K10D graduated exposure across frame

Hi All,


I was taking some shots of some jewellery my wife made and noticed there was a graduated effect of the exposure across the frame. See the pictures below. Notice the grey band on the bottom of the top picture, then on the left side of the second pic.








It only really became apparent beause I switched from portrait to landscape and noticed the dark section moved from the bottom of the frame to the left side when I tilted the camera over. I had thought it was just fall-off of the lighting nearer the camera until I switched to portrait.

Set-up as follows:
K10D - f5.6 on 'X' setting
Pentax 35mm Macro Ltd with Kenko 2X teleconverter (tried it without teleconverter, still same problem)
2 studio flash heads, one fired remote and the other slave.


Anyone else experienced this phenomenon, or can anyone explain what it might be?

I'm hoping it's just some aspect of 'user error' and not a fault with my beloved camera!

Any help greatfully recieved!!!!

Looks to me as though the flash/s wasn't/weren't in sync with the shutter. What camera setting did you use.

Cheers,

Stephen

Oh sorry, see you were using X setting. Only other thing I can think is maybe the fill flash set up isn't correct. I'm not familiar with the K10, but I don't think there is a problem with the camera. Did the lens have a hood? Could this have been the problem?

Sorry, only guessing now. I'll leave and have a think.

Good luck,

Stephen

Hi Stephen,

It was on the 'X' (flash sync)setting!

Cheers
H

Sorry - cross post.

Just pulled out the lens's built in hood a bit - its circular so I can't imagine it only blocked one side. It's got me stumped!

Cheetrs

What an idiot I am!! Look at the shadow/s following the ring. Seems obvious to me now that there is a lighting problem. Maybe I should study more and open my mouth later.

Cheers,

Stephen

If you are using the built in flash, at close distances it can be partially obscured by a lens hood. Work without a hood and the effect should disappear.

Hi John,

not using the built in flash, just the two studio strobes, one behind / above the subject, and one just to the left of camera.

I've not changed the lighting setup between shots here, just tilted the camera over to get portrait format - the dark area has followed the camera orientation.

I can only think it's something to do with the shutter - does anyone know what direction it travels in? If it's top to bottom in lanscape orientation I can't think of anything else.

Cheers
H

It's a vertical shutter, but if there was a problem there the missing section would be black and quite sharply defined.

Thanks John,

still it must be a camera problem rather than a lighting problem for the effect to move with the camera,

H

I would say, install the firmware again and see if that change a thing.

I can't see why this would be shutter related either, flash is 1/10.000 of a sec so it would leave a clearly definable edge like John says and not such a graduated darkening.

Hi Stefan,

I can give the firmware reinstall a try, but won't get a chance to try a reshoot under similar conditions until later in the week now though, as I'm going to be busy.

Out of interest, I just tried photographing a blank piece of white paper on the bathroon floor under under ceiling light using Av (aperture priority) and didn't get the same result, the exposure looked pretty even across the frame.

I'm even more confused now!

H

Aha, just thought of something - should I have had the flash mode in 'wireless' as I was using a wireless trigger? - It was in the normal mode - no idea what difference this would make tho.

H

It might be a glitch, I've had blank or green photos once and after turning it on and off it works like it should, it might be the same thing.

As for the flash you already said this yourself.

It should not matter if you've the flash on Wireless or not with a trigger.
On wireless it will fire when it gets a "trigger" or when he gets the wireless signal.
When you set it on normal it will only be triggered by the "trigger" if you get what I mean.

Sadly it doesn't seen to be just a one off - all the shot that session were the same.

I've just looked back at these below I took a month ago with a similar setup. At the time I though the darker left-hand edge was just the way I had lit it (quite liked it at the time), but I don't want this to become known as my 'style', with every shot like this!







When I get some time I will try a few similar shots but using available light, that way I can at least see if it is a general problem or one when I'm using flash.