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Thread: extension tube query

  1. #1
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    Default extension tube query

    Can anyone give me a comparison between using an extension tube and getting a dedicated macro lens? What is the approximate cost of an extension tube? Also if you know, could you comment on the canon 100mm f2.8 macro lens? Is it much better than the sigma 105 that was recently discussed? What are the advantages/disadvatages of either approach? (extension tube vs dedicated macro)

    Thanks

  2. #2

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    when using an extension tube, u can't focus at infinity. U have to take off the tube if u wanna focus at infinity. Something which a true macro lens can do...focus from infinity to 1:1 without any assist.
    DR KOH KHO KING

  3. #3
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    Default extension tubes

    Ok, but how about the quality of the pics? The extension tube will not reduce the quality will they?

  4. #4

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    If you have the budget, then by all means get Macro Lens. If not, getting ext tubes will be a good alternative if you already owned a prime lens.

    When you use extensions on sharp lenses, you may not be able to tell a difference (optically) compare to those using dedicated macro lens. Some major drawbacks in using ext tubes would be 1) some light loss, thus you may need to use slower shutter speed 2) cannot focus on infinity 3) Inconvinience, as you need to add or remove extension to get the magnification that you want.

    I saw 1 set of kenko ext tubes at TCW last week. You may want to check it out.

  5. #5

    Default Re: extension tubes

    Originally posted by toasty
    Ok, but how about the quality of the pics? The extension tube will not reduce the quality will they?
    they will not. However, micro/macro lens is designed to give even flat sharpness. Meaning that if u shoot a completely flat subject (newspaper on the wall), it should be sharp from corner to corner. Normal lens tends to be sharper in center, softer in corner.
    DR KOH KHO KING

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    Thanks for the comments, Is it necessary that the lens used with the extension tube be prime? I cannot use a zoom lens? Having an extension tube will turn all my lenses into macros is it true?

    About the comment that macro lenses are sharp corner to corner. I believe an extension tube should do something similar to a 1.6x focal multiplier. That is some of the light will fall outside of the CCD (because the rays have travelled further to get to the CCD and diverged more). Therefore the light from the normal corners of the lens will not be on the CCD. The CCD will be taking a crop of the center portion of image produced by the image. Therefore any unsharpness at the corner will not be visible in the pictures. Is this accurate?

    Originally posted by Sgt. Pepper
    If you have the budget, then by all means get Macro Lens. If not, getting ext tubes will be a good alternative if you already owned a prime lens.

    When you use extensions on sharp lenses, you may not be able to tell a difference (optically) compare to those using dedicated macro lens. Some major drawbacks in using ext tubes would be 1) some light loss, thus you may need to use slower shutter speed 2) cannot focus on infinity 3) Inconvinience, as you need to add or remove extension to get the magnification that you want.

    I saw 1 set of kenko ext tubes at TCW last week. You may want to check it out.

  7. #7

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    You can use ext tubes with any lenses. It's just more often than not, prime lenses are sharper.

    Pls bare in mind that the soul purpose of ext tubes existence is to let you focus the subject at a closer distance. Using ext tubes other than this purpose may implies negative effect.

    May I know what are the current lenses you have and how much magnification do you want to attain?

  8. #8
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    I currently have a 50mm f1.4, 28-70 F2.8 and 70-200 F2.8 all canon lenses. I tried using a +2 and +4 filter, but the effects are only so-so. Somehow my macro subjects are not really clear, although they are not really unsharp either. It is because the subject still occupies a relatively small portion of the frame. I would like to be able to achieve a 1:1 magnification.

    I've heard that the canon 100mm USM macro lens is very good. But then, the lenses I've currently got are also quite good, and I wonder if using an extension tube will get me some extra mileage out of my lenses. I'm not sure what "other purposes" you had in mind when you said that it could have a negative effect? Could you clarify? Thanks

    Originally posted by Sgt. Pepper
    You can use ext tubes with any lenses. It's just more often than not, prime lenses are sharper.

    Pls bare in mind that the soul purpose of ext tubes existence is to let you focus the subject at a closer distance. Using ext tubes other than this purpose may implies negative effect.

    May I know what are the current lenses you have and how much magnification do you want to attain?

  9. #9

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    Originally posted by toasty
    I'm not sure what "other purposes" you had in mind when you said that it could have a negative effect? Could you clarify?
    Other purpose like this:
    I believe an extension tube should do something similar to a 1.6x focal multiplier.
    It wont function as multiplier, but it will allow you to focus closer thus magnifying the image.

    Well, you can use ext tubes to any of your lenses. But it wont be practical carying L lenses to the field for macro, you may end up capturing sharp macros and muscle pain.

