Help- progressively worse black corner bottom right 5DMk3

[Spearo]

Hi Everyone,
I have a 5D Mk III and just noticed today that all my photos from the weekend had a significant portion of the bottom right hand side black. see attached example.
I salvaged shots with cropping.
I then looked into it a bit and it seems to occur with any lens (definitely occurred with the 100-400 and the 100mm macro).

Then i went through a series of images and was surprised to see it steadily progress over time!

Never really noticed the very slight problem initially but it is now quite significant.

I guess I'm going to have to have the camera serviced (i have had it a few years now).

But any idea what is causing it? Its not lens hood petals (i use circular hood) its not flashes, it cant be the curtain timing as this would be horizontal at bottom.

Its got me stumped...especially the progressive worsening.

Any ideas as to cause/ remedy?
Thanks
frank

[Koko]

Sorry I can't help but would like to follow..

[ricktas]

Looks to me like the shutter mechanism is on its way out. Basically it is a series of small metal plates that sit in front of the sensor and move back out of the way when you press the shutter button. These shutters are what allow you to choose 1/20th second, 1/100th second etc. Being mechanical they can fail and the end result is either what you are seeing as the failure progresses, or in most cases, just an error message and the shutter completely fails at one time.

Have a look at this video, the DSLR shutter mechanism bit starts at about 1 minute 16 seconds



Solution, take it to your local Canon authorised repairer and get a quote for replacing the shutter mechanism.

[ameerat42]

I think Rick is on the track. Does this happen in all shutter modes, and at all shutter speed ranges? Just for interest, as it's a fairly drastic symptom I think.
Am.

[bitsnpieces]

If the shutter curtain begins failing, wouldn't the black bar be horizontal being that the curtain is horizontal? o.O
Like what you see when you try to shoot flash in HSS mode, and your camera doesn't support it.

The side to side, angled, shutter curtains are more so on point and shoots, I wouldn't think the Canon 5Diii is operating like that, is it?

I would wonder if the mirror or sensor has been nudged or something, a heavy bump somewhere, causing it to mis-align a little? o.O
Could be out of place on the x, y, or z plane I guess.

Maybe try taking the lens off, and take some shots while looking into the camera, see if the mirror is flipping properly, see if it's straight, etc. Don't know.

[ricktas]

If the shutter mechanic begins failing, wouldn't the black bar be horizontal being that the shutter is horizontal? o.O

I would wonder if the mirror or sensor has been nudged or something, a heavy bump somewhere, causing it to mis-align a little? o.O

Maybe try taking the lens off, and take some shots while looking into the camera, see if the mirror is flipping properly, see if it's straight, etc. Don't know.

depends on the camera/model as to whether the shutter goes side to side, top to bottom etc.

[Spearo]

Thanks
I'll follow Rick's advice and get it looked at...
nice little video btw
thanks
frank

[arthurking83]

Going by the curve shape .. my guess is that something with the mirror is the problem!

Have you tried an exposure in liveview mode?
In Lv mode the mirror is always up, so of course shouldn't create this effect.

if the mirror actuator servo is going fauly, slightly misaligned mirror, or a loose mechanism could cause such a problem.

My first reaction would be to try a few exposures in Lv mode and see how they look.
If they turn out OK(ie. none of this black) then take a peel into the mirror box to see if something foreign has entered into the mirrorbox area and getting dragged with the mirror, and also chack that the mirror looks straight too.

[jev]

depends on the camera/model as to whether the shutter goes side to side, top to bottom etc.

There really aren't any DSLR's that I know of that have a horizontally travelling shutter. A mirror, as Arthur suggests, isn't very likely either, the mirror always moves vertically. I suspect some of the black stuff on the side of the mirror-box is slowly peeling off which you may not notice normally. The wind from the mirror may cause it to move in the way of the light.

Anyway, repair-time it is.

[swifty]

I'd give Arthur's LV method a try but like Jev, I have my doubts if its the mirror.
The image is inverted so the obstruction should be in the upper LHS corner of the camera if I'm not mistaken.
Taking a stab in the dark, like Jev I think something is peeling off, maybe a flex cable's come loose or something?
I tried to look for a tear down of the 5D3 to see what's in the area but I can't find any pics.

[jev]

Google is your friend - you should be able to find the 5D Mark III Parts Catalog online (or even better: the service manual that seems to have coloured images). Most of the inside of the mirrorbox is metal, but there might be some tape as well (the original 5D had lots of tape!). Also, might be a mirror cushion from the top of the mirrorbox or perhaps a part of the viewfinder assembly that sits on top of the mirrorbox (it has some parts extending into it).

[Spearo]

hi
its being fixed by an authorized repairer
shutter mech replacement...
thanks for all the input
frank