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02-19-2009, 04:59 PM
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#11 (permalink)
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Join Date: Jul 2007
Posts: 2,869
| Quote:
Originally Posted by Galah With regard to the "light loss": is this "automatically" compensated for by TTL metering for both tube and converter? | Yes. |
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02-19-2009, 05:16 PM
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#12 (permalink)
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Join Date: Feb 2009 Location: Oz
Posts: 286
| Thanks for the quick response, OG.
I have heard that some photographers use a mixture of both tubes and teleconverter in the one exposure.
Has anyone here done that, and do they have any comments as to the advantages/disadvantages of such a technique? |
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02-19-2009, 06:01 PM
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#13 (permalink)
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Join Date: Jul 2007
Posts: 2,869
| I have a comment: it's a bad technique that cannot be discouraged enough.
What it does is either enlarge the faults the lens itself may show more when used at close range, and add the poor correction or the extender.
Or enlarge the poor correction of the extender and what that thing makes of the perhaps somewhat lesser performance of the lens that's on it.
In short: having the extra glass somewhere between subject and film is still not a good idea. |
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02-25-2009, 09:30 AM
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#14 (permalink)
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Join Date: Apr 2005 Location: Sumner, Washington
Posts: 400
| Any reason you can't use bellows? That would be the best bet. |
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02-25-2009, 05:28 PM
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#15 (permalink)
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Join Date: Feb 2009 Location: Oz
Posts: 286
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Originally Posted by Galah OK, I have read your responses (thanks  ) ) and I Is there anything else? | Actually, yes, there is: with extension tubes you lose "infinity focusing", with teleconverter you don't.
Bosaiya, at this stage, I'm only interested in "close focus", as opposed to actual "Macro", so bellows would be overkill for me at this stage.
It would seem that some practitioners are not overly fussy about their choice of equipment (close focus lenses, tubes or tele-extenders) and some mix them and match them at will. See the attached link (once open, make sure to go on to "part three": http://www.shutterfreaks.com/Tips/tomhicksmacros.html
Last edited by Galah; 02-25-2009 at 06:57 PM..
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02-26-2009, 12:08 PM
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#16 (permalink)
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Join Date: Jul 2007
Posts: 2,869
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Originally Posted by Galah Actually, yes, there is: with extension tubes you lose "infinity focusing", with teleconverter you don't. | When your goal is to get close, infinity is the least of your worries.  |
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02-26-2009, 04:45 PM
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#17 (permalink)
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Join Date: Feb 2009 Location: Oz
Posts: 286
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Originally Posted by Q.G. When your goal is to get close, infinity is the least of your worries.  | Yes, if that's your only purpose. But, imagine strolling about a botanic garden or park: now you're photographing a flower close up, next you see your partner looking over the parapet of a romantic bridge. It could be helpful if you didn't immediately have to remove your extension tubes or change lenses.  |
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02-26-2009, 05:06 PM
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#18 (permalink)
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Join Date: Sep 2002 Location: Roswell, Ga. USA
Posts: 3,133
| Quote:
Originally Posted by Galah Thanks for the quick response, OG.
I have heard that some photographers use a mixture of both tubes and teleconverter in the one exposure.
Has anyone here done that, and do they have any comments as to the advantages/disadvantages of such a technique? | I've done that when I had a Minolta set. I found I got the best magnification when I put the extender between the lens and the telextender, got about a .8 inch field of view. Stopped down with a flash for illumination got some pretty sharp images.
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Gary Beasley
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02-26-2009, 05:20 PM
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#19 (permalink)
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Join Date: Feb 2009 Location: Oz
Posts: 286
| Thanks, Gary. |
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02-26-2009, 05:22 PM
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#20 (permalink)
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Join Date: Apr 2008 Location: Los Angeles, CA
Posts: 3,768
| They are two different birds built to acheive two different aims.
A teleconverter magnifies the image, but actually reduces close focusing ability. They are used to decrease the angle of view; usually of a lens that is already at least a medium-long lens. They are not made for close-up photography. They contain optics. Infinity focus is maintained.
Extension tubes increase close focusing ability at the expense of far focusing ability. They do not contain any optics. They are made for close-up photography. They simply move the glass farther from the film so you can focus on closer objects. Infinity focus is not maintained.
A bellows unit is the same basic idea as an extension tube, but lets you vary the length of the extension as needed. It is more versatile, but also less portable, of course.
Diopers are accessory lenses that are mounted in filter rings. They screw into your filter threads and increase the close focusing ability. Though these are the worst option for optical quality, there are good ones out there that give fine results, and they can certainly give "special" effects if that is what you want!
TCs, extension tubes, and bellows units all cut light by making it travel farther from the glass to the film. A 2x TC doubles FL, but the physical aperture of the lens remains the same, therefore you only transmit 1/4 as much light at a given f stop (or 1/2 as much with a 1.4x TC). I have only screwed around with diopters; never taken a pic with them, so I am not sure if they cut light to a notable degree or not, but I don't think that they do.
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2F/2F
Last edited by 2F/2F; 02-26-2009 at 06:53 PM..
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