    I suggest you use ext tubes on your 50mm 1.4. You need 50mm extension to get to 1:1 magnification (Magnification = focal length / extension tubes).
    Or, reverse another 50mm lens to your existing 50mm to get 1:1. You need a male-to-male coupler in this setup.
    But for more flexibility, I think it would be better if you use ext tubes, or buying 3rd party marco lens would be more convenient in the field.

    hope it helps.

  10. #10

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    Originally posted by toasty
    Can anyone give me a comparison between using an extension tube and getting a dedicated macro lens? What is the approximate cost of an extension tube? Also if you know, could you comment on the canon 100mm f2.8 macro lens? Is it much better than the sigma 105 that was recently discussed? What are the advantages/disadvatages of either approach? (extension tube vs dedicated macro)

    Thanks
    Using the lens with ext tube to compare the quality is depend on the lens quality. If the lens originally does not produce not sharp quality, I don't think you can get good quality. Unlike macro lens , they (including 3rd party brands ) are build to be sharp in quality.

    Since you own a 70-200 F2.8, I suggest you to consider to get the 77mm Canon 500D. I have tested it with the same lens and manage to get some good shots.

    Following are my sample shots taken

    with 70-200 f2.8 L + 500D
    http://megaweb.clubsnap.org/d60_ah10/crw_3407.htm
    http://megaweb.clubsnap.org/d60_ah9/crw_2611.htm

    with 70-200 f2.8 L + ext tube
    http://megaweb.clubsnap.org/d60_ah/233-3354_crw.htm
    http://megaweb.clubsnap.org/d60_ah/233-3333_crw.htm

    with 70-200 f2.8 L IS + 500D
    http://megaweb.clubsnap.org/d60_ah14/crw_7851.htm
    http://megaweb.clubsnap.org/d60_ah14/crw_7855.htm

    with 100mm macro
    http://megaweb.clubsnap.org/d60_ah13/crw_6241.htm
    http://megaweb.clubsnap.org/d60_ah13/crw_6205.htm
    See my Photo Gallery at the Clubsnap

  11. #11
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    I was referring to the comment by Kho that dedicated macro lens gives corner to corner sharpness when I talked about the "similar effect" to the 1.6x multiplier. Actually it is just taking a crop of the image which is created by the lens (which is what I meant when I refer to the 1.6x multiplier, not that it will give you more zoom), sorry for the confusion.

    When you move the lens further forward (with the extension tube) I believe (but am not sure) that you create a larger image on the CCD and therefore do not see the corners where the image is softer. I am just thinking about how the extension tube works. It is not very clear in my mind, but I am making a guess.

    Thanks for all your info and advice, it has been helpful. I still got to make a decision though What setup do you use? Macro or ET? Seems you are knowledgeable in this area.

    I didn't quite understand the part you talked about reversing another 50mm lens with a male-male coupler. How does one take the photos with this setup?

    Originally posted by Sgt. Pepper
    Other purpose like this: It wont function as multiplier, but it will allow you to focus closer thus magnifying the image.

    Well, you can use ext tubes to any of your lenses. But it wont be practical carying L lenses to the field for macro, you may end up capturing sharp macros and muscle pain.

    I suggest you use ext tubes on your 50mm 1.4. You need 50mm extension to get to 1:1 magnification (Magnification = focal length / extension tubes).
    Or, reverse another 50mm lens to your existing 50mm to get 1:1. You need a male-to-male coupler in this setup.
    But for more flexibility, I think it would be better if you use ext tubes, or buying 3rd party marco lens would be more convenient in the field.

    hope it helps.

  12. #12
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    Nice photos megaweb. Yeah my pics with the +2 or +4 never turn out anything like that

    Thanks for the advice. Have to do some reseach on that.
    Originally posted by megaweb
    Using the lens with ext tube to compare the quality is depend on the lens quality. If the lens originally does not produce not sharp quality, I don't think you can get good quality. Unlike macro lens , they (including 3rd party brands ) are build to be sharp in quality.

    Since you own a 70-200 F2.8, I suggest you to consider to get the 77mm Canon 500D. I have tested it with the same lens and manage to get some good shots.


  13. #13

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    I was referring to the comment by Kho that dedicated macro lens gives corner to corner sharpness when I talked about the "similar effect" to the 1.6x multiplier
    Ooops, sorry I didnít read properly.

    When you move the lens further forward (with the extension tube) I believe (but am not sure) that you create a larger image on the CCD and therefore do not see the corners where the image is softer. I am just thinking about how the extension tube works. It is not very clear in my mind, but I am making a guess.
    Itís true that one advantage of macro lens is for taking photo of flat subject like documents, but if you are taking insects or flowers you wont see any difference when you use sharp lens + Ext tubes. It has been proven by Megaweb shots using L lens and ET.

