Lens Buyer’s Guide, Part Two

You don’t have to be a frequent visitor to photography forums to have asked yourself whether you should be investing in bodies or in lenses. My personal opinion, for what it’s worth ($.05, adjusted for inflation) is that if you choose your glass wisely, you’ll have an arsenal that you won’t outgrow, and that will be equal to any camera body you put it on. Your investment in lenses will probably surpass what you spent on your camera body, so it’s best to research carefully before buying.

Sometimes the latest glass really is your best bet, especially when there are performance issues addressed in later iterations of something, or when the design is significantly upgraded (quicker autofocus, better coatings, et cetera). The issue there is that the latest lenses also come with the highest price tags. When I posted Part I of the Lens Buying Guide yesterday, I hinted that there are ways to save significantly. There are two ways of doing this: one is by purchasing older lenses, some of which are still made (or were made in sufficient quantity that your local camera shop will still new copies in stock). Another option is buying used.

A word of caution before we get started: before buying a lens — new or used — consider whether or not you actually need it first. If you’re undecided, check out the Ultimate Photographer’s Guide to Buying Anything and Everything, which is your handy Magic 8 Ball for buying camera gear. For the rest of you who’ve decided, here’s an annotated checklist for your next lens purchase. Some steps will apply mainly to purchasing used lenses, while others are a good idea whether it’s used or brand new.

1. Check your mount: Some systems, like Pentax or Nikon, are very flexible. Nearly everything ever made for Pentax SLR’s will fit nearly every Pentax SLR ever made, and Nikon’s used the same F mount on its SLRs since 1959, though not all lenses support all functions (see below). If you’re using another brand, your mileage may vary; if you’ve got older Canon,  Olympus or Sony lenses, you can use older glass (in Sony’s case, lenses made by Minolta before Sony bought them out lock, stock and barrel), but in some  cases you’ll need an adapter.

2. Autofocus (AF) Type: If you’re using an older film body that doesn’t autofocus, or if you prefer/don’t mind manual focus, AF stops being an issue. Some SLRs use a screw drive AF system, while others require the lens to use a built-in motor. Consumer SLR’s generally won’t have an AF motor, so lenses that require one in order to autofocus will only focus manually. If you’re used to manual focus, or if it’s a lens that’s as likely to require manual focus to work correctly (like a macro telephoto), an AF motor isn’t as much of an issue.

3. Lens Speed: Consumer zooms typically have a variable aperture, with many starting at f/3.5 at the wide end and stopping down in stages as you zoom in (typically stopping down to f/5.6 by the time you’ve hit the end of the zoom range). Prosumer and professional zooms tend to have a constant aperture throughout the zoom range (generally f/4 or f/2.8), but the size, weight, and cost of those lenses are going to be higher (often much higher) as a result. The cost of a prime, in the meantime, is dictated in large part by their maximum aperture. An f/1.4 will be more expensive than an f/1.8, which will be more expensive than an f/2 or f/2.8. The added speed does give more options when you’re trying to blur a background out of focus or shoot in very low light, but unless you need that all the time, it might be hard to justify spending several times more on a 1.4 for a fraction of a stop of extra light.

Now that you’ve got an idea of what you’re dealing with, it’s time to start getting a bit more specific about your research.

4. Check Reviews: As I mentioned yesterday, reviews can be a good indicator of whether a lens is worth your time and consideration. They’re not foolproof, but they’re certainly helpful. Poke around enough and you’ll see references to other lenses – sometimes older/newer versions from the original manufacturer, and sometimes alternatives from a third party manufacturer like Sigma, Tamron or Tokina – that may also be worth a look. If you’re looking for a single lens (let’s say a macro telephoto), make a list of your options.

5. Build Quality: This may be covered in your research ahead of time, but you’ll also be able to tell quite a bit from an in-person inspection. See if the lens mount and filter threads are metal or plastic, and also how much plastic is used in the rest of the body. Heavier lenses tend to be better-built, but they’ll also tire your neck and shoulders that much faster when the camera’s around your neck for any length of time. It’s up to you to decide whether you want (or may need) to sacrifice a bit for the sake of weight.

6. CPU vs. Non-CPU Lenses: Newer lenses will have a CPU or “chip” that communicates distance and exposure information to the camera. As with AF, if your camera doesn’t support those features, you may not need the added cost that they bring. If you can do without the chip (maybe you’re using a light meter, for instance, or maybe your camera can be programmed to meter without the chip), that’s another opportunity to save money.

