I have had it for several years, so my opinion is settled. Before I continue, I must mention a negative aspect that concerns all camera brands (not just this one): Unfortunately, the quality control has greatly exceeded the limits within which production pieces are considered acceptable. So make sure to buy from a reputable store/company, so that if you happen to get a "lemon," you can return it.

Now, about the lens: it is incredibly small and lightweight, perfectly made, and optically very good to excellent. It fits perfectly with small m4/3 bodies, and the focal length between the classic 28-35mm in FF equivalence may be a bit strange at first, but it proves to be a good 2-in-1 approach - especially at night when you don't want to carry much equipment. The sharpness OF THIS PARTICULAR PIECE is excellent in the center, with a slight drop towards the corners, even at f1.7. It improves even more around f4, but don't expect significant differences. We are talking about raw files, already slightly corrected by the camera, which become better if you pass them through DxO, LR, etc. The jpegs from a Panasonic GX9 body are flawless, so if you set it up correctly and pay attention to exposure, you can avoid the process of editing on the computer. Also, the Leica-like color rendering is noticeable. As for the pros (theoretically), the aperture ring is included, but a) it doesn't work on Olympus, and b) it remains useless (at least for me) due to habit - since all my other lenses don't have it.

Overall, a very good lens that pairs well with small bodies with IBIS (in-body image stabilization), while if you intend to use it with Panasonic GM1/5 or GF7-GX800, etc., think again because the "kit" 12-32 lens that you probably already have has stabilization of around 2-3 stops, so you don't gain anything at night, and its performance is decent. Also, the price asked for the 15/f1.7 lens is high; when it was initially released, it stayed on the shelves, and the price dropped - I got it for around €350 from abroad. Then it was "discovered," and its price started to rise - unfortunately.

Nevertheless, if the above conditions are met, the lens is worth having in your bag.

A masterpiece lens in terms of construction, but it does not deliver what its brand represents. Average in terms of sharpness, average in terms of color reproduction, and being a 30mm lens doesn't help in any way. I used it on the gh5 and what I saw on YouTube from various tests has nothing to do with reality... At f1.7, it doesn't have the sharpness I expected, and from f3.5 to f5.6 it is sharp... Overall, it is an overpriced lens that doesn't perform well as a wide-angle or portrait lens.

Quiet, with very good speed and quality. Perfect lens for night. It is my favorite lens in the 4/3 system (I use it with Olympus)