I was at a swimming event today and I noticed a black band across my images. At first I thought it was the strap but then I did a "clean sensor" and the shutter stayed open and I noticed a plastic blade across the sensor. I needed these images so I gently went in there a pulled it out. The rest of the day went fine and I see nothing wrong with any of my images after I removed that blade.
How long could I expect this to continue? What could happen next if anything?
Yes, I needed the images and had no backup camera with me, so I carefully pulled the blade out and the images looked fine. No more black band across and no problems.
dacop wrote:
BTW...does anyone know what the shutter blade does?
This is a serious question?
If so, the answer is simple. The shutter blocks incoming light from striking the sensor. The functional portion of the shutter consists of two curtains, each of which is composed of multiple individual shutter blades. Pulling one of these blades out may affect exposure, assuming that the shutter is not otherwise damaged by its removal.
Yes its a serious question...and why not. Because my camera is functioning fine without it. How, is this possible? And if I knew the full function of a camera shutter I would fix it myself.
dacop wrote:
Yes its a serious question...and why not. Because my camera is functioning fine without it. How, is this possible? And if I knew the full function of a camera shutter I would fix it myself.
Here's the thing. The assumption that your camera is working fine without the blade is based on your limited observations. You can only tell that the exposure appears correct. You don't know if your shutter has suffered some other kind of damage as a result of the initial failure or your subsequent removal of the blade. Your response is a bit like seeing a bolt or washer fall out from your car, and since your car doesn't seem to be any worse off, you shrug it off and think "oh well it couldn't have been THAT important." Meanwhile something has come loose and a few months later you have a catastrophic failure.
So to be clear, there are NO extraneous components in a camera shutter. None. If it was there when they built it, it was there for a very, very good reason. It's a shutter blade, not a stick of gum from a 5-pack.
It's obvious how it will end... a broke body and an unhappy shooter. I'd send it in for repair while the invoice 'may' not be as much as it could be later. Think instead of a blade the whole shutter goes while shooting and scratches the sensor glass. That would be much more costly to fix.
dacop wrote:
...What could happen next if anything?
Another blade could come loose and drag across the sensor's protective filter or antialiasing filter, destroying it, and then become detached and fly into the mirror, destroying that, before finally coming to rest imbedded in the AF sensor.
...so do I. Well I have a dance to cover on Thursday and I will be using the camera, but will have a backup on hand just in case. 
