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Best lenses for sunstars (phillipreeve.net)
21 points by luu 82 days ago | hide | past | favorite | 7 comments

Ten blades is better than 5 blades because the spikes are half the width on defocused points.

Newer Canon lenses have been 9- and 10-bladed.

Hasselblad's old V system lenses had 5 blades, curved in C lenses and straight in CF and later.

Fun fact for manga fans: the heavy use of Hasselblads in fashion and the resulting pentagonal bokeh lives on today in the frequent appearance of pentagons in the screentones of shoujo manga.

I get these sunstars (I hadn't heard that name before) in my normal vision at night. I see them on all the street lights and car headlights.

Is that normal or does it indicate some sort of problem?

If I were to ask an optician about it, what words should I use to explain the problem? Would they know what a "sunstar" is? Is it different to "lens flare"?

You might have astigmatism. A simple examination will tell you. When I put on my first pair of prescription glasses in my early 20s, I was astonished at how different everything looked, and how so many weird optical effects like starbursts/sunstars slowly crept up on me such that I didn't realize my vision had changed so drastically. (The period between my last eye examine in adolescence and when I sought help for night driving was also the period I discovered computers and Linux and long nights hacking.)

Ah, thank you. I do have astigmatism and my glasses do correct for it. That explains it then.

I've had a few lens corrections over the years, but starbursts seem to only get worse with time since that first prescription where they completely disappeared.

Whenever I bring up the question of corrective surgery my ophthalmologist manages to somehow change the subject. I suspect that my astigmatism has gotten so bad that lenses can't completely correct it (thus worsening starbursts), making me a poor candidate for surgery in his opinion, notwithstanding all the marketing promises out there. Perhaps we're both in the same boat if you're also still seeing starbursts with your prescription.

Another thing that can cause sunstars are your own eyelashes. If you look at a bright light at night while drooping your eyelids, you will see vertical bands that match the shape/direction of your eyelashes.

Straight blades+even number of blades get the best sun stars.

Rounded blades can still get a cool effect but the sunstar points look like a triangle instead of a straight line.

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