macro 1:1 what does it mean? what is true macro?

the forums across the net talk about a 1:1 macro and true macro

lenses, now what does that mean? how diff is it from the lenses

marked macro or the flower symbol? they say canons ef 65mm macro lens

is the true macro lens why is that?

Some people will claim that TRUE macro is 1:1 (or a lens which will do 1:1) to differenciate it from a host of other zoom lenses which claim to be MACRO.

 

1:1 is also called life-size. It just means whatever you're shooting is re-produced exactly the same size on film/digital sensor. Meaning if you shot a rectangle with dimensions of 24mm x 36mm straight on, it will fill exactly the full frame of a 24mm x 36mm film (35mm).

oh ok, so tell me if the macro lenses are 1:1 what is the ratio for the 'false' macro lenses? and what is the ratio if i use a close up filter set at the end of the lens? what is the ratio when i attach a reversed 50mm lens? thanks in advance :)

pradeep, may i suggest John Shaw's Closeups in Nature as a good intro to the topic. Lots of good info and it covers different ways such as ext tubes, macro lenses, diopters, etc.

The ratio for the "false" macro lenses will vary depending on the lens. Check the lens specifications. They may say something like 1:4, meaning the image on the film is 1/4 the actual object (which means a 4x6 print will be bigger than the actual object, so that's not too bad).

 

The ratio using reversing rings and close-up filters will vary depending on which ring, which lens, which filter you're using, so there's no single answer.

 

It might help to know what you need to photograph?

thanks stephen i love to shoot macro, i just started photography somwehere mid 2003, i have a canon G2 and u can find some of my works here, esp the snaps of the ant was taken with the g2, lensmate adapter and the nikon 50mm lens attached reverse to the adapter.

 

http://tinyurl.com/2apr2

 

would this help?

Erb you say "Meaning if you shot a rectangle with dimensions of 24mm x 36mm straight on, it will fill exactly the full frame" but how far away are we talking? Is there a distance the subject needs to be at?

Macro is defined as between 1:1 (life size on film) to 20:1 (20 times life size on film) and greater magnifications than this are classified as Micro.<br>The term 'Macro' is abused and mis-used by some manufacturers to describe lenses that focus more closely than some other lenses - in other words the term is meaningless

>"Is there a distance the subject needs to be at"

 

This depends on the focal length of the lens. An object at 1:1 shot through a 50mm lens will be a lot closer to the camera than one shot with a 90mm lens, and with a 200mm lens it will be further away still. Exactly the same as for any other photography.

 

Which to choose? You make a trade-off of price (50mm macro lenses are cheaper, in general), a tradeoff in size, handling and convenience (50mm macro lenses are lighter but you have to get very close to the subject, which may be difficult) and a tradeoff in safety (how close do you want to get to something poisonous?). I get the best tradeoff by using a Nikon 70-180 zoom macro (goes to 1:2, not 1:1 but you can use a 6T filter to get 1:1). Oddly, no-one else has ever made a similar lens, but nearly every review of the 70-180 is very positive.

 

Regards, Ross

 

Regards, Ross

The simple lens equation is: 1/f' + 1/f" = 1/f, where f is the nominal focal length, f' is the optical center to the film, and f" is the optical center to the subject. The reproduction ratio is f'/f".

 

At a 1:1 ratio, the subject is the same size on film as in real life. f' equals f" equals 2x f. For a 50mm lens, the subject will be 8" (2x4") from the film plane, or 4" from the optical center of the lens.

 

Dedicated macro lenses are better corrected for close distances than standard lenses, and often do a poorer job than standard lenses at reproduction ratios greater than 1:10. Curvature of field is arguably the most import correction, but chromatic aberation is a close second.

 

The best true macro lenses may be process lenses used for publishing. They are highly corrected (apochromatic, flat-field) at 1:1 ratios, nearly symmetrical in design, and slow (f/8 or smaller.) They achieve their design coverage only at 1:1 or greater enlargement.

 

Most standard lenses are assymetric. Reversing the lens at close distances sometimes improves performance due to this assymmetry.

 

The best practical macro lenses, i.e. for 35mm, rearrange internal elements to correct curvature of field over a wide range of reproduction ratios, and compensate for exposure factors due to the lens extension. All this without extension rings or auxillary lenses.

Have you seen the Macro Primer of photo.net? In the menu at the top of this page, select Learn / Taking Pictures... / Macro. It answers your question.

thanks everybody, i just read the macro primer and i guess i need to read it a couple more times (my uptake is a bit slow sometimes ;)). cheers and happy shooting