I’ve been thinking about this for a while now, but only just bothered to try googling it. Does anybody know whether discrete zoom lenses (meaning zoom lenses that don’t have continuous zoom but rather a discrete set of fixed focal lengths) are something that may one day become reality?
I found this paper from 2016 about discrete zoom lens designs, where such constructions are discussed as a plausible compromise between prime lenses and continuous zooms due to simplified design and lighter weight, better image quality over continuous zooms etc.
That paper is pretty much the only thing I managed to find about such designs, and it discusses mostly high-end applications, not photography. With all the back-and-forth-brouhaha in the photography community about primes vs zooms, it would be true innovation in photography that I would be massively stoked about. Just imagine a lens that you can electronically switch between, say, 24, 35, 50 and 85 mm of focal length, with image quality to rival a set of four different prime lenses, but lighter and smaller than a continuous zoom with a similar range.
Usually prime lenses offer very good image quality and low aperture that cannot be matched by zoom lenses within 2–3x of their price, but this does not mean that there aren’t superb zoom lenses. It’s just that they are larger and more expensive.
Since “discrete zoom” solutions also add bulk and complex mechanics (= price), maybe manufacturers just decided to go with premium zooms instead. An occasional 1.4x or 2x built-in teleconverter maybe makes sense for zooms which are already bulky and expensive, but complicating the lens beyond that point is probably not worth it.
I use prime lenses exclusively and do not even own zooms, but I am mainly doing this as a learning experience. If I was a pro photographer who was concerned about missed shots (weddings, sports, etc), I would just get one of those expensive and large constant aperture zooms for a few thousand dollars and be done with it.
I just googled around a bit for reviews of the Tamron 35 150 f2.0-2.8 lens which was just released for the Nikon Z mount. I found one shop where that lens is explicitly advertised as “replacing a manifold of prime lenses”. Obviously, it doesn’t quite do that, but it comes so close that I would rather save up for something like that and end up saving money and weight as compared with a bag of primes, and don’t have to play lens jockey in the field or decide on focal lengths before leaving the house.
But yes, I do have a prime lens as well, and I got it for the same reason as you: as a learning experience, and it is actually very valuable for that. (I got the little plastic Nikon Z 40mm f2.0; it isn’t perfect by any means, but it’s a great little lens, super lightweight and inexpensive, so perfect for beginners like myself imho.)
There’s certainly some impressive zooms around. I have a secondhand Sigma 18-35mm f1.8 in F-mount and it’s a most impressive optic.
Sadly this lens has a wobbly reputation of AF issues, which is at least partly down to the fact it’s so sharp at f1.8 that you really notice any errors, but whatever the reason it’s slightly temperamental. Also only covers an APS-C sensor which is really the main reason I’m not using it much now.
I’ve also used it adapted to micro 4/3 where it shines, even at 48MP pixelshift! But weighs twice as much as the camera…
