How to Check a Used Lens You’re Buying in Person

 

In this post, I’ll show you what to look for when inspect­ing a used lens that you’re buy­ing in per­son. The fol­low­ing is a tran­script of the video linked above.

New pho­tog­ra­phers who are pas­sion­ate about their hob­by quick­ly devel­op an enthu­si­asm for lens­es and the cre­ative pos­si­bil­i­ties they open. This desire often leads them to the sec­ond­hand mar­ket, which offers a cost-effec­tive way to buy pho­to­graph­ic equip­ment. 

Unfor­tu­nate­ly, when buy­ing a pre-owned lens direct­ly from a sell­er met through online clas­si­fieds such as Craigslist, Face­book Mar­ket­place, and Kiji­ji, you’re giv­ing up the peace of mind offered by store refunds and man­u­fac­tur­er war­ranties in exchange for a low­er price. Such trades involve items sold as-is using cash-only (or cash-like) trans­ac­tions. The nature of these deals means it’s your respon­si­bil­i­ty to con­firm that the sell­er’s descrip­tion of the item is accu­rate because if you dis­cov­er a prob­lem after the sale is com­plete, you almost cer­tain­ly have no recourse.

For­tu­nate­ly, you can pro­tect your­self against a bad trade and con­firm that a lens is in good work­ing order by per­form­ing a thor­ough inspec­tion of the lens on the spot. The fol­low­ing is a detailed list of what you should do and check when buy­ing a used lens is person.

1. Bring your camera

Although I rec­og­nize that this point is obvi­ous, it bears men­tion­ing: Remem­ber to bring the cam­era for which you’re buy­ing the lens, and don’t for­get the bat­tery and mem­o­ry card. 

This point deserves a short sto­ry. A few years ago, I was sell­ing my Canon 85 mm lens and arranged to meet with a young woman at a Star­bucks near my home. She was about fif­teen min­utes late and, cru­cial­ly, had for­got­ten to bring her cam­era. Her real­iza­tion quick­ly turned into embar­rass­ment, which threw her off bal­ance. She per­formed the most rudi­men­ta­ry inspection—confirming that the front and rear glass ele­ments weren’t broken—gave me her cash, and quick­ly left. I’m hon­est, so she got a good lens; how­ev­er, she could’ve eas­i­ly been ripped off because she did­n’t bring a cam­era to con­firm that the lens was functional.

2. Examine the lens exterior for wear and tear, scratches, and dents

Unless you’re buy­ing a rare col­lectible that’s spent its entire exis­tence in a pro­tec­tive case or a lens adver­tised as “like new,” most cam­era lens­es will have devel­oped some wear and tear from reg­u­lar use. Your goal is to estab­lish that the used lens you’re inspect­ing match­es the adver­tise­ment. Sig­nif­i­cant dif­fer­ences from the adver­tised descrip­tion and images of the lens serve as a con­ve­nient warn­ing that the sell­er is not entire­ly trust­wor­thy. 

In most cas­es, the pre-owned lens will match its adver­tised descrip­tion, and you can con­tin­ue with your exam­i­na­tion. Wear and tear are inevitable on lens­es that see use, espe­cial­ly by pro­fes­sion­al pho­tog­ra­phers. For exam­ple, it’s nor­mal to find scuff marks and wear of the paint on the fil­ter ring because it’s the front-most part of the lens. The ridges on rub­ber­ized zoom and focus­ing rings wear down with years of use. Hair­line scratch­es and scuff marks on the paint­ed or plas­tic exte­ri­or are also expect­ed and large­ly unavoid­able. Such super­fi­cial wear is nor­mal and won’t impact the opti­cal per­for­mance and char­ac­ter­is­tics of the lens. 

Dents on the bar­rel of the lens deserve greater scruti­ny because they sug­gest a more force­ful impact or drop. Such force could eas­i­ly knock the pre­ci­sion optics out of align­ment and reduce opti­cal per­for­mance. Ask the sell­er about the nature of the dam­age, keep it in mind, and con­tin­ue. 

3. Examine the front and rear glass elements.

Remove the lens caps to check the front and rear glass ele­ments. Clean glass is eas­i­er to check, so if you find fin­ger­prints, smudges, or dust on the glass, ask the own­er to clean them off before pro­ceed­ing with the inspec­tion. 

Exam­ine the front and rear glass ele­ments. Observe how reflec­tions pass along the sur­face of the lens­es. Ide­al­ly, the glass should be smooth and free from scratch­es, abra­sions, or thin­ning of the anti-reflec­tive coat­ing. 

In prac­tice, tiny scuffs and hair­line scratch­es, espe­cial­ly to the coat­ing, won’t affect image qual­i­ty in any mea­sur­able way. The only down­side to buy­ing a lens with scratched glass is that it may affect your future resale val­ue. Addi­tion­al­ly, if such a scratch wasn’t part of the seller’s descrip­tion of the lens, you could use it to your advan­tage by sug­gest­ing a reduced price.

