Canon 5D Mark IV and 24-70mm L and when shooting vertically, camera bottom side is dark

[lifer311]

So i'm shooting product photos for an auction and I shoot vertically a lot. Usually I turn the camera clockwise, with the camera bottom being on my left. When I take the picture, the left edge of the photo seemed shadowed or slightly darker. I thought it was a lighting problem, but I've noticed that if I turn the camera counter clockwise, the right side is dark, not the left. Never experience this before. Suggestions?

[Waddizzle]

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@RobertTheFat wrote:

It looks as though something on the top or bottom of the camera is interfering with the light from one of the softboxes. (Which one depends on which way the camera is oriented.) A tripod mount, perhaps?

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Whatever the issue is, it is staying one the same side of the camera.  It's not switching sides.

[TCampbell · Accepted solution]

What shutter speed are you using?

Some 3rd party flashes have a tiny bit of lag and the camera needs to be backed off the normal flash-sync speed by about 1/3rd of a stop.