Ugly Hedgehog® - Photography Forum
True Macro... or NOT?
Feb 9, 2012 17:00:43   #
CanonShot Loc: Lancaster County, PA
 
Following the N72/Silver discussion... a question popped up. Below are two representations of the same image. First one is the original just resized. Second one is the original only "square" cropped then resized for this space.

Do they both represent true macro, does one of them, or neither of them? I can't tell if the bee looks 1:1 or larger than 1:1 until this post appears. It sure does on my screen.

Just want to get a sense of what on-screen macro really is, or is not. Please consider this as a legit question... not a parody of what occurred previously between N72 and Silver.
Canon PS S5 IS f/3.5 1/160
Canon PS S5 IS  f/3.5  1/160...
--same image cropped--
--same image cropped--...

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Feb 9, 2012 20:23:30   #
Nikonian72 Loc: Long Beach CA
 
Macro is not determined by how large an image may appear on your computer monitor or television screen. Macro is based upon the relationship between the size of your subject to the size of the display field, or sensor size.

I believe your Canon S5 sensor size is 22.2-mm x 14.8-mm = 328.6-mm2 (top image).

Your cropped image represents approximately 12-mm x 12-mm = 144-mm2.

If your bee is 10-mm long (guesstimate), then it occupies approximately 10 x 10 = 100-mm2.

100/328.6 = 0.30:1 = 1:3.3 (1/3 life-size)
100/144 = 0.69:1 = 1:1.4 (7/10 life-size)

By calculation, both are considered close-up images, but your cropped image is quite close. A bit more cropping would yield life-size.

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Feb 9, 2012 20:53:54   #
CanonShot Loc: Lancaster County, PA
 
Nikonian72 wrote:


By calculation, both are considered close-up images, but your cropped image is quite close. A bit more cropping would yield life-size.




Thanks for putting the numbers to it, N72. A lot closer to understanding it. All of my macro and close ups are now done with my 60D and 100mm 2.8 macro lens, so I should be in the true macro zone soon.

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Feb 9, 2012 21:27:57   #
naturepics43 Loc: Hocking Co. Ohio - USA
 
Nikonian72 wrote:
Macro is not determined by how large an image may appear on your computer monitor or television screen. Macro is based upon the relationship between the size of your subject to the size of the display field, or sensor size.

I believe your Canon S5 sensor size is 22.2-mm x 14.8-mm = 328.6-mm2 (top image).

Your cropped image represents approximately 12-mm x 12-mm = 144-mm2.

If your bee is 10-mm long (guesstimate), then it occupies approximately 10 x 10 = 100-mm2.

100/328.6 = 0.30:1 = 1:3.3 (1/3 life-size)
100/144 = 0.69:1 = 1:1.4 (7/10 life-size)

By calculation, both are considered close-up images, but your cropped image is quite close. A bit more cropping would yield life-size.
Macro is not determined by how large an image may ... (show quote)


I'm lost. I'm missing something. How does the actual size of the bee compare to the area of the image on the screen? Where did you get 12mm x 12mm for the second image?

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Feb 9, 2012 21:55:20   #
Nikonian72 Loc: Long Beach CA
 
naturepics43 wrote:
I'm lost. I'm missing something. How does the actual size of the bee compare to the area of the image on the screen? Where did you get 12mm x 12mm for the second image?

View height of top image, If 14.8-mm high, then bottom image is close to 12-mm high, and square.

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Feb 9, 2012 23:02:53   #
naturepics43 Loc: Hocking Co. Ohio - USA
 
THe bottom image is taller than top one. Properties says #1 600x450, #2 600x600. How do I view to get 14.8mm?

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Feb 10, 2012 00:36:13   #
Nikonian72 Loc: Long Beach CA
 
naturepics43 wrote:
THe bottom image is taller than top one. Properties says #1 600x450, #2 600x600. How do I view to get 14.8mm?

You are correct. I missed that. I read OP's original statement "First one is the original just resized. Second one is the original only "square" cropped then resized for this space." If first image is "original" then must be 14.8-mm high.

The process for figuring ratio was correct, but second image is not square (as I mis-read), so second image is most likely right at 1:1 (life-size). Nice catch.

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Feb 10, 2012 15:30:04   #
tinusbum Loc: east texas
 
if i remember right when my sigma 150 macro is focused at 1:1 the bumblebee takes up the whole screen.tom

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Feb 11, 2012 09:19:04   #
hangman45 Loc: Hueytown Alabama
 
This is a honeybee at just a little over 1:1. It is not cropped just re-sized for ease of uploading



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Feb 11, 2012 14:01:17   #
Nikonian72 Loc: Long Beach CA
 
hangman45 wrote:
This is a honeybee at just a little over 1:1. It is not cropped just re-sized for ease of uploading

Nice "hairy" detail upon download for greater magnification.

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