De coronapandemie bestrijden is niet als fietsen

▼ (Sorry, weer een lange introductie... kan je overslaan, fietsgedeelte onder het plaatje.)

Ik maakte me best zorgen over hoe de COVID-19-pandemie zich zou ontwikkelen wanneer in september de kinderen weer naar school en studenten naar HBO en universiteit zouden gaan. Dat bleek mee te vallen: de besmettingscijfers gingen zowaar omlaag. Niet vreemd dus dat het kabinet besloot om per 26 september versoepelingen door te voeren. Wel gingen ze hier verder dan de aanbevelingen van de experts van het OMT. En een stijging van de besmettingen was ingecalculeerd, ook al moest je bij de horeca en dergelijke voortaan met een QR-code aantonen dat je gevaccineerd bent, COVID doorgemaakt hebt of negatief getest bent.

En de cijfers liepen inderdaad redelijk vlot op, met een R-waarde van al snel 1,2, wat betekent dat het aantal besmette mensen per dag elke twee weken verdubbelt. Dus vanaf 1700 per dag op 30 september naar 23600 op 18 november. Overigens is diezelfde trend te zien in de landen om ons heen en in oost-Europa. In zuid-Europa is ook een opgaande lijn in het aantal besmettingen, maar dit gaat wel veel langzamer. Hogere vaccinatiegraad? Ik denk eerder het weer: Bijvoorbeeld, in Madrid is het in oktober nog heel prettig zomer-achtig weer.

Dat gaat natuurlijk niet goed, dus het kabinet kondigde in twee stappen een aantal maatregelen aan. Vanaf 13 oktober gaat de horeca om 20 uur dicht, weer mondkapjes in de winkels en een beperkte groepsgrootte voor evenementen en onderwijs. Ook het verzoek om zo veel mogelijk thuis te werken en niet meer dan vier mensen thuis te ontvangen.

Sindsdien is het wachten op het effect. Mijn inschatting: lang niet voldoende om een R-waarde van 1,2 terug te brengen tot bijvoorbeeld onder de 0,9. Dan duurt het nog altijd acht weken om terug te komen op 4000 besmettingen per dag, waarvan Ernst Kuipers zegt dat de zorg het zonder problemen aankan.

Dan komen we nu bij mijn punt: een pandemie is niet als fietsen.

Bij het fietsen moet je continu balanceren om niet naar links of naar rechts om te vallen. Hierbij loop je het risico om te snel bij te sturen, terwijl je al de goede kant op ging. Dus schiet je nog harder de andere kant op om dat weer te compenseren. Vandaar het geslinger van een beginnende fietser.

Het kabinet past die logica toe op het bestrijden van de pandemie: neem maatregelen, wacht dan zo'n twee weken of die effect hebben, ga dan eventueel denken over nieuwe maatregelen.

Maar wat nu als de huidige maatregelen niet werken? Vrijdag was de verwachting dat we twee weken later op 2600 mensen in het ziekenhuis zouden zitten. Vandaag is het al 2500. Het hoogste punt tot nu toe was 2900 in januari, maar intussen zijn zorgmedewerkers vertrokken en er zitten er erg veel ziek thuis.

Een zorginfarct is al niet meer te voorkomen, waarbij de ziekenhuizen alleen nog de alleracuutste patiënten behandelen. Maar wat daarna? Als we nog een paar weken op het niveau blijven waar wekelijks bijna 1% van de bevolking positief getest wordt, dan denk ik niet dat we net op tijd weer terug kunnen vanaf de rand van de afgrond zoals bij de eerdere grote golven. Ofwel: code zwart, het officieel of de facto weigeren van patiënten die een levensreddende behandeling nodig hebben.

Voor veel mensen is de zorg een ver-van-hun-bedshow, en die willen "gewoon" de deur uit. Of: ze zien de bui al hangen, en nu nog snel zolang het kan. (Stond in een uitnodiging die ik een tijdje geleden kreeg.) De mensen die wel weten, of aan den lijve ondervonden hebben, hoe belangrijk een functionerende gezondheidszorg is gaan op deze manier ook hun vertrouwen in de politiek verliezen.

