Shadows in flash pictures - 20D

[kevinma]

When taking pictures of a fast-moving 5 year old, I have encountered unusual shadows in images taken using the built-in flash on P. As best I can ascertain, these shadows only occur when the subject is moving and not when everything is still. The shadows are always in the same location and are longitudinal finger-shaped shadows that extend into the image from the bottom left corner. And they're not fingers. What's going on?
Kevin.

[DocFrankenstein]

post a sample... Cause it's hard to imagine what it looks like.

Also consider the fact that the duration of the flash is 1/1000 of a second and your shutter have been open for much more than that.

[robertwgross]

It wouldn't be the shadow of a long lens, would it?

---Bob Gross---

[kevinma]

Not a long lens; the 18-55. Will see if I can manage to post an image.

[DaveG]

When taking pictures of a fast-moving 5 year old, I have encountered unusual shadows in images taken using the built-in flash on P. As best I can ascertain, these shadows only occur when the subject is moving and not when everything is still. The shadows are always in the same location and are longitudinal finger-shaped shadows that extend into the image from the bottom left corner. And they're not fingers. What's going on?
Kevin.

What shutterspeed is P (Program) giving you? It could be some form of ghosting if the subject is moving - and you are moving the camera as well.

The other thing that occurs to me is that they ARE your fingers.

When things move and you attempt to shoot in a hurry your left hand position is the last thing that you think about. I watched a pro shooter at a hockey game yesterday. He was using a Canon 200 f2.8 without the lens shade and was handholding it (?). Anyway his idex finger drifted up and was in front of the lens. With the 1D he was using I'm fairly certain that he didn't have any problem but he may well have with a full frame DSLR. I'm also sure that he was completely unaware that he was doing it.

[KarinaB1970]

Do you have a lens hood on? I had a finger shaped shadow on all of my flash shots one evening and could not figure it out for the life of me....I still had the hood on :)

[kevinma]

Dave, it occurred to me that they could be my fingers because they look like they should be, but I concentrated on keeping them out of the way when I had noticed it first - and thought that I had excluded that possibility. But of course now I am second guessing myself and wondering whether they were. Anyway I will do more experimenting and report back; also re the shutter speed.

Karina, I DO have a rubber hood on, but it wasn't extended, although it also wasn't folded back. And the shadows weren't on all of them. I suppose the other possibility is that because the hood wasn't folded back I may have been squeezing it into the frame with my left hand. Will have to investigate that too! Thanks for your help.

Kevin.

[dhbailey]

If the hood wasn't extended and wasn't folded back, what was it then?

It has to be one or the other. It may not have been fully extended, but anything other than pulled back may result in shadows where the flash is blocked by the hood.

[kevinma]

dhbailey: If the hood wasn't extended and wasn't folded back, what was it then? It has to be one or the other. It may not have been fully extended, but anything other than pulled back may result in shadows where the flash is blocked by the hood.


My particular rubber lens hood has 3 positions:
1. Extended
2. Not extended
3. Folded back over the front 1/2 inch of the lens.

During the picture-taking in question, it was in position #2. This position imparts a greater lens hood circumference that position #3, so it may have been the culprit, and my fingers may have compressed it during some shots, explaining why the shadows were present on some, absent on others. Additional testing awaited.

Kevin.