Sentences 3 and 4 in the article seem to excuse this. Is there further information that I may be missing regarding why the bias is still a problem?

The "bad" pattern he calls out is not exactly the Trioplan soap-bubble style, it's the thing you get from a mirror telephoto lens.

In Trioplan images[1], the light intensity smoothly increases towards the edge of the disk of confusion, and creates a sharp edge. I agree that this looks kind of nice, although it's a quite specialized effect.

In mirror lens images[2], the "disk" of confusion is actually a ring, with two sharp edges rather than just one. This is not at all pretty, and as far as I know basically nobody buys these lenses for this effect.

This actually matters a lot, because other than this, mirrors are superior to refractive glass lenses in almost every way (note that astronomical telescopes are always mirror-based), so if it was not for the bad bokeh we'd all use them.

[1] https://fujilove.com/the-legend-and-the-bubble-bokeh-review-... [2] https://hoaiphai.wordpress.com/2011/10/18/recumbent-review-t...

>>This actually matters a lot, because other than this, mirrors are superior to refractive glass lenses in almost every way

No. Reflective designs (mirrors) are usually of the casigrain type, and casigrain designs offer very narrow but limited zoom range field of views. This is at the cost of obscuration of the secondary mirror. Note that there are still refractive elements (lenses) in a casigrain design. This very narrow fov is why such designs are prefered in telescopes and other narrow fov application areas.

The majority of lens designs are refractive and this should give you an indication that a statement such as mirrors are superior to refractive designs simply is not true.

Edit - added application areas

I didn’t say the author was talking about the Trioplan. I only said the Trioplan’s Bokeh shape would be an example that he purports as undesirable.

As a photographer I don't care so much what optical design choice gave rise to an artifact (that I want to exploit artistically).

One thing I notice is when people get into photography bokeh is one of the first things that they want to emulate (another was HDR). But once they know the basic rules[1] of photography well enough to break them, they tend to view bokeh as that puppy-love attraction and now they are on to more serious photography. That is to say, bokeh is sometimes used as a crutch before people learn the basic rules and then learn how and when to break them to create a better photograph.

[1]https://www.flickr.com/groups/94761711@N00/discuss/721576221...

Exactly my experience! This is especially true for people who are into street photography. I've come full circle and I find myself looking for the sharpest picture across the whole frame.

Aesthetics aside, I think the reason we reach out for bokeh first is that it's an easy way to isolate subjects and obscure clutter. That gives your photography an instant boost. A lot easier than using composition, timing, and relying on luck.

It's also this quasi-metric for "professional quality" so first timers tend to spend the money to acquire these fast lenses in hopes it will suddenly make them a quality photographer.

> Two key terms in this definition are SUBJECTIVE and IMAGE. One cannot measure bokeh, as it is something that may be pleasing to one person and not another. I have my opinion of what makes for good bokeh, and, as I own this site, I get to define good and bad Bokeh for the purposes here!

And every time he mentions it he uses those caveats.

> You may have your own idea of what good bokeh is, but this site will be evaluating lenses based on MY opinions. And lets face it, there are actually times when BAD bokeh really works for a shot, but that is usually for people who have a whole lot more artistic talent than I do.

To my personal taste, the bubbles in photos of your link 1 is very distracting.

Yeah, and the swirls in Van Gogh's Starry Night are distracting too.