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[test] extension tubes on magnification of macro lenses



 
 
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  #1  
Old July 24th 08, 01:04 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Troy Piggins[_15_]
external usenet poster
 
Posts: 142
Default [test] extension tubes on magnification of macro lenses

I've been meaning to do this for months. Finally took the
opportunity. Wanted to take shots of a measurable subject at
different magnifications to:

- show what 1:1 really means (even though I know)
- measure the real magnification of extension tubes on my macro
lens, other than saying it's about 2:1
- see what the magnification of extension tubes is at infinity
focus on my macro lens.

Lately I've been shooting with full set of extension tubes on,
and I realise you lose infinity focus, but I've been wondering
what the minimum magnification really is.

All shot with Canon EOS 30D (sensor size 22.5mm x 15.0mm), EF
100mm f/2.8 Macro USM lens. Extension tube set was Kenko 68mm
full set. I didn't bother testing individual tubes because I have
never used less than the full set since I want them for maximum
magnification, and also because testing the various combinations
of 3 different length tubes would drive me nuts.

I realise it's probably not the most accurate test. If I'd shot
with the ruler across the diagonal it'd be a little more precise
because when scaling things, the longest measurable distances are
the best. I also could have used a tripod and made sure the scale
was dead level. But I figure it's near enough for my purposes and
still helpful for others.

So here we go.

Bare 100mm macro lens, 1:1 magnification. Near enough to
22-22.5mm on the scale, 22.5mm sensor width, so the 1:1 mag seems
correct.
http://piggo.com/%7Etroy/photos/00_e...n/img_8750.jpg

100mm macro lens with 68mm of tubes, focused to minimum distance.
Near enough to 11mm, 22.5mm sensor width, so 2:1 mag seems about
right.
http://piggo.com/%7Etroy/photos/00_e...n/img_8748.jpg

100mm macro lens with 68mm of tubes, focused to infinity. Near
enough to 34mm on the scale, 22.5mm sensor width, so around 2:3
or 1:1.5 magnification. Keep in mind the lens is focused to
infinity, but this shot is all that is in focus due to the tubes.
Everything more than a couple of millimetres behind it is out of
focus.
http://piggo.com/%7Etroy/photos/00_e...n/img_8749.jpg

--
Troy Piggins
I always appreciate critique.
  #2  
Old July 24th 08, 01:37 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
jimkramer
external usenet poster
 
Posts: 428
Default [test] extension tubes on magnification of macro lenses

"Troy Piggins" wrote in message
...
I've been meaning to do this for months. Finally took the
opportunity. Wanted to take shots of a measurable subject at
different magnifications to:

- show what 1:1 really means (even though I know)
- measure the real magnification of extension tubes on my macro
lens, other than saying it's about 2:1
- see what the magnification of extension tubes is at infinity
focus on my macro lens.

Lately I've been shooting with full set of extension tubes on,
and I realise you lose infinity focus, but I've been wondering
what the minimum magnification really is.

All shot with Canon EOS 30D (sensor size 22.5mm x 15.0mm), EF
100mm f/2.8 Macro USM lens. Extension tube set was Kenko 68mm
full set. I didn't bother testing individual tubes because I have
never used less than the full set since I want them for maximum
magnification, and also because testing the various combinations
of 3 different length tubes would drive me nuts.

I realise it's probably not the most accurate test. If I'd shot
with the ruler across the diagonal it'd be a little more precise
because when scaling things, the longest measurable distances are
the best. I also could have used a tripod and made sure the scale
was dead level. But I figure it's near enough for my purposes and
still helpful for others.

So here we go.

Bare 100mm macro lens, 1:1 magnification. Near enough to
22-22.5mm on the scale, 22.5mm sensor width, so the 1:1 mag seems
correct.
http://piggo.com/%7Etroy/photos/00_e...n/img_8750.jpg

100mm macro lens with 68mm of tubes, focused to minimum distance.
Near enough to 11mm, 22.5mm sensor width, so 2:1 mag seems about
right.
http://piggo.com/%7Etroy/photos/00_e...n/img_8748.jpg

100mm macro lens with 68mm of tubes, focused to infinity. Near
enough to 34mm on the scale, 22.5mm sensor width, so around 2:3
or 1:1.5 magnification. Keep in mind the lens is focused to
infinity, but this shot is all that is in focus due to the tubes.
Everything more than a couple of millimetres behind it is out of
focus.
http://piggo.com/%7Etroy/photos/00_e...n/img_8749.jpg

--
Troy Piggins
I always appreciate critique.


