This weekend, I was photographing and video recording a skateboard and scooter competition.
Since the skate park was fairly spacious, and so many people were everywhere, I used the Panasonic Lumix 35-100mm f/2.8 instead of the Olympus 12-40mm f/2.8.
I have not really used the 35-100mm lens since sending it for repair due to a very ugly purple lens flare with the sun out of the frame. That was over one year ago. If I need such reach, I get one of my Olympus dSLRs (E-1, E-5) and use the Olympus 35-100mm f/2.0 or 50-200mm f/2.8-3.5.
However, recently, Panasonic had developed and released firmware to make the Optical Image Stabilization better than it had previously been when recording video. Apparently, it stuttered terribly.
In any case, I took 1014 photos and 23 video clips. A buddy and I were going to work with the video clips today, and I tried to weed out the worst of them. I was shocked at how horrible and jumpy they were. I don't have such a problem with the GH4 and the Olympus 12-40mm f/2.8 or the Leica/Lumix/Panasonic 15mm f/1.7 lenses, and they're not stabilized at all. (The still photos were reasonable, especially since it was afternoon and there was plenty of sun.)
This lens is unfortunate, especially at a retail price just under US$1500. The image quality is good, especially for a lens that would cost $750 (compare to Sigma's 18-35mm f/1.8 for US$799.99), but it's only average for a $1500 lens. The build quality seems weak for such a lens, although it is supposedly weather-sealed. Zacuto mentioned in an online interview with Panasonic representatives that it seemed much less high quality (did he say "cheap-feeling construction"?) than the 12-35mm f/2.8 also made by Panasonic.
I swore off Panasonic lenses, but the 15mm f/1.7 was too good to ignore. It functions well, aside from some low light AF hunting.
I was considering the 12-35mm f/2.8 because of the OIS but forget that. I've been told that it was much better, but that was before the firmware release "fixing" the 35-100mm f/2.8 lens. If this is normal behavior for the 12-35mm f/2.8, how are they selling any of them? How can I be more disappointed than I already was?
After handling the Olympus 50-200mm f/2.8-3.5 for 14 hour days, I wonder if Olympus' new 40-150mm f/2.8 will be a problem to hold steady on the GH4 or E-M1?
Update 2015.11.04: I shot a competition at a skate park more recently and the 35-100mm f/2.8 behaved fairly well. I still don't believe the price is appropriate but I got the work done and the video was not entirely as bad as that from the previous competition.
More recently, I got the GX8 with 12-35mm f/2.8 and, not surprisingly, I've found the 12-35mm to be a much better lens. It didn't hurt that I got it at a US$300 discount, due to instant rebates and the bundling with the GX8.
It really does seem as though Panasonic went through some design compromises to get the size of the 35-100mm f/2.8 down to that same 58mm filter size. I just wish that they'd made it a lens I could want to use.
Update 2016.11.16: There were rumors that the 12-35mm f/2.8 and 35-100mm f/2.8 would be replaced or their replacement announced at Photokina 2016. That didn't happen, unfortunately. I've seen some hate over the 35-100mm f/2.8 not performing well and the only people who seem to love it don't seem to tax it much. It's close to half the original price, which suggests that it's about to be discontinued or maybe, Panasonic realized all along that they'd made a 2nd rate lens and still priced it as 1st rate, only to let it fall after they have reclaimed their R&D expenses.