperture (smallest f/number). This will give you the fastest shutter speed for the existing lighting conditions. The fast shutter speed will freeze the action and the large aperture will blur the background, though the amount of freezing may be limited if the lighting is relatively dark, as in a high school gym.
Be aware that if you're shooting indoors you're going up against the laws of physics. The human eye can adapt much better than any camera. A high school gym will appear light enough once you've been inside for a few minutes, but it is much, much darker than a bright day outdoors.

I would delete Apeture from the machine and do a clean install of the application. Do not know if there is an unistall on the installer disk but to get rid of apeture manually try dragging the application to the trash.

Then delete the following folders and files ...

~\Library\Preferences\com.apple.Aperture.plist
~\Library\Caches\Aperture
~\Library\Application Support\Aperture
\Library\Application Support\ProApps\Aperture System ID

Hope this helps

It is possible that you have set your Camera to RAW+L instead of RAW. Take card out ofb the camera, use a card reader and browse the card using the OS (as auxillary drive) rather than Aperture. I suspect that the RAW files are present, juts not visible on your computer possibly because of some setting in Aperture.

You mention everything except the shutter speed. When the aperture shows "Lo" it's saying that there isn't enough light at your selected shutters peed to produce a good exposure. That's why you have dark photos. You may need to bump the ISO up higher, or use exposure compensation to make it work well. For a football game, 1/750 is nice, but you can usually make 1/500 work.

i am an train picture guy but neverthe less u cant take anything for granted put cam on "P" and see whad happens and check your manual

Hello, I very much doubt that a small piece of dirt on the lens is a problem. It is more likely that your sensor needs to be cleaned. Sensor dirt is more visible at small (f11 to f32) apertures. I expect that you are shooting bright snow with a small aperture & this is why you are seeing the problem. To check, try the following.
Set camera to Av, ISO 100.
take some photos of the sky, a blank wall, or some other featureless surface, as follows:
1 - Set aperture to highest possible f - number.
2 - set aperture to lowest f-number.
3 - repeat 1 with a different lens
4 - repeat 2 with a different lens.

I expect that you will see photo 1 and photo 3 will have identical smudges of dirt on them. Photos 2 and 4 should have no smudges. If this is the case, your problem is dirt on the camera sensor. The only way to fix it is to clean your sensor.

changed the auto aperture under custom settings to permit and that was it

Digital cameras allow you to take pictures at different quality setting. The higher the setting the better the photo quality. Higher settings use more memory then lower settings. If you intend to make prints, always use a medium or high setting. The low setting should only be used when all you want to do is view the pictures on your computer or send them by email or over the Internet.

Recommended camera settings for portraits:
Focal length: 100 mm
Aperture: F2.8 (as large a f/stop as is available for proper exposure)
Exposure / Shooting Mode: Aperture Priority / Portrait
Flash: Fill-in, if face is in shadow

Recommended camera settings for landscapes:
Focal length: 38 mm
Aperture: F16 (as small a f/stop as is available for proper exposure)
Exposure / Shooting Mode: Aperture Priority / Landscape
Tripod: Yes, for long exposures

Digital Camera Tutorial - Better Photo Taking - Taking Digital ...Jus check this site for more details

It does different things depending on the camera settings and only works in the creative zone settings not the automatic settings.

In AV mode it changes the aperture
In Tv Mode it changes the shutter speed
In M mode it changes the shutter speed unless the AV button is pressed when it then changes the aperture