For the night heron shots, I think I was only at 520mm with the extender (could go as much as 560mm) because the framing was too tight. It would have been an f/8 aperture. The shot without the TC was at f/7.1 and 400mm, if I recall. The lighting probably changed a little between shots since the sun was going in and out of the clouds, plus I shoot in RAW format and I would have made adjustments for highlights and shadows for each shot in Lightroom afterwards. Those adjustments may not have resulted in exactly the same look.