Useful feature of the 1DmkIII

Trawling the net today I stumbled across the 1DmkIII white paper and aside from the 10mp, 10fps, twin digic III ravings, I found the AF micro adjust feature, giving the user the ability to finely adjust focus precision without going to a service centre.
Although it doesn't read lens IDs, so the adjust is global.
This could also be quite useful for those who like to use 3rd party lenses. Nice touch!

Hi John,

Are you saying we could calibrate lenses for use in another Canon DSLR?

Asher

It does read lens ID's at least to the extent of being able to distinguish your 400 f/2.8 from your 50 f/1.2 and allowing you to calibrate them separately. It can't distinguish between two lenses of the same model though.

Asher, the answer to your question is no.

Nill
~~
www.toulme.net

My interpretation of the white paper....

I got the sense from reading the white paper that the micro-AF adjustment feature is specific to the 1D Mark III body -- similar in concept to the EC function. Again, this is just my interpretation, but I don't get the sense that the lens itself is actually adjusted -- just its performance on a Mark III body is adjusted. I think I agree with Nill -- I don't think you can adjust the AF on a lens for use on other bodies.

Of course that is one of those factual questions that Chuck Westfall could answer -- so Chuck, if you're checking in.....

John raises an interesting question of whether that same adjustment capability could be used to fine tune third party lenses. That would be a useful feature. We may have to wait until people actually have MkIIIs in their possession to get an answer to that one.

Tom

Hi, Tom:

Your interpretation is correct. The EOS-1D Mark III's AF Microadjustment feature adjusts the AF calibration of the camera body for up to 20 individual Canon EF lens models. The lenses themselves are not adjusted. Canon does not vouch for the performance of this feature or any other camera feature with lenses from other manufacturers.

Best Regards,

Chuck Westfall
Director/Media & Customer Relationship
Camera Marketing Group/Canon U.S.A., Inc.

Thanks Chuck,

Does the camera record the serial number of the lens or is it generic for that design of lens. So an adjustment for a 70-200 f4.0 L IS would be used for any such lens even one picked up from a rental house?

Concerning the number of lenses, why is there a limit? Could that set of 20 be stored on an SD card so more could be added?

Again, you are a treasure for us!

Asher

Asher — no s/n recognition, adjustment is "generic" to a given lens model.

Nill
~~
www.toulme.net

Thanks, Chuck, for the clarification. Also....

Asher Kelman said:

Concerning the number of lenses, why is there a limit? Could that set of 20 be stored on an SD card so more could be added?

Asher

Click to expand...

Twenty lenses seems more than reasonable -- I suspect the limitation is a PROM capacity/performance issue. I think the AF micro-adjustment feature was designed to allow you to fine-tune the AF for lenses you use most frequently. I don't think it was created to be a uniquely-tuned database of every EF-series lens with an AF capability.

And lets face it, if you're walking around with 20+ lenses every day, offering an in-camera option to store the names/phone numbers of 20 orthopedic surgeons would be a useful feature to have too ;^)

Tom

Tom Henkel said:

...[snip]
And lets face it, if you're walking around with 20+ lenses every day, offering an in-camera option to store the names/phone numbers of 20 orthopedic surgeons would be a useful feature to have too ;^)

Tom

Click to expand...

LOL… Perhaps a new wireless feature, enabling you to connect directly with their surgery, for an ultra-fast service… rolf…

Tom Henkel said:

Twenty lenses seems more than reasonable -- I suspect the limitation is a PROM capacity/performance issue. I think the AF micro-adjustment feature was designed to allow you to fine-tune the AF for lenses you use most frequently. I don't think it was created to be a uniquely-tuned database of every EF-series lens with an AF capability.

And lets face it, if you're walking around with 20+ lenses every day, offering an in-camera option to store the names/phone numbers of 20 orthopedic surgeons would be a useful feature to have too ;^)
Tom

Click to expand...

Nope,

I'd have a few quick dial buttons: one would be to say I'm coming home for dinner, get the Bordeaux wine decanted and breathing, the next would call the hair designer, makeup artist and my home to say we are shooting in 1 hour, the last would say I'm shooting somewhere, don't touch the wine and don't wait up for me!

Asher

Meanwhile, I'd love this new feature and would hope it's easy to use.

On the subject of non-Canon lenses; A while back as part of a CRW decoding effort, a numbre of us established a location in the CRW files produced by early models (D30 and 1D AFAICR) that stored an 8-bit lens ID. While this was unique for each Canon lens it was not always so for 3rd party lenses. Also, again from memory, I think Canon lenses that were the same except for an edition had the same ID. If people are really interested in this then I can go find a link to the spreadsheet with these numbers in - as an academic exercise.

Summary: i would closely note Chuck's comment re non-Canon lenses and this feature.

Time will tell...

Peter Galbavy said:

Summary: i would closely note Chuck's comment re non-Canon lenses and this feature.

Click to expand...

I interpreted Chuck's comment regarding the use of the micro-AF feature for third party lenses to be a generic corporate party-line statement, simply reminding us that Canon does not guarantee that any feature will work with non-Canon equipment. I would have been surprised if he said anything else. I don't think there was a hidden message.

As I said earlier, when people actually get their Mark IIIs and try to fine-tune the AF on third party lenses will be the real indicator of whether there are problems. Until then, it's just speculation.

My speculation (based on nothing other than gut feel) is the feature will work, but the adjustment might not be recorded in memory. Hence, with an EF-series lens the body will remember the adjustment; with a third-party lens you might have to reset it every time. Again, that is purely a personal guess and not based on any sort of inside information.

And if the micro-AF feature isn't transparent to third party lenses, I suspect Sigma, et al, will be working to rectify the problem. I'm sure it's solvable.

Tom