Extension tubes?

Discussion in 'Photography Beginners' Forum' started by TJ K, Oct 29, 2009.

  1. TJ K

    TJ K No longer a newbie, moving up!

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    Ok so does it really matter if it's just like a 5 dollar tube on ebay? It has no optics or anything in it it's just for space so it shouldn't matter if it's good or not right? 80 dollars just seems crazy for a gap. It will just be to mess around. Thanks
    tj
     
  2. NateWagner

    NateWagner TPF Noob!

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    the best answer is yes and no.

    Optically there isn't going to be a difference between the 5dollar one and the 80dollar ones. The main difference will be in features. The 5 dollar one is usually a cheap plastic, whereas the 80dollar one may be more heavy duty,

    but Most Importantly the 80dollar one will probably have contacts allowing you to edit the aperture of the lens and you will also still have AF (not that autofocus really helps much in macro work). However, in macro work you do usually want to be stopped down a fair amount to give yourself more DOF to work with, and while this can be done with the cheaper tubes it is generally a pain to do, unless you're using an old lens with an aperture ring on it that you can manually open and close, because most current lenses have aperture controlled from the camera body which you would no longer be able to do with the cheap tubes..
     
  3. TJ K

    TJ K No longer a newbie, moving up!

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    Gotcha. When you attach a lens to the tube it automatically goes wide open. No af isn't really a problem I would just use it to mess around and see what kind of pics I can get.
     
  4. Torus34

    Torus34 No longer a newbie, moving up!

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    Like, for messin' around, what's 5 bucks, right?
     
  5. Dwig

    Dwig TPF Noob!

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    Its varies from one mount to another. With Nikon the lens will close to minimum aperture, rather than maximum, when disconnected from the diaphram control linkage in the body when you use a G-series lens that has no f/stop ring of its own.

    With older style lenses that have their own f/stop ring the lens will close to the f/stop set on the ring. These lenses work with simple tubes but you have to manually open the lens to maximum to view and focus and manually close to working aperture when you take the picture.
     
  6. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Interesting - so all modern nikon lenses will close the aperture blades when they are attached to tubes without contacts - or is it that they close upon release from the contact mounts on a camera (and thus remain closed since when attached to the tubes there are no contacts present).

    I knew that modern nikon lenses could not be tricked to adjust the aperture like canon lenses can be, but not that you are forced to the minimum aperture as well - something I will have to bare in mind when advising nikons looking at cheap tubes
     
  7. NateWagner

    NateWagner TPF Noob!

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    yeah, that surprises me as well. I guess I figured they were like Canon where the lenses stay open all the time because they have to be open to make it easier to focus and the close down later. hmm.

    Either way if you are at either extreme you will be costing yourself some sharpness and IQ.
     
  8. Dwig

    Dwig TPF Noob!

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    No, it has absolutely nothing to do with the electrical contacts. Nikon lenses open and close the aperture via a mechanical lever system. If the tubes don't provide mechanical linkage the aperture will close to the aperture selected on the f/stop ring, if the lens has one, or to minimum, if the lens lacks an f/stop ring of its own.

    The electrical contacts provide for AF and for information needed by the advanced metering systems in modern Nikon bodies. Some Nikons require this electrical information to provide any form of metering. Others will provide some rudimentary metering functions without it provided there is mechanical connection between the lens and body for both the internal diaphram lever (aka "auto diaphram" linkage) and the external f/stop ring (aka "AI" coupling)
     
  9. Rifleman1776

    Rifleman1776 TPF Noob!

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    It has all been said. Tubes are great for macro to near-micro work. Make yer choice.
    Extension bellows are also excellent but expensive and a bit clumsy to use.
     

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