A Fine Bokeh

...soooo, the size of your lens' aperture affects your depth of field. What about the shape of the aperture? Welcome to the concept of bokeh.

Digital Photography School - How to Achieve Better Bokeh

Yes, the shape of those fuzzy highlights in the defocussed areas of your perfectly crafted image is dependent on the shape of the aperture.

Image from: www.meh.ro/wp-content/uploads/2013/08/

Image from: cdn-7.nikon-cdn.com/Images/Learn-Explore/Photography-Techniques/2012/Bokeh-for-Beginners/Media

The quality of the iris diaphragm can vary in number of segments and quality (straight or curved) between cameras. Higher end cameras tend to have a more segments and a more rounded aperture. Some people even want to build their own oversized versions... for demonstration purposes only I hope...

And, supposedly, you can customise the bokeh by carefully taping a stencil to your precious and expensive equipment!

Image from: digital-photography-school.com/wp-content/uploads/2010/04/

Image from: www.everkelly.com/wp-content/uploads/2010/04/

I thought I was getting some sort of handle on the relationship between the fixed physical attributes of  the camera/lens and the variable bits. Trying to understand how a stencil over your lens can be beneficial has knocked that into a cocked hat for the time being.