En ondertussen geven Rutte en De Jonge de bevolking de schuld: hou je beter aan de maatregelen! Eveneens een smeekbede in hoofdletters van het OMT. Natuurlijk, moeten we allemaal doen. Maar het is wel erg goedkoop de schuld af te schuiven op de burgers. Dit virus is in deze tijd van het jaar gewoon zo ontzettend besmettelijk dat zelfs oppassende burgers een aanzienlijk risico lopen. Hier gaat alleen voldoende stevig overheidsingrijpen een effect hebben. Dus: die lockdown komt er, de vraag is alleen hoe snel.

Ondertussen blijkt dat de grootste stijging bij kinderen onder de 12 zit. Van de kinderen van 11 jaar werd afgelopen week maar liefst 1 op de 40 positief getest, bijna een verdubbeling in een week (van 1,38% een week eerder naar 2,51% vorige week). Dus moeilijk te zien hoe we dit onder controle krijgen zolang de scholen open blijven.

Permalink - posted 2021-11-23

Test post preparing for HTTPS

▼ For some time now there's been a push to move the entire web from HTTP (no encryption) to HTTPS (with encryption).

I never felt it was necessary to encrypt static content. But the time has come to cave to peer pressure, and enjoy a few benefits such as the ability to post images to web forums.

However, I still feel very strongly about everything remaining accessible over HTTP. If you go HTTPS-only, you are now relying on a certificate authority (as well as your own ability to keep certificates up to date!), and you're cutting off some older systems and losing some performance. Also, having to change everything wholesale will be somewhat of a nightmare.

The trouble is: how do use HTTP images and links on an HTTP page and HTTPS images and links on the HTTPS version of the same page? With dynamically generated pages that's not too difficult: just let the script insert HTTP or HTTPS as required. Or, even easier: use relative links, that don't include the domain name.

Unfortunately, I have my content spread around a number of subdomains, and most of it is in static pages.

Turns out that you don't have to choose between:

http://www.iljitsch.com/2021/11-20-test-post.html (absolute URL)

and

/2021/11-20-test-post.html (relative URL)

but you can also use:

//www.iljitsch.com/2021/11-20-test-post.html

That's a protocol-relative URL. So you do specify the domain name, but not HTTP or HTTPS (or any other protocol). So if you use such a URL as a link on an HTTP page, the link will use HTTP. If you use it on an HTTPS page, the link will use HTTPS. So that's perfect for links within the site and images on static pages that may be served over either HTTP or HTTPS.

Paul Irish has a blog post that initially explained that it's a good idea to use protocol-relative URLs, but the current wisdom (added to that post) is they are better avoided, as there may be some cross site scripting possibilities. But as I don't use any cross site scripting on iljitsch.com that's not an issue here.

So I still need to go over the entire website to make sure protocol-relative URLs are used where I can't use regular relative URLs.

Apart from that, the main complication is my RSS feeds. Unless I'm misremembering, I started using absolute paths for my images because otherwise the images wouldn't show up properly on RSS aggregators. So I probably need to rewrite relative and protocol-relative URLs in my RSS feed script.

This is a test post to see how relative and protocol-relative images and links are handled in RSS. So don't be alarmed if links or images in this post don't work if you're viewing this post through an RSS aggregator.

Let me plug Esperanto and do the opposite for nuclear energy with this relative image (link):

Then again, fossil fuels aren't ideal either, using a protocol-relative image URL (link):

More later.

Permalink - posted 2021-11-20

Review: Peak Design Anchor Links to quick-release your camera strap

▼ I've had a few Nikon cameras, and those always come with a perfectly usable strap. The only issue is that putting the strap on a camera and getting the length just right is a rather involved process.

And sometimes I need a strap, but in other situations, it gets in the way. So I asked about straps that are easy to attach and detach in a forum, and one of the suggestions was for a Peak Design strap.

Peak Design as an entire system, with different kinds of straps that all use the same quick release mechanism. Their straps seem pretty good but a bit more than what I need for my non-pro cameras and matching lenses.

So I decided to get the Peak Design Anchor Links. (About $20/€20.)

