What makes a lens a macro lens?

[cutsman]

I've noticed that there seems to be a range of focal lengths for macro lenses. My question is what makes a lens a "macro" lens if the focal lengths overlap with those of regular non-macro lenses?

 

[Buschmaster]

Most good 'macro' lenses have a 1:1 magnification rating.

Otherwise a lot come close to that.

 

[Grimace]

I've noticed that there seems to be a range of focal lengths for macro lenses. My question is what makes a lens a "macro" lens if the focal lengths overlap with those of regular non-macro lenses?

It doesn't really have anything to do with focal length. You'll find macros from 60mm up to 180mm. