Results 1 to 18 of 18

Thread: what to check for when buying second hand lenses

  1. #1
    Member
    Join Date
    Jan 2003
    Location
    Singapore, Singapore, Singapor
    Posts
    337

    Default what to check for when buying second hand lenses

    as above......

  2. #2
    Member
    Join Date
    Dec 2003
    Location
    CCK
    Posts
    1,051

    Default

    Quote Originally Posted by SuperRaY
    as above......
    Quite new to this myself, but here is what I do (assuming digital SLR).

    1) Read up as much as possible about the lens first. Sites such as dpreview and photo.net have lots of people posting their experiences with their lenses. This will give you an idea what to look for when buying.

    2) Fix up a time to view the lens when there is still plenty of sunlight. You (and the seller) should be prepared to spend at least 30-45 minutes testing.

    3) Bring along your camera, tripod, laptop (borrow one if need be) and card reader.

    4) Before attaching to the camera., check external appearance of lens. Some scratches and scuffing is probably ok, but be aware of dents. If it is a zoom, zoom in and out to get a feel of the zoom mechanism. Point the lens towards the floor and look for zoom creep.

    5) Check the glass. Look through the front and back elements and zoom in and out. Be aware of scratches on the optics, dust and fungus. Small specks of dust are ok and don't affect image quality, but fungus is poison!

    6) Attach to camera, set up tripod and take test shots. Use centre point focus. Check focussing speed and mechanism. Is it smooth, does the cam/lens hunt for focus? Focus on an object with some contrast and with some edges. Fix your focus point and remember it! Shoot at maximum wide angle, maximum tele and a focal length in between. For each focal length, take a shot at max aperture, min aperture and in-between (minimum total of 9 shots). Download pics and view at 100%. Look for sharpness of pic, accuracy of focus (is the focus point sharp), contrast, colour, CA.

    In all this, it helps if you already have a lens you can benchmark against.

    7) If all OK, pay up!

    Just some my basic steps above. Maybe somebody with more experience can add or correct any inaccuracies.

    Cheers

  3. #3
    Member
    Join Date
    Jan 2004
    Location
    West Singapore
    Posts
    464

    Default

    Quote Originally Posted by dkw
    Quite new to this myself, but here is what I do (assuming digital SLR).

    1) Read up as much as possible about the lens first. Sites such as dpreview and photo.net have lots of people posting their experiences with their lenses. This will give you an idea what to look for when buying.

    2) Fix up a time to view the lens when there is still plenty of sunlight. You (and the seller) should be prepared to spend at least 30-45 minutes testing.

    3) Bring along your camera, tripod, laptop (borrow one if need be) and card reader.

    4) Before attaching to the camera., check external appearance of lens. Some scratches and scuffing is probably ok, but be aware of dents. If it is a zoom, zoom in and out to get a feel of the zoom mechanism. Point the lens towards the floor and look for zoom creep.

    5) Check the glass. Look through the front and back elements and zoom in and out. Be aware of scratches on the optics, dust and fungus. Small specks of dust are ok and don't affect image quality, but fungus is poison!

    6) Attach to camera, set up tripod and take test shots. Use centre point focus. Check focussing speed and mechanism. Is it smooth, does the cam/lens hunt for focus? Focus on an object with some contrast and with some edges. Fix your focus point and remember it! Shoot at maximum wide angle, maximum tele and a focal length in between. For each focal length, take a shot at max aperture, min aperture and in-between (minimum total of 9 shots). Download pics and view at 100%. Look for sharpness of pic, accuracy of focus (is the focus point sharp), contrast, colour, CA.

    In all this, it helps if you already have a lens you can benchmark against.

    7) If all OK, pay up!

    Just some my basic steps above. Maybe somebody with more experience can add or correct any inaccuracies.

    Cheers
    wow nice info and thanks for sharing.. hehe.. but seriously if i see dust on second hand lens also its a heart ache.. but well atleast its cheaper.. but as i know i won't affect your sharpness..

  4. #4
    Member
    Join Date
    Dec 2003
    Location
    CCK
    Posts
    1,051

    Default

    Quote Originally Posted by metals99
    wow nice info and thanks for sharing.. hehe.. but seriously if i see dust on second hand lens also its a heart ache.. but well atleast its cheaper.. but as i know i won't affect your sharpness..
    ur welcome...... . Frankly I'm having more problems with sensor dust than lens dust!

  5. #5

    Default

    Hi dkw, Do you know how to see/check if the camera is affected by fungus?
    Thank you.

  6. #6
    Member
    Join Date
    Dec 2003
    Location
    CCK
    Posts
    1,051

    Default

    Quote Originally Posted by Lister
    Hi dkw, Do you know how to see/check if the camera is affected by fungus?
    Thank you.
    Gosh,
    I'm a newbie myself and you are asking such a tough one! Dust or fungus on the mirror or focussing screen are irritating and will show up as you look through the viewfinder. They shouldn't affect optical quality though, as they are not involved in image capture (mirror lifts when shutter opens).

    I don't know if fungus can grow on the sensor, but you can detect dust (and other stuff) sitting on the sensor by shooting against a clear bright background (sky will do) with a heavily stopped down aperture. I can only start to make out sensor dust with apertures of f/16 and smaller. At f/32, it becomes very obvious.

    How? Any old hands with better advice?

    Cheers,

  7. #7
    Member
    Join Date
    Dec 2003
    Location
    CCK
    Posts
    1,051

    Default

    Quote Originally Posted by dkw
    Gosh,
    I'm a newbie myself and you are asking such a tough one! Dust or fungus on the mirror or focussing screen are irritating and will show up as you look through the viewfinder. They shouldn't affect optical quality though, as they are not involved in image capture (mirror lifts when shutter opens).

    Cheers,
    I should add, you can't see sensor dust by looking through the viewfinder, it will only be seen on the final captured electronic image.

    A technique for cleaning off sensor dust can be found here -->

    http://www.pbase.com/image/15471306

  8. #8

    Default

    Look through the lens and check for dirt,fungus, scratches on the lens elements. Also, check the aperture blades for wear or oil.

  9. #9
    Senior Member
    Join Date
    Jan 2004
    Location
    Catchment Area
    Posts
    2,441

    Default

    Hi DKR, wonderful procedure to test a lens on a dSLR + laptop. Only for the rest of us still using analog film cameras, it is somewhat more difficult.

    Anybody out there got any good tips on how to test a used lens with the traditional type of camera as I suppose there are still quite a handful using film SLR? Apart from looking for fungus, dust, scratches and other telltale signs like screws that are no longer virgin. Also, basic functions like zooming, and focusing,etc.

  10. #10

    Default

    Quote Originally Posted by SuperRaY
    as above......
    the price and a test roll.

  11. #11

    Default

    Quote Originally Posted by smallaperture
    Hi DKR, wonderful procedure to test a lens on a dSLR + laptop. Only for the rest of us still using analog film cameras, it is somewhat more difficult.

    Anybody out there got any good tips on how to test a used lens with the traditional type of camera as I suppose there are still quite a handful using film SLR? Apart from looking for fungus, dust, scratches and other telltale signs like screws that are no longer virgin. Also, basic functions like zooming, and focusing,etc.
    Zooming: zoom through the entire range slowly and try to see if there is any "jerk" or any point where the zoom action is stiff or not as smooth.

    Focusing: focus the lens manually throughout the whole range (if there is an AF/MF switch, remember to set it to MF ). Again, the objective is to feel if there are any jerky points etc.

    If AF lens, AF on the body and listen for any screeches or unusual sounds. One way is to keep the lens cap on and press the shutter button lightly to start the lens auto focusing. With the lens cap on, the auto focus will hunt and will therefore run through the whole focusing range...

    For actual lens performance, shoot a roll of slides (not negatives). For me, since I use mostly zooms, I would shoot at different focal length settings. The extreme ends have to be tested, for intermediate points, I would pick the focal lengths that are printed on the lens eg in a 24~85 lens, you might get markings like 24, 28, 35, 50, 70, 80 etc. For each focal length that I test, I would usually take a shot at wide open and the next (or next 2 apertures).

    I would do 2 rounds of objects, one round at the closest (or near there) and the other round at infinity. If there are shots left, maybe do one one round at a intermediate distance.

    Shooting conditions, If I am indoor, tripod mounted. If I am outdoors, I would pick good lighting conditions and shoot ISO 200 slides and make sure that the shutter speeds are good enough to avoid camera shake.

    Shooting objects - pick something other than blank walls .

    Inspect with a good loupe. Have fun...

  12. #12

    Default

    Quote Originally Posted by Cash
    the price and a test roll.
    Hi Cash, are you refering to the price whether it is too cheap to be true? For a test roll, what if we are using SLR and not DSLR? It is impossible to do a test roll on the spot right?
    Last edited by Lister; 4th February 2004 at 09:59 AM.

  13. #13

    Default

    Quote Originally Posted by Lister
    Hi Cash, are you refering to the price whether it is too cheap to be true? For a test roll, what if we are using SLR and not DSLR? It is impossible to do a test roll on the spot right?

    I always shoot a roll of and develop in 1.2 hr to see the lens if it's good for the price given. There's no too cheap or too ex, just the price worth for that lens.

    I may even take a day or 2 to consider. But shooting a roll off using cheapo film, is a must. Just don't bring it home though.

  14. #14

    Default

    Quote Originally Posted by Cash
    I always shoot a roll of and develop in 1.2 hr to see the lens if it's good for the price given. There's no too cheap or too ex, just the price worth for that lens.

    I may even take a day or 2 to consider. But shooting a roll off using cheapo film, is a must. Just don't bring it home though.

    Thanks for the advise. So what kinda of object shld i shoot? I dun think the seller will accompany you for a photo taking session which means you only have 1/2hr of photoshoot session.

    Thanks you.

  15. #15

    Default

    Quote Originally Posted by Lister
    Thanks for the advise. So what kinda of object shld i shoot? I dun think the seller will accompany you for a photo taking session which means you only have 1/2hr of photoshoot session.

    Thanks you.

    shoot at all apertures and at all focusing distances especially the close focussing distances. Shoot a few into light bulbs or oblique to it and check for flares. If lens has fungus u cannot see, flare will show badly.

    dun forget to bargain.

  16. #16
    Senior Member
    Join Date
    Jan 2004
    Location
    Catchment Area
    Posts
    2,441

    Default

    Yeah, I think it is worth to shoot a roll of film to test a used lens that cost more than 500 bucks. A roll of film cost say 4 to 8 bucks, neg or slides, plus development and scanning for 8 to 15 bucks, so, adds up to 12 to 23 bucks.

    It is no use printing 4R prints, as it is too small to see. Slides are better. Scanning is a good way to see the result on the monitor screen, to check corners. I prefer the scanning way rather than looking at tiny loupes - getting old already - the monitor screen is so much easier on the eyes. Eyes are very, very important for this hobby!

  17. #17
    Senior Member
    Join Date
    Jan 2003
    Location
    my heart in san francisco
    Posts
    2,233

    Default

    Quote Originally Posted by Zerstorer
    Look through the lens and check for dirt,fungus, scratches on the lens elements. Also, check the aperture blades for wear or oil.
    Hi, how will the aperture blades that are worn or with oil affect the lens?

    thanks!

  18. #18

    Default 2nd hands Lens

    okie.. after seeing all these reply ..i have a question to ask ALL .. how about Nikon G lens . As it doesnt have aperture control ,like a D Lens . Which you can open up the max to see thru it...

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •