Yoshizen's Blog

Internal Structure of Canon 5D

5D Body-1-A09A2224

Some days ago, I got an opportunity to disassemble a Canon 5D body as I’ve bought it almost nothing. (still fully functioning) — Then, what I found inside was rather disturbing — hence I made this post.  

As the people who has been using Canon DSLR may know, new 5DS, 5DSR are having not only 30 Mp large image sensor (for 35 mm full-frame) but also mechanically, structurally much improved design = that’s what they said.

—– While planning, designing, developing new camera, Canon must have a lots of tests and analysis to achieve their objective = at least twice better image quality than the predecessor with its big sensor.  

Canon Open 5D_MG_0005

(Photo above is the inside of the 5D Mk-III)


(And this is the 5D Mk-IV = basic design is the same = plastic mirror box was connected to the tripod screw by a stamped panel and few screws.  — Photo from Lens Rental site)

Though my guess was, when they tested new sensor on the temporally adapted 5D Mk-lII body, they must be realized that the crispy sharpness was not there.  Even if the image of the lens alone on the optical test bench was good, it couldn’t  be replicated if the same lens was mounted on the 5D body —– it’s mean, 5D body structure was shaky and giving blur, deteriorating the image quality.  (Which was not so visible on the 22Mp sensor, but showing up on the 30 Mp.)

What Canon boasted about the New 5DS was, not only rethink of the mirror shock damping mechanism, but also much solid tripod fixing. —– But it was too funny to  hear that, when I opened and saw the inside of an old 5D body,  I almost dropped  my jaw, because the design of 5D was the remotest from the solid structure.  

—– I’ve been seeing the inside of cameras more than 40 years thus I know how they were designed and made.   (When Canon developed EOS 1, production team brought a prototype here and asked my advice.  When they asked me which camera was my  favorite, I answered “Contax” a man responded “You can’t have that quality any more” “Why ?” “The man designed the Contax was no longer there.  I am the Man”

= The man, Mr. Morota had been headhunted and came to Canon to develop EOS 1.

—– I guess, he must be pretty annoyed to see the design of 5D series cameras. ) 


When I changed my 35 mm camera, from Nikon to Contax, it was not only I’ve encountered the  Zeiss 85 mm F1.4 lens but also I found that the structure and the way their camera was made, was such solid therefore reliable.

(Preceding to this, I’ve been utterly annoyed  by the erratic behaviour of the Nikon’s motor-drive = always at the most crucial moment, they stop to work. — but they  worked always perfect on front of the Nikon’s Service Engineer.  😦  and  😀  )  

Canon 5D-open 1-001The photo left here was the inside of 20 years old EOS RT body. = You can see the  metal frame of which all the mechanism was built-in and holding the lens mount.  And the tripod screw was directly fixed to this metal frame.  

In contrast, what I found the inside of 5D (photo center) was = the structure framefor Mirror Box and the Shutter was made by injection mold plastic and even a lens mount base was a plastic.  

The photo right shows the almost the same design of 5D Mk-III.

In all those 5D, a stumped 1 mm thin metal connecting the plastic mirror box to the 1/4″ tripod screw on the bottom of the camera. = I couldn’t believe my eyes, IS this plastic camera priced for £3000 ? ? ?  

5D Body-2-341-001

(Photo left =Lens Mount base, on the plastic frame.

Photo center = Thin white metal alone connects the Mirror Box to the Tripod screw.

= Almostly, the camera body is floating on the tripod !

Photo right = Plastic frame is soft, hence so easy to cut.
5D Body-3-A09A3333-001— Plastic could be more resilient to the shock with its flexibility but the same flexibility is the enemy to hold the moving shutter and the lens solidly together.

Think about the situation when you use the camera on a tripod, like the photo left = even if a lens was firmly mounted on the tripod (therefore, the lens mount was solid) still, behind the mirror box, the shutter mechanism and the image sensor could be jumping and dancing, because the mirror-box is not rigid, even if its bottom side was having a metal plate.

Imagine a car, when the main chassis was made by plastic, I wouldn’t be impressed by the buzz-word that the outer shell was made by “magnesium alloy” = it’s a cover-up cosmetic.[]

—– (I remember, EOS RT body was not more than £400. = A camera body which has a film wind-up and rewind mechanism, all together  built onto a metal die-cast, was still £400, £500)    In comparison, just a shutter and a sensor were built into a plastic mirror box (+ a bit more electronics and the Memory) cost £3000 !

—– Oh ! C’mon it’s not fair.  = So, it was obvious, so-called new feature in 5DS, 5DSR = “improved anti-vibration and the solid connection to the Tripod” was not a new achievement but a necessary  patch-up against the old shoddy design.  Though, despite the patch-up work, the test report from Japan saying that 5DS still showing high susceptibility to image blur which would negate the crop use of the photo. 

( As a matter of fact, I haven’t checked the “claimed to be” improved 5DS yet.  And I’m not sure whether I would buy this camera in order to see their fix ! )  Reading the Tech Reports here and there —– I haven’t seen any report showing the superiority of New Canon 5DS or SR over Nikon D810 = even on the chart test 30Mp image didn’t show a difference over 36Mp Nikon image —– I wonder  what’s going on and why ?  = It seems better wait till the matter sorted out.  🙂


PS:  Related post “Camera stability test” would be good to read.


4 Responses

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  1. […] I’ve disassembled and checked the inside of several Canon 5D cameras, I […]

  2. […] who pay  £3000 to a plastic camera ?) […]

  3. […] and selling it £ hundreds more price !   What a profitable business.   […]

  4. Oct’ Moon by SONY | Yoshizen's Blog said, on October 10, 2017 at 11:13

    […] one “August Moon” because all the conditions were the same except the camera was not Canon 5D Mk-III but SONY A7R.   The picture was taken through the double glazed window therefore it was not as […]

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