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Thread: Advice on buying lenses

  1. #1

    Default Advice on buying lenses

    Hi , just wanted to know if there are any "must follow" steps to tkae note of when buying camera lenses.

    Say after the choice of lens has been made, how do you go about choosing the lens you tkae home?

    For instance,

    If you buy from a shop and it's a new lens that is out of the box: What do you check for and how?

    What if its a second hand lens?

    I know how to physically check the lens but I've read on various forums on how buyers have had to scan through many sets before finding the "sharp" one. I've not come across a "blur" one so I'm wondering maybe there is something I'm not doing.

    Thanks in advance!

  2. #2
    Senior Member erictan8888's Avatar
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    Default Re: Advice on buying lenses

    what i normally do when i buy a new lens is:

    1. bring my own camera and test
    2. check for dust in the lens
    3. check on oil leaks
    4. shoot at wide end and tele end of the zoom at maximum aperature, then check for picture sharpness.
    5. step down one or two stops and do the same
    6. check for focusing error
    7. check for front or back focusing error
    8. check for stiffness or looseness in the zoom
    9. check for VR or AFS motor sound to make sure it is not too loud
    10. check the M/A and M switch working as they should
    11. shoot into the light and check for flare
    12. check for corner sharpness
    13. check for wear and tear (or signs of being used) on the exterior of lens
    14. check the contacts are clean and make sure there are no scratches
    15. check to see filter threads are not worn
    16. lastly, ask if they allow exchange should the lens be a lemon.

    that's usely what i do when i get a new lens that is expensive.
    will take me about 1 hour to do the above, so far it has served me well.... but i would take extra caution when the review on a particular lens says it is a good lens with QC issues...

    if time does not permit, then bring home and test....

    as for testing the sharpness, shoot at various types of targets on a tripod and check that the lens is "sharp" as it should be....
    if have friends having the same lens, borrow one and do a comparision of the same shot...

    hope that helps....
    Hope to learn from everyone here....

  3. #3

    Default Re: Advice on buying lenses

    How to chk front and back focusing?

  4. #4
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    Default Re: Advice on buying lenses

    Quote Originally Posted by rexlim View Post
    How to chk front and back focusing?
    shoot some object that are placed close together and see if the one you focused or in focus or not... best would be newspaper.

  5. #5
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    Default Re: Advice on buying lenses

    Quote Originally Posted by erictan8888 View Post
    what i normally do when i buy a new lens is:

    1. bring my own camera and test
    2. check for dust in the lens
    3. check on oil leaks
    4. shoot at wide end and tele end of the zoom at maximum aperature, then check for picture sharpness.
    5. step down one or two stops and do the same
    6. check for focusing error
    7. check for front or back focusing error
    8. check for stiffness or looseness in the zoom
    9. check for VR or AFS motor sound to make sure it is not too loud
    10. check the M/A and M switch working as they should
    11. shoot into the light and check for flare
    12. check for corner sharpness
    13. check for wear and tear (or signs of being used) on the exterior of lens
    14. check the contacts are clean and make sure there are no scratches
    15. check to see filter threads are not worn
    16. lastly, ask if they allow exchange should the lens be a lemon.

    that's usely what i do when i get a new lens that is expensive.
    will take me about 1 hour to do the above, so far it has served me well.... but i would take extra caution when the review on a particular lens says it is a good lens with QC issues...

    if time does not permit, then bring home and test....

    as for testing the sharpness, shoot at various types of targets on a tripod and check that the lens is "sharp" as it should be....
    if have friends having the same lens, borrow one and do a comparision of the same shot...

    hope that helps....
    wow.. that's quite comprehensive. haha thanks! im a noob at lenses too - maybe i'll print your post out and bring it along with me when i look around for lenses. haha.

    thanks!


    regards,
    jizeng

  6. #6
    Senior Member erictan8888's Avatar
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    Default Re: Advice on buying lenses

    you are welcome.....
    Hope to learn from everyone here....

  7. #7

    Default Re: Advice on buying lenses

    how about bubbles? I hear about bubbles but don't know how to tell apart a bubble and dust....

  8. #8

    Default Re: Advice on buying lenses

    Quote Originally Posted by erictan8888 View Post
    what i normally do when i buy a new lens is:

    1. bring my own camera and test
    2. check for dust in the lens
    3. check on oil leaks
    4. shoot at wide end and tele end of the zoom at maximum aperature, then check for picture sharpness.
    5. step down one or two stops and do the same
    6. check for focusing error
    7. check for front or back focusing error
    8. check for stiffness or looseness in the zoom
    9. check for VR or AFS motor sound to make sure it is not too loud
    10. check the M/A and M switch working as they should
    11. shoot into the light and check for flare
    12. check for corner sharpness
    13. check for wear and tear (or signs of being used) on the exterior of lens
    14. check the contacts are clean and make sure there are no scratches
    15. check to see filter threads are not worn
    16. lastly, ask if they allow exchange should the lens be a lemon.

    that's usely what i do when i get a new lens that is expensive.
    will take me about 1 hour to do the above, so far it has served me well.... but i would take extra caution when the review on a particular lens says it is a good lens with QC issues...

    if time does not permit, then bring home and test....

    as for testing the sharpness, shoot at various types of targets on a tripod and check that the lens is "sharp" as it should be....
    if have friends having the same lens, borrow one and do a comparision of the same shot...

    hope that helps....
    THis IS really comprehensive..may i ask if we are allowed to try out all the lens the shop has and then pick our best choice?if that's the case does that mean that most lens are all used before in some way..

    May i also know where do you usually go buy lens to carry out such detailed checking..?(or any shops to recommend where the staff are friendly and can be trusted to "guide" me at the same time?)some shops have not very friendly salespersons and i would feel werid doing all that in front of them..

  9. #9
    Senior Member erictan8888's Avatar
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    Default Re: Advice on buying lenses

    that's why stick to one shop and let them earn your $, then if you are a regular, they are more lightly to let you do all these without the BLACK face....

    but as a customer, you can and its your right to test the lens till you are satisfied then make your purchase. but pls dun test for 5-6 hours hor.... kanna whacked i dun know

    there are shops that tell you lens is ok la... QC from manufacturer good la... all these dun believe... test yourself to see...

    some shops tell you any problem can come back la... then when you come back, they tell you go to manufacturer... so dun believe...
    dun be pressured into buying a defective product....

    as to your question on whether can ask them take out more lens to see, answer is YES you can. just ask in polite way... i ever but a tamron 90mm macro, check on 3 pieces before finally decide on one. when i bought the sigma 70-300mm, i also tested 3 pieces before finally settling on the last piece... standard issue would be dust in lens, zoom ring too tight, etc...

    normally i just sit in one corner and do all the testing i want and they dun waste their time waiting for you... they can serve other people if there are other people around....
    Hope to learn from everyone here....

  10. #10

    Default Re: Advice on buying lenses

    Okie thanks for the advice. Is there a standard way of checking for sharpness of the lens or do you just go with your gut feeling?

  11. #11
    Senior Member erictan8888's Avatar
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    Default Re: Advice on buying lenses

    if you have a comparable lens or something in the overlapping zoom range, you can bring down to the shop and shoot with your lens at the same setting and compare with the lens you are buying....

    then you will have a better idea whether the lens you are buying is sharp or not....
    or if you trust the shop, shoot with the few lens they have and compare among the few lens. then take the one without any defects and is the sharpest.
    else, you can go by gut feeling, but make sure the shop allows you to do an exchange if the lens turn out to be a lemon...
    Hope to learn from everyone here....

  12. #12

    Default Re: Advice on buying lenses

    bring notebook to see at 100%?

  13. #13

    Default Re: Advice on buying lenses

    Quote Originally Posted by erictan8888 View Post
    what i normally do when i buy a new lens is:

    1. bring my own camera and test
    2. check for dust in the lens
    3. check on oil leaks
    4. shoot at wide end and tele end of the zoom at maximum aperature, then check for picture sharpness.
    5. step down one or two stops and do the same
    6. check for focusing error
    7. check for front or back focusing error
    8. check for stiffness or looseness in the zoom
    9. check for VR or AFS motor sound to make sure it is not too loud
    10. check the M/A and M switch working as they should
    11. shoot into the light and check for flare
    12. check for corner sharpness
    13. check for wear and tear (or signs of being used) on the exterior of lens
    14. check the contacts are clean and make sure there are no scratches
    15. check to see filter threads are not worn
    16. lastly, ask if they allow exchange should the lens be a lemon.

    that's usely what i do when i get a new lens that is expensive.
    will take me about 1 hour to do the above, so far it has served me well.... but i would take extra caution when the review on a particular lens says it is a good lens with QC issues...

    if time does not permit, then bring home and test....

    as for testing the sharpness, shoot at various types of targets on a tripod and check that the lens is "sharp" as it should be....
    if have friends having the same lens, borrow one and do a comparision of the same shot...

    hope that helps....
    How exactly would you know how loud the focusing motor should sound, how much distortion should be present (since all lens have varying distortion), and how stiff the zoom/focus ring should be if you haven't owned the lens before, or used someone else's?

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