But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm
-Jim


  #3  
Old July 24th 08, 01:47 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Troy Piggins[_15_]
external usenet poster
 
Posts: 142
Default [test] extension tubes on magnification of macro lenses

* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]
enough to 34mm on the scale, 22.5mm sensor width, so around 2:3
or 1:1.5 magnification. Keep in mind the lens is focused to
infinity, but this shot is all that is in focus due to the tubes.
Everything more than a couple of millimetres behind it is out of
focus.
http://piggo.com/%7Etroy/photos/00_e...n/img_8749.jpg


But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm


Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.

Thanks for sharing. Bookmarked.

--
Troy Piggins
I always appreciate critique.
  #4  
Old July 24th 08, 02:06 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
jimkramer
external usenet poster
 
Posts: 428
Default [test] extension tubes on magnification of macro lenses

"Troy Piggins" wrote in message
...
* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]
enough to 34mm on the scale, 22.5mm sensor width, so around 2:3
or 1:1.5 magnification. Keep in mind the lens is focused to
infinity, but this shot is all that is in focus due to the tubes.
Everything more than a couple of millimetres behind it is out of
focus.
http://piggo.com/%7Etroy/photos/00_e...n/img_8749.jpg


But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm


Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.

Thanks for sharing. Bookmarked.

--
Troy Piggins
I always appreciate critique.


Inches are just like mm only 25.4 times as big. :-)
-Jim


  #5  
Old July 24th 08, 02:39 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Blinky the Shark
external usenet poster
 
Posts: 827
Default [test] extension tubes on magnification of macro lenses

Troy Piggins wrote:

* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]
enough to 34mm on the scale, 22.5mm sensor width, so around 2:3
or 1:1.5 magnification. Keep in mind the lens is focused to
infinity, but this shot is all that is in focus due to the tubes.
Everything more than a couple of millimetres behind it is out of
focus.
http://piggo.com/%7Etroy/photos/00_e...n/img_8749.jpg


But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm


Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.


I have no series (and certainly no art g) to contribute but a few weeks
ago I just had to see what this setup would do[1]: D60, 18-55mm (at 18mm)
reverse-mounted on the front of 55-200mm (zoomed in until the image was no
longer inside a black circle g). These are mm marks on a wooden ruler;
the image is not cropped.

http://blinkynet.net/stuff/mm_marks.jpg

Thank God for the new rails.

[1] There was probably math to do this, but, you know...


--
Blinky
Killing all posts from Google Groups
The Usenet Improvement Project: http://improve-usenet.org
Need a new news feed? http://blinkynet.net/comp/newfeed.html

  #6  
Old July 24th 08, 03:11 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Troy Piggins[_15_]
external usenet poster
 
Posts: 142
Default [test] extension tubes on magnification of macro lenses

* jimkramer wrote :
"Troy Piggins" wrote in message
...
* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]

But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm


Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.

Thanks for sharing. Bookmarked.


Inches are just like mm only 25.4 times as big. :-)


You whacky Americans. What will they think of next.
Sounds like a catchy system of measuring. It should really take
off.

Ok, I googled it. 12 inches to a foot. 3 feet to a yard. 1760
yards to a mile. It's so easy to remember. I don't know why us
in the rest of the world are using this silly metric system where
it's 1000mm to metre, 1000m to km. :-D

--
Troy Piggins
I always appreciate critique.
  #7  
Old July 24th 08, 03:17 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
David J. Littleboy
external usenet poster
 
Posts: 2,618
Default [test] extension tubes on magnification of macro lenses


"Troy Piggins" wrote:

Inches are just like mm only 25.4 times as big. :-)


You whacky Americans. What will they think of next.
Sounds like a catchy system of measuring. It should really take
off.

