Discussion in 'Photography Forum' started by Poseidon, Jul 26, 2008.

What extension tubes do.

  1. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    What extension tubes do.

    Okay, this is my first photo how to thread in a while, so please bear with me.

    Extension tubes are available in a variety of sizes for SLR cameras, there are 3rd party brands and there are ones made by the OEM, but they all have the same purpose, to reduce the minimum focus distance of a given lens. All of my examples are taken with the same camera, the same lens, and the same aperture, so that depth of field was not affected in that way. The camera is a 1D from Canon, the lens is a 70-200 2.8L with a minimum focus distance of 1.5m without any modifiers. Here is a sample of the absolute closest that I can get to my Milliapora without any modifiers:



    Not to bad right? Wrong! Well, it is OK for an overall picture, it is in focus etc... but you can't really see any detail. How can you get closer? Well I could CROP the image in photoshop or lightroom, or any other of the many post processing programs that are available today. The biggest problem with cropping, is that you are reducing the percentage of pixels that are actually used on the subject. I know, that sounds weird, but think of it this way, if I were to crop that image in close, even though I used an 8MP camera to take the image, I may only be using 2-3MP on the cropped image. So what right? Nope. The fewer MP you have, the less detail you can keep. The best solution is to put more of the subject on the sensor. That is the advantage of the extension tubes, by reducing the minimum focus distance I can put more pixels on the subject. These next images were captured using increasingly more and more extension tubes. In order from least to most:


    12mm Extension Tube


    20mm Extension Tube


    36mm Extension Tube

    Okay, that is it for single tubes, how about stacking them? Yup!!! I can do that too!


    48mm


    56mm


    68mm

    So why wouldn't you use extension tubes all the time? Well there are some disadvantages to their use. One is the reduction in depth of field, you can see in these images how the background (and foreground) gets more and more out of focus as the length of extension tubes increases. Another disadvantage is that the longer the tube gets, the longer your shutter speeds need to be. Longer shutter speeds mean that you have to use a tripod, it also means that unless you are VERY good at panning, that you will not be using an extension tube for fish pictures.

    Is there a way to get even closer? Yup! You can add a diopter to the front of the lens, this last image is captured with all 68mm of extension tubes, PLUS a 500D diopter on the front:


    More on diopters later!

    If you have questions about extension tubes, feel free to ask them in this thread.

    Thanks for reading,
    -Mike
     
    Last edited by a moderator: Nov 19, 2016
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  2. revhtree

    revhtree Owner Administrator Staff Member Team R2R R2R Supporter Photo of the Month Award R2R Excellence Award Partner Member 2018 Article Contributor Build Thread Contributor

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    Wow very awesome!!!

    Can you take a picture of your camera with all the extensions on there?
     
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  3. Paintguru

    Paintguru In need of tank

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    Can you use them with macro lenses or just standard lenses?
     
  4. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    Thanks Rev, YES I can. I will borrow the wife's 20D.

    You can use them with just about any lens. So if you have a macro lens with a very large "working distance" an extension tube would close that up a little.
     
  5. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    By request:

    Full length shot:
    [​IMG]

    Close up of all 3 tubes stacked together:
    [​IMG]

    I would guess the total length of the tubes, camera, and lens to be 12-13".
     
  6. surfn

    surfn I bleed orange and maroon

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    I got some kenko extension tubes a few weeks ago. Still need to try them out on my sigma 150mm macro (40d)

    I haven't taken any reef tank pictures in forever
     
    Last edited: Jul 26, 2008
  7. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    I was thinking of the Sigma 150mm macro when paintguru asked about using them on a Macro lens! I'll bet the results are excellent, just make sure to have that tripod out. ;)
     
  8. surfn

    surfn I bleed orange and maroon

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    Yeah I always use a tripod for reef tank pictures anyways.
    I mainly got them for bug shooting, along with the canon ring flash which I've yet to figure out how to use

    Any ring flash tutorials? LOL
     
  9. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    LOL! Nope.

    I don't have a ring flash, and never used one. Most of my photography revolves around Weddings and Sports, so my reef tank work is purely for fun. (and frustrating sometimes.) ;)
     
  10. revhtree

    revhtree Owner Administrator Staff Member Team R2R R2R Supporter Photo of the Month Award R2R Excellence Award Partner Member 2018 Article Contributor Build Thread Contributor

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    Think the 100mm Canon macro would work well with these?

    I have been meaning to get these and need to. Where would you suggest getting a whole set at?
     
  11. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    The 100mm has a very shallow working distance, so I would only get a small one Rev, using the 36mm tube may cut your focus distance to only a few mm. I would be concerned about the depth of field as well, it would be tiny!

    As for where to buy, I will only buy high end photo gear from either www.bhphoto.com or from www.adorama.com .
     
  12. Paintguru

    Paintguru In need of tank

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    My problem is my 90mm Tamron macro can't quite reach (at least, in uber macro form) the stuff in the middle of my tank. I was hoping the extension tube would help with that.
     
  13. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    I think that a diopter is what you are looking for Chris. The extension tubes will REDUCE the distance that you have to work with, the diopter (glorified magnifying glass) will help bring those corals into macro range.
     
  14. surfn

    surfn I bleed orange and maroon

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    I've seen some people use their tubes with the 100mm macro over on canon photography forum. They are mostly bug taking pictures, and most are probably image stacked to get decent depth of field
     
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  15. Eklikewhoa

    Eklikewhoa Fish Thumper!

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    Awesome info!
     
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  16. Paintguru

    Paintguru In need of tank

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    Ahh, thanks for the info, I guess that would be what I need. I'll have to look into those I guess.
     
  17. oceanparadise1

    oceanparadise1 The Coral Dudes

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    Wow those pictures came out MINT bro
     
  18. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    Thanks! I hope you are able to put the information to good use.
     
  19. Poseidon

    Poseidon Valuable Member R2R Supporter R2R Excellence Award

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    No problem! What is the thread diameter on your lens? It would be something like 52, 58, etc...
     
  20. oceanparadise1

    oceanparadise1 The Coral Dudes

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    Can u use those things with a d3?
     
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