Different pixel sizes while using Sigma 8mm fisheye for Pano photos

[jgrinta]

I have been using a Canon T4i for a few months now to take panoramic shots of apartments.  I use a Sigma 8mm fisheye lens on a Nodal Ninja Ultimate R10 head.

I have the camera set to 16:9 aspect ration with 3456x5184 resolution (Not the highest "L" setting but the next highest "L" setting).

I've noticed that when I look at the dimensions on the images, sometimes  they are at 2912x5184 and other times it is 3456x5184.

During a shoot I do not change any settings on the camera other than white balance.  I do shut off the camera and have to re-enable "Exposure Comp / AEB Setting" but that is all I am changing.  

Can anyone tell me why I am seeing images with different widths?

[Medic427]

The very important thing is not just the lens and resolution but please tell me what software perhaps you are using in post? Do you tripod mount your camera and sometimes it looks as if it is 4x3? Please describe to me as best you can what settings are you shooting in landscape? Are you using any custom functions and I knew these may seem irrelevant but if you are I was wondering if you are the only user of the camera and if there was another photographer in involved? Did someone mess with your camera's firmWare Note please do not admit to this here aka Magic Lantern or other possible hacks? PM me or if you have registered your product to your account I have strong feelings this is what people do with other people's cameras because well it is not there own and they are vindictive at times. I apologize for my endless speculation please let me know if you can provide the exact camera settings and any questionable things that may be afoot ;(.