35mm Camera Lenses by Ron Davison

As you read through this article you will see “Stop Signs” along the way. Pay attention to these. A Stop Sign means that there may be major problems with the lens and you will want to think twice (or three times!) before buying that lens. My area of expertise is with Nikon equipment, but most of the techniques I use to evaluate lenses can be applied to any lens.

For the purposes of this article I will refer to the part of the lens that attaches to the camera as the rear of the lens. You need a few items at your disposal in order to evaluate lenses. You will need:

• Lens cleaning fluid and a lens cloth, available at a good camera store. (Do not use anything not specifically for camera lenses, or disposable lens tissues)

• Sheet of white paper or white card Let the Games Begin! The lens should have two protective covers: the lens cap (also referred to as the front cap), and the mount cap (also referred to as the rear cap). Both are important, but it’s a Stop Sign if the mount cap is missing, as it’s easier for dust to get inside the lens through the mount. Rubber grips should be securely glued to the lens, and not peeling back or loose. If you find a lens that still has a lens filter screwed to the front, then that’s a good sign. A lot of people will protect their lens from scratches by putting a UV filter, skylight filter, or haze filter on it.

Look at the lens mount. What color is it? If it is anything other than shiny metal, that is a Stop Sign. Various camera companies have tried using polycarbonate for their lens mount systems. Polycarbonate lens mounts shear off easily, making the lens undesirable. Nikon has never made a decent lens with a polycarbonate mount, so steer clear. Polycarbonate has a matte charcoal black appearance.

All lenses have a focusing ring. Try twisting it both ways. The operation should be smooth in both directions. Some focus rings are very easy to turn, and that is fine, but a focusing ring that is very stiff or inconsistent is a Stop Sign. Zoom lenses zoom in one of two ways: “push-pull” or “twist”. In both, the action should be smooth throughout the whole range of motion. When evaluating a “push-pull” lens, do the following: with the mount cap in place, extend the lens out as far as it goes and set it down vertically on the mount cap. A good lens should either stay extended, or slowly contract smoothly. No tension at all should be considered a Stop Sign.

Nikon auto focus lenses (marked “AF”) have a series of metal contacts. These are spring loaded. Press them and make sure they pop in and out. A contact that is stuck in will likely prevent the auto focus from working properly and is a Stop Sign. Older styles of Nikon lenses also have an aperture ring. The aperture ring is found at the rear of the lens. Most auto focus compatible Nikon lenses have some sort of lock switch on the aperture ring that must be unlocked prior to attempting to turn the aperture ring. Try gently turning the aperture ring. If it doesn’t move, look for either a little switch near the aperture ring, or a push button on the aperture ring. Move the switch (or push in and hold the button) and try turning the aperture ring. It should move with little clicks smoothly

from the smallest number through the biggest. If it doesn’t, then that’s a Stop Sign. Hold the lens up to your ear and give it a gentle shake. Lenses have moving parts, and some small noise is normal, but hearing things rattling and clanging around in there is a definite Stop Sign. Take the mount cap and lens cap and off and look through the rear of the lens. Turn the aperture ring back and forth as described above. The opening you can see through should expand and contract, much like the pupils of your eyes. The opening should look symmetrical. If it’s not, that’s a Stop Sign.

Next, turn the aperture ring so the opening is as

small as possible. With the rear of the lens facing you, hold the lens so that the numbers on the aperture ring are at the top (if it was a clock face, the numbers would be between 11 and 1 o’clock). At about the 3 o’clock position there is a little lever facing you. Push the lever upwards. The opening should expand smoothly, and spring back when you let go of the lever. If it doesn’t, that’s a Stop Sign. Finally, turn the aperture ring so the opening is as big as possible and look through the rear of the lens at a sheet of white paper or card. Hold the lens up close to your eye and slowly move the lens away from your face. Look for haziness, dark spots, scratches, and dust. In a perfect lens, you won’t find anything, but some small flecks of dust are acceptable. Anything else is a Stop Sign. Stick with Big Name Brands, with a Few Exceptions Chances are that you’ve heard of Canon and Nikon. Your target market will have too, making reselling easier. Other brands to look for are Leica, Hasselblad, and Bronica. These can be worth some serious cash. Youth is Not Necessarily Desirable Newer lenses are more likely to be made with more plastic and polycarbonate than older models. This makes them less valuable. While it is true that newer lenses may have various coatings to improve performance, older lenses were often made with superior glass in the first place. As you do your shopping, you’ll find there is a certain look to older lenses that you’ll quickly grow to recognize. It is not that all newer lenses are poor quality lenses, but lenses with lots of plastic and polycarbonate are less valuable in the resale market. Location, Location, Location The best Nikon lenses are made in Japan. If the lens was made in the Philippines or Malaysia, it’s not as desirable. Beauty is Only Skin Deep But it sure helps. You’ll get more money for a lens that looks brand new. A lens with scuffed paint, scratches, dings or dents has seen more action and less care and may not function as well as it should. Weight as A Sign of Reliability

