[MartijnBraam]

I've always wanted to know how the various autofocus systems worked. This page is incredible. I wish there was another one with the Nikon autofocus systems since that's what I actually have.

I still have several lenses with autofocus that don't have an AF motor in it at all, the motor is in the camera body instead there's a tiny screw on the lens mount that transfers the motor rotation to the autofocus parts in the lense. This was very slow and noisy though on my cameras.

[nayuki]

Nikon's lens/body compatibility matrix is horrendously complicated. https://www.kenrockwell.com/nikon/compatibility-lens.htm

Whereas I think "no metering" is never a problem on Canon.

Over the decades as a DSLR shooter (on Canon), I even saw Nikon shoot themselves in the foot not once but twice.

* When Nikon introduced "E" lenses (electronic aperture, like Canon and all modern designs), very few bodies were compatible with it. They didn't have the foresight to introduce compatible bodies before any lenses with E were released. For example, this was released in 2008 ( https://www.kenrockwell.com/nikon/24mm-pc.htm ), and the earliest compatible body is from 2007. It doesn't work with tons of crop (DX) bodies like the D90, as well as any film camera.

* When Nikon introduced "AF-P" (stepper motor) lenses in 2016, there were no compatible bodies before 2013. Again, not enough future-proofing.

Meanwhile, Canon took a different approach. They pissed off users twice - when transition from the FL mount (1964) to FD (1971), and FD to EF (1987). They basically got it all right with EF - fully electronic, no aperture slider, no focus screw, big diameter.

I have even successfully used a year-2017 Canon lens with Ring USM AF and IS on an original EOS 650 film body (released in 1987), and both AF and IS work perfectly. Mind you, both of those features did not even exist at the birth of EOS. Presumably the AF electronic protocol is agnostic of what motor technology is in the lens, and IS can be a lens-only thing without the body knowing.

Nikon's compatibility gotchas don't hold a candle to Canon's excellent (albeit imperfect) compatibility. Nikon keeps making the same mistakes over and over again, such as not having a screw-drive motor in the F to Z mount adapter; the company really seems to hate people with old lenses and bodies. Oh and this is not new either; Nikon's F to 1 adapter (does anyone remember that highly cropped mirrorless camera?) also lacked certain features.

[lizknope]

This third party company announced a Nikon F to Z lens adapter that will autofocus with older screwdriver autofocus lenses. They already had a Nikon F to Sony adapter and now they have a Nikon F to Nikon Z adapter.

https://nikonrumors.com/2025/02/28/monsteradapter-la-fz1-off...

I've been using my old 85mm f1.4 "D screwdriver" lens and others in manual focus mode on my Z8 and Z5.

[MartijnBraam]

What annoys me is that the AF-P could probably be supported on a lot more cameras, they did add it to the D3300 with a firmware update. They just didn't do it for more cameras...

[omoikane]

Nikon's lenses seem to follow a similar timeline, with different names:

Wave motor = AF-S (1998)

Stepper motor = AF-P (2016)

Voice coil motor = SSVCM (2022)

https://imaging.nikon.com/imaging/lineup/lens/glossary/

[pnathan]

Tolerably modern Nikon lenses have in-lens AF I believe.

[hypercube33]

Newer Nikon lenses have a few motor types but if I'm not mistaken they support old mechanical (body driven) aperture and focus drive as well (the D6 and somewhat recently F6 film camera were still for sale)

Nikon has a complex ecosystem keeping generally the same mount for many decades and general support for it, where others developed a specific autofocus mount when they moved towards those systems.

[danhau]

Their mirrorless Z mount and lenses don‘t have mechanical drive. Neither do their official F-to-Z adapters - much to the chagrin of people using their older glass.

[MartijnBraam]

Yeah the in-body motor thing is only for the older Nikon lenses, I don't think AF for that is still supported if you're using Z-mount adapters. Nikon seems to have a few similar AF motor technologies like the canon ones in this article.

[acomjean]

Canon being late to the AF party (last century).

They ended up with all electronic contacts when they switched lens mounts for the “eos” series cameras though at the expense of not having backward compatable lenses. (I had a bunch of manual focus lenses at the time…) They had one “auto focus” camera for the old lenses the t80. (https://global.canon/en/c-museum/product/film115.html) but almost no lenses supported autofocus.

I think most of settings the camera sent to the older lenses (aperture primarily) was done mechanically.

The way these old cameras autofocused was pretty interesting. With some light passing through a semi transparent mirror onto different sensors.

Edit: this site has another page about autofocus. Quite extensive.

https://exclusivearchitecture.com/03-technical-articles-DSLR...

Shorter canon article: https://support.usa.canon.com/kb/s/article/ART170280

I have one of those mirrorless slrs now. The focus is amazingly good. Lots of software (eye detect etc). The focus sensors are integrated into the image sensor I believe.

[MartijnBraam]

All my nikon cameras focus with a semi transparent mirror on a specialized autofocus sensor. I even have an nikon film camera that has that cicuitry. You can't autofocus like mirrorless cameras with PDAF pixels in the main sensor with a mirror in the way.

[bydo]

There's a new third-party F to Z adapter that does have the screw drive: https://nikonrumors.com/2025/02/28/monsteradapter-la-fz1-off...