My personal lens preferences: I typically use a focal length of anywhere between 14 to 300mm, depending on what I'm shooting. I'm talking about the focal length for a "full frame" 35mm sensor (for a "crop" sensor or medium format sensor these numbers would not be the same). I hesitate to make too many generalizations, because there are always exceptions, but I'll make some anyway:

• Generally for portrait shots (single person) most people recommend 85 to 135mm focal length.
• Generally for group portraits, I use roughly 50 to 85mm focal length.
• For landscape, I'm more likely to use a wide angle lens, but telephoto lenses are still great for many shots (esp. in the desert or other wide open spaces)
• For sports, generally you need a telephoto lens since the action is some distance away
• For "birding" (which I've never done) most people seems to use telephoto or extreme telephoto (200 - 500mm)

Zooms vs prime lenses:
A zoom lens has a focal length range, e.g. 24-105mm, whereas a prime lens is just a single (i.e. fixed) focal length (e.g. 50mm).
Zoom advantages:

• Convenience - allows you to perhaps carry just one lens instead of 2 or 3
• May also save you money (buy one zoom vs 2-3 primes)

• The greater the zoom range, generally the more image distortion (you can correct with image processing software to some extent)
• Zooms are typically heavier/larger lenses than a prime lens with a similar aperture.
• Zoom lenses are not available in really wide aperatures (e.g. f/1.4).

My preferred lenses

First I will speak generically about lenses designed for a "full frame" 35mm sensor - independent of any particular brand.

Single lens: If I can only carry one lens around I'll generally go for f/2.8 24-70 or f/4 24-105 zoom. I might prefer a f/4 14-35 zoom if I'm doing landscape. I might prefer a large-aperture prime (e.g. f/1.8 50mm) if I'm going into a low-light situation, or doing strictly portraits. Obviously I might prefer a macro lens (e.g. f/2.8 100mm) if I'm doing strictly macro work.

If possible, what I really like is to carry around two cameras, each with a different lens. For example a 14-35mm f/4 zoom and a 85mm f/2. I tend to not be interested in having a wide aperture with wide angle lenses (because I want most of the frame in focus) but find I'm more likely to want a wide aperture with a portrait (85mm) lens or other telephoto lens because I'm more interested in a nice background blur with these longer shots. (This is a personal preference of mine - I've never heard anybody else say the same thing.) I might also carry around a third lens in a bag for possible lens change, but I don't like to change lenses a great deal. A great stratgey can be to shoot with a friend and have each person carry different lenses so you can swap and no single person has to carry a lot.

Next, I will focus (no pun intended) on lenses from two popular brands - Canon and Nikon.
- And I will focus just on their newer lens selection for their newer mirrorless full frame cameras.
(They have many older lenses for their D-SLR cameras but I expect these cameras will eventually be phased out.)

Canon's RF lenses and the ones I might actually buy (if I had the money)

Also see: Canon website