SUN. The white mark is due to the fact that one of your shutter blades is now loose and that portion is over exposed. That dark spot is your shutter blade.
And yes mine looked exactly like that.
Canon sent me a quote for 331 USD to repair it. I told them it was a disgrace that a camera rated for 200,000 clicks could not even get a quarter of the way there. They told me " you should send you camera in every 100,000 actuations to have it checked." I told them I would be happy to if they could make a camera that could get to 100,000 actuations because this one bit the dust at 36,000.
They agve me a 20% discount.
So total was 269 USD and I will have a 6 month warranty on my camera .
Good luck and sorry about your shutter.
so half way the dSLR should be checked it. Let's see my 40D is rated at 150K...so at 75K...drop it at canons....


