Flash Fall Off Problem: 550EX

Hi All,

I have been using a 550EX, 30D, and 17-85mm EFs lens. Many of my indoor flash shots show light fall off, almost like vignetting, in the corners. If I take the same pictures without my flash (using a high ISO), the light fall off is mimimal.

I shot these two pictures of a wall from about 7 feet away. Is this a flash problem, or is it something else?

Thanks,
Dom

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What's the flash head zoomed to? Does the 550 have a wide angle diffuser like the 580?

Edit: You know.. that's some pretty heavy vignetting/light falloff in the corners anyway with just ambient - have you got a chunky filter on or something?

I think the widest that zooms to is 24mm. It has a diffuser you can use but at 17mm on an object 7 feet away I am not surprised at what I am seeing. This looks like what I would expect to see. Then at 85mm I wouldn't expect to see so much, but at an object 7 feet away it isn't unheard of. What does the 85mm shot at 7 feet away look like without flash? If it looks similiar then it could be the lens.

Using the wide panel on the 550EX moves the zoom head to 17mm.

Thanks for the replies.

I took my Canon UV filter off and shot these pictures:

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