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Old 10-02-11, 21:06
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bend the light bend the light is offline  
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Join Date: Aug 2010
Location: Barnsley
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Default Macro Magnification...calculating correctly?

Hi,

I like a bit of macro from time to time, but don't have the money for a proper lens. So I make do...

...so, I have a 135mm M42 lens which I use on my Canon 400d. I put macro tubes to it, attach an old flash on a bar, trigger with a cheap radio trigger.
I was interested in the magnification...so, I put 10.5cm of macro tube on with the 135mm, and took this photo, handheld. It's a JPEG straight from the camera.

Photoshop says the image is 137.16cm wide. Well, my ruler shows 2.5cm across the frame.
So, quick maths...137.16 / 2.5 = 54.864.

1cm in real life is 54cm printed at 100%?

So, I have 54x magnification? Is that how it works?

http://farm6.static.flickr.com/5293/...85ba42ff_z.jpg
10 and a half cm macro on 135mm lens by Bend The Light, on Flickr
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