Took Cookie out for a drive toward our office this AM and she put her birthday gift behind a Canon 500mm. Yes, one has to make a little more effort at holding things stable, but here's a sampling of images taken from the window of her rig. Looks like it can bring in some cracker jack detail. These birds were all around 50 yds out. A bit gray with no shadows this morning, but still plenty of fines.
She tried about a 1 stop underexposure bias on the geese, and it seemed to help a bit with the detail. Typically they're heavily washed out.
Worked seamless with the 500 but one has to use manual focus with the Canon 100-400. I'm out of gift ideas now, so she's going to have to take up another hobby for the balance of her life events. Thanks for your advice here, as I think the extender will get some use.
Pintail drake
Rosse's Goose
And another blue phase Ross.
Have a good one,