(For those of you won­der­ing how bad­ly dam­aged a lens must be before its evi­dent in the pho­tos, take a look at the fol­low­ing pic­ture. Try to imag­ine what sort of dam­age caused this degree of soft­ness and loss of con­trast. Is it a scratch, or sev­er­al? Is it a crack, or sev­er­al? Now take a look at the lens that took the pho­to. How did you do? As it turns out, it takes sig­nif­i­cant dam­age to the front of a lens for the effect of that dam­age to be read­i­ly appar­ent in prac­ti­cal pho­tog­ra­phy.) 

4. Check lens for internal dust and fungus

With the lens caps removed, shine your phone’s LED light through the back of the lens while look­ing at its inter­nal com­po­nents through the front. Avoid look­ing direct­ly at the mag­ni­fied LED, as it’s incred­i­bly bright. 

If you’re in a dim­ly lit envi­ron­ment, you’ll see the con­cen­trat­ed beam form through the lens ele­ments. You’ll also see a heap of dust and tiny imper­fec­tion that will make you regret ever try­ing this tech­nique. Lens­es get dusty, and zoom lens­es get dusti­er. That’s because every  time you zoom a lens, glass has to move back and forth, expand­ing or col­laps­ing the inte­ri­or vol­ume. This motion dis­places air, either push­ing it out or suck­ing it into the lens. (On some cam­eras, you can feel air “blow­ing back” into your eye through the viewfinder.)

For­tu­nate­ly, the dust found inside lens­es is mean­ing­less to pho­tog­ra­phers because it’s too small to mat­ter and does­n’t resolve in your pic­tures. You want to look for fun­gus, which can show as soft fluffy dots or fuzzy fibres or webs sprin­kled through­out the inte­ri­or glass. Fun­gus spores find their way into a lens on dust and pro­lif­er­ate after extend­ed peri­ods of stor­age in warm and humid envi­ron­ments. The fun­gus can grow and per­ma­nent­ly dam­age the glass of your lens unless it’s pro­fes­sion­al­ly cleaned. Always store your lens­es in cool and dry environments.

5. Examine the electronic contacts for signs of wear and dirt (where available)

The elec­tron­ic con­tact points found on the back of mod­ern lens­es facil­i­tate com­mu­ni­ca­tion with the cam­era. Ensure that the con­tacts are clean and don’t exhib­it signs of cor­ro­sion. The pres­ence of dirt and oth­er deposits on the elec­tron­ic con­tacts of a lens can wear down the thin gold-plat­ing and cause data com­mu­ni­ca­tion errors, which can result in loss of aper­ture con­trol, aut­o­fo­cus, opti­cal image sta­bi­liza­tion, and lens-relat­ed meta­da­ta. You can clean dirty pins, but cor­rod­ed ones require repair.

6. Examine the lens mount for damage

A lens is attached to a cam­era using the mount, which pro­vides a secure point of attach­ment and ensures that the lens and cam­era are cor­rect­ly aligned. The vast major­i­ty of mod­ern lens­es have met­al mount­ing rings, but a few bud­get-ori­ent­ed lens­es fea­ture plas­tic mounts. 

When you’re exam­in­ing a lens with a met­al mount, visu­al­ly con­firm that there’s no defor­ma­tion of the met­al tabs at the base of the lens. This kind of dam­age could pre­vent the lens from secure­ly attach­ing to the cam­era, or worse, dam­age the cam­er­a’s mount­ing ring if forced. Addi­tion­al­ly, check to ensure the lens mount is firm­ly attached to the lens barrel—the attach­ment screws shouldn’t loose or missing.

Plas­tic mounts are less like­ly to deform but more like­ly to crack, chip, or wear down. Exam­ine the plas­tic mount and tabs for signs of cracks, and con­firm the mount is firm­ly attached to the lens bar­rel.  

Now it’s time to attach the lens to your camera.

7. Make sure the lens attaches tightly and locks into place with a click 

Attach the lens to the cam­era body and make sure it locks into place with an audi­ble click. The lens should fit rel­a­tive­ly tight­ly, although a tiny amount of rota­tion­al give is nor­mal. With that said, there should­n’t be any tilt­ing or sag­ging; the lens axis must always remain per­pen­dic­u­lar to the image sensor.

8. Confirm that the focusing ring works

Inspect­ing the focus­ing ring requires some under­stand­ing of what you’re buy­ing. To help you, I’ll cov­er the three main categories.