Ok, I googled it. 12 inches to a foot. 3 feet to a yard. 1760
yards to a mile. It's so easy to remember. I don't know why us
in the rest of the world are using this silly metric system where
it's 1000mm to metre, 1000m to km. :-D


Overheard (really!) in a Navy ROTC course* at a well-know institute of
higher education in the US.

Professor: We will now compute the density of sea water in slugs per cubic
yard.
Cadet: Sir! Excuse me, sir! But, sir! Are you serious or making a joke, sir?
Professor: I'm terribly sorry, but I'm serious.

*: Air, Water, and Interface Vehicles. A seriously great course for anyone
even vaguely interested in boats.

--
David J. Littleboy
Tokyo, Japan


  #8  
Old July 24th 08, 03:19 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Troy Piggins[_15_]
external usenet poster
 
Posts: 142
Default [test] extension tubes on magnification of macro lenses

* Blinky the Shark wrote :
Troy Piggins wrote:
* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]

But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm


Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.


I have no series (and certainly no art g) to contribute but a few weeks
ago I just had to see what this setup would do[1]: D60, 18-55mm (at 18mm)
reverse-mounted on the front of 55-200mm (zoomed in until the image was no
longer inside a black circle g). These are mm marks on a wooden ruler;
the image is not cropped.

http://blinkynet.net/stuff/mm_marks.jpg

Thank God for the new rails.

[1] There was probably math to do this, but, you know...


That's pretty big magnification! Impressive. Understand now how
hard it must've been to control.

--
Troy Piggins
I always appreciate critique.
  #9  
Old July 24th 08, 04:40 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Blinky the Shark
external usenet poster
 
Posts: 827
Default [test] extension tubes on magnification of macro lenses

Troy Piggins wrote:

* Blinky the Shark wrote :
Troy Piggins wrote:
* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]

But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm

Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.


I have no series (and certainly no art g) to contribute but a few weeks
ago I just had to see what this setup would do[1]: D60, 18-55mm (at 18mm)
reverse-mounted on the front of 55-200mm (zoomed in until the image was no
longer inside a black circle g). These are mm marks on a wooden ruler;
the image is not cropped.

http://blinkynet.net/stuff/mm_marks.jpg

Thank God for the new rails.

[1] There was probably math to do this, but, you know...


That's pretty big magnification! Impressive. Understand now how
hard it must've been to control.


Rails and remote IR shutter release. Won't be shooting any busy bees with
that 12:1 setup.

http://blinkynet.net/stuff/compound.jpg


--
Blinky
Killing all posts from Google Groups
The Usenet Improvement Project: http://improve-usenet.org
Need a new news feed? http://blinkynet.net/comp/newfeed.html

  #10  
Old July 24th 08, 04:42 AM posted to rec.photo.digital.slr-systems,rec.photo.equipment.35mm
Blinky the Shark
external usenet poster
 
Posts: 827
Default [test] extension tubes on magnification of macro lenses

Troy Piggins wrote:

* jimkramer wrote :
"Troy Piggins" wrote in message
...
* jimkramer wrote :
Troy Piggins wrote :
[---=| Quote block shrinked by t-prot: 41 lines snipped |=---]

But testing the 100mm with tubes is sooooo much fun!!!
http://www.jlkramer.net/Pictures/100mm/100mmTest.htm

Good tests. Wish I'd seen them earlier, but I still would
have done my own. I don't understand inches, I'm all metric
baby! I also wanted to understand it all in terms of
magnification. Perhaps you could add that sort of info to your
page.

Thanks for sharing. Bookmarked.


Inches are just like mm only 25.4 times as big. :-)


You whacky Americans. What will they think of next.
Sounds like a catchy system of measuring. It should really take
off.

Ok, I googled it. 12 inches to a foot. 3 feet to a yard. 1760
yards to a mile. It's so easy to remember. I don't know why us
in the rest of the world are using this silly metric system where
it's 1000mm to metre, 1000m to km. :-D


Yours are all so similar...this-m, that-m, some-other-m. No wonder
they're so confusing!


--
Blinky
Killing all posts from Google Groups
The Usenet Improvement Project: http://improve-usenet.org
Need a new news feed? http://blinkynet.net/comp/newfeed.html

 




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