No perceptable difference with a good quality uv filter. Some help reduce dust and fingerprints so perhaps a positive impact on image quality.

I like the d7200 and d7500 for the extra controls that make shooting quicker and easier. In most cases, your camera will take pictures of equally quality. You would enhance basic picture quality with a better lens. The exception is focus acquisition and speed. The d7200 is better. The d7500 better still. More advanced focus mechanism and higher shot per second for action.

Depth of field will differ, with D750 having shallower dof at same lens settings.

With a crop sensor camera if you are interested in improving sharpness, I would consider the Nikon 24mm f/1.8 lens. It will present as about a 36mm in full frame. That is a good angle of view for general photography and landscapes. You can get a wider angle with modest stiching. It is an excellent lenses on a full frame camera. It will give very good sharpness at f/8. And still quite decent at f/11 or acceptable at f/16. Any of those can be adjusted for nice prints with modest post processing.

I generally agree, unless the lens has a feature Nikon does not have. The 45mm Tamron is image stabilized and sharper than the 50mm Nikon lenses, for example.

I have not had that problem with the Tamron 45mm or the newer 28-300mm or the 150-600mm G2.

Sharpness will vary from lens to lens at different f stops. It will also vary from center to edge. DXOmark labs has tested various lenses and their performance at different settings. You might look at those results.

Online, I prefer no mat or, perhaps, a thin black or white edge. Sometimes there might be a reason to show a mat--but not generally. For displaying prints I have settled (mostly) on 16 x 20 black metal gallery frames--a standard size makes it more economical--can cut 4 mats out of a standard 40 x 32 sheet, etc. Sometimes will use without a mat. My hope is to make the mat and the frame a non-topic of discussion. I hope they will not be noticed but simply help the viewer consider the merits of the photograph. When I shoot with film, I will do a print showing the edge of the film to indicate a lack of cropping (though I am thinking about whether this is somehow a distraction or vanity about "shooting with film").

I have seen some websites post photos where the page background is all black which I think is an effective presentation on line. However, for a printed photo I prefer a white or off white mat--no double mat or colored edges. In some cases, I find a black mat effective--but in general worrying about mats is something I used to spend a lot of time on and now I try to resist the temptation.

I take it you meant from "24 to 70mm" and not from "24 to 27mm"? Making the super zoom sharper only in a range for which the 24-70mm is incapable of shooting?

I have used Southwest 8 times in the last year and a half, traveling for free on a "companion pass" (a program that I understand is discontinued) which gives you no special priority. You must call to check in 24 hours in advance, I believe (my wife does this). You need to call right on time, have it in your speed dial--or you will get a low priority check in. Generally, some place in the B group will get you on the flight with a seat which includes overhead space. However, often there is no overhead space in the seats towards the back of the aircraft because supplies and other things are stowed there. Various seats have some kind of electrical box which takes away leg room in front of your seat and may prevent using a rigid underseat bag (this is not unique to Southwest). Further, the aisle seats generally have a narrower opening for leg room--again a problem for a rigid underseat bag. I always travel with camera gear, and use a soft bag--Domke F6, F2 or F1x. I have fit all three under the seats without a problem--the F6 and F2 are the easiest--you might compare the size of those bags to your bag. I probably would not try a fully stuffed F1x as it might exceed the permitted carry on measurements (which Southwest does not seem to enforce very strictly). I would never take a camera bag on a flight without guaranteed overhead space if I thought I might need to use it for my camera bag. Based on your gear, a soft bag in the F6 or F2 size should work to carry your kit. Without the guarantee, I would make sure I could fit the bag under the seat, if needed. Good luck.

That is the choice I would make as a current owner of both.

Both promising. On first shot might have tried to place sun more towards upper left or right corner. On second might have zoomed in a bit more to emphasize sky more. But I am impressed with the experiment and think using a different approach will result in more interesting photos.

Hitchcock films are good to study for framing ideas. Some nice ideas for black and white as well. I saw an entire photo exhibit in Vienna devoted to still photos taken on movie sets. Quite interesting.

4 is like Alfred Hitchcock in The Birds.

I have both. Just recently got the D7500. The reason was a faster camera for kid soccer, primarily. I usually use both at a match. I find the D7500 has better focus acquisition. A bit better high ISO JPEG engine. I like the group autofocus option. I also like the two different basic jpeg settings. Thus I would likely opt for the D7500, but for most uses the D7200 is also excellent.