Macro 1:1?

[D-50]

What exactly does 1:1 mean with regard to macro? Also I have read true macro is 1:1 yet my 70-200 says itsmacro but is only 2:1 how can they claimmacro when it is not.

 

[nicfargo]

1:1 is the magnification ratio, or at least this is how I've alway understood it. 1:1, and anything higher (1:5), is considered true macro. 2:1 would mean there's no magnification, and because of the closest your lens can focus, the image will fill the sensor at a ratio of 2:1. I think this is how this all works.

 

[Big Mike]

The ratio is between the size of the subject and the size of the image at the 'film plane'.

So if you were taking a photo of a dime...and you were at 1:1 magnification, the size of the image (on the film/negative) would be the same size as the actual dime. The same principle applies to digital, at 1:1, the image at the sensor would be life size.

Very few lenses actually get you 1:1 magnification. Many believe that it's not actually 'Macro' unless you can get to 1:1...but the lens manufacturers think that 'Macro' helps to sell lenses...so they put that on a lot of their lenses...even though they can't actually get close enough to get a 1:1 ratio.

 

[D-50]

so you cant take a true macro image of anything larger than a cameras sensor/negative?

 

[Phranquey]

so you cant take a true macro image of anything larger than a cameras sensor/negative?

Technically, correct. If you are photographing a flower that is 3" across, and the film plane is 36mm (1.4") x 24mm (0.9"), and you want to fit the whole flower onto the frame, then you are no longer truely in macro, just close-up. But, if you shoot the stamen in the center, you can get those to 1:1.

 

[eminart]

I'm a little confused about this as well. I've seen photos of tiny spiders that fill up the whole image. What is this? 1:5 or something? The numbers confuse me. And how do you attain an image that big? Is it not possible with a normal 1:1 lens? Or is it just a crop?

 

[Phranquey]

1:1 is a direct representation of the reproduction ratio comparing lifesize : image size on the focal plane. If a dime is 3/8" in diameter (guessing, here), then a 1:1 would be a 3/8" image if you measured it on the piece of film. If you were at 1:2, then the dime would be 3/8" in real life : 3/16" on the piece of film...half the size.

EDIT - To put it in better perspective, replace the : with a / and make it a fraction. 1/1 is a whole size image...1/2 is a half size image on the film itself. When this is printed on paper, it is going to look HUGE.

Found this link...it pretty much says the same thing I just did.

http://www.shutterfreaks.com/Tips/tomhicksmacros.html

 

[eminart]

1:1 is a direct representation of the reproduction ratio comparing lifesize : image size on the focal plane. If a dime is 3/8" in diameter (guessing, here), then a 1:1 would be a 3/8" image if you measured it on the piece of film. If you were at 1:2, then the dime would be 3/8" in real life : 3/16" on the piece of film...half the size.

EDIT - To put it in better perspective, replace the : with a / and make it a fraction. 1/1 is a whole size image...1/2 is a half size image on the film itself. When this is printed on paper, it is going to look HUGE.

Found this link...it pretty much says the same thing I just did.

http://www.shutterfreaks.com/Tips/tomhicksmacros.html

Ah, I get it now. The math is not strong in this right-brained one. So, it would be the opposite for even larger reproductions. For example 2:1 (or would it be 1:0.5) would give you an image twice life size on the focal plane. And when printed it would be amplified by whatever size you're printing. I'm schmart. :scratch:

 

[Phranquey]

For example 2:1 (or would it be 1:0.5) would give you an image twice life size on the focal plane.

You are correct, but I have always seen at as 1:2 (half), 1:1 (full), 2:1 (double), etc. Always try to think of it as a fraction, just with a different symbol. If you were to express it as 1/0.5, you would still be technically correct, but it would just confuse the issue even further.

 

[PaulBennett]

Consider taking a 35mm slide film picture of a common ruler which has inch marks.

Setup the camera/lens so the slide film picture is exactly the same size as the ruler, and test it by placing the ruler on top the slide. Got a mental image of that? That's macro 1:1 (image size = real size)

Obviously you can create pictures where the image is larger and smaller than real life, and the ratio becomes greater or less than 1:1. I.e. 1.1:1 or 0.6:1.

Now translate that mental image of slide film to a digital sensor and resultant jpeg. Everything said above still holds. Or translate that mental understanding to a 4x5 film image. Everything said above also still holds.