Exposure Trinity

Sony A200 ■ f/9 ■ 1/60 ■ ISO 100

This photo was taken in the summer of 2008 at Massanutten Resort. When I look at it now, I notice a few things that could be improved. For example, I should have focused on the snowboarder in the shot, but I'm not sure if I did at the time. Should I have slowed down or sped up the shutter speed to change the texture of the water? Should I have opened up my aperture or closed it down to get everything in focus?

I think I have a good grasp of the exposure trinity and how they make or break a photo. The trinity is composed of ISO, shutter speed, and aperture (not necessarily in that order).

ISO (International Standards Organization)

This is the adjustment of exposure from lighter to darker. The higher the value the brighter the exposure. An example, when shooting in broad daylight or with ample lighting ISO is adjusted to say 100 (or the lowest sweet spot of your camera). When shooting in the dark or less light, ISO can be bumped up to several hundreds to thousands depending on your camera. The downside is the higher ISO the more noise is introduced. However, it may not be the case all the time. Noise will be introduced when there is not enough light getting to the sensor, hence, the sensor will work harder, thus, noise is introduced.

SHUTTER SPEED

It is a measure of time in seconds the camera sensor (film stock) is exposed to light. The faster the speed the more it freezes movement. The shutter speed used in the photo is 1/60 of a second. It freezes the water but still keeps its texture. However, if I changed the shutter to 0.5 seconds the water texture would be smoother. A tip for hand-held photography, the shutter speed should be twice the focal length. For example, for a focal length of 200 mm, the speed should be 1/400.

APERTURE

Is the opening of the lens that allows light to pass through it to the camera sensor. This is measured in f-stop, for example, f/2.8. The lower the number the bigger the opening. Aside from controlling the volume of light passing through the lens, it also defines the depth of field. For shallow depth of field, use a smaller f-stop, like f/2.8 or lower. This means that part of the foreground and background will be out of focus. A smaller depth of field is great for getting good bokeh. For landscape, f/11 or higher will give you much focus from front to back. Camera lens cost is driven by f-stop and glass quality. The smaller the f-stop like f/2.8 or lower is much more expensive compared to the larger numbered f-stop.

OPTIMAL EXPOSURE

The optimal exposure is based on the combination of the three. Most cameras have three or more shooting modes: M-manual; S-shutter priority; A-aperture priority; and Auto. For Manual mode, the shooter controls all three settings but in some cameras, the ISO can be set to auto and the camera decides what ISO to use. For Shutter priority, the shooter selects how fast the shutter is and the camera decides what aperture to use if ISO is set in auto the camera also decides what ISO to use. For Aperture priority, the shooter selects the f-stop and the camera decides what shutter speed to use, same thing if ISO is set to auto the camera also decides which ISO to use. How does the camera decide how to set f-stop, shutter speed, and ISO? It all depends on where you point your camera and how the metering is set up.

WHAT NEXT

Any photographer can get the correct exposure for a picture but it may not be compelling. The exposure trinity can be achieved but this is still not a guarantee that the picture will turn out great. Like any form of art, there should be a story that can capture an audience. Exposure without great composition equals boring photos. I started photography back in 2008 and look at the above photo, it's blah. I could have used a different aperture or shutter speed. I could also change my focus and angle. I am hoping to take you on my journey through this blog and be my judge if I have improved or not in my photography.