This got me thinking!
We know that if you attach extension tubes you get magnification depending on how much extension you put on, and to get lifesize with a 50mm lens you need 50mm of extension(extension/focal length=M:1)
But what if your 50mm is a macro lens and already gives you lifesize or 1:1, and you put 50mm of extension between it and the camera?
Extension tubes with a macro lens, a thought.
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- GreenLarry
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- twebster
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Hi ya' GreenLarry
Best regards,
If you add another 50mm of extension tubes to a 50mm macro lens focused at 1:1 already, you then get 2:1 (2x life size).But what if your 50mm is a macro lens and already gives you lifesize or 1:1, and you put 50mm of extension between it and the camera?
Best regards,
Tom Webster
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Think about this...maybe Murphy is an optimist!!!
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!
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Hi ya' GreenLarry
Best regards,
Well...not really. You will lose another f. stop of light for focusing and exposure. Check out Kenko tubes. They are as good as the Canon tubes but much cheaper.Oh now thats cool, free magnfication!Sometimes you DO get something for nothing!
Best regards,
Tom Webster
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!
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I have taken literary thousands of shots with my Kenko Extension Tubes, they are worth their weight in Gold. Try these settings, its one of my favorites, manual setting, manual focus, ISO of 100 to 400, depending on lighting, ( I try to use flash on these settings for fill-in) 1/125, f11 to f22. I use a tripod for this with a remote shutter release. all this with 68mm of tubes on a Tamron 28-300 Macro. hope this helps.GreenLarry wrote:Oh yea and a few years ago that would be a problem, but with TTL flash available to all, its just great!You will lose another f. stop of light for focusing and exposure
I do have trouble selecting a smaller aperture than what the camera suggests tho, will have to experiment with it on Manual.
Always look at Nature with wide eyes.
Rick Cowen
Canon 5D, Canon 70-300 IS USM.Sigma 150 2.8 Macro, Sigma 170-500. A set of Kenko tubes. Check out my Gallery here!
http://www.pbase.com/1bald_eagle/macro
Rick Cowen
Canon 5D, Canon 70-300 IS USM.Sigma 150 2.8 Macro, Sigma 170-500. A set of Kenko tubes. Check out my Gallery here!
http://www.pbase.com/1bald_eagle/macro
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Check my set-up with Kenko tubes and a Tominon 17mm lens.
http://www.macrophotography.org/modules ... _album.php
The problem is to find these lenses, I was lucky enough to get one, that I glued to a eos-M42 adapter, because the lens has a M40 screw
Now I will use it in a bellows.. magnification will be close to 40X.
You have to set your camera to manual or TV and change the shutter speed until it shows right exposure (stop-down metering)
http://www.macrophotography.org/modules ... _album.php
The problem is to find these lenses, I was lucky enough to get one, that I glued to a eos-M42 adapter, because the lens has a M40 screw
Now I will use it in a bellows.. magnification will be close to 40X.
You have to set your camera to manual or TV and change the shutter speed until it shows right exposure (stop-down metering)
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You are right Rik.
40X is the specification of this lens for the original setup with Polaroid MP-3/4 system which has a big Bellows, and I was measuring magnification as if I had taken the picture with a film camera (36mm), but it was a digital with a 22,2mm sensor.
So, let's see: If with no tubes it gives me 5,5 mm in a 22,2 sensor, it means 4X magnification, and the distance from "center" of lens (sorry if I do not know the actual name of it) is 17x4=68mm (roughlly).
If I ad 36+20+12mm tubes I will have a total of another 68mm (coincidence!)
So, with tubes plus the normal distance of lens, the total distance will be 136mm. 136/17=8X magnification (I pictured 2,5 mm which is 22,2/2,5= 8,8X) ok, for me the calculation is close enough
With a bellows of 200mm I will have (200+68 )/17 = 15,7X magnification, but I can add the tubes before the bellows...
(200+68+68 )/17 = 19,7X
I can add some more screwed extension tubes to the other side... can you imagine the assembled device???
(200+68+68+68 )/17 = 23,7X what means I would be picturing a 0,93mm subject...
OK OK better to use the scope that I just put up hehe...
40X is the specification of this lens for the original setup with Polaroid MP-3/4 system which has a big Bellows, and I was measuring magnification as if I had taken the picture with a film camera (36mm), but it was a digital with a 22,2mm sensor.
So, let's see: If with no tubes it gives me 5,5 mm in a 22,2 sensor, it means 4X magnification, and the distance from "center" of lens (sorry if I do not know the actual name of it) is 17x4=68mm (roughlly).
If I ad 36+20+12mm tubes I will have a total of another 68mm (coincidence!)
So, with tubes plus the normal distance of lens, the total distance will be 136mm. 136/17=8X magnification (I pictured 2,5 mm which is 22,2/2,5= 8,8X) ok, for me the calculation is close enough
With a bellows of 200mm I will have (200+68 )/17 = 15,7X magnification, but I can add the tubes before the bellows...
(200+68+68 )/17 = 19,7X
I can add some more screwed extension tubes to the other side... can you imagine the assembled device???
(200+68+68+68 )/17 = 23,7X what means I would be picturing a 0,93mm subject...
OK OK better to use the scope that I just put up hehe...