This week's lesson with Reese was a fun lesson on bokeh. The term bokeh comes from the Japanese word boke, which means "blur" or "haze". Bokeh is the blur or the aesthetic quality of the blur found in out-of-focus areas of an image. To achieve this effect, a shallow depth of field must be used to create these out-of-focus regions. The bigger the aperture (smaller the f/number), the more blur in the background. The smaller the aperture (bigger the f/number), the less blur in the background. For the photos below, I used a Nikon 50mm f/1.4 prime lens. I started off with f/1.4 for maximum background blur, then increased each photo by 2 full stops until I got to this lens' smallest aperture of f/16.
Reese had a really simple way of explaining how to calculate full stops. Hopefully I can explain it so you can understand too.
Take the numbers 1 and 1.4. If 1.4 is the first stop, to figure out the next stop, you double the number before 1.4, which is 1. So the second stop would be 2.
To figure out the next stop after 2, you take the number before 2, which is 1.4 and double it. The third stop would be 2.8.
To figure out the next stop after 2.8, you take the number before 2.8, which is 2 and double it. The fourth stop would be 4.
To figure out the next stop after 4, you take the number before 4, which is 2.8 and double it. The fifth stop would be 5.6.
When you get to double digit f/number, the decimal number is dropped. So 11.2 is just 11 and so on.
For this particular lens, if you start from f/1.4, the full stops after that are f/2, f/2.8, f/4, f/5.6, f/8, f/11 and f/16. In my explanation above, I had stated that I increased each photo by 2 full stops. This is true only to f/11. The very last photo in each set is only 1 full stop, since the smallest aperture on my lens was f/16. Otherwise, it would've been f/22.
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ISO 100, f/1.4, shutter 1/4000 |
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ISO 100, f/1.4, shutter 1/4000 |
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ISO 100, f/2.8, shutter 1/1250 |
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ISO 100, f/2.8, shutter 1/1600 |