Photo courtesy "dirt cheap" lens.
This (above) photo was taken with
a 7Artisans 25mm f1.8
Brand new it was +/- $70.
When I bought back into the Panasonic system again I took a chance and purchased the Olympus 12-100mm f4.0 Pro zoom lens and figured it would be my standard, do everything lens for the system. It's a big lens and has something like 60 elements in 50 groups; all either aspherical or ED (not really, just: 17 elements in 11 groups (1 DSA lens, 3 Aspherical lenses, 5 ED lenses, 2 Super HR lenses, 1 HR lens).
It's a wonderful lens and does everything I want it to. It handles wide angles of view out to the equivalent of 24mm on a full frame camera, and on the long end it reaches out to an equivalent of 200mm. It does all this while maintaining high sharpness and resolution at every focal length and at every aperture, from f4.0 (wide open) to about f8.0 (that's where diffraction kicks in). In addition to being satisfyingly sharp it's also blessed with in lens Image Stabilization that works not only on Olympus cameras but on all the recent Panasonic cameras as well. No, you don't get dual I.S. with it on a G9 or GH5 body but you do get at least 4 stops of image stabilization, and maybe a bit more at the longer end.
I've used this lens for all kinds of projects, jobs, assignments, dalliances, walks, etc. and I'm always happy with the results. So, what possessed me to buy the Panasonic/Leica 12-60mm f2.8-4.0? Besides reckless spending and mindless product duplication? Well, to start with the Olympus lens is bigger and heavier. Sometimes, when you're out strolling, it's nice to take along a lens that's almost half the weight. Then, especially with the G9s, there was the alluring idea of dual image stabilization which promised to put the stabilizing performance of a Panasonic body and lens in close competition with that offered by Olympus. It was tempting. I almost plopped down the credit card just to test out the image stabilization marketing hype.... No, the thing that tipped the scales was a video job on which we used two Panasonic GH5s and wanted two good lenses, with the same basic range of focal lengths, to have two camera angles on each scene of the project. If I was a purist I'd have bought a second Olympus 12-100mm so the lenses would match exactly but I saw this need for a second lens as an invitation to spend less money and try a new lens without feeling apprehensive, or spendy.
The Panasonic/Leica 12-60mm has fourteen elements in 12 groups with four aspheric elements and two ED elements so as far as construction goes it's no slouch. I've also owned and extensively used the Panasonic/Leica 8-18mm lens and have come to trust the line of Panasonic/Leica lenses because of the exemplary performance of that particular lens.
We used both standard lenses for what turned into an extended project and I thought that by the time we finished up I'd have divined which lens was the "keeper"; and which lens was going to be thrown out of the nest... But each has a different look; a different visual style. The Olympus feels a bit more clinical and profoundly sharp. It's the lens I use most (after the 40-150mm Pro) for live theater documentation and any video project that requires tremendous lens flexibility.
The Leica isn't quite as ferociously sharp (still better than almost any other mid-range zoom on the market!) but it seems to do a better job on portrait work. For the recent project on which I shot the first part with Panasonic G9s and the last part with a Fuji X-T3 I tended to gravitate toward the Panasonic/Leica whenever I photographed people with the Panasonic camera system. It has a slightly softer or perhaps more graceful flow between tones but still resolves good detail. It also seems slightly warmer than the Olympus lens. The more elegant tonal transition is subtle but makes the Leica lens render more like color negative film and good lenses from the film days.
You would think that I'd take one or the other on a series of projects where space and weight were essential to good logistics but from Sacramento, California to Reykjavik, Iceland I ended up always making space for both lenses in my backpack. In Iceland I took the 12-100mm instead of the Olympus 40-150mm; I wanted something that was long enough but more flexible than a resolutely telephoto zoom lens. I grabbed the Olympus whenever I knew I'd be shooting in snow, sleet or the kind of driving winds that make lens changing problematic. I'd grab the Panasonic/Leica lens when I headed out to shoot in the streets, slightly (very slightly) preferring its color rendition and not needing the last 40mm of reach. There was also the security of having a perfect back up lens no matter which one I chose to shoot with in the moment. If you bring a back up camera then why not also a back up lens?
The difference between the two lenses is really very subjective. If you photograph people, gravitate more to wide angle use over telephoto, and shoot with Panasonic cameras, I'd push you towards the Panasonic/Leica 12-60mm with no hesitation. If you are more of a portrait and long lens shooter, or an Olympus camera user, or both, I'd push you toward the Olympus.
If you could only have one I think it would depend on the way you use lenses and your tolerance for size and weight. If I worked only in the studio I'd end up with the Olympus because the vast range of focal lengths would allow me to use the lens for nearly every project. But if I was out roaming the world and shooting in a wide-to-normal-to-slight-telephoto documentary style (and I shot with Panasonic cameras) I'd select the Panasonic/Leica because it's smaller and lighter. Less burden/more good shots.
Don't take the apertures into consideration if you shoot as I do. The f2.8 is only available on the Panasonic/Leica lens at its very widest focal lengths and quickly heads toward the f4.0 as you zoom in. Since I shoot in manual exposure a lot of the time I choose to think of the P/L lens as an f4.0 lens and just use that as my maximum f-stop. Same as on the Olympus. Then I never worry about variable apertures.
If you only consider the image quality at focal lengths between 12-60mm, and exclude the extra reach of the Olympus lens, you'll find very little measurable (discernible) quality difference between the two but you will find a big difference in pricing. The Olympus lens is around $1200 while the P/L 12/60mm is usually $1,000 (but available for a limited time over the holidays, at Amazon, for $750).
It's a bit crazy to have both. For my use, experience and comfort level I should probably sell the Panasonic lens and keep the Olympus but it's never that easy. Once you've found the sweet spot and the perfect use profile for each lens one comes to think of each lens as a different tool for different looks. Same reason I seem to own so many "normal" focal length lenses, across systems.
My bottom line advice is to be rational. If you have a marvelous long lens like the Olympus 40-150mm f2.8 you really don't need the last 40mm of the 12-100mm. If you are logical you'll snag a good copy of the 12-60mm P/L and be very happy. If you don't have a longer lens and you don't need the reach then the 12-100mm can cover most of the range that most photographers use without having to slip into a two lens system.
Here's my desert island conclusion: If you could only have one lens it would instantly and without question be the Olympus. More reach, the manual focus clutch with hard stops at close focus and infinity, and amazingly good optical performance would allow me to spend my days completely satisfied with my singular lens. If I was a working photographer with more income than common sense I'd make up some nonsense about being able to depreciate the lenses and then I'd add in some self-serving crap about how the lenses will pay for themselves in no time and I'd end up with both. But no one ever claimed I was a brilliant business man.
I can look at it in one more way: if you shoot only stills then the Panasonic/Leica 12-60mm is for you. It's bright, sharp, easy to use, well behaved, and less a burden to carry around. If I shot mostly video I'd choose the Olympus lens for the better manual focusing implementation and wider focal length range, which would mean stopping less for lens changes.
Oh well, I guess I haven't really come to any final conclusion. Sorry to have wasted your time....
