Why are my images always underexposed in Tv/M mode?

Question

With the 18-55 mm kit lens on my Canon 1100D in Tv or M mode, when the shutter speed is more than 1/200th it always always produces dark images. The max f-stop this lens can go to is f/3.5.

SMALL F-STOP NUMBER = LOTS OF LIGHT

I know that a fast shutter speed lets in less light, but a small f-stop lets in more light. In my case with the 18-55 mm kit lens, the camera always produces dark image and I'm not able to use the full flexiblity of my camera even if the lighting condition is good.

Do I have to use a smaller f-stop like f/1.8 and then try or is ther something wrong with the settings?

Answer 1

Look at your exposure meter. Your gear is only capable of so much and in the Av/Tv/P modes it will attempt to use your settings (such as your specified shutter speed), and adjust the other settings to get the right exposure. If you adjust a setting too far then it won't be able to keep up. You should see your meter and/or shutter/aperture settings (whichever one isn't being set manually) blinking to indicate that it won't expose correctly.

Answer 2

Additionally, if you're in Tv mode, when you half-press the button, if you see the Aperture number blinking, it means you are underexposing your picture. You can force the camera to take the picture, but the blinking was there to warn you.

In Manual mode, as was said by @tenmiles, the Exposure Meter will tell you whether you are properly exposed.

Additionally, check the ISO setting. If you want to keep the shutter speed at 1/200s, and the aperture is blinking, you'll have to bump the ISO up. You may want to try out ISO Auto instead of a fixed ISO setting.

Another thing you can try, take a picture with your Tv mode, take the same picture in Full Auto (green square mode), and compare the EXIF data for both pictures...