Well, some folks have those old lenses left over from the 60's and 70's and wonder if they are any good or not. I have several of them and do use them from time to time. One of my favorite old lenses is the Pentax Super Takumar 35mm f/3.5, for this I took three shots with this lens to demonstrate how well it performs on my DSLR. The first I set it as a point and shoot, by setting the aperture at f/11 and focusing the lens at about 20 feet I then just pointed and shot across the back of the patio to see if everything comes into acceptable focus. A second shot was of my dog to see just how well the lens performs as far as sharpness and clarity, and for the last pic I mounted the lens backwards to an old m42 bellows and took a shot of Hibiscus pollen getting close enough to see the barbs on the pollen.

These lenses are very inexpensive as compared to their modern counterparts (this lens is aroung $50 used) and perform very well in my estimation. If you don't have one you can find them on ebay or sometimes in garage sales. Just make sure which of the old lenses are easily adapted to your camera before purchasing, not all work on the different manufacturers bodies.

The m42 lenses work great on canon cameras due to the positioning of the mirror.the old canon fd lenses work but a focus glassed adaptor is needed and that can ruin the glass quality.but I love the asahi range easy to clean and smooth focusing.now I own the asahi 50mm 1.4 (warning radiation) asahi 600mm 1.8, asahi 135mm 2.5 series two serial number 43812 better than the newer L series lens, asahi 300mm f4, helios 55mm f2 awesome boken can't be beat.just to name the must get vintage lens.welcome it's addictive but fun :)

Those of us who shoot Pentax film and digital can enjoy our old glass without adaptors, except from 42mm to the K mount. I enjoy using my 50mm f1.2 on my K 5. Wonderful bokeh, and if you want to control depth of field.... At 1.2 its a little dreamy, but by f1.4 really sharp. A good length for portraits. Since it has the A on the diaphragm ring, as do several of my old optics, its easy to use on the K 5. IIRC the majority of Pentax glass from the 70's and on was multicoated. And of course the feel of an all metal lens is wonderful.

Other old glass: I have a 100mm f3.5 Vivitar macro lens. No autofocus, but 1 to 2 from infinity, and then on to 1 to 1 with its matched achromatic plus lens. Really sharp. I bought it for my Pentax LX, and with the A it works wonderfully well on the K 5.

BTW, it comes or came under several names, Cosina for example, and in MF and autofocus mounts for several marques. Mine I bought new for about $100. If you see one it's worth buying.

I go to a lot of estate sales here in Houston, and I'm always on the lookout for good primes for my D7000. What I see out there, at house after house, is junk. Old zoom lenses, damaged lenses, screw mount lens, old film P&S cameras, you name it. Most should be sent in to the recycle bin. In 3 years of looking I have not found one decent old camera or lens at an estate sale, even for collectible purposes. If I had to have an old prime I'd buy one online or at my local camera store where it has been checked out.
My ex still has the Vivitar Series I 90mm macro lens that I used for many years with my Nikon FM. If I didn't already have the 105mm Micro-Nikkor macro I'd buy it from her.

Yes, I have a Sigma 50/1.4 and use it more often than I do the Takamur 50/1.4 that I also have. But, the older lenses are good too, Canon has dropped it's inexpensive 35mm lens and replaced it with a newer one that costs $600, the Sigma is closer to $800 so this little Tak is a gem in my book. The other think is that you take more time with a manual lens and have to pay closer attention to your camera and what you are doing. My adapter is telling my camera that I am shooting a 50mm at f/1.4 so the light meter is fooled when I stop down the lens and I have compensate the EV values, also when manual focusing I think that you pay a little bit more attention to what you are shooting.



Anyway, I would never go entirely manual, but it is a good way to pick up a couple of great lenses until you are ready to shell out the big bucks for that really special one that we all seem to want.