About lenses YONGNUO YN50 f1.8, If you are interested in this model, I found a discount for aliexpress https://www.firstordercode.com/ , where you can buy it, so this model will be cheaper for you.
I have found a site what I talked about https://www.firstordercode.com/ . So if you are interested on this laptop you may to get a discount.
This is a strange comparison in my opinion. These laptops have a different OS, so I think you should choose OS which you like. But also I think that you can get more powerful laptop for this price. For example try to consider lenovo ThinkPad X1 Yoga. It has i7 processor, 1 Tb SSD, sensor rotary display (it's real conveniently) etc. And its cost are lower. Also I found a discount for lenovo's laptops in internet about 45%.
For Nikon F I used just 50mm, it was YONGNUO YN50 f1.8 lens. This lens is cheap so I thought that I get a low quality, but I was surprised! I made a perfect photos. So if you want to get a excellent photo for low price I can recommend this one.
I wish you good luck in your business.