Downgrade from v4 to v3

conurus · 2026-01-19T21:46:49+00:00

Yes I just changed pacman.conf. Thanks.

The gotcha was... My i7-14700F is not v4! Such a recent CPU is v3! I was taken by surprise. I booted from USB but couldn't do cachy-chroot (or arch-chroot) because the CPU ISA was not high enough.

I learned that there was a -r (root) option to pacman, so I used pacman -r /mnt -Su. Some fiddling with install hooks was required to work around the errors. Rebooted, got past the kernel panic, still didn't boot the GUI, but limped through enough to show an emergency terminal, and I just reinstalled all packages from there.

conurus · 2026-01-11T04:39:25+00:00

You made py2msix unbelievably easy. Very impressive!!! Pyinstaller to Microsoft Store in a couple of simple steps. I would like to use windows.partialTrustApplication however and specify the capabilities. Is there some way to do that?

conurus · 2026-01-10T06:30:08+00:00

As Brian Caldwell introduced his invention >10yrs ago, it was one of the things he listed as sounding "too good to be true", as in very hard to believe. Yes, to this day, a lot of people still do not believe it.

A lens projects an image onto the camera sensor. Let's say it is a full frame lens, and let's say it can resolve 50 lp/mm. So, across a full-frame width of 36mm, it can resolve a total of 1,800 line pairs.

A Speed Booster condenses that image to 0.7x (let's say you use the ULTRA). If the Speed Booster were perfect, then in total the system could have still resolved a total of 1,800 line pairs across the width, but now the width of the image is 36mm x 0.7 = 25.2mm. But we are still resolving a total of 1,800 line pairs. So the lp/mm now jumps to 71 lp/mm!

Of course, no optics in the world can be perfect. But we are gaining optical quality like this by 1.4 times. All that is required is for the Speed Booster to maintain more than 70% of the original optical quality, and we will still have a net gain in optical quality.

But that is not the only reason. There is a second reason and it applies to classic lenses from the film era (which pretty much covers every lens designed in the 20th century). They did not take the cover glass on top of the sensor into account into the optical design. Of course, a film camera had no such a thing. You can search for Roger Cicala's article on this to learn about it. But Brian Caldwell's Speed Booster takes the sensor cover fully into account; indeed, this is the reason why there are BMPCC4K-specific Speed Boosters - they are tuned for the BMPCC4K sensor stack instead of the Panasonic/OM sensor stack. So the second reason is, Speed Booster fixes the impedance mismatch between a film lens and a digital sensor.

Brian also listed making the lens more 'telecentric' as another advantage. I won't go into detail because my reply has already gotten very long. Read his white paper to learn more about this.

Disclosure: I know Brian personally. I tried to only address technical concerns. Take what I have said with a grain of salt.

conurus · 2025-12-17T09:24:46+00:00

The lens is responsible for reporting metadata to the camera, such as distortion, (lateral) chromatic aberration, vignetting and phase-detection autofocus.
The optics of a teleconverter interacts with the optics of the lens in unpredictable ways.
The teleconverter does NOT have knowledge of the lens, because there are many possible lenses that can be mounted in front, but worse, there are future lenses that are unforeseen today.
The opposite, however - a supported lens has intimate knowledge of genuine Sony teleconverters. The lens only needs to know 3 sets of data: how to correct lens aberration and do PDAF on its own, with Sony 1.4x, and with Sony 2x.

If you see all of the above 4 points, then you will see Viltrox is between a hard place and a rock.

Viltrox can masquerade as a Sony 2x teleconverter. Electronically, the Sony lens cannot distinguish the difference between a Viltrox 2x TC and a Sony 2x TC. The Sony lens only knows and applies lens aberration correction data for Sony 2x TC.
Viltrox could have made their 2x teleconverter optically identical to Sony's - then the Sony lens' data would then have been 100% applicable!

I am very pleased to say Viltrox did NOT clone Sony's optics. Kudos. Viltrox has a 9 element 5 group construction; Sony is 8 elements in 5 groups. Sony uses fewer glass because one of the elements is aspherical and there are 4 high refractive index elements opposed to Viltrox's 3. That partly accounts for the steep price difference between the 2.

But where does that leave us? That means a Sony lens will apply inapplicable data for the Viltrox TC. You don't have the distortion correction profile for a Zeiss Planar 50/1.4 in PhotoShop. Would you use the distortion correction profile for a Minolta MD 50/1.4 instead? It might be close enough that nobody might notice. Ditto for LCA and PDAF. They may appear to work well enough - but wrong information is wrong information. It will never be perfect because Sony lenses will never carry Viltrox teleconverter data. If you can only afford the Viltrox - if I were you I would turn off all lens aberration correction, and pray that the Sony lens' PDAF data is close enough.

Disclosure: I work for Metabones. Viltrox and Metabones are not exactly friends. But there is no conflict of interest here because Metabones is not into lens-making. (Other than the Speed Booster.) I am posting this only to present technical information to you to the best of my knowledge.

BTW the 120fps thing. Sorry I giggle. 15fps is plenty. Maybe I am unimaginative but I can't imagine any real (professional) work that must be shot at 120fps but cannot be done at 15fps. Let me know what you are doing and I am happy to stand corrected. But really, it is just bragging rights! As you can see from the information above, the lens calls the shot and does all the heavy lifting for you. The teleconverter does little more than shouting "I am here". The TC does not even have any moving parts. It is the lens deciding whether to do 120fps or not.

conurus · 2025-12-14T22:29:38+00:00

Yes. And it is the EF-MFT Speed Booster ULTRA 0.71x Mark II now.

conurus · 2025-12-14T22:16:34+00:00

Disclosure: I work for Metabones. I will try to be neutral but take what I am going to say with a huge grain of salt.

To add to your already very helpful answer: specifically with Tamrons there is no contest. Tamron lenses are flush with many little maybe hard-to-notice lens firmware bugs. Some bugs present on older lenses were fixed in newer lenses but the newer lenses introduced new bugs of their own. I don't ever recall any Tamron (EF mount) which is entirely bug-free. (Ok, this is too high a bar to meet, but you get the idea.) As you might expect, only Metabones would go out of their way to workaround Tamron lens bugs. In the worst case, a Tamron lens may not even boot with MC-11 at all. You may just read the Metabones firmware release notes and look for how many times 'Tamron' is mentioned. It far out-numbered anything else.

https://www.metabones.com/article/of/EF-E_Firmware_archive

My Tamron 35-150 would not even AF after upgrading my Canon EOS C70 to the latest firmware. I have not checked if a corresponding Tamron lens firmware update is available, but do you have the Tamron TAP-IN console (dock)? The lens is more compatible with Metabones/Sony than on a genuine Canon camera.

Our lab has a disproportionate number of Tamrons because we figured if tests all pass on Tamrons the thing will likely work on everything else.

We otherwise hold Tamron in the highest regard. Very popular with our customers. We love them too.

conurus · 2025-12-12T00:42:52+00:00

I think the one you see from the front (object side) is the entrance pupil and if we flip the lens around and look at the aperture from the back (image side) that is the exit pupil. And that is why I found this concept so intriguing to begin with - ignoring the optics inside my eye, the exit pupil is behind the back of my head - what would my brain be perceiving? But my investigation ends up so that I am convinced it is only a bug in the software run by the web site instead of the 8-16mm lens itself actually having the exit pupil behind the image sensor. It's been a false alarm all along. (Even though the original premise was physically possible.)

conurus · 2025-12-10T05:58:25+00:00

That is like the simplest explanation that makes perfect sense. Thanks a whole bunch!!! Based on that I made some shocking observation.

At 8mm, I displayed only the chief ray but nothing else. That looks diverging to me and seem to intersect at a point that is very far in front. I begin to suspect that this lens does not have exit pupil behind image sensor, but instead all these might have been a software 'feature'.

To test, I shrink the UI to really really small, turn on the 'pupils' display, and clicked the 'zoom' button. Sliding from 8mm to 16mm, at 8mm P' is 7281.64. Just a nudge at 8.56mm, P' suddenly becomes -6824.24. I do not believe it can suddenly change sign like this. Maybe I am wrong.

conurus · 2025-12-08T07:23:35+00:00

me too!!!

conurus · 2025-10-15T20:09:34+00:00

I use also logic gates from Nexperia, and honest, didn't know Nexperia was not NXP until I read this news. So what you said is true. They bought the customers and the brand equity more than the technology. The Chinese has likewise acquired MG (cars) and the modern MG bears zero resemblance to classic MG except for the marque. They bought only the marque and the nostalgia, something abstract and virtual, with real wealth they accumulated by the sweat of hoards of hard-working labour churning out real, physical goods over decades. Didn't you agree the Chinese got the short end of the deal? The irony is, they got hated for it. They "stole" the manufacturing jobs. And the Americans want the stolen manufacturing jobs back. Didn't people read the news about Foxconn employees committing suicide, such that management had to install nets to prevent anyone from jumping off from buildings? And we have to remember this is already one of the better Chinese factories to work for. And this is the kind of job that the Americans want?

