Live view shooting + no chip = busted shutter effect

whom

whom

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Steve
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Now I am hoping someone can help explain this recent phenomenon I have encountered.

I was digiscoping and when taking pictures I noticed a black bar at the bottom of the shot. I did some investigating and found it only occurred when shooting in live view. A normal shot did not exhibit this behaviour and neither did slow shutter speeds.

I have since recreated it by shooting with live view at 1/8000. With the lens attached, it is fine. If I twist the lens so there is no contact between lens and body the exact same shot has the bar at the bottom.....

I'd be grateful is someone else could re-enact this to confirm it isn't just my body. Below is an example shot from the scope.

IMG_7394.jpg
 
No I can't repeat it on 1dIII. Unless part of the lens is blocking some light (24-105 might do), it could be the first signs of shutter cancer. It starts to develop at 1/8000s.
 
daugirdas said:
No I can't repeat it on 1dIII. Unless part of the lens is blocking some light (24-105 might do), it could be the first signs of shutter cancer. It starts to develop at 1/8000s.
Click to expand...

What's shutter cancer?
 
Is this normal Liveview or Silent Mode Liveview?

Bob
 
Ah its only silent mode 1 or 2.
 
lingyiui said:
No I can't repeat it on 1dIII.
kv.gif
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Thanks for trying.

For anyone else who is kind enough to try it the following is what needs testing...

Silent mode 1 or 2

Live view shooting

1/8000

No communications between lens and body (if there are then the same settings stop this weird effect)
 
The opening at the back of a lot of lenses isn't square, it's a rectangle.

Kinda lost as to why you would want to twist the lens in the body anyway ?
 
ChrisH said:
The opening at the back of a lot of lenses isn't square, it's a rectangle.

Kinda lost as to why you would want to twist the lens in the body anyway ?
Click to expand...

Like I said in the first post, digiscoping. And it has a circular image circle. This is not caused by the non circular lens opening.
 
I'm afraid I can't simulate Silent modes 1 & 2 on my 1Ds3

I can't see how it can be a shutter failing as the exposure should be complete before the shutter moves. I suspect that the shutter is closing too early as the lens communication has been taken out of the equation.

Briefly, this is how it works.
Mode 1 Mirror stays up and shutter stays open. The electronic shutter then completes the exposure followed by the mechanical shutter closing and re-opening to resume Liveview display.

Mode 2 Identical to mode 1 except that the mechanical shutter stays closed whilst you maintain pressure on the shutter button.

Removing the lens from the equation has removed a small delay between the end of the electronic shutter and the mechanical shutter closing...the delay is for the aperture to open up again.

Only a theory here....
To keep things as fast as possible, the control may send the aperture open command to the lens slightly before the end of the exposure (knowing the mechanical delay won't affect things) to speed up the cycle. It may well be that <open aperture> and <close shutter> become coincident if there's no lens sensed. The shutter then moves before the end of the electronic shutter's cycle and voila.

Bob
 
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Thanks for the theory and info guys but it still seems crazy that this problem would exist across all 5D mk2s. Anyone able to recreate it with a 5D2?
 
whom said:
Thanks for the theory and info guys but it still seems crazy that this problem would exist across all 5D mk2s. Anyone able to recreate it with a 5D2?
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Lens-less at 1/8000 in Liveview silent mode is pretty obscure.

Bob
 
Canon Bob said:
Lens-less at 1/8000 in Liveview silent mode is pretty obscure.

Bob
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Well not really. Any lens old lens with an adapter is considered no lens. And anything that requires manual focus is easier to manual focus in live view mode. I always have silent mode on, can't see why you wouldn't. And it isn't just 1/8000, it is also obvious at 1/6400 and just apparent at 1/5000.
 
Ah, sorry Steve, I hadn't picked up that it also happened at different shutter speeds. Does the dark area change height with changes in shutter speed?

Bob
 
Canon Bob said:
Ah, sorry Steve, I hadn't picked up that it also happened at different shutter speeds. Does the dark area change height with changes in shutter speed?

Bob
Click to expand...

Yes it does appear to be less for 1/6400 than 1/800.

It is hard to get a clear line at the moment. The same with sensor dust being most obvious stopped down, this seems to be the same and indoors at 1.4 ISOH2 isn't making it easy.

It just seems such a weird thing to happen unless there is something wrong with my camera..
 
what size of digiscoping adaptor are you using?

The reason I ask is that using something smaller than 2" diameter on a crop can produce vignetting, let alone on a full frame.
The placement of the vignetting can depend on the alignment of the camera to adaptor.

I use a 500D with a small 80mm refractor for astrophotography, I use an extension tube so that I can direct couple it without using an eyepiece and still bring it to focus, if I want more magnification I use a 2" barlow
 
iancandler said:
what size of digiscoping adaptor are you using?

The reason I ask is that using something smaller than 2" diameter on a crop can produce vignetting, let alone on a full frame.
The placement of the vignetting can depend on the alignment of the camera to adaptor.

I use a 500D with a small 80mm refractor for astrophotography, I use an extension tube so that I can direct couple it without using an eyepiece and still bring it to focus, if I want more magnification I use a 2" barlow
Click to expand...

I don't know the adapter size but I know that isn't the problem. The exact same shot but through the viewfinder rather than live view gave a normal image. Cheers though. I hadn't thought of astrophotography with the scope... it is my Uncles and I am on holiday here in the Lakes so I'll have a go before I leave if the sky ever clears of clouds!
 
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