Is this brokeh fringe?

Started 2 months ago | Discussions thread
Mark Scott Abeln
Mark Scott Abeln Forum Pro • Posts: 17,154
Doughnut bokeh
2

As mentioned, the word is 'bokeh', which is derived from the Japanese 'boke', and means "the way the lens renders out-of-focus points of light".

It's kind of hard determining the kind of blur by looking at extended out-of-focus objects; usually, tiny distant out of focus lights are used to get a clear idea of the structure of bokeh. If you look at the top of the device, you'll see two small blurred specular reflections. Here they are enlarged and enhanced:

This should give you a better idea of the bokeh. It has a strong ring around the center, which is informally called 'doughnut bokeh'. This kind of bokeh is associated with lenses that have overcorrected spherical aberration, which can make the in-focus parts look sharper. Under-corrected spherical aberration will often be very smooth, but the in-focus parts won't be particularly sharp, and lenses with this property were valued for beauty portraiture. Your lens may not be well-suited for this purpose, but it should be fine if you stop down a lot or don't have a background that will be too distracting when blurred.

You might want to do an experiment with a highly out of focus distant point of light against a black background. Even better, you can have a string of lights around the frame, so you can see how the bokeh may vary within the image; often shape of the point spread will vary as it goes from the center to the corners.

The bokeh will typically be different for out-of-focus objects that are in front of the point of focus.

https://en.wikipedia.org/wiki/Bokeh

 Mark Scott Abeln's gear list:Mark Scott Abeln's gear list
Nikon D200 Nikon D7000 Nikon D750 Nikon AF-S DX Nikkor 35mm F1.8G Nikon AF Nikkor 28mm f/2.8D +4 more
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