Friday, November 27, 2009

Aperture priority shooting

It was gorgeous outside but there were some clouds, and our walk had us going from shade to direct sun and back every few steps, so I set the camera to aperture priority and started shooting. I wanted to see what the shutter would do. In a nutshell, the shutter was all over the place.
Shutter 1/30 Aperture f/5.0 ISO 100 (note: shooting in shade)

Shutter 1/125 Aperture f/5.0 ISO 100 (note: shooting in sun)

Shutter 1/200 Aperture f/5.0 ISO 100 (note: this shot and the following were taken less than a minute apart)

Shutter 1/160 Aperture f/5.0 ISO 100

Shutter 1/400 Aperture f/5.6 ISO 100 (note: closed the opening a bit)

Shutter 1/50 Aperture f/5.6 ISO 100

Shutter 1/200 Aperture f/5.6 ISO 100

Shutter 1/500 Aperture f/2.2 ISO 100 (note: had opened the aperture up for a large shaded area and wanted to see how the shutter would compensate for so much light once I was shooting in sun again - it got very fast)


Amber said...

Genius! This would have come in really handy when we trekked across the bridge on Sunday when it was really sunny. It would have at least given me an idea of where to start. You're so smart! :)

Cathy said...

Why did you decided on f/5.0 and how come I can't seem to get my camera below f/5.6? So, maybe the first part of that question you can answer and not the second... but why did you set the aperture so low? (and that is low, correct?)

Christie said...

Cathy - I don't remember why I chose f/5.0 because I hadn't yet learned about metering. But sometimes just going with an idea will work out okay. I learned that it was very difficult to hold the camera for 1/30 of a second when shooting a moving target in shade. :)

Aperture is weird and it took me some time to get use to it because it seems opposite how it should be - the bigger (i.e. the wider) the aperture, the lower the f/ratio number. Most lens have adjustable aperture settings ranging from f/1.4 to f/22.0.
F/1.4 is when the lens opening is at its widest, f/22.0 is when it is a teeny, tiny opening.

To get a feel for the differences, take the same shot over and over just adjusting one thing. I would start with ISO since that is the easiest to see the difference on and there are probably far less increments than with either aperture or shutter speed. If you do this for shutter speed, I would probably not try every increment as it is difficult to discern the difference of a picture taken of a toy at 1/400 and 1/500 of a second. You'd likely see a huge difference if you took the shot with your camera's shutter speed set to 1 second, half a second, 1/60 of a second and 1/100 of a second.

For aperture, I found this explanation for depth of field:

"Another thing that the f/ratio determines is the depth of field, or depth of focus. At smaller apertures (higher f/ratios) the lens acts more like a pinhole, and both objects relatively close and far away from the lens will appear sharp. At larger apertures, the depth of focus decreases, and everything except objects within a narrow range of distance will be unsharp."

I would recommend looking at the settings of the pictures you're taking so you can see what the camera is doing. That's how I learned an ISO of 200 was the sweet spot for most of my pictures. (Using ISO 100 made faces too sharp and overexposed a lot of the time.) I wish I lived closer. I would totally meet you to go out shooting.