..... you axed about Sigma lens a day or two ago and I'm kinda bored today so I fired two off for you to check out.The flash btw doesn't like a lens longer than 105mm so says the book.
These haven't been edited in any way and If I did something with them it would be minor.
This was shot on automatic ( cuz I'm too lazy to fool around ) RAW indoors with my flash and the Sigma 150 - 500mm. He's laying about 20 feet away.

Camera Model Canon EOS 50D
Shooting Mode Program AE
Tv( Shutter Speed ) 1/60
Av( Aperture Value ) 6.3
Metering Mode Spot Metering
ISO Speed 200
Auto ISO Speed OFF
Lens 150-500mm
Focal Length 403.0mm
Image Quality RAW
Flash On
Shot outside from my deck. The flower is in some very heavy shade so once again I used the flash. The plant is about 25' away. Same Sigma lens.

Camera Model Canon EOS 50D
Shooting Mode Program AE
Tv( Shutter Speed ) 1/60
Av( Aperture Value ) 6.3
Metering Mode Spot Metering
Exposure Compensation 0
ISO Speed 100
Auto ISO Speed OFF
Lens 150-500mm
Focal Length 500.0mm
Image Quality RAW
Flash On
These haven't been edited in any way and If I did something with them it would be minor.
This was shot on automatic ( cuz I'm too lazy to fool around ) RAW indoors with my flash and the Sigma 150 - 500mm. He's laying about 20 feet away.

Camera Model Canon EOS 50D
Shooting Mode Program AE
Tv( Shutter Speed ) 1/60
Av( Aperture Value ) 6.3
Metering Mode Spot Metering
ISO Speed 200
Auto ISO Speed OFF
Lens 150-500mm
Focal Length 403.0mm
Image Quality RAW
Flash On
Shot outside from my deck. The flower is in some very heavy shade so once again I used the flash. The plant is about 25' away. Same Sigma lens.

Camera Model Canon EOS 50D
Shooting Mode Program AE
Tv( Shutter Speed ) 1/60
Av( Aperture Value ) 6.3
Metering Mode Spot Metering
Exposure Compensation 0
ISO Speed 100
Auto ISO Speed OFF
Lens 150-500mm
Focal Length 500.0mm
Image Quality RAW
Flash On