what makes macro lenses special?

[florenceinitaly]

Hi,

For macro photography, I'm confused as to what distinguishes "macro" lenses from regular prime lenses. For example (I use the sony a500), there's a 50mm F2.8 macro lens, and then a 50mm F1.8 prime lens.

What is it about the "macro" lens that would enable it to do things the 50mm F1.8 prime lens can't? Can you take "macro" pictures with the prime lens rather than the macro lens?

 

[Josh66]

1:1

That's it, pretty much.

Macro lenses let you get close, real close. A postage stamp, for example, would fill the entire frame - and then some.

 

[Pugs]

A macro lens will allow much closer focusing distances so that you can get more magnification of a subject, or rather, less reduction of the subject.

 

[florenceinitaly]

And say if I tried to take the same picture with the 50mm F1.8 prime lens, it wouldn't be able to focus at such a close up distance?

 

[florenceinitaly]

ohh i see, so is there a "spec" on the camera to tell you how close you can focus on the subject?

 

[Pugs]

No.

 

[TJ K]

The Macro part.

 

[Josh66]

ohh i see, so is there a "spec" on the camera to tell you how close you can focus on the subject?

Yes, and it will be expressed as a ratio. A macro lens will be 1:1.

A "Normal" lens will be something like 1:3.

The spec is on the lens though - not the camera.

EDIT

Also, don't confuse this with the aperture. Some lenses will say "1:2.8" (for example) on them - this only means that the maximum aperture of the lens is f/2.8.

 

[florenceinitaly]

lol

How about choosing between different focal lengths of macro lenses (ie. 50mm, 100mm vs 200mm), i know a 200mm would let you shoot from further distance...but if i had a 200mm macro lens and walked right up to a flower petal, will it focus?

 

[Josh66]

Yes.

All that changes is how close you have to be to attain 1:1. Longer lens lets you be farther away (which is generally good).

My 100mm Macro, for example, does 1:1 at about 6 inches from the front of the lens.

 

[florenceinitaly]

i see, that likely explains why the price difference increases a lot between a 50mm to 100mm to 200mm macro lens.

Does someone mind defining to me what the 1:1 thing means for macro photography?

 

[milesy]

1:1 just means that you can focus on something (say a fly) and it will fill the entire size of the sensor where as 1:3 for example means that something willonly fill 1/3 of the sensor

 

[Josh66]

Yes, 1:1 means "life size".

Think of it like this:

(Size of object in real life) : (Size of object image on sensor)

If you were to take a picture of a US Dime at 1:1, the size on your sensor would be the same as if you had just laid the dime right on top of it.

edit
I may have that backwards... Anyway - you should be able to understand what I'm saying...

 

[KR.]

ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

 

[Phranquey]

Josh pretty much hit it...

1:2 is half size on your sensor
1:1 is full size
2:1 is double size