Good, Fast, Cheap -- You *can* have all three!

You've probably heard the old saying (usually applied to manufacturing): You can have it good, fast, cheap. Pick any two.
Well, when it comes to lenses for your digital camera, it turns out you can have all three! And when I say cheap, I mean really cheap...

Now that digital has pretty much fully taken over, the used equipment market is flooded with older camera equipment being sold at well-below bargain prices. A fair amount of that used equipment is in excellent condition, and very much still usable today. My favorite bargain? Pentax screw-mount lenses.
Take the Vivitar 135mm f/2.8 lens above. Made in 1972, I actually purchased this lens new in 1973 for my then-current screw-mount SLR. It cost a little over $200 new at the time (which today would be about $700, I'm guessing, and more than a year's worth of my allowance at 13 years old!). It's one of the sharpest lenses I ever owned, all-metal, and very well made -- with silky smooth focusing, a pop-out velvet-lined lens hood, and gorgeous bokeh. I sold the SLR I bought it for a very long time ago, but I kept the lens, it was so good I just didn't want to part with it.
A couple of years ago, as I was going through some old boxes, I found it -- lying forgotten but in a soft case, sealed in plastic, with a sili-gel pack tucked in with it. It had survived all the years of storage wonderfully. No dust inside, no leaking lubricants, and everything still working super smoothly. I remembered what a great lens it was, and so looked around the internet to figure out how to mount it on my Canon EOS digital slrs.

I found this Fotodiox Adapter M42 Lens to Canon EOS DSLR Adapter on-line for less than $10, and decided to give it a try. And boy, am I glad I did. The lens is as sharp and distortion-free as I remember, and the smooth bokeh is to die for. Using the very simple adapter, just mount the lens on most brands of DSLRs, and shoot away.

The image above was shot with this lens, on a Canon XTi DSLR, wide-open at f/2.8. Nice, huh?

There are, of course, limitations to using old screw-mount lenses on a modern DSLR. First, there's no mechanism to stop down the aperture when you press the shutter release, so it's all manual. Typically I focus wide-open, then stop down to the shooting aperture just before taking the shot (unless you're shooting wide-open, which is kind of the point of using a lens like this!). The upside is that with most DSLRs, you do still get aperture-priority auto exposure if you want to use it, the camera will set the shutter speed depending on the light coming in no matter what f-stop you use on the lens.
Speaking of focus, it too is all manual. You remember manual focusing, don't you? Unless you're younger than about 30? It's what we used to do in the old days, when we had to actually turn the lens focusing ring to focus instead of having a motor do it for us and a computer decide when things were in focus. In practical terms, it's not that big of a deal, and with a fast lens like this one (which produces a nice, bright viewfinder image) manual focusing is quick and easy. For more "contemplative" photography like portraits, product shots, still life, etc. it's just not an issue.

You younger readers are probably thinking about now, "Sure, but I wouldn't want to use manual focusing for sports or action, that would be stupid!" Well, maybe not...the lens at left is another screw-mount bargain I picked up from Craig's List, a 200mm f/4 Pentax SMC Takumar lens. This was a premium lens in its day, had Pentax's outstanding super multi coating, and when new cost about $500 in early 1970's dollars (around $1500 today). It is an outstanding lens...and I picked it up for $40. This one's physical condition isn't as good as my Vivitar, as it's been well-used and has some minor "cosmetic" issues, but both mechanically and optically it's in outstanding condition. Shots made with it are sharp, contrasty, and gorgeous. And yes, I use it for sports:

That's a shot of my son at a lacrosse game, shot with the SMC-Takumar wide open (f/4) and manually focused. It really doesn't take much practice to be able to follow fast action while manually focusing, and since you're deciding what to focus on instead of a computer, I get just as many sharply-focused "keepers" using this old manual focus lens as I do when using my $1200 Canon 70-200mm f/2.8 L lens and autofocus. For $40. Like I said, good fast and cheap.
Craig's List and e-Bay are good places to scout around for used screw-mount lenses, with the usual caveats about "buyer beware." Try to meet the seller locally and examine the lens (or get a return guarantee) before you buy it. Make sure the mechanisms all work (especially the aperture stop-down mechanism!), the glass is clean and not scratched, there's no fungus or dust *inside* the lens, etc. A quick glance around the 'net before I posted this found 30 Vivitar 135mm f/2.8 lenses like mine readily available, for an average price of about $35. There are plenty of bargains out there if you shop carefully, and you can put them to some really good, creative use without breaking the bank.
Local photo shops also often carry used equipment, as do the big guys like B&H, Adorama, KEH, etc. I picked up a Fujinon 55mm f/3.5 macro lens in excellent condition for $30 from a local camera store with a good used selection.
So next time you're lusting after a fast, sharp lens but don't have the $$ in your bank account to pay for the latest high-end model from your camera maker, consider giving some screw-mount classic lenses a try. You just might get a real bargain and a great lens.