Nikon AF-S FX NIKKOR 28-300mm f/3.5-5.6G ED Vibration Reduction --- is my go to lens. If I can only carry 1 or 2 lenses it will be one of them. It is a very good all purpose lens in my opinion.

Beautiful work! Personally, I do my best work when I'm up late nursing a sore groin. :-)

Did you check your light metering mode? The metering mode determines how the camera detects exposure, a spot or over the whole photo, etc. MAtrix is the default for my d750.

I have a d750. I almost always shoot in manual mode and I never use exposure comp. If my camera were set like yours, manual with auto iso and my meter showed my photos were overexposed it would mean that my auto iso would be at 100, as low as it will go. I would quickly grab the shutter speed and adjust it until the exposure meter looked right.

Are the photos over or under exposed? Did you check all of your settings, metering mode, iso, etc? If the iso was accidently changed to manual and set at a higher number that could cause it. I would try a factory reset if you can't find a problem with your settings.

I believe you have developed a timing problem. The next time you see an interesting bird flapping around ignore it and leave your macro len on.

yep, hit 'auto' white balance and 'auto' tone in lightroom too

My absolute favorite is Hit Film 4 Express. It is completely free, the website has many good tutorials, and besides the basic cutting/pasting of clips it can do all sorts of special effects. The only issue is that it is so complex the learning curve can be longer than many people would want to do for small edits. After reading the tutorials for severals hours I created my own clip turning a bbq lighter into a laser pistol and disintegrating a bird with it.

There is almost no difference of the weights of the D500 & D750. The D500@10.9oz weighs more than the D750@10.4oz, not less and if you need a little flash add the weight of your external flash to the D500.