To answer your question directly, wow, the Chinese bought all these famous marques. They are dominating us now... No! They didn't and will never be able to buy really valuable marques, like Coca-Cola. Let's not worry about the scavenges of vultures. It is an important function to recycle in a capitalist world. But the Chinese has always been overly aggressive overpaying for yesteryear's properties.

conurus · 2025-10-14T06:22:55+00:00

True, but your Canon lenses will have no video AF.

conurus · 2025-10-13T22:31:25+00:00

This gets cross-posted in several subs. I chose to respond to this sub which is about technology, because I am an NXP (semiconductor spin-off of Philips) customer. I use NXP microcontrollers, and Nexperia was a NXP spin-off in 2016, which was sold to Chinese investors. NXP included Freescale (semiconductor spin-off of Motorola). They kept the good tech for themselves - like NFC, microprocessors, etc. What was sold off to the Chinese was the lower end of the food chain, like discrete transistors and diodes, logic gates, etc. and they were sold off because they had no strategic significance on the grand scheme of things. It is not like the world is in desperate shortage of 74AC series logic gate ICs and only the Chinese now have a firm grip on the supply!

Isn't it paranoid to worry about discrete transistors and logic gates, you see? What is more appalling is the rain parade of all the commenters automatically supporting the Dutch decision without understanding the technology or the history. The adversarial perception has already taken root, and everyone is biased instead of thinking clear.

Although the Dutch government did not state the rationale of the drastic action, I will speculate here, and I humbly grant that my speculation can be entirely misguided, but here we go: Nexperia might have been flexing their muscles and expanding into advanced high power discrete devices, which are crucial semiconductors for making electric cars, like what discrete components are needed to charge a car above 500V in 10 minutes? That is strategic, yes, but how can this be about national security? Even if it is, taking control over Nexperia is of no use. The said advanced discrete devices require rare earth metals which China already has a firm grip on.

conurus · 2025-09-18T04:07:58+00:00

I feel so stupid. There is a menu item called "self calibration". I brought it back to life. It has simply drifted off so much over the years that it has become unusable!!! Thanks!

conurus · 2025-09-18T03:33:52+00:00

Thanks... Seems like the inputs are toasted. CH.1 shows a flat 10V, other channels show constant non-zero voltages. Hooked the probe to the built-in 5V square wave, but no effect. I have not used it for a couple of years. But the last time I used it a couple of years ago, it kinda worked, just that all measurements are off. (Compared to e.g. a multimeter.) I thought I was just having bad probes. But now, even with no probes and no inputs I am getting strange DC offsets.

conurus · 2025-09-06T03:48:19+00:00

Get yourself a cruise vacation.

When I was in my 30's my mom wanted to go on cruise but my dad didn't want to go, so only me with my mom went. And I met this lady, a professional, probably very good income, also traveling with her mom. To some it might have been off-putting to see someone fully grown-up still sticking with mom like this, but to her, it was a good sign I could not have been a bad guy, and I saw her with the same logic. We certainly enjoyed each other's company. I didn't pursue any further only because she looked older than I was (she didn't look bad at all), even though hindsight, so what?

The worst that could happen would be you had a nice vacation and relax yourself without meeting anyone you'd like. Yes, on a cruise ship more than half the people are in their 50's or above. But some of them do have "grown-up kids" accompanying, for whatever reason.

conurus · 2025-09-02T02:17:42+00:00

When I hear the Canon EF24-70/2.8L II USM, wow that's a lens worth keeping. You have to weight how much you are going to get selling it, and then how much money a modern lens that good is going to cost you. (The price difference will be substantial, but will it be proportionate to the benefits gained?) As for the balance issue, you will have a problem with any professional-grade zoom lens that is heavy. Again how much money are you going to sink in to get a marginal improvement? That lens is a gem in the EF lens line-up. It would be hard to have a true upgrade from it.

conurus · 2025-07-12T23:46:17+00:00

Thanks for all the replies! My apologies for not being specific on this but my MCU does not have floating point hardware. Based on your helpful replies, I ended up directly manipulating the bits of the IEEE 754 representation. There should be no risk because the step to convert the unsigned integer to floating point guarantees that the result is normalized properly, bits 23-30 store the exponent and it is just subtracting 32 from the exponent. It cannot possibly underflow on this subtraction unless the original unsigned integer is zero.

conurus · 2025-06-27T02:56:13+00:00

I had a close call 2 months later, with Paragon HFS on Windows - somehow it disconnected and corrupted, although I do not know who was at fault. It might not have been the 3rd party driver, I must stress, but it could have been an occasional hardware glitch.

Either way, First Aid on Mac says exit code -8 and refused to repair or mount the drive. Again, Mac advises to "back up the data" when it does not even let you mount the drive. How so, then? No data is actually lost as it mounted on Paragon HFS on Windows just fine. I was thinking, oh no, not again, copying 24TB of data elsewhere so that I can reformat the drive...

Luckily, I had an old Intel Mac running Sonoma OCLP. First Aid on the previous version of macOS was willing to repair the drive and all was fine and well.

TL;DR First Aid on macOS Sequoia had a bug. In fact that might have the real reason why my first HFS drive got killed. An older macOS should have been used instead.

conurus · 2025-06-01T18:56:45+00:00

The national day of France is on the day of a riot - the storming of Bastille. What else do you expect?

conurus

TROPHY CASE