Fantastic images. Being in Yosemite is like being a kid in a candy shop. With your skill level it doesn't matter where you point your camera. Nice!!!!

Image 1 Slight motion blur from squirrel but acceptably sharp

Image 2 Slight back-focus but motion blur from bird

Image 3 Slight back-focus and motion blur from bird

Image 4 Good job panning squirrel. Still slight blur, this is mostly from camera movement not in sync with motion of squirrel.

Small animals move their bodies incredibly fast. You will need at minimum of 1/500 sec shutter to freeze their movements. I will always use continuous focus (Servo on Canon) so as to lock onto the area needed for sharp focus. If you are doing that consistently and still getting back-focus images, adjust micro-fine focus if your camera has it or send in for service.

Stunning photographs photolady. I want to go!

The original post is "Why use 18% for METERING". Your analysis is correct if the goal is for reduced noise levels in dark objects (as it should be) Using my method the bird would be correctly/accurately exposed and appropriately black. Pushing exposures "to the right" is always desirable when post processing is your regular workflow. But if and when your images must be sent directly to a lab or news outlet for processing, you can't count on auto-exposure lab equipment to render your work correctly. Most of us are simply looking at our camera screens and making quick evaluations on the fly. When you have the opportunity to use a gray card or white card you have the best chance of getting it right without the estimated interpretation needed to evaluate a reflective meter reading. You make good points however and I appreciate your incite.

My method for perfect exposures is to use a simple small white sheet of paper. Purposely overexpose a test shot, then stop down until the "highlights-over" stops blinking. Once this is achieved you will have detail in all white objects with all other tones (including blacks) falling into their true and correct tonality with little or no need for post adjustment. I prefer this over a gray card because it's fast and easy, and it can be packed in a shirt pocket. Incident meters are notoriously inaccurate and don't take into account variations from different chips, shutter/aperture variations. Particularly useful if you're a jpeg shooter and have little room for error. I have even used this method for ratio lighting in a studio.

Many many years. Yes I'm a pro and recently retired from my day job. Ready to learn new things.

Start your group with the family matriarch or patriarch. Place them near the center of your group. Hopefully the ground is dry so you can have people sitting and standing. Add family members one at a time while keeping heads dis-aligned so no face is stacked on top of each other or on the same plane horizontally if possible. Look to create triangular formations for the most pleasing result. See my groups below and imagine adding people one at a time to make your group of 15. Use the longest lens possible at a wide aperture to help separate the group from the background. Focus carefully!

Gorgeous!

When you repeatedly save a jpeg you are repeatedly compressing an already compressed file, thus degrading quality. A TIFF or PSD file is a "lossless" format that simply adds more data when you make changes and save. As far as printing jpegs vs tiff however, I have never seen a difference. I have sent both formats to labs (even extremely large prints) and concluded the tiff files are no better in quality than jpegs. Shoot raw, edit as needed as PSD or tiff, save as jpeg. That is my workflow.

The study of light

On my 5Dllll if you press the "info" button multiple times it will show.

In film days there was no LCD screen, no auto focus, no ISO change on the fly, no WB change and a 36 exposure burst max if you even had a motor drive. Superior technical results have never been easier. Experience and practice is still what separates the good from the great. Practice, practice, practice, and above all SHOOT RAW!

Let's not forget about fisheye.

I couldn't begin to explain the square lens question but I have always wondered why very few lens shades are made rectangular. A round design wastes valuable shading that results in flare when shooting toward the sun or other small/hard light sources. An old Leica camera I had the pleasure to photograph with had one. Doesn't seem like a difficult engineering problem to me.

You can use your LCD screen like an old fashioned hand held meter. Set your camera to manual mode, point the camera toward the scene and adjust shutter or aperture until centered reading is achieved. You wont get pinpoint accuracy since you can't be certain of exactly what the camera is pointed to but it will be close enough for most applications.