Manual focus lenses:

Many vin­tage and some third-par­ty or spe­cial-pur­pose lens­es are focused by man­u­al­ly rotat­ing the mechan­i­cal­ly cou­pled focus­ing ring. Since there’s no aut­o­fo­cus fall­back, it’s essen­tial to con­firm that the focus­ing ring works cor­rect­ly and focus­es the lens. With the cam­era switched on and your eye to the viewfind­er, rotate the focus­ing ring from one extreme to the oth­er. The scene in the viewfind­er should shift in and out of focus. Addi­tion­al­ly, the focus­ing ring should rotate smooth­ly across its entire range of motion with­out any grit or sense of slack. 

Autofocus lenses (with mechanically coupled focusing rings):

The major­i­ty of aut­o­fo­cus lens­es designed for SLR cam­eras fea­ture focus­ing rings that are mechan­i­cal­ly-cou­pled to the opti­cal sys­tem. These types of lens­es often have a focus mode switch on the lens bar­rel that let’s you select between man­u­al focus and aut­o­fo­cus shoot­ing. In most cas­es, the focus­ing ring will always work regard­less of the focus mode. (Keep in mind, there are some excep­tions to this, so know what you’re buying!)

Switch the cam­era on, turn the focus mode to Man­u­al Focus (MF), look through the viewfind­er, and rotate the focus­ing ring from one extreme to the oth­er. Then, repeat those with the focus mode turned to Aut­o­fo­cus (AF). In either case, the scene should shift in and out of focus and the focus­ing ring should move smooth­ly across its range of motion.

Autofocus lenses (with “focus by wire”):

There’s a small but grow­ing class of aut­o­fo­cus lens­es with elec­tron­i­cal­ly cou­pled focus­ing rings. These types of lens­es are infor­mal­ly called “focus by wire” because there’s no direct mechan­i­cal con­nec­tion between the focus­ing ring and the inter­nal lens ele­ments. Instead, your inputs are trans­mit­ted elec­tron­i­cal­ly to the motors dri­ving the focus­ing sys­tem. 

Turn the cam­era on, set the focus mode to Man­u­al Focus, look through the viewfind­er, and rotate the focus­ing ring. Since there’s no phys­i­cal con­nec­tion, you’re most­ly con­firm­ing the elec­tron­ic con­nec­tion is intact, that the motors work, and that the focus­ing ring rotates smooth­ly across its range of motion.

9. Confirm that autofocus works

Unfor­tu­nate­ly, aut­o­fo­cus errors can occur on both DSLR and mir­ror­less cameras—even on brand new lens­es. For exam­ple, the zoom lens I use to make these videos is my sec­ond copy. The first one had an aut­o­fo­cus so faulty that every two out of five shots were mis­fo­cused. I was lucky to notice the prob­lem before my 14-day return peri­od end­ed. Sad­ly, there’s no return pol­i­cy when buy­ing a used lens from some­one you meet on Craigslist. So don’t be shy about car­ry­ing out a thor­ough inspec­tion when buy­ing an item that’s sold “as-is.”

To con­firm that the elec­tron­ic focus­ing sys­tem works and the lens can aut­o­fo­cus accu­rate­ly, set your cam­era to use a sin­gle aut­o­fo­cus point and take sev­er­al pic­tures of near and far objects, chang­ing between them with every shot. Review each pic­ture at full mag­ni­fi­ca­tion to ver­i­fy that the aut­o­fo­cus was con­sis­tent­ly accu­rate. 

Pro-tip: you can shift between pho­tos while review­ing them at full mag­ni­fi­ca­tion by rotat­ing the main com­mand dial on your cam­era. 

10. Check the zoom ring for function and smoothness

The major­i­ty of zoom lens­es have mechan­i­cal­ly cou­pled zoom rings. Switch on your cam­era, look through the viewfind­er, and rotate the zoom ring from one extreme to the oth­er and con­firm that your angle of view changes. The zoom ring should rotate smooth­ly with an even amount of resis­tance through­out the range of motion. You should­n’t sense any under­ly­ing grit, impinge­ment, or slack. 

Since some zoom lens­es extend out­wards at longer focal lengths, it’s a good idea to inspect the new­ly exposed part of the bar­rel for abra­sions, dam­age, and debris. Gen­er­al­ly speak­ing, there should­n’t be much give or wob­bling, even at its max­i­mum exten­sion. How­ev­er, some lens­es can slow­ly extend when point­ing down or slow­ly retract when point­ing up. 

11. Can the lens communicate with your camera?

When inspect­ing an elec­tron­ic lens, it’s nec­es­sary to con­firm that the lens can suc­cess­ful­ly com­mu­ni­cate with the cam­era. In a sense, you’ve already con­firmed this by engag­ing the aut­o­fo­cus. How­ev­er, since there are some man­u­al focus lens­es with elec­tron­i­cal­ly con­trolled aper­tures, it’s a good idea to be spe­cif­ic. 