    Thanks for all your info and advice, it has been helpful. I still got to make a decision though What setup do you use? Macro or ET? Seems you are knowledgeable in this area.
    Its fun trying out different techniques to get the magnification you want. But now I used my sigma 105mm often.

    I didn't quite understand the part you talked about reversing another 50mm lens with a male-male coupler. How does one take the photos with this setup?
    Normal closeup filter like hoya and other brands are only single element, only canon (250D/500D) and Nikon (6T/4T) make 2 elements closeup filter. The effect of reversing the lens is like a ďmulti-elementsĒ close up filter. Wherein, magnification = focal length of the lens mounted on the cam / focal length of the reversed mounted lens. Thus, if you reverse 50mm to a 50mm lens will gove you 1X magnification. The shorter the focal length of the reversed lens, the higher the magnification. Note: Before you reverse any lens, make sure you set it to infinity focus and widest aperture to reduce the vignette.

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    Originally posted by Sgt. Pepper
    Normal closeup filter like hoya and other brands are only single element, only canon (250D/500D) and Nikon (6T/4T) make 2 elements closeup filter.
    Sigma also make 2 element closeup filters.

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    Just been calling AP and CP for ET and for the 100mm F2.8 macro. AP doesn't have stock for the canon 100mm, CP is asking $1020. There is another nice electronics shop called Paris Silk in Holland V which I have always found to be excellent with their prices. They are asking $988 for the macro lens.

    As for extension tubes, they all only carry 25mm extension tubes, price is $90 at CP and $75 at AP, although the brands are different.

    Just now Sgt Pepper was saying that in order to get 1:1, you need to have an extension equal to the focal length of the lens. Does that mean that at 200mm, I need a 200mm extension tube? None of the shops I checked carried even a 50mm ET.

    At this price difference, I am thinking that the disadvantage from having an extension tube is outweighed by the approx 10x difference in price... But still feel that the canon 100mm F2.8 is nice. I heard it is even sharper than 70-200 F4 L, which according to photodo is the same as the 70-200 F2.8 L lens.

    Anybody else have something enlightening to share concerning the macro lens and the extension tube (and/or the 500D)?

  16. #16

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    Originally posted by toasty
    Just now Sgt Pepper was saying that in order to get 1:1, you need to have an extension equal to the focal length of the lens. Does that mean that at 200mm, I need a 200mm extension tube? None of the shops I checked carried even a 50mm ET.
    Yes you need 200mmm ext tubes to get 1X magnification which all of us will find impractical.

    That's why im saying, better use your existing 50mm lens and use 50mm ext tubes to get 1:1, or better yet get 3rd party macro lens.

    Can I ask you why do you want to get Canon 100mm macro which costs 900+$ instead of getting 105mm Sigma which costs 560+$?

  17. #17
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    I've read a lot of nice things about the canon 100mm macro lens, that it is sharper than the sigma. It is true though, I should put the sigma on my list of considerations, since it will beat the filters and extension tube in terms of convenience and focusing range, and only slightly worse than the canon in terms of picture quality. The other reason is that someone is selling a second hand canon, which I am considering to get, and just doing some research on. Have you tried both the canon and the sigma? Since you use the sigma, I assume you find it to be quite good.

    Originally posted by Sgt. Pepper
    Yes you need 200mmm ext tubes to get 1X magnification which all of us will find impractical.

    That's why im saying, better use your existing 50mm lens and use 50mm ext tubes to get 1:1, or better yet get 3rd party macro lens.

    Can I ask you why do you want to get Canon 100mm macro which costs 900+$ instead of getting 105mm Sigma which costs 560+$?

  18. #18

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    I have tried using canon 100mm (non-USM) before which I loaned from a friend. Itís a fine glass since I donít mind it being a Non-USM for macro work.

    Well, based on the Ďexpertsí optical quality testing on www.photodo.com I can say that canon 100mm is sharper than sigma 105mm macro.

    Canon 100mm USM scores Ė 4.2
    Sigma 105mm scores Ė 4.1

    If you donít mind paying almost double price for a .1 difference, then get the canon. But if you can get 2nd hand at a cheaper price than brand new 3rd party, then grab it.

    Anyway, at the end of the day itís still the proper exposure and technique that matters.

    Good luck to buy!

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    I understand that there will be some light loss when we use extension tube. Lets say we use 2 X 25mm extension tube for a EF 50mm F/1.8 lens. This will give us a 1:1, but what is the light loss?

  20. #20

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