Now that you’ve researched your options, it’s time to get down to brass tacks in the camera shop. Some of the steps below will apply more to buying a used lens than a new one, but many of them should be done whether it’s new or straight from the factory.

7. Inspect Filter Threads: Check to make sure the filter threads aren’t dented or stripped. Dents usually indicate that the lens has been dropped or mistreated, and stripped filter threads will keep you from using filters on the lens. Also bear in mind that larger filters are more expensive, so a polarizing filter that’s downright cheap in a 52mm size could be frighteningly expensive if you need it in 82mm.*

8. Inspect Front and Rear Elements: The “elements” are, in this case, the glass on either end of the lens. Make sure it’s clean, and free of chips/scratches. You’ll also want to make sure that the lens coating isn’t worn or cloudy.

9. Try the Zoom and Focus Cams: does the zoom work smoothly, or is it too stiff/loose? Is it working across the zoom range, or does it stop at a certain point (i.e., does it get to about 105mm on a 200mm lens and continue to “zoom” without actually changing distance)? Check focus as well, to make sure that it doesn’t feel too loose, and that the lens manually focuses accurately at different subject distances.

10. Check Aperture Function: The aperture blades should open and shut smoothly, and the blades should not be oily.

11. Bring a Flashlight: Open the aperture fully, and shine the light from both ends around the inside of the lens. Look for mold, fungus, bugs (yes, bugs; I’ve seen dead creatures in lenses) and any other kind of foreign matter in the lens. A little dust in the lens isn’t terrible (and is pretty much inevitable when you’re dealing with a lens that telescopes when you zoom – they breathe), but mold and fungus can turn a sharp lens foggier than a bathroom mirror. Not sure what a dead crawly in your lens does to your photos, and I’m not eager to find out… if you’ve had the experience, please share.

12. Check the AF: Slower lenses (f/3.5-f/5.6) are also a bit slower to autofocus. The reason for this is that a lens will go to its maximum aperture when it’s focusing (even if you have it set to f/16) in order to send enough light to the AF system. For this reason, a 1.8 will generally focus faster than a 3.5. Try the AF in different lighting conditions. Is it quick and reliable, or does it “hunt,” especially in low light? Also check the accuracy of the AF, and make sure it’s not front or back focusing.

13. Check for Sample Variations: If the lens is reviewed well and your results don’t match, it could be a poor sample. This goes both ways, obviously, since it’s also possible to get a good copy of a lens that’s gotten bad reviews (I speak from experience here). If a lens performs worse than expected, ask to see multiples (and if it performs better than expected, be happy). If the person helping you is serious about photography, they’ll understand.

14. Pixel Peep: If at all possible, bring your camera body with you to the camera shop (and let me underscore, to the camera shop; they won’t let you do this in a chain store) to test the lenses. You’ll see how the lens performs on your camera as you’ve set it up, with all your quirks. I don’t know what in the hell they do to cameras at the camera shop, but it seems like every last thing is ass-backwards on them. Save yourself the frustration.

But I digress. Shoot plenty of photos, and then get them home. Look at them nice and close. How’s image quality? Check at different apertures, with different subjects and distances. Look for distortion, vignetting, lens flare, color fringing, and sharpness. Also look at the lens’s color rendition; some lenses will be warmer or colder than others, or a bit more or less contrasty. Remember to check various focal lengths and apertures, since a lens that tends to distort or vignette wide open at 24mm (for example) may perform differently when it’s stopped down, or when you zoom to 28mm.

If you’ve done all that and the lens passes with flying colors, it’s probably a safe bet.

Oh, and before I forget: If you’re buying used, consider buying a good UV filter, caps and a hood. Make sure the type of hood is appropriate to your lens type; petal hoods are a must for wider lenses, and bayonet mount hoods are much easier to use than their screw-in counterparts (besides which, they don’t always give good results on wides).

Do you have any tips, or have you scored a killer deal on a used lens? Share your tips and experiences in the comments section below!

*If you have lenses that take filters in similar sizes – one that takes a 72mm and one that takes a 77mm, for instance – consider buying the larger size along with a step-up adapter, and use the same filter on both lenses. Buying the bigger filter means a bigger hit to the wallet initially, but it’s a savings longer-term when you’re not buying two of everything.