Need some help, please.

[Evertking]

OK, I was going outside today to take pics of my kiddos with my new lens. A Canon 50 mm 1.8 a few turned out fine and all of a sudden I look at them and they all are white(overexposed?) And the same this morning at sunrise. One photo was fine and the other although not white was dark. I was shooting in AV mode. And as I understand it, I set the f-stop and the camera handles the rest. Or am I misunderstanding and missing something?

 

[snowbear]

Yes, in Av mode, you set the aperture and the camera will set the shutter speed. ISO, the other part of the exposure triangle, will be set separately (either automatically or manually.) Metering mode will also affect the overall photo,

If you post one of the photos here and list the EXIF data (there are free readers), I'm sure someone can help you figure it out. Without see the photo, we are just guessing.

 

[dennybeall]

So many things could be wrong. If ISO is on manual or you are set on spot metering and the spot is pointed at a too dark or too bright spot or the camera is broke. To name a few of the things that could be wrong. Upload a photo with the EXIF data intact.

 

[table1349]

Digital Photography Tutorials

 

[weepete]

Chances are you've knocked out the exposure compensation, that is normally the culprit for over exposure in AV mode. With the under exposure it could be the same thing or possibly lighting wasn't good enough or your have matrix metering on and are exposing for the wrong part of the scene. There are other possibilities but these are the most common IME

 

[Evertking]

 

[Evertking]

 

[480sparky]

Camera Maker: Canon
Camera Model: Canon EOS DIGITAL REBEL XT
Image Date: 2016-07-02 18:31:50 (no TZ)
Focal Length: 50.0mm
Aperture: ƒ/2.5
Exposure Time: 0.0050 s (1/200)
ISO equiv: 400
Exposure Bias: -1.00 EV
Metering Mode: Average
Exposure: aperture priority (semi-auto)
White Balance: Auto
Flash Fired: Yes (Auto, return light detected)
Orientation: Normal
Color Space: sRGB
GPS Coordinate: undefined, undefined

 

[table1349]

Yep add the EV to the below and it's going to get blown out.

Camera Maker: Canon
Camera Model: Canon EOS DIGITAL REBEL XT
Image Date: 2016-07-02 18:31:50 (no TZ)
Focal Length: 50.0mm
Aperture: ƒ/2.5
Exposure Time: 0.0050 s (1/200)
ISO equiv: 400
Exposure Bias: -1.00 EV
Metering Mode: Average
Exposure: aperture priority (semi-auto)
White Balance: Auto
Flash Fired: Yes (Auto, return light detected)
Orientation: Normal
Color Space: sRGB
GPS Coordinate: undefined, undefined

 

[Evertking]

OK, how to I correctly adjust this for future reference.
Thanks for taking the time to help me.
I told myself that I'm not going to use auto modes and force my hand at learning this. Seems like a daunting task at the moment.

 

[480sparky]

The only difference between Auto and Manual is whether the camera sets the aperture/shutter/ISO or you do. 1/500sec is 1/500sec regardless of which one chooses it. Same for ISO400 or f/5.6.... they're all the same.

Put your camera in Auto and take a photo. Then look at the shutter speed, aperture and ISO. Now put your camera in Manual and set the shutter speed, aperture and ISO to the exact same settings and take another photo.

Assuming there has been no change in the lighting, the exposures will be identical.

 

[table1349]

Start by reading the manual if you haven't, especially the part on metering. Then read the tutorials I posted a link to. Especially the part on the exposure triangle. Once you understand metering and the exposure triangle you should be able to get the exposures you want. Finally seek out and read Understanding Exposure by Bryan Peterson. He will teach you how to achieve the more creative exposures you are going to want to be able to do at some point.

 

[Evertking]

Thank you!