I think I am a bit late to this, but, here goes. I started in photography in the '50s while I was n the military, and have gone through 4X5 press cameras, Leica rangefinder, Practika SLR Canon Rangefinder, early Pentax SLRs, 2 Rolleiflexes, Nikon SLRS, until I finally came to to Digital! Even the simplest of today's Digital SLR has features that make us oooold photogs dance and sing!
Even the simplest of the DSLRS have features that even the Pro's won't tell you they don't know how to use!
That's just expected!
None of the "Big" Camera makers offer a "bad" camera...especially for the average snapshooter. NONE of them are "simple"! EXCEPT...If you only set it on one of the programs, and leave it! "P" for "Professional" comes to mind!
You want a real hoot, watch "MWAC Attack" on YouTube. She explains things soooo well!
"Battle at F/Stop Ridge" I and II are also entertaining!
Canon gets about 60% of the market, Nikon gets maybe 30, and the rest fight for the remainder.
There are two ... actually three systems...Full Frame FX , APS-C (crop)DX frame...about 3/4 the size of full frame, and the newer 4/3 format. I don't know enough about it to discuss it.
The FX and DX cameras use "kit" lenses, that are made mostly with plastics, especially the mounts, and they are designed for the smaller sensor. They can do marvelous work! Don't believe anyone that sneers at them. Not top quality, but VERY adequate ror most needs!
Full-frame lenses are built a bit better, cost more, and, obviously, fit full-frame cameras. They also fit "crop" cameras, where the coverage of the lens is more than the camera needs. Nikons have a 1.5X factor, and Canon has several...1.3, 1.4, and 1.6, iirc. It has the effect of a longer focal length.Technically, the smaller sensor uses the central, most highly corrected and sharp portion of the lense's coverage. I say technically, because I haven't seen much sharpness difference between the two classes of lenses. I make 12 X 18 prints from my 12 MP DX sensor camera, with no quality problems, as long as I have done my part!
Won a few awards with them, too! VR is a goodness for anyone, and especially for me, as I approach 80!
The "Big Guns" of the photo world will co$t! Generally, "Kit" lenses...~$100-300, the mid-range "prosumer"~ $4-600...my Nikon 70-300mm VR was about $600 when I bought it.
The "Immortals" which richly deserve their legendary status...the 85mm /1.4, 70-200 mm vr f/2.8 is built like a tank, and costs ~$ 2,300, the vaunted f/2.8 wide angle zoom, nicknamed the "beast", about the same. The lighter, "economy" 70-200 f4 Vr. about $1400.
But! the mid-priced lenses are quality, and cost significantly less than the others. They don't have the "Gee Whiz" factor of the "Big Guns"...orrr...is it big 'uns?
the Nikon 85mm f//1.8 is every bit as good as the f/ 1.4, imo.
A portrait lens? Any 50-60 mm lens on a smaller sensor will be all you ever need..IF you remember to stay about 6-8 feet from your subject. Full-frame 85-135mm, and a zoom, if not abused is as good as any.
Nikon lenses fit most cameras, from approximatley the First World War, with the loss of a few features, and Canon has two series of lenses That will not work interchangeably on their two camera body offerings. This was discovered by two of my friends, who are Canon shooters. So, ask questions, and try each lens on your body, especially if you get one of the 19 year-old "sales people " that are more interested in the $ale!
Good-quality used lenses, etc. can be had at reasonable prices from KEH Camera.
As I get older, I attempt to lighten the burden. I find a lightly loaded photo vest...not the ones that make you look like the Michelin man on steroids, and an across the shoulder strap, rather than the regular neck strap do lessen the strain on neck and shoulders marvelously! Two lenses....my 24-85 zoom and the 70-300 do me for a day at the track, walking around town, or at an airshow. My 50mm f/1.8 and the 100 mm 2.8 Macro usually find themselves at home in the bag whenever photomania strikes!
My buddy, the Canon shooter, has bought himself a beautiful, expen$ive point and shoot camera...he has gotten somewhat tired of carrying his DSLR and 70-200 f/2.8 with him. He loves it, with the 1200 mm telephoto capability. It is nice, and is great for stuff that doesn't move...they're still working to eliminate the shutter lag...but for racing cars, airshows, kids, not quite the thing.
If you want to go beyond "P" for Professional, you'll need to know a bit about exposure. Bryan Peterson's book "Understanding Exposure",3rd edition will tell you everything you will ever need to know, and do it understandably.
Now: I hope I haven't told you how to build the bicycle, when all you wanted is to know how to change a tire!
Good luck in your search. It is a truly Magical pastime!