As Borris the Blade from the movie Snatch stated, weight is the sign of reliability. A heavy lens is a lens made of metal and glass, not polycarbonate and plastic. Cheap camera lenses may have plastic lens elements, which is not what you want---you want glass elements. Metal bodied lenses are rugged and tough, and can withstand the occasional knock or jostle that comes with use without knocking the lens elements out of alignment.

Lens Mounting Systems All Nikon lenses made since 1959 use the same mounting technology (the Nikon F-mount system). As autofocus and camera-controlled aperture were introduced, the mount adapted to incorporate such technology, without changing the basic functionality. The upshot of this is that a fifty-year-old Nikon lens will work on a much newer camera, making reselling easier.

It’s What’s Inside That Matters Or rather, what isn’t inside matters. The only place it’s remotely acceptable to see anything on the glass of a lens is on the surface, and then only if it can be cleaned off. If it can’t be cleaned off with a lens-safe cleaning solution and a cloth specifically made for camera lenses, then the lens is essentially worthless. As stated earlier, excessive dust, dark spots, flakes of metal, and even mold can be found inside some lenses. For the purposes of making a quick sale, avoid such afflicted lenses.

F-Stops and Zoom Rings and Such, Oh My! Some older lenses have all sorts of numbers and lines on them, but what do all those numbers mean on a lens? Money, that’s what! Knowing how to read those markings is one of the keys to success in buying and selling lenses. You should be able to identify the focal length and f-stop range of the lens. The focal length is the “size” of the lens. The smaller the number, the wider the view, and the bigger the number, the more magnified the view.

The common format for a fixed lens (one that doesn’t zoom) is “Xmm 1:Z”, where X is the focal length and Z is the brightest f-stop of the lens. For example, a lens marked “28mm 1:2.8” means that the lens is a 28mm lens with a maximum aperture (f-stop) of 2.8. Zoom lenses have more complicated strings of numbers, and the common format for them is “X-Ymm

1:Z-A”, where X is the minimum focal length, Y is the maximum focal length, Z is the

brightest f-stop of the lens at it’s minimum focal length, and A is the brightest f-stop of the lens at it’s maximum focal length. For example, a lens marked “28-300mm 1:3.5-5.6” is a zoom lens that will zoom from 28mm (wide angle), all the way to 300mm (telephoto) and has a brightest f-stop of 3.5 when zoomed out to 28mm and a brightest f-stop of 5.6 when zoomed in to 300mm. Why is this important? Cheaper zoom lenses let more light through them when zoomed out than they do when zoomed in. Expensive lenses let the same amount of light through them no matter how zoomed in they are. If you’re looking for the most valuable zoom lenses, look for a lens that says “X-Ymm 1:Z”, where X is the minimum focal length, Y is the maximum focal length, and Z is the brightest f-stop of the lens.

How much difference does this make to the price? Well, a Nikon 80-200mm 1:4.5-5.6 lens will give the photographer the same zoom range as a Nikon 80-200mm 1:2.8 lens but will let in only a quarter of the light. This is very important to a photographer, as the more light a lens lets through, the more versatile the lens is. The kicker: the 80-200mm 1:2.8 lens is seven times more expensive than the 80-200mm 1:4.5-5.6

lens! So What’s Worth What? As a general rule of thumb, when looking at a lens with a focal length (size) of 80mm or more, the bigger the number, the more expensive the lens. Also, when looking at a lens with a focal length (size) of 28mm or less, the smaller the number, the more expensive the lens. Again, generally speaking, the lower the f-stop number, the more expensive the lens. Shopping Checklist Cosmetically good Heavy No imperfections inside the lens Metal lens mount Focal length above 79mm or below 29mm Low F-stop Nikon, Canon, Bronica, Leica or Hasselblad brand names My Home Run

While visiting London I bought a Nikon F3 camera and two lenses for £100.00 and sold them later that day to High Street camera store for £500. Not bad for a few hours work. About Me I studied photography in the United Kingdom before embarking on a career as a cruise ship photographer. I have visited over 100 countries, shot hundreds of thousands of photographs, and in doing so have witnessed the heartwarming to the heartbreaking, literally seeing the world through a viewfinder. I now live in Jackson Hole, Wyoming. My work can be found at my web site, http://www.rondavison.com/