Aperture(DoF)

Aperture is one of the holy trinity of taking photographs. Combined with Shutter speed and ISO, aperture is how we expose our images.  Aperture is referred to in f-stops.  The aperture however has nothing to do with your camera however (if it’s a DSLR) but on the lenses that you own. For instance I own one very fast (large aperture lens) a 50mm f 1.8. This is the lens I use primarily in the evening when I am trying to capture images where I can’t use a tripod. Having such a large(fast) aperture allows me to use a relatively high shutter speed even in less than ideal lighting without having to raise my ISO. This allows me to capture nice, well exposed images without having the grainy effect that takes place when using too high of an ISO. 

 This photo was taken with a 18-50 f2.8 lens.  I shot it at f2.8 in the dusk hours.  As you can see my daughter is in focus while the background is blurred together almost as if there was a backdrop behind her and not a bunch of trees.  This effect is referred to as bokeh. It’s something I love to strive for in portrait shots because it brings the subject into main view of the audience.  The person looking at the photo is drawn to her face rather than getting lost looking at the nature that is behind her. 

 In this photo I didn’t quite nail the depth of field as well as I would have liked. I capture this street performer and focused her rather well, however because of where the gentlemen next to her is located he is still in focus as well which I’m not happy about. In this instance I would have loved to have him blurred out much like the people in the background are so that she would be the center of attention in the photo. For this I would’ve needed some sort of tilt shift lens I believe, which allows you to blur things in a different way than a normal lens.

 Another feature of aperture is that it can produce lovely lighting effects in a photo. While the lines in the parking lot and the beams coming from the light are a result of a slow shutter speed, the star light effect coming from all the lights comes from the sweet spot aperture on my lens. I’ve found that on most of my lenses an aperture of f8-f12 will produce the awesome effects I refer to as star bursts.  I never see these effects when using a large aperture nor when I have a tiny one. I believe it has to do with this range being the optimal for lens sharpness. It captures everything terrifically. 

Lastly for a landscape photograph one would want to have a smaller aperture so that everything appears in focus, because in a landscape, the scenery is the object, and everything needs to be relatively similar so that all of the picture is admired.

This photo uses a small aperture to achieve a rather large depth of field I generally only use large apertures at night when I have a tripod with me. Because so much light is let in it can be hard to have a steady hand with a slow shutter speed.