I've had a slew of manual-focus lenses since I got my first G1. I've had the Panasonic 20mm the whole time, but for a long time I guess I thought MF lenses were the cheap route to lots of other focal lengths. But lately I've realized that I'm down to very few adapted lenses. Partly I'm finding that AF is very helpful for macro and wildlife stuff, and partly I've gotten sick of the problems and work-arounds with lots of the adapted stuff. I also went for quite a while trying to get wide lenses to work with scale focusing. But the focus scales were never accurate, and shimming the adapters to fix that was frustrating, difficult, and time-consuming. And usually not all that successful. And now that i have the 20, the 45, and the 100-300, I'm in pretty good shape for what I need to do. Looking back, it's amazing the number of lenses I went through. I'm not sure I can even remember them all. (Most of the Nikkor lenses were ones I already had.) Cosina Voigtlander 15mm f/4.5 [I wanted to love this lens. It was sharp and had great colors, but it didn't work well with a digital sensor -- lots of bad blurring in the corners. Sold it.] Tokina 17mm [OK, but limited range of useful f stops; also a failed scale-focusing experiment. Sold it] Vivitar Close-focus 28mm [lousy image quality. Sold it.] Konica 40mm f/1.8 [People rave about this lens, and I really wanted to like it as a short telephoto. But it seemed to have really poor contrast; maybe it was just the one I had. Sold it.] Nikkor 50mm f/1.4 AIS [really soft wide open, otherwise not needed - sold it] Voigtlander 50mm Color-Skopar X [cool old lens, but I don't really need collectors' items. Sold it] SMC-Pentax 55mm [OK, not exciting, replaced by...] Micro-Nikkor 55/3.5 [Great lens, but I was missing too many pictures due to focus problems. Finally got a good deal on the 45/2.8 and switched to that] Canon 100mm f/2 FD [got this insanely cheap, but found that I didn't need f/2 and usually stuck with the 100-300mm. Sold the Canon for about $200 more than I paid for it.] Canon 135mm f/3.5 [OK, but didn't have much use for it. Sold it] Konica 135mm f/2.8 [guess I don't like 135s Sold it.] Nikkor-Q 200mm f/4 [Got it for $12; why not? Don't use it much at all] Nikkor 300mm f/4.5 AI [Nice lens, but I need AF at this focal length. Also realized the 100-300mm had much better close focus, and that the zoom would help with closer wildlife like lizards, etc.. Sold the 300.] Vivitar 70-210 Macro zoom [heavy, hard to focus, never used it. Sold it.] Vivitar 120-600mm (!) [Big, heavy, seemingly good--but I realized that could get better IQ with the 800mm adapter on our old spotting scope. Sold it.] Celestron 1000mm mirror lens [Great idea--finally, a way to get those distant shorebirds, with a 2000mm EFL. Bad idea--low resolution, low contrast, blurring from reflections--really frustrating. Sold it.] Even with all those, I'm sure I've forgotten a few, and I'm not even dealing with the 7x50 "Photo Monocular" that I've attached to several of those lenses without much luck. Lots of energy spent. Not *too* much money, since I generally sold them for about what paid, or for a lot more in a few cases. But, having gone through it all, I wouldn't do it again. I'm happier with a few lenses that were actually built for the cameras I'm using. YMMV.