Why don't they make extension tubes adjustable?


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dRebelXT

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May 14, 2005
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#1
For example, like a sliding tube which user can adjust the tube length. bellows look
cubersome and fragile, plus it's expensive.

:confused:
 

sk.images

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Dec 9, 2005
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#2
To make a sliding metal/plastic tube that is also light tight with mounts on either end would probably be just as if not more expensive then manufacturing belows.
 

catchlights

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Sep 27, 2004
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#3
the lens is already adjustable, why should make the tube adjustable, the tube still have to do the coupling of aperture, it will make the tube "cumbersome and fragile, plus it's expensive" also.
 

Artosoft

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Aug 31, 2005
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#4
dRebelXT said:
For example, like a sliding tube which user can adjust the tube length. bellows look
cubersome and fragile, plus it's expensive.

:confused:
Later you will ask why the extension tubes creep?

Regards,
Arto.
 

lsisaxon

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Nov 29, 2004
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#5
dRebelXT said:
For example, like a sliding tube which user can adjust the tube length. bellows look
cubersome and fragile, plus it's expensive.

:confused:
I think I came across one which is adjustable a number of years back.

Here's one for OM mount.
http://www.alanwood.net/photography/olympus/telescopic-auto-tube.html

And here's one for Pentax.
http://www.bhphotovideo.com/bnh/con...076&is=REG&addedTroughType=categoryNavigation
 

lsisaxon

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Nov 29, 2004
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#6
cyber_m0nkey said:
To make a sliding metal/plastic tube that is also light tight with mounts on either end would probably be just as if not more expensive then manufacturing belows.
Just wrap a black cloth around the opening while holding the lens with your hand. Can tilt and shift somemore. :)
 

sk.images

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Dec 9, 2005
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#8
lsisaxon said:
Just wrap a black cloth around the opening while holding the lens with your hand. Can tilt and shift somemore. :)
This would be fun to try, bu the depth of field wide-open would be impossible to use.
 

lsisaxon

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Nov 29, 2004
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#9
cyber_m0nkey said:
This would be fun to try, bu the depth of field wide-open would be impossible to use.
But then you can tilt to get sharpness across your field.
http://www.trenholm.org/hmmerk/SHSPAT.pdf

Otherwise, borrow a Nikon mount lens with an aperture ring to try. ;) Then again, with the aperture stopped down, the image would be so dim that it's near impossible to hold still and get a decent exposure too.
 

sk.images

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#10
lsisaxon said:
Borrow a Nikon mount lens with an aperture ring to try. ;)
Good idea, but that would be sacrilege, like Luke using Darth Vaders light saber. I will use my 645 Mamiya lenses instead ;p , these would be better anyway as they throw a larger image circle.
 

lsisaxon

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Nov 29, 2004
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#11
cyber_m0nkey said:
Good idea, but that would be sacrilege, like Luke using Darth Vaders light saber. I will use my 645 Mamiya lenses instead ;p , these would be better anyway as they throw a larger image circle.
Sorry, I'm a Nikon person. Using Mamiya would be a better solution for you. :)
 

#12
Olympus make the 1st adjustable extension tube many many yrs ago, provides full flexibility to extent between 65-116mm, there is a lock at any preferred extensions.

I bought this for my OM system recently... with the 90mm macro, I can achieve ~2x magnification at f2. :bsmilie:

http://www.star.ucl.ac.uk/~rwesson/esif/om-sif/macrophotogroup/auto_tube_65-116.htm

Still available in the ebay, u can buy it to use with Olympus E DSLR system too, but will need adaptor.
 

GmbH.

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Jul 6, 2006
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#14
the Triplus extention tubes does AF.
if extention is required, maybe the user may have to look into bellows.
 

ricohflex

Senior Member
Feb 24, 2005
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#15
I do own an extendable extension tube for Canon FD.
Beautifully made.
 

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