On this days, "computer get slow because much installed stuff" is a thing if the past.

The "best" way to slow down a computer is to have
a) less than 5% space left on a SDD and/or
b) a highly fragmented HDD and/or
c) something heavy running in the background

a and b are hardware related and c is user related. It will happen on a Windows box, a Mac or even Linux.

Stop "fanboying" Macs... from a sysadmin point of view they are not better than equivalent non-Mac computers, only more expensive.

Diffraction happens at the edge of any discontinuity, eg. the iris

The length of the edge of the iris is 2.pi.D where D is the diameter of the iris.

The amount of light is proportional to the surface of the hole, which is pi/2.D^2.

Therefore the effect of diffraction is inversely proportional to the diameter of the iris.

Aperture (/F) is D/f where f = focal length.

So to get the same aperture on a lens with less focal length, yo need a smaller D to achieve the same /F number.

So lenses with shorter focal leghts tend to have more diffraction effects.

This is a strong simplification, because there are other effects which I neglected, like the diffraction at the edges of the lens elements, at the surface of each element, etc. but you get the idea.

Just google " Airy disk", and you'll get the approximate formula for a given focal length, aperture and pixel size.

Extremely interesting.

Diffraction is a phenomena derived from the fact that light can behave as a wave, and therefore is suitable to be treated as a big bunch of wavelets. Wavelets bounce inside the lens and can might hit the wrong pixels.

Therefore diffraction is very dependent on the lens... Other lenses might behave differently.

The best thing to do is, when a new lens arrives, is to test it and find it's limits.

My first O/S was - in reality - none at all, but looked like this:

Well the damn Windows 11 got my standard treatment... reformatted DISK0, installed Ubuntu 22.04 Server , installed gdm, installed VMWare Workstation, created three virtual computers on top of Ubuntu, two with Windows 10(*) and the third one with MacOS 10.11(**).

Now I run the show, not Microsoft nor Apple.

* to run my photo apps
** to emulate Apple environment, some of my customers insist on using that.

After a heavy computer crash, which I traced back to a motherboard failure, I decided to upgrade my main computer.

So I purchased a brand new i9-13900K CPU, a good Gigabyte B760 motherboard, a couple of 2TG SSD's, a couple of 40TB HDD's , a 4090 GPU, 128 GB DDR5 RAM and 1 KW PSU for good measure.

Because of the amount of purchase, my supplier tossed in a Windows 11 license for free.

Reluctant, after building my system and playing around with that pesky Windows 11 sticker, I decided to give it a try.

What a rubbish!

Bad, really bad user interface if you need many programs for work. No way to organize, change, customize, no nothing. I had to purchase "Start11" ap to make it almost as usable as Windows 10.

It does nasty things to the files. Without asking: for example: I copied all my photos and videos to the E: drive (the 40 TB's HDD's configured as RAID) ... the next morning I had a "no sapce left on drive" error on the C: drive. What had happened? Windows decided that photos should be backed up in OneDrive, so it moved everything to C:\Users \<my_user>\Onedrive\Pictures **without asking **

As I tried to move them back, Windows 11 refused with a stupid error message stating that it was an amovible linkl included. ** I HAD TO MANUALLY SHUT DOWN ONE DRIVE, AND PERFORM A REGISTRY TRICK TO BRING ALL THE FILES BACK TO WHERE THEY BELONG**

After that, Windows complained that there was a Backup error, every time I accessed the folder. So I killed OneDrive altogether and deleted it from disk (after another PoweShell+Registry hack)

Windows 11 came with Copilot installed and activated (It's a MS rebranding of ChatGPT ), so I asked this question to the bot: "Why is Windows 11 so bad?"

And this was it sincere answer:

Windows 11 is the latest operating system from Microsoft, released on October 5, 2021. It has been praised for its clean design and improved performance, but it has also received a lot of criticism from users who are unhappy with some of its features and limitations. Some of the reasons why Windows 11 is so bad are:

High hardware requirements: Windows 11 demands some minimum hardware requirements that many current computers do not meet, such as a 64-bit processor with at least two cores and 1 GHz of frequency, 4 GB of RAM, 64 GB of storage space, a graphics card compatible with DirectX 12 and a TPM 2.0 security module. These requirements exclude many old or low-end devices that work perfectly with Windows 10, and force users to buy a new PC or stick with the previous system12.
Performance and compatibility issues: Windows 11 has arrived with several bugs and errors that affect the performance and compatibility of the devices that install it. For example, a performance loss has been detected in AMD Ryzen processors, which is due to a problem with the power plan of Windows 112. There have also been problems with printers, which stop working or give errors when printing2. In addition, some applications and games do not work properly or simply do not run on Windows 11, such as some Android emulators3.
Changes in the interface and functions: Windows 11 has introduced some changes in the interface and functions that nobody asked for and that make the user experience worse. For example, the taskbar is less customizable and functional, the context menus are inconsistent and cluttered, the default apps settings are complicated and tedious, and the Microsoft account is mandatory to use the system124.
These are some of the main complaints that users have about Windows 11. However, there may be more issues that have not been discovered or reported yet. Windows 11 is still a new and unfinished system, and it may improve over time with updates and fixes. However, for now, many users prefer to stay with Windows 10 or look for alternatives.

*** BOTTOM LINE ***

For or those folks which are asking about upgrading to Windows 11, ** DO NOT DARE TO **

Beware, I found many more problems as the one described above.

End of the experiment. I'll be throwing Windows 11 away... together with Windows 95, Vista and Windows 8.

All in all I'm a Linux sysadmin and developer, I don't need to go through this s**t.

He did not use tungsten but vegetal carbon fibers.

Tungsten requires a very complex technology and was mastered after Edison's death.

Hah!

I've got a turbo diesel car... Best engine ever.
320.000 km and running like new!!

It's a joke made by AI, just like this one:

I've heard something about that as graduate student... What was your professor's name?

A) didn't notice the other video
B) spotted it on YouTube and shared it
C) I don't care about attention or whatever
D) get a life

Here is the link, enjoy!

https://youtu.be/r5HFLkNrbIU?si=sG0l_pWqPa_Fvm5u

Found this mesmerizing video on how Sigma manufactures lenses...

No coefficients in Metrics System

To lift an object that weights 1 Newton to a height of 1m, you need 1 kg x 1 m = 1 Joule
If you need to lift it in 1 second, then you need a motor capable of outputting 1 J x 1 s = 1 Watt.

That's it.

Metric is simple:
Steel/barbed wire is sold by kg (nails, also btw)
Electrical wire is sold by mm2 (square milímetros) because the amperage is directly proportional to it.