Nikon 1 System
The Nikon 18-55 VR kit lens is awesome. Having vibration reduction means that you will be able to shoot two or even three stops faster and still get a sharp picture.
I also had the Nikkor 35mm DX f/1.8, which is an incredible lens. The only reason I sold it was when I decided to start experimenting with manual focus lenses. If you are a Nikon shooter in APS-C, you owe it to yourself to have this lens, it is really nice.
This is the same deal as the Nikkor kit lens: it is a fantastic lens that gets a lot of bad press simply because it is the entry level lens for the platform.
This is a 30mm f/3.5 macro lens I have just received, I had to pay MSRP since nobody was trying to sell it used. The hood is tiny but seems to work really well. While it looks about as big as the kit lens, it is also very light. As a macro lens it is absolutely fantastic, I am taking incredible shots barely an inch away. I use a Neewer macro ring light on a 49mm disc mount, which screws right into the outside of the hood and even within an inch I get really good illumination of my subjects.
As a walk around lens? Meh. It's nice, but I am so used to rely on the 16mm for my walking around shots that I get frustrated with the 30mm, and it seems to have a bias for picking up the closest item it sees while trying to focus. DMF fixes this of course, but it is the only AF lens that I have that gives priority to the item focused based on distance.
Still, as a macro lens, it rocks, especially when shooting static objects. I have not really tried to shoot insects, and taking closeups of the cats has yielded great results but only after a ton of work.
I have this lens on order, I'll expand once I have a chance to play with it.
Lenses adapted to Sony E-MountFor a long time I didn't have auto focus lenses for the NEX system, all I had was a bunch of legacy non-CPU manual focus lenses with cheap Chinese adapters. So far I have shot for C/Y, Minolta MC/MD, M39, M42 and Pentax K, all of the adapters have worked extremely well and except for some minor issues (like a self-destructing Soviet era lens, or a lens with a small internal flake that shows up at random times) all of my manual lenses are awesome, and all of them were dirt cheap.
Carl Zeiss Planar T* 1.4/50 in C/Y mount
The only lens that I have here that cost more than $30 shipped is this Carl Zeiss Planar T* 1.4/50 in C/Y mount that I bought from a friend for $225, a lens impossible to find in that fine condition for less than twice that much. This lens is frickin awesome, I have no other words to describe it. It is my go-to lens for any less than ideal light, and it is great for portraits.
Industar-50-2 3.5/50 in M42 mount.
This lens was built by Krasnogorski Mekhanicheskii Zavod (KMZ) – Mechanical Factory of Krasnogorsk (near Moscow) sometime in 1973, which makes this lens two years younger than me.
Sold to a very good friend on December 2012.
Helios-44-2 2/58 in M42 mount
Built by Krasnogorski Mekhanicheskii Zavod (KMZ) – Mechanical Factory of Krasnogorsk (near Moscow) sometime in 1983.
I am not in love with the smooth aperture action, but the lens looks and shoots as if it came out of the factory a week ago. It feels solid and balanced. Optically it is really damn nice, very very sharp.
UPDATE: This lens basically fell apart, the front ring shot out, and the two front elements fell off. The dilemma now is that it will cost me more to either get the right tool, or to have it fixed, than what I paid for it, which is a shame because it is a damn nice lens.
Minolta MC Rokkor-PF 1.9/55 in MD/MC Mount
I really love this lens. I got it for $2.25 on eBay, even with shipping it was about $13 or so. Optically it is extremely nice, and it feels really damn solid and balanced.
This lens is now in the hands of a friend halfway across the country, it became his first manual lens for his NEX-5N. His "test" shots are pretty damn impressive for somebody that has only used that camera for a day or two.
Minolta MD Rokkor-X 1.7/50 in MD/MC mount
I got this lens on eBay for very little, its only obvious problem is a dented filer thread. Optically it is pretty damn nice.
It is a little longer than the 1.9/55, and it doesn't feel as sturdy (the 1.9/55 feels very solid, as if it was part of a military device). I don't think it is a construction issue, it is probably that it needs a tuneup.
This lens is now in the hands of another good friend of mine that bought my Nikon D5100.
SMC Pentax-A 2/50mm in Pentax-K Mount
I got this lens bundled with the NEX-C3 when I bought it used on eBay. I got the body, Pentax K adapter and the lens for less than the cost of a new NEX-C3 body minus the cost of the kit lens. Optically it is OK, except for some loose flakes inside. Mechanically it feels pretty solid, and weighs close to nothing.
I sold this lens in December 2012 to a student in Maryland.
Industar-61 L/D 2.8/55 in M39 Mount
This lens was built at the FED factory in Kharkov, Ukraine sometime in 1988.
It is 55mm, f/2.8 for the M39 thread mount (that's the "D" in the model designation). The L stands for Lanthanum, which means that the glass is slightly radioactive. The overall size of the lens plus adapter is nearly identical to my Industar-50-2 plus its NEX adapter.
It is a really nice lens, especially when you take into account that it was $30 including shipment from Ukraine. The lens has two really small marks on the outside of the lens thread area, as if somebody used a clamp on it and scratched it. Optically it is really nice, both aperture and focus rings work really nice. My only complaint is that the minimum focus distance is over half a meter. Maybe I can get an adapter with a helicoidal adjustment so I can focus it a bit closer. The maximum aperture is not great, but it is workable.
In terms of weight and balance, it feels as if it was made for the NEX, very nice and compact.
I sold this lens in December 2012 to a lady in California.
Mitakon Wide MC 2.8/28 in MD/MC Mount
I found this lens on eBay for $24 shipped and immediately became my walking-around lens. It is compact and light, and it has its own character. There have been times when I have preferred a shot taken with this lens from the exact same shot taken with the Carl Zeiss 1.4/50. Optically it is pristine, mechanically it looks as if it left the factory last week.
Vivitar Auto 2.8/35 in Nikon F mount
Sold in December 2012.
Focal MC Auto 2.8/135 in M42 mount.
Sold in December 2012.