4 ms·

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 l

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-of-the-meyer-optik-goerlitz-trioplan-100mm-f2-8/ https://fujilove.com/the-legend-and-the-bubble-bokeh-review-... [2] https://hoaiphai.wordpress.com/2011/10/18/recumbent-review-the-mighty-reflex-nikkor-c-500mm-f8/ https://hoaiphai.wordpress.com/2011/10/18/recumbent-review-t...

kabouseng 7y ago
>>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
virtualritz 7y ago
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).

kabouseng 7y ago

>>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

virtualritz 7y ago

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).