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Is my vision that bad? No, it's just a bug in Apple's Calculator

(martin.wojtczyk.de)
631 points wojtczyk | 6 comments | 31 Aug 24 04:29 UTC | HN request time: 0s | source | bottom
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dylan-m ◴[31 Aug 24 05:51 UTC] No.41406819[source]▶
One of my favourite unreported MacOS issues comes from how, at some point, they changed the appearance of the window close button to be a particular shade of red with a tiny little X in the center. And if you happen to be using a particular kind of screen and possibly wearing glasses, that little X kind of wanders around in the button, appearing just slightly off center in a maddening way. Made only more maddening by the glasses component: https://www.robbert.org/2014/10/the-off-center-close-button/.

That post points out it’s probably just subpixel stuff causing the issue, but I think my thick, cheap glasses at the time were adding a layer of chromatic aberration to something that was already visually confusing.

I assume it’s kind of gone away at this point with all the high DPI screens these days. But I remember thinking at the time, if there was a public bug tracker, that issue would be a fun one.

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mrob ◴[31 Aug 24 06:52 UTC] No.41406994[source]▶
>More expensive lenses have a coating to compensate for this chromatic aberration.

You can't compensate for chromatic aberration with a coating. You need a compound lens made from multiple elements each with a different dispersion, e.g.:

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

More expensive glasses lenses usually have worse chromatic aberration than cheap ones. The cheapest material for glasses lenses (PADC, often called by the brand name CR-39) has one of the best Abbe numbers (measure of dispersion).

https://en.wikipedia.org/wiki/CR-39

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

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1. w4rh4wk5 ◴[31 Aug 24 09:18 UTC] No.41407534[source]▶
I can confirm this. I had annoyingly bad chromatic aberration with my previous glasses. I specifically asked for CR-39 lenses for my next set of glasses and now it's barely noticeable at all.

I would recommend this to any programmer who uses high-contrast syntax highlighting. To me, it felt fatiguing every time I noticed differently colored words scrolling slight further than other words on a terminal screen on the same line.

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2. agent86 ◴[31 Aug 24 10:12 UTC] No.41407736[source]▶
One thing to keep in mind is that CR-39 is not impact resistant. They will shatter and can do horrible things to your eyes when they do. Kids should always be put in impact resistant lenses.

If you’re a desk jockey, or impact resistance is not a concern, CR-39 will give the least aberration with the exception of crown glass.

The hidden hack here if you need/want impact resistance is to ask for Trivex lenses. Same impact resistance as polycarbonate but much better ABBE value. It’s often overlooked because it costs a little more than polycarbonate and most people don’t complain about the distortion.

Also, anecdotally, you get what you pay for with progressive lenses. I have a cheap lens in my sunglasses and a higher end lens in my daily drivers and I can easily tell the difference.

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3. jrockway ◴[31 Aug 24 10:20 UTC] No.41407764[source]▶
This really bothered me many years ago, and I tried CR-39 and even glass, just for fun. I was never that happy with the results. I could always distract myself with chromatic aberration, and I think I eventually decided not to care anymore.

But right now, I have high index lenses and am reading HN with Dark Reader, and even if I use the maximum strength of my glasses (progressive bifocals), I can't really see any chromatic aberration.

I'm not sure if I should be happy or worried.

4. xattt ◴[31 Aug 24 12:30 UTC] No.41408408[source]▶
> It’s often overlooked because it costs a little more than polycarbonate and most people don’t complain about the distortion.

I just started wearing glasses. I asked about fringing and they had brushed my concerns off as me being new to glasses.

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5. kps ◴[31 Aug 24 15:06 UTC] No.41409404[source]▶
For those with stronger prescriptions who want higher index lenses to reduce thickness (and weight), look at http://opticampus.opti.vision/tools/materials.php and/or talk to your optician about available materials. (Personally, I've settled on MR-8 for my last couple pairs of computer glasses.)
6. w4rh4wk5 ◴[31 Aug 24 16:55 UTC] No.41410150{3}[source]▶
Deal with it for a few weeks, your brain will likely adapt.