You can con­firm that a cam­era rec­og­nized an elec­tron­ic lens when it dis­plays an aper­ture val­ue oth­er than 0. As anoth­er option, you can take a pic­ture and look at its meta­da­ta. When every­thing works cor­rect­ly, the cam­era should dis­play the zoom range, set focal length, and set aper­ture val­ue in the picture’s metadata.

12. Does the aperture work?

It’s impor­tant to make sure the aper­ture changes in size when adjust­ing the aper­ture val­ue. Don’t assume that putting the cam­era into Aper­ture Pri­or­i­ty mode, rotat­ing a dial, and watch­ing the f‑numbers change cor­re­sponds to a func­tion­ing iris diaphragm. Regard­less of the f‑number you set, a mod­ern lens will keep its aper­ture ful­ly open up to the point that you push the shut­ter but­ton to take a pic­ture. The aper­ture’s size is adjust­ed to your cho­sen f‑number only when you push the shut­ter but­ton. This behav­iour facil­i­tates more accu­rate aut­o­fo­cus­ing in dark­er envi­ron­ments and pro­vides a brighter view in the find­er. 

The fol­low­ing method should work for both DSLR and mir­ror­less cam­eras, even those with­out a depth of field pre­view but­ton. Put the cam­era into Man­u­al Expo­sure mode, select a large f‑number and a slow shut­ter speed (some­thing like 2 to 4 sec­onds), look into the lens from the front, and press the shut­ter down to take a pic­ture. Take note of the aperture’s size dur­ing expo­sure, and then take sev­er­al pic­tures more. The iris should close down to the same size con­sis­tent­ly. Any devi­a­tion in aper­ture size with­out a cor­re­spond­ing change to the f‑number could spell trou­ble for the con­sis­ten­cy of your exposures.

13. Does the optical image stabilization work?

If you’re check­ing a used lens that fea­tures opti­cal image sta­bi­liza­tion, ver­i­fy whether it oper­ates by turn­ing the switch on and off while look­ing through the viewfind­er and half-press­ing the shut­ter but­ton. And if you hap­pen to be inspect­ing a vari­able focal length lens, make sure you’re ful­ly zoomed in, because the sta­bi­liz­ing effect is more obvi­ous at longer focal lengths.

You can also place the cam­era into Shut­ter Pri­or­i­ty Mode, select a rel­a­tive­ly slow shut­ter speed, and take sev­er­al hand­held pho­tos with the sta­bi­liza­tion fea­tured enabled and then sev­er­al with it disabled.

When func­tion­ing cor­rect­ly, image sta­bi­liza­tion should reduce or elim­i­nate the motion blur asso­ci­at­ed with a shaky cam­era. 

Bonus tips

And now it’s time for the bonus round of quick tips. 

Many vin­tage lens­es have mechan­i­cal­ly-cou­pled aper­ture rings. When check­ing such lens­es, ensure the aper­ture opens and clos­es all the way and con­sis­tent­ly, and make sure the detents indi­cat­ing inter­me­di­ate steps are clicking.

If you dis­cov­er that the lens comes with a UV or “pro­tec­tion” fil­ter already attached, ask the sell­er to remove it. Remov­ing the fil­ter accom­plish­es two things: it gives you a bet­ter look at the con­di­tion of the lens under­neath, and it demon­strates that the fil­ter thread­ing isn’t dam­aged. Imper­cep­ti­ble dents can dam­age the thread­ing and make it prac­ti­cal­ly impos­si­ble to remove or attach a fil­ter. 

If the lens fea­tures “weath­er resistance”—often des­ig­nat­ed by the char­ac­ters WR—check the con­di­tion of the rub­ber flange around the lens mount for cracks, tears, or notch­es. This type of dam­age will essen­tial­ly nul­li­fy the weath­er-resis­tance of both your lens and camera.

If the lens has a focus dis­tance window—which is a clear plas­tic win­dow with focus dis­tance mark­ings underneath—make sure that turn­ing the focus­ing ring or using the cam­er­a’s aut­o­fo­cus moves the under­ly­ing dis­play. 

Last­ly, it’s tremen­dous­ly impor­tant to under­stand what you’re seek­ing to buy. Before meet­ing with any­one, read reviews of the lens you’re con­sid­er­ing so that you can tell the dif­fer­ence between nor­mal quirks and flaws or faults. Such basic research could inform you, for exam­ple, that the focus­ing sys­tem of the Fuji­film 90 mm ƒ/2 lens can wob­ble about when there’s no pow­er to the lens—and that it’s a com­plete­ly normal.

Con­clu­sion

Now you should know what to check for when buy­ing a used lens in per­son. If you have requests for top­ics, let me know in the com­ments, and I’ll con­sid­er them for future videos. In the mean­time, you can learn more about pho­tog­ra­phy by join­ing on of Expo­sure Ther­a­py’s group pho­tog­ra­phy lessons.

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