Silverbased

Girth doesn’t equal worth

Try to guess which of the lenses pictured above is worth a lot of money. Gotcha! The two smaller ones can fetch hundreds of dollars; the medium one about $40, and the big honker maybe only $15 (on a good day).

So unfortunately you can’t gauge a lens’s value just by shape. It’s really the specs engraved around the barrel of the lens which tell you whether it’s a yawn or a nugget of hidden treasure. But you’ll have to learn to decode some numbers.

Key markings on a camera lens

“Focal length” is just a number telling you how large or small a lens makes the photo’s subject appear. A telephoto lens has a larger focal length (bigger number) and magnifies the subject. A short focal length makes subjects very small; but this allows you to fit in a wide angle of view.

For several decades the standard-issue lens that came with almost every cameras was 50mm in focal length (give or take a few mm). So 50mm was dubbed the “normal” lens (although many photographers have different preferences). Needless to say most normal lenses are not rare or valuable today.

The maximum aperture tells you how well you’ll be able to take photos in dim lighting. The convention is for lens-makers to engrave this like ” 1 : 1.7 ” —but normally photographers think about lens “f-stops,” and say “an f/1.7 lens.” Note that smaller numbers are wider (more desirable) apertures.

For normal lenses, f/2.0 is unexciting, f/1.8 or f/1.7 is good, f/1.4 is definitely desirable… and f/1.2 or better gets into the costly and exotic realm.

The three most common focal lengths

Since practically every hobbyist owned a 50mm, when the time came to buy their next lens it made sense to jump to something giving visibly different results—but nothing too extreme or expensive. So, by far the most popular “next lenses” were a 28mm wide-angle or a 135mm telephoto. Camera companies and third-party lens manufacturers seem to have cranked them out by the millions. Of course, this means they’re hardly rare today; and their in-betweener focal lengths are not always the most useful. For example, a 135mm is a bit long for portrait shooting, but doesn’t give enough reach for wildlife.

These numbers you can usually ignore

Don’t be distracted by other numbers which you may find engraved on the lens. The symbol Ø followed by a number is the diameter of the threading used to attach filters, hoods, and lens caps. A five- to eight-digit number is the serial number for that individual copy of the lens. In most cases neither of these matter to the lens’s worth.

Now we’re ready for zooms—lenses which have a variable focal length. Their enlargement of the subject changes as you push or twist one of the lens rings.

And behold, here’s one lens type which seems to have sold by the billions:

These telephoto zooms are fricken everywhere

Old zooms like this just aren’t very valued today. They’re particularly large and heavy; their maximum aperture is limited; and zoom quality has evolved greatly since 1985. Zoom ranges of 28-80 or 35-105 mm are also common, but are similarly kind of unloved in 2015. (Note: Vivitar was the best-selling of several discount third-party lens makers.)

Whenever some eBay camera listing blares, “includes many lenses and extras—LQQK,” I die a little inside… Because I know the “lenses” will be things like this:

These aren’t “lenses” but are frequently found with them

On the left are threaded filters which screw into the front of a lens. Many photographers routinely keep a clear Skylight or UV filter on the lens just to protect the front element. If you see brand names like Tiffen or Hoya printed around the front of a lens, you’re looking at a removable filter, not the lens itself.

A tele-extender is a way of taking a regular lens and squeezing a bit of emergency telephoto reach out of it. A few better-quality teleconverters do exist; but there are so many sucky ones that most photographers avoid them.

So that’s all the stuff that is quite common and not very exciting. But any lens which feels unusually dense or has an extra-large front element should probably be looked at by an expert. Lenses from the same brand as the camera are usually more valued than from third parties like Vivitar and Soligor. And anything made in Germany has a special mystique.

Examples of lenses that can be highly valued include: a 50mm f/1.2 normal lens; a 24mm (or shorter) ultra wide-angle; an 85mm f/1.8 portrait lens; a 50, 90, or 100mm dedicated Macro (not a zoom); and ultra-telephotos of 300mm and higher. But all those are pretty uncommon. It’s hugely more probable that some hobbyist photographer just bought the same 28mm wideangle and 70–200 zoom which everyone else had.