TUESDAY TIPS: Av Setting

So you got a brand spankin’ new DSLR or high-end P&S camera for the holidays, and you’re wondering what all the letters on the dial are for. Tv, Av, M… It’s all greek to you. The next few Tuesday Tips are going to (hopefully) get you started.

First of all, if you have a DSLR, and shoot with the dial on auto (often designated by a little green box,) stop. That’s like doing 25MPH in a Lamborghini. You’ll want to experiment with some of the manual settings on your camera to really get the most out of it.

Essentially, we’re taking about exposure. We’re always talking about exposure. The combination of Shutter Speed, Aperture (f-stop), and ISO. Photography is about light, and how to get it from the outside world onto your camera’s sensor. I don’t want to tackle everything in one post, so we’ll start with Aperture. Aperture value is also referred to as the F-Stop value or number.

The Av setting on your camera’s dial (or menu, if you’re using an advanced Point and Shoot camera,) tells the camera that you will specify the size of the aperture, and the camera will choose the shutter speed. Aperture is the size of the “hole” in the lens that lets light in to your camera. The number is displayed with an “F” in front of it: F 1.8, F 5.6, F 22 are all aperture (f-stop) values.

After you’ve selected Av, there is generally a dial or some other way to adjust the f-stop. The available settings are limited by your camera and/or lens. Point and Shoot cameras have defined low and high aperture values. Aperture values available in DSLR cameras are defined by the lens attached to the camera. For example, Canon’s “Nifty Fifty” (a lens that I think every canon DSLR owner should have in their bag,) can go from F1.8 to F22. Zoom lenses vary based on the zoom. A lens that can go as low as F5.6 when zoomed out all the way may only be able to get down to F8 when zoomed in as far as it can go.

This is where it gets a little confusing. The lower the f-stop number, the bigger the aperture, and vice versa. (See diagram in gallery.)

What setting do you want to use? That depends. Since we’re not digging into the guts of exposure here, we’ll stick to the aesthetics. Lower f-stop numbers provide a shallower depth of field. That is, the object you’re focusing on is sharp, while the foreground and background is blurred. You’ve heard of bokeh? Bokeh is the result of a shallow depth of field. So if you’re shooting a portrait, and really want to separate your subject from his/her background, a lower f-stop will do that.

On the other hand, if you’re shooting a landscape and want to get as much as possible in focus, you’d use a higher f-stop number. One caveat, though. Higher f-stops let in less light, so your shutter speed will be slower. In some cases, you may need to use a tripod to ensure pictures with no motion blur.

What now? Experiment. Grab your camera, set it on Av, find a subject, and take the same photo at different f-stops. Start at the lowest number your camera/lens allows, and work your way up. This is especially useful for DSLR users–different lenses perform better at certain aperture value ranges. Practice, practice, practice. You can study all the books you can get your hands on, but nothing will teach you more than picking up your camera and experimenting.

For more reading, hit these links:

• F-number
• Bokeh

What about the Tv setting, or ISO?