Zeiss 80mm Planar on a Sony a77. Delicious combo.
Yes, the 16 or 17mm to 35mm f2.8 zooms seem sharp enough but are they sufficiently well corrected to be used for what I think they should be used for (architecture and technical work)? Invariably not. And I hardly need a wide zoom to photograph people. I would almost always be better off with the well corrected prime lens. Perhaps a nice 21mm f 2.8 Zeiss? Then, when I'm playing around with the longer zooms it always seems to me that f2.8 on an 85mm prime or a 100mm prime gives me a little extra pop and sparkle, a bit more bite than the wide open apertures of the 70-200mm behemoths. Not to mention that there are times when one actually wants to experiment with what happens visually when we use our fast primes at or near their widest apertures. None of this takes into consideration the comfortable formalism of being cosseted by not having to choose variations in focal lengths...
I bought a Nikon D7100 a week or so ago with the idea of using it for quick events with on camera flash. Nikon's flash system has always been really good. I figured the camera, along with the 18-140mm zoom lens would be a great "grip and grin" system for walking around in dark conference halls and gala ballrooms making flash lit snapshots. No question that the focus is quick and the files are great. But within a day of buying the camera and zoom there I was, back to pick up an AF 50mm (even though I have drawer of fun, manual focus 50's.). And then a couple days later for a 35mm lens. I just like the way prime focal lengths work with my brain.
I have a Samsung camera that was sent to me for evaluation and it came with a nice 18-55mm zoom lens and a very competent 50-200mm zoom lens. I shot a bunch of "test" frames with the NX30 camera and the zooms and the images were good but I quickly got bored and put the camera in a drawer. Then I started getting unexpected boxes via Fed Ex. First came a 30mm f2, which got my attention. It's a fun lens and close to the 50mm focal length on a 35mm film camera. It was the lens that made me pull the camera back out of the drawer. But the fun quotient jumped up ten notches when the next box came and it had an 85mm f1.4 NX lens inside. Now the camera and the small collections of primes is packed in an Airport Security wheeled case for use on a job tomorrow. No question, the zooms would do the job well enough but the primes do it with added fun.
This is not a new phenomenon for me or anyone else who shoots both for fun and business. We're always covering the bases and then dropping in a bigger dose of fun. And it's usually all about the lenses. Take my Panasonic system as an example. I made my initial lens selection when I bought the GH4 and it included the 12-35mm f2.8, the 35-100mm f2.8 and the 7-14mm f4. All great lenses and all more than enough for my use in still photography and video productions. But I just had to add those unique and quite sharp Sigma dn Art lenses (19, 30 and 60mm). Then I realized that I really wanted a fast 85-90mm equivalent so I grabbed one of the Olympus 45mm 1.8's. But that made me realize that a nice, two lens, travel and art system would be well served by tossing in a 17mm f1.8. The 45mm and the 17mm do make a nice duo but they are both well balanced by the addition of the 25mm f1.4. And so it goes.
When I pack the bags for work I tend to take the zooms. When I pack the bag for fun I tend to take the primes. Rarely do I pack both. When it comes to shooting I think I have the most binary brain. It's always this or that but never both. It's either an assortment of primes or two wide ranging zooms on two bodies. It all seems easier if you can start the day making that overarching choice and ignoring whatever you chose to leave behind.
When I need to go bare bones it always makes sense to consider a wide angle to short tele zoom as a sole optic but it never works that way for me. Maybe it's my history and habit born of repetition but if I can only bring one body and one lens it's invariably a prime that finally, after an agonizing selection process, makes it onto the camera and, nine times out of ten, it's a 50mm equivalent. Something about balance. Anything wider is too wide. Anything longer is too constricting.
When it all gets distilled down my taste in cameras and lenses is all about regression to the prime.