You didn't mention your use, but this is my 2cents. I have a Tamron 150-600 (225-900 on the d7200). I use it for wildlife on my D7200 and D750. It works great for that, but is large and not a lens that you can use on a daily basis. Focus distance is over 8 feet and it is large to cary around. All the 150-600s are similar in that respect -great for wildlife and not much more. I also have the Nikon 70-200 f4 (107-300 on the D7200). Focal distance is under 3.5 ft. It is one of my favorite and sharpest lenses. It is small and great for travel. The lens sell for about $1400 new and under $1000 refurbished (they don't come up to often). This is an FX lens, I wouldn't spend money on DX lenses in case you wanted to get an FX camera in the future
Checkout these links.
https://www.flickr.com/photos/129992705@N03/27960543612/in/datetaken/
https://www.flickr.com/photos/129992705@N03/24579390670/in/datetaken/
http://www.kenrockwell.com/nikon/70-200mm-f4.htm

The conversation was about the quality and properties of a lens, nothing to do with art or the critique of a photograph. There are many "Professional Photographers" who have never studied art and have no understanding of composition, color theory, or design, but they call themselves Pros. This has nothing to do with Pros and Amateurs. A real artist doesn't have to delineate between a pro and amateur, his work will speak for itself.

The DXO comparison that Oldtigger posted wasn't a fair comparison. He put the 36megapixel D800e against the 22megapixel 5D mark lll.
A better comparison would be between the D750(24mp) and the 5D mark lll(22mp).
http://www.dxomark.com/Lenses/Compare/Side-by-side/Nikkor-AF-S-NIKKOR-85mm-f14G-on-Nikon-D750-versus-EF85mm-f-1.2L-II-USM-on-Canon-EOS-5D-Mark-III__388_975_270_795
This still shows the nikon lens as being much sharper.
Nikon does make a f1.2 in a 50mm. Nikon's rear mount opening is much larger then it's full frame sensor, how much larger does it need to be? When they start making larger format cameras is when they will need to change their mount.

This is an interesting comparison:

http://www.dxomark.com/Lenses/Compare/Side-by-side/Nikkor-AF-S-NIKKOR-85mm-f14G-on-Nikon-D750-versus-EF85mm-f-1.2L-II-USM-on-Canon-EOS-5D-Mark-III-versus-Zeiss-Carl-Zeiss-Apo-Planar-T-Star-Otus-85mm-F14-ZE-Canon-on-Canon-EOS-5D-Mark-III__388_975_270_795_1383_795

I have the same problem with the Nikon 750 eye piece (the 7200 has the same eye piece too). I was losing them all the time until I bought a Hoodman. I think Vello make one too. It fits very tight you will even have a tough time to get it off. It also cups your eye.
Here are links I found for the Sony cameras.

https://www.bhphotovideo.com/bnh/controller/home?O=&sku=1165086&gclid=CJnVj4eaxs4CFcsbgQodqr0HUg&is=REG&ap=y&m=Y&c3api=1876%2C92051677562%2C&A=details&Q=

https://www.bhphotovideo.com/c/search?Ntt=Vello+eye+piece+Sony+Alpha+a7&N=0&InitialSearch=yes&sts=ma&typedValue=&Top+Nav-Search=

I have the Tamron 150-600 and like it very much. I use it on my D750 and D7200.
I got it when it was first available for Nikon in 2014. Wow, I still have 4 years left on my warrantee.
It is my only non-Nikkor lens.
Also, Tamron has great customer service. I've sent it back for updates and they were great. You can actually talk to someone there.
You can check out some of my images with the Tamron on my Flickr site.


https://www.flickr.com/photos/129992705@N03/

This is also interesting, because the comparison of the D500 and the D750 is the same price ($1996). It is often asked- D500 or D750.

http://www.dxomark.com/Cameras/Compare/Side-by-side/Nikon-D500-versus-Nikon-D7200-versus-Nikon-D750___1061_1020_975

When I initially input images into LR they sometime are not in order, but when they are in the library, they are in order.

I use the Tamron 150-600 with my D750. It's very sharp, It's been great.

https://www.flickr.com/photos/129992705@N03/

I use a Tamron 150-600 on my D750. It is a great lens, very sharp. You can's beat it for around $1000.

https://www.flickr.com/photos/129992705@N03/with/23761682932/

Larger DPI creates larger file size.
72 dpi works great for video.
Make your image for display on an HD TV monitor 1920 x 1080.
That is the broadcast standard for 1080 HD.

1080 is 1920x1080 72ppi
720 is 1080x720 72ppi

1920 x 1080 -72ppi
or
1080 x 720 -72ppi

I haven't looked for one.

I recently got the Tamron 150-600. I'm using a D750 with it.
It works great. Focuses quickly and is light for that size lens. Most of all it is Sharp. I use it with a monopod with VC on.
I read that its sharpest at F8.
See the attached photos.

@400mm, f/9, 1/800sec, iso 500- not cropped


@600mm, f6.3, 1/4000sec iso 500 - slightly cropped

I just got the lens too and used it for the first time this past weekend. I'm using a D750 and a monopod with the VC on. It's sharp, light, works great. I read the lens is sharpest at F8.
You'll be very happy with it.

@400mm f9 1/800 iso-500


@600mm f6.3 1/4000 iso-500