This is a small set that contains:

1. Four anchors
2. Two anchor links
3. Two rings

If you're into watching Youtube photography channels, you've probably seen the little black discs with a red edge that hang off of the sides of a camera before. The anchors click into the anchor links, which are of course attached to the ends of a strap.

A Nikon strap with anchor links on the ends and the anchors in the middle:

The anchors are quite small, here compared to some coins: 20 South African rand cents, 1 US dollar cent, 1 euro cent and 10 Canadian dollar cents:

The anchor's cord loops attach quite nicely to a Panasonic DMC-TZ70 compact camera:

However, the cord won't go through the holes on most Nikon cameras. I used the included rings with this Z fc:

On the Nikon F65 on the left there are no issues attaching the anchors, and on the D7100 on the right I used the triangles that the Nikon strap normally loops through. Not very elegant, though:

Verdict:

Attaching to many Nikon cameras is not ideal, but being able to take off the camera strap in seconds is really great.

The system is rated for 90 kg. When you start to see the yellow core of the anchor cords, you know it's time to replace the anchors. The anchors definitely won't come out of the links by themselves: you have to push the anchor down and slide it up until it comes out of the anchor link. So this seems like a very secure system.

The anchors are plastic so they won't scratch your camera, but I believe the anchor links are aluminum, so you'll probably want to take off the strap when putting away the camera.

I like the fact that you get four anchors, so you can outfit two cameras with anchors. Also, the anchors themselves are pretty easy to attach/detach, so you can use them with even more cameras without much trouble.

The only thing that could make this better would be "slim anchors" option with thinner cords for lighter cameras.

Highly recommended.

Permalink - posted 2021-10-16

Mixing old and new Nikon lenses and cameras

▼ Seven years ago, I wrote Understanding old Nikon lenses: AI, AI-S, AF and AF-S. A few things have changed since then, so I thought it was time to do a follow-up that looks at how well different Nikon lens generations go with different Nikon camera generations.

The easy solution is of course to uses lenses and cameras of the same generation. All Nikon cameras introduced since about 2015 work with all Nikon lenses introduced since about 2000. But where's the fun in that?

First: what’s new since my previous article: AF-P lenses, E lenses and the new Z mount.

AF-P

For the past 20 years or so, Nikon’s autofocus lenses used ultrasonic "silent wave" motors in their AF-S lenses. AF-P lenses use pulse / stepper motors. Those can make small changes very quietly, so they're great for video. A big difference between AF-S and AF-P lenses is that the manual focus ring on AF-P lenses is not mechanically connected to the lens elements. Instead, the focus ring sends information back to the camera, which then uses the focus motor to change the focus.

This change means that the camera needs to know about AF-P lenses, or you won't be able to focus. Cameras introduced starting around 2013 support AF-P lenses. For some of these, a firmware update is required, and possibly there will be some reduced functionality.

E (electronic aperture) lenses

AF-P lenses also tend to be type E, indicating the lens has an electromagnetic aperture diaphragm actuator. (Not to be confused with "E series" manual focus lenses.) Support for E lenses goes back a few years further than AF-P lenses, to around 2008-2010, depending on the camera type.

Z mount

In 2018, Nikon introduced the Z line of mirrorless interchangeable lens cameras, and these cameras no longer have the F mount that Nikon's SLRs have used since 1959. Nikon has released a number of Z mount lenses, which are all AF-P as well as type E lenses. Of course these lenses don't work on older cameras, but F mount lenses will work on Z series cameras through the FTZ adapter. All the discussion below is about F mount lenses, for Z type cameras use of the FTZ is assumed.

The lens types

From left to right: pre-AI, AF-S type G, AI, AF type D, AI-s

So now we have an understanding of the following types of lenses:

• Pre-AI: manual focus
• AI or AI-s: manual focus
• AF: focus motor in the camera body
• AF-S, DX and FX, ultrasonic focus motor in the lens
• AF-P, DX and FX, stepper focus motor in the lens

All types of AF lenses also have a CPU in them which lets the lens tell the camera its properties. Let's see how they work on different cameras. I'll talk about the following specific cameras that I own, or more broad categories:

• Nikon FE, standing in for the AI type manual focus film cameras (around 1980)
• Nikon F65, as an example of a late lower end autofocus film cameras (around 2000)
• DX, the lower end crop sensor DSLRs (D3x00 + D5x00 and their predecessors)
• D7x00 and their predecessors mid-range DX camera with AI/AF lens support
• FX, the full frame high(er) end cameras
• Z DX: the Z50 and Z fc
• Z FX: the Z5, Z6 and Z7

So here we go.

