Canon Lens News

Teardown: Canon EF 400mm f/2.8L IS III

Lensrentals.com has done something I’ve never seen before, and that’s tearing down a working Canon super telephoto lens. In this case, it’s the brand new EF 400mm f/2.8L IS III, the world’s lightest 400mm f/2.8 lens.

An interesting bit of information that Roger and Aaron did get from the teardown, is that the EF 400mm f/2.8L IS III uses the same focusing motor as the RF 50mm f/1.2L.

This is a great teardown and not for the faint of gear heart.

From Lensrentals.com:

Some things we were already aware of or assuming. The lens elements are moved towards the mount side of the lens. There are lots of optical adjustments like all Canon lenses. Despite being far lighter, it’s still very solidly built with a very strong frame, tons of big screws holding everything together, and no weak joints that we can see. It’s what we expected; Canon’s been building super telephotos for a long time.

There were some other, more interesting things. The spring-loaded adjustable collar collection is something of a mystery to us and will remain so until we can spend some days doing optical adjustments on one. The use of the same motor as the RF lens is very interesting in several ways. Only some more tear downs will tell us if this is just a superior motor type that Canon is going to use in all electrically focused lenses (I suspect this is probably the case), or just in lenses with a lot of glass in the focusing element (another likely thing). Read the full article

Canon EF 400mm f/2.8L IS III in stock at Adorama

LDS

EOR R
Sep 14, 2012
1,563
146
I just wonder that Canon builds those lenses in dust-controlled environments with technicians wearing gloves, masks and other protective apparel.... LensRentals chooses a very different approach... or do they change it when reassembling them?
 

Graphic.Artifacts

EOS 7D MK II
Aug 1, 2017
421
243
I was kind of hoping Roger would find some evidence that these lenses could be factory "upgraded" to RF mount/electronics in the future. Sounds like the internal components share a lot of RF design but they will always require EF to RF adapters. I guess they'll be a separate RF version at some point.
 

dolina

millennial
Dec 27, 2011
1,983
127
29
34109
www.facebook.com
Sony introducing a 400 accelerated Canon's release of a new lens. Congratulations to all sports photogs who are scheduled to get this one. You will not be disappointed.
 
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Del Paso

M3 Singlestroke
Aug 9, 2018
525
500
Just waiting for the Sony 400mm disassembly, will it fall apart like their 70-200 F 2,8?
 

RogerCicala

I'm New Here
Mar 6, 2013
24
29
I just wonder that Canon builds those lenses in dust-controlled environments with technicians wearing gloves, masks and other protective apparel.... LensRentals chooses a very different approach... or do they change it when reassembling them?
And yet, they all have dust in them when we get them. :) Every lens does, it's just whether you have a strong enough light to see it. Also we aren't working in a large factory with machines milling things, etc. While not a clean room, we have pretty good dust scrubbers where we work.

But yes, to some degree we change tactics during reassembly. We can be cavalier during disassembly: the pieces are all going to sit on a table for a while so they will all have dust on them when reassembly starts. The main reason that reassembly takes longer is every piece is cleaned as it's reinserted. It's not unusual, too, for Aaron to do a bit of disassembly during reassembly because he finds he missed a piece of dust or a smear on an element.

As a TMI aside, this is part of the reason I can no longer do the disassemblies myself. As I've gotten old my close vision isn't good enough to find the small bits of dust that Aaron sees easily. Bifocal jokes may start now.

Roger
 

padam

EOS 7D MK II
Aug 26, 2015
581
208
I was kind of hoping Roger would find some evidence that these lenses could be factory "upgraded" to RF mount/electronics in the future. Sounds like the internal components share a lot of RF design but they will always require EF to RF adapters. I guess they'll be a separate RF version at some point.
When they do RF-mount superteles, they will be completely different lenses (possibly DO lenses to cut down weight - increase price - even further, different interface, control ring, different aperture mechanism, etc.) but that's another 7 years when it might become somewhat feasible for the agencies to switch cameras and lenses. But in the meantime they might also launch more compact ones that are more similar to what they had considered for the EF-mount in the past.
 

magarity

EOS 80D
Feb 14, 2017
166
71
I like these teardown articles but I have to wonder, doesn't Canon have a "factory trained repair tech" program? The LR people always seem to be having to guess how things come apart when it seems like they should be able to go learn how to do it from Canon.
 

Del Paso

M3 Singlestroke
Aug 9, 2018
525
500
I like these teardown articles but I have to wonder, doesn't Canon have a "factory trained repair tech" program? The LR people always seem to be having to guess how things come apart when it seems like they should be able to go learn how to do it from Canon.
What if Canon prefers to do the repairs themselves ($$$$$) ?
Lens Rental is , obviously, a rental, not an official repair facility. They must be busy enough with their own stuff, without being asked to repair customer's warranty damages.
 

Don Haines

Beware of cats with laser eyes!
Jun 4, 2012
8,124
1,642
Canada
Sony introducing a 400 accelerated Canon's release of a new lens. Congratulations to all sports photogs who are scheduled to get this one. You will not be disappointed.
It true! When Sony introduced their Lens, canon decided to grow the fluorite crystals faster :)
 

Graphic.Artifacts

EOS 7D MK II
Aug 1, 2017
421
243
Read a post on another forum that Canon may be growing Sony's flourite crystals as well since they don't have internal capacity for flourite. Similar design, similar release date. Could be true. It always seems to me that these camera companies get along much better than their respective fans.