Thought I’d post about f/1.4 (wider) vs. f/5.6 (narrower) lens apertures. I’m not going to get into the science behind this, but instead show a practical difference in how your photos will look.
If you look at the image above you’ll see a fairly sizable difference. Here are some more details:
– blurred background (known as bokeh)
– darkened image borders (known as vignette)
– sharper background (wider area in focus = wider depth of field)
– corner exposure more uniform (less vignette)
Why use f/1.4?
This setting means your aperture is wide open on your lens. This will let in the maximum amount of light and result in a very shallow depth of field (high bokeh). This is a perfect setting if you want your subject to really stand out and you want to get that ‘artistic’ look of a photograph. It’s also great in really low light as you can keep your ISO low and your shutter speed fast. I really like to use this when taking portraits.
Note: not all lenses can go to f/1.4. As a matter of fact, most lenses can only go as wide as F/3.5. I think it’s worth the investment to get a lens that can achieve f/2.8 or wider and you’ll be able to achieve these nice photographic styles.
Why use f/5.6?
I used f/5.6 as the example in this post because it just happened to be what I shot today, but for all purposes this could be any of the smaller apertures like f/8, f/10, f/11, and above.
I use the smaller apertures if I want to capture the background because it’s just as interesting as the subject; or it happens to be the subject. Definitely use f/8 and smaller if you’re shooting landscapes.
A couple more thoughts
If you’re shooting with a larger sensor camera (e.g., full frame or APS-C) you will likely still find a nice background blur at f/5.6.
The closer you are to your subject, the narrower your depth of field will be. This is true for all apertures, but is more pronounced the wider you have you lens open (smaller aperture numbers).