Nikon FE and contemporaries

• Pre-AI: camera doesn't know aperture setting, so problematic metering
• AI or AI-s: perfect!
• AF: good!
• AF-S type G: no aperture ring, so fixed aperture and problematic metering
• AF-P: focussing impossible

Nikon F65 and similar

• Pre-AI: mounting will cause damage
• AI or AI-s: no CPU, so no or problematic metering (manual focus)
• "AF": perfect!
• AF-S, FX: perfect!
• AF-S, DX: typically black corners, some lenses may work to some degree
• AF-P: focussing impossible

DX DSLRs (lower/mid-range)

• Pre-AI, AI, AI-s: no CPU, no metering
• AF: manual focus
• AF-S: perfect!
• AF-P: depends on camera age

D7x00 and its predecessors

• Pre-AI: mounting will cause damage
• AI, AI-s: no CPU, enter lens data manually (manual focus) (no metering on D7500)
• AF-D: perfect!
• AF-S: perfect!
• AF-P: depends on camera age

FX DSLRs

• Pre-AI: mounting will cause damage
• AI, AI-s: no CPU, enter lens data manually (manual focus)
• AF-D: perfect!
• AF-S, FX: perfect!
• AF-S, DX: automatic cropping, but viewfinder shows black corners, some lenses may work in FX mode to some degree
• AF-P: depends on camera age

Z mount DX with FTZ

• Pre-AI, AI, AI-s: no CPU, so stop down metering, reduced focus aids
• AF: manual focus, reduced focus aids
• "AF-D": manual focus
• AF-S: good, somewhat hunting and noisy focus in video mode
• AF-P: perfect!

Z mount FX with FTZ

• Pre-AI, AI, AI-s: no CPU, so stop down metering, reduced focus aids
• AF: manual focus, reduced focus aids
• "AF-D": manual focus
• AF-S FX: good, somewhat hunting and noisy focus in video mode
• AF-S, DX: automatic cropping, also the viewfinder image, somewhat hunting and noisy focus in video mode
• AF-P FX: perfect!
• AF-P DX: automatic cropping, also the viewfinder image

As always, additional caveats may apply, be sure to check compatibility for your specific camera before you go out and get new lenses.

Conclusions

It looks like the D7100/D7200 as well as the not-too-old FX cameras are compatible with all F mount lenses. There is not a single lens type that works fully with the entire range of cameras, but the AF type D lenses come closest: they work on the old manual focus cameras, work with with autofocus on the mid/higher end DSLRs and still work fully as manual focus lenses on all other cameras.

An AF type D lens is still largely usable on cameras like the Z family, where you'll have to focus manually. But with the traditional "electronic rangefinder" focus aid available, where the autofocus system tells you if you've achieved focus, that's actually a bit easier than on an old manual focus camera such as the FE. However, manual focus lenses without a CPU for some reason don't get full focus aids on the Z cameras. You can still focus very precisely by zooming the viewfinder, but this is quite slow.

So there you have it. I'm sure the next few years the second hand F mount lens market is going to quite interesting, as more and more Nikon users migrate to a Z camera or a non-Nikon mirrorless camera.

Update:

In the original version of this article, I mistakenly said AF lenses that are not AF-D lenses don't have a CPU. That's incorrect. On DSLRs AF and AF-D lenses work the same, but for some reason on a Z camera (through the FTZ) the AF-D lenses have full focus aids but AF lenses have reduced focus aids. However, AF lenses are still more functional than non-CPU manual focus lenses because on AF lenses, the camera can control the aperture.

On non-CPU lenses, the camera doesn't know the aperture so it's difficult to use apertures smaller than about f/5.6 or f/8 because focussing gets more difficult at smaller apertures, so you may have to use stop down metering.

Permalink - posted 2021-10-09