Black cropping on flash photographs

[zthutch]

So I'm relatively new to photography. I have only been taking pictures since June. I recently got a secondhand flash and was really excited to use it because I take a lot of indoor photography. I have been using slower shutter speeds and wider open apertures to (more or less) correctly expose inside, but the pictures come out slightly dull with shallow depth of field. The problem I have been noticing with the pictures taken with my flash is on the left side of most of the pictures there appears a large black rectangle from the top to the bottom of the image. Now I'm not sure but I think i might be using apertures that are too small and it is simply cutting out the light or shutter speeds that are too fast. I wasn't sure how to compensate for the additional light so I have just been stopping up and up the shutter speed hoping for sharper pictures.

I have been shooting through a Canon AE-1 program with a 50 mm 1:1.8 lens and my flash is a vivitar 251. Any suggestions are appreciated. I haven't been able to find anything on the internet of similar problems.
Thanks.

 

[Bitter Jeweler]

Sounds like you are beyond your flash sync speed (shutter too fast).

 

[Josh66]

Do your shutter curtains travel vertically, or horizontally?

99% sure the the problem is that you are using too fast of a shutter speed - you are exceeding the x-sync limit. The solution is simple - longer shutter speed with flash. Not sure what the x-sync is on your body... 1/200 or 1/250 is typical on modern bodies - 1/60 or so is typical on older bodies.

 

[Bitter Jeweler]

They travel horizontally on the old AE-1, and you are right, the sync speed is 1/60.

 

[zthutch]

Thanks a bunch guys. I was certain that it was the aperture. Hopefully now I can get some better trial and error out of my flash.

 

[Josh66]

Just don't let the shutter speed get over 1/60 and you should be fine (with flash).

 

[Josh66]

Zthutch, in case you didn't know - the x-sync limit is the fastest shutter speed where both shutter curtains are fully open. This speed will naturally be longer if your shutter curtains travel horizontally - as there is more ground to cover. At any shutter speed faster than the x-sync, the opening is just a slit moving across the frame - the second curtain starts moving before the first one has finished.

Without high speed sync, the flash has to fire while both curtains are fully open.