Results 1 to 16 of 16

Thread: My 25mm extension tube initial impressions

  1. #1

    Default My 25mm extension tube initial impressions

    While my good friend here at clubsnap bought a hoya +10 at a good price to reduce the MFD (min focus distance) of his camera, I got hold of a 25mm extension tube to do the same for my lenses. Here are what I tried (pardon any blurness, all shots handheld indoors):


    24-135mm macro lens @ 135mm, no extension tube, distance = 0.4m (MFD)


    24-135 @ 135mm, with extension tube, distance = 0.05m (MFD)


    80-200 @ 100mm, with extension tube, distance = 0.5-0.6m (MFD)


    80-200 @ 200mm, with extension tube, distance > 1m (MFD)


    Pretty satisfied with the results. The 24-135 macro lens could focus at 5cm away at 135mm, that's quite enough for me. I did a rough check, with the ext tube on, the 24-135 lens could focus from 5cm to about 1m, quite a good range for insect macros. Couldn't get a high enough magnification with the 80-200 lens, but the lens will come in useful when coupled with the ext tube for farther working distances, like for easily perturbed insects.

    Even tho can focus at 5cm, that's too close for most insect shots, so I tried a shot at a comfortable working distance of about 15cm. Here's it:


    24-135 @ 135mm, with extension tube, distance = 0.15m

    Botanic gardens, here I come tomorrow!
    Last edited by Tweek; 8th November 2002 at 09:55 PM.

  2. #2

    Default

    do u have a photo of what it looks like and how much it costs?

  3. #3
    Senior Member
    Join Date
    Feb 2002
    Location
    L2TPYSG
    Posts
    4,057

    Default

    never try streetshooter's panagor 60mm?
    wonder if still got sell that one...
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  4. #4

    Default

    photo don't have....kept camera liao lazy to take it out again. Anyway it's just a black tube with a through hole. A bit like a 1.4x teleconverter with the lens all smashed out. Paid $80 at fotoguide, don't know if that is an ok price.

  5. #5

    Default

    Originally posted by denizenx
    never try streetshooter's panagor 60mm?
    wonder if still got sell that one...
    i think this one good enough for me...
    at a fair price too.

  6. #6
    Senior Member
    Join Date
    Feb 2002
    Location
    L2TPYSG
    Posts
    4,057

    Default

    Originally posted by Tweek


    i think this one good enough for me...
    at a fair price too.
    cheap at 80? hmmm for 25mm... no xp not sure hehe...
    thought u got the CANON one LOL...
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  7. #7

    Default

    Originally posted by denizenx


    cheap at 80? hmmm for 25mm... no xp not sure hehe...
    thought u got the CANON one LOL...
    this is probably as good as the canon one in terms of optical quality lor...

    LD APO L quality

  8. #8

    Default

    Originally posted by Tweek


    this is probably as good as the canon one in terms of optical quality lor...

    LD APO L quality
    what brand is that ext tube?

  9. #9

    Default

    Originally posted by mervlam


    what brand is that ext tube?
    teleplus

  10. #10

    Default

    Originally posted by Tweek


    teleplus
    Well no point paying 200++ for the Canon one when there is no optic inside...

  11. #11

    Default

    this is probably as good as the canon one in terms of optical quality lor...
    hm, and I always know ext tube to be hollow?
    ever wonder why nikon don't have AF ext tube then ?
    or does it have contact then?

  12. #12
    Senior Member
    Join Date
    Feb 2002
    Location
    L2TPYSG
    Posts
    4,057

    Default

    Originally posted by Tweek


    this is probably as good as the canon one in terms of optical quality lor...

    LD APO L quality
    should be Extra Ultra Gazillion LD...

    seriously though, how many stops lost ah?
    hehe
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  13. #13
    kailord
    Guests

    Default

    i see the difference u were showing with 24-135 and 80-200 but.. how do u calculate how come the differences ended up like that?
    80-200 seems quite useless with the tube whereas 24-135 works.

    what're the mathematics behind it?

  14. #14
    Senior Member
    Join Date
    Feb 2002
    Location
    L2TPYSG
    Posts
    4,057

    Default

    Originally posted by kailord
    i see the difference u were showing with 24-135 and 80-200 but.. how do u calculate how come the differences ended up like that?
    80-200 seems quite useless with the tube whereas 24-135 works.

    what're the mathematics behind it?
    more dependent on the original minimum focusing distance of the lens at each focal length.
    so if reduce by 25% of a "macro" lens it's more impressive...

    think it's a linear function
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  15. #15

    Default

    Originally posted by tucker


    hm, and I always know ext tube to be hollow?
    ever wonder why nikon don't have AF ext tube then ?
    or does it have contact then?
    sorry saw the replies only now...
    yup ext tubes are hollow, that's why they have the best "optics"! Well, maybe vacuum is best, but air is good enough.

  16. #16

    Default

    Originally posted by kailord
    i see the difference u were showing with 24-135 and 80-200 but.. how do u calculate how come the differences ended up like that?
    80-200 seems quite useless with the tube whereas 24-135 works.

    what're the mathematics behind it?
    Hi,

    for 80-200 the magnification is less than that of 24-135 mainly because of 2 reasons: one, the minimum focus distance of the 24-135 is less than that of the 80-200, so after using the ext tube, the 24-135 can go closer than the 80-200, and the difference is enough to offset the focal length disadvantage of the 24-135. Two, in addition, the amount of reduction of minimum focus distance is dependent on focal length. The longer the focal length, you need a longer extension tube to reduce the minimum focus distance by the same proportion.

    hope this helps.

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
  •