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Canon EF and RF Lenses – All Autofocus Motors

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Re: Canon EF and RF Lenses – All Autofocus Motors

#101

Post by gkanai »

DidYaWipe wrote: post #64

Really interesting work. I have been aggravated by (and bellyaching about) the ridiculous lack of a way to control the focusing motors in these lenses directly when shooting video, using a follow-focus wheel. Video shooters are still strapping janky gear-tooth strips onto these lenses, and then bolting bulky mechanical follow-focus mechanisms on the OUTSIDE of lenses that have focusing motors already built in. I can…

Nikon has just released a powered zoom lens. So hopefully there will be more of these in the future.

https://www.nikon.com/company/news/2025/0213_imaging_02.html

Re: Canon EF and RF Lenses – All Autofocus Motors

#102

Post by lambdasquirrel »

PaulHoule wrote: post #17

I was a big fan of USM lenses when I had a Canon, but I had one go bad with fungus or something and for a while had only a 35mm prime which I even used to take pictures of birds. Then I lost my Canon and decided to get a Sony circa 2019 or so because all the reviews I saw for Nikon and Canon said the autofocus sucked on entry-level full frame cameras.

You should be able to get fungus CLA’ed. Leica shooters using true vintage lenses sometimes need to do this when picking up a find from a flea market.

Re: Canon EF and RF Lenses – All Autofocus Motors

#103

Post by tonyarkles »

ryandamm wrote: post #80
fusionadvocate wrote: post #73

Earlier quoted context omitted.

The system stops the motors once it reaches focus. Therefore is a closed loop system.

It’s open loop in that the measurement of it being in focus is reliant on the subject matter, and a different measurement. I’m not making this up, camera manufacturers have told me to my face that focus is open loop, period. They can’t guarantee repeatable focus. Notably the measurement isn’t of the state of the motor/gearing. Furthermore, being “in focus” means the subject matter’s out of focus blur is below some th…

I can back you up on that. I work on a highly custom system that uses EF lenses through an EF-to-serial adapter. The lenses don't even know what position they're at when you power them on. If you want to move them to a specific focus step you have to go through a homing procedure that drives the focus motor to a stop (I don't recall if it's the near or far stop).

Lens-to-lens it's definitely not consistent. Step 142 on two different lenses will have a different focal depth. We calibrate each lens ourselves (thankfully you can read the serial number through the EF mount) and then still have to do closed-loop image-based sharpness estimation to guarantee that things are as good as we can get.

Re: Canon EF and RF Lenses – All Autofocus Motors

#104

Post by shagie »

dghlsakjg wrote: post #69
shagie wrote: post #32

Earlier quoted context omitted.

The traditional Nikon mount has a small screw that is turned. The camera autofocus speed is limited by the amount of torque that can be applied to the screw - which can make focusing some of the heavier lenses slower. https://www.discoverdigitalphotography.com/2012/lens-mounts-... The "AF-D" lenses have contacts back to the camera body that communicate distance information (that is in turn used by the camera body to…

> you can't jiggle the film around to keep it in the same place. Contax had an AF solution (Contax AX) that actually moved the entire film plane to focus. I suppose that the same thing could be done in other axises, but I also suppose that there is a reason that only one manufacturer tried it.

The challenge would be to move the film around multiple axis at a range that would be useful.

https://www.canon.com.cy/pro/infobank/image-stabilisation-le...

> Optical Image Stabilisation is effective with movement across a range of frequencies, so it can cope not only with simple camera shake (0.5Hz to 3Hz), but also with the engine vibrations encountered when shooting from a moving vehicle or helicopter (10Hz to 20Hz).

Re: Canon EF and RF Lenses – All Autofocus Motors

#105

Post by post_break »

Canon is dead to me after they forced 3rd parties to stop all RF lenses. I bought the last AF lens by Viltrox and it's fantastic. I regret getting an RF body after they threatened them, and now only allow 3rd parties on their crop sensor bodies. Fuji, Sony, Leica, Nikon, all allow 3rd party lenses. I switched to Fuji and won't go back.

Re: Canon EF and RF Lenses – All Autofocus Motors

#108

Post by josh_carterPDX »

post_break wrote: post #105

Canon is dead to me after they forced 3rd parties to stop all RF lenses. I bought the last AF lens by Viltrox and it's fantastic. I regret getting an RF body after they threatened them, and now only allow 3rd parties on their crop sensor bodies. Fuji, Sony, Leica, Nikon, all allow 3rd party lenses. I switched to Fuji and won't go back.

I'm feeling a little bit of buyer's remorse for that same reason. I love my Canon, but having a closed loop lens system is not ideal and is insanely pricey. All of the "adapters" that allow you to use 3rd party lenses suck.

Re: Canon EF and RF Lenses – All Autofocus Motors

#109

Post by SAI_Peregrinus »

roblh wrote: post #93
divan wrote: post #86

Earlier quoted context omitted.

Sony A9 III even has a configuration setting of whether it should focus on the left or right eye of the person :) It also can remember faces and prioritize them if there other faces. Let's say someone shoots their kid on the football field and wants only them to be in focus.

The left eye/right eye option has been around even on lower end cameras for the better part of a decade, which is kinda wild. My fuji from 2017 has that, and Fuji are specifically known for having worse autofocus performance than Canon or Sony or Nikon. Nikon and Sony specifically seem to be top of the pile right now. The Z8 has a whole separate processor dedicated to autofocus and the viewfinder which, in practice,…

The a9 iii shoots 120FPS 24.6MP raw files with continuous autofocus and without blacking the viewfinder. Top-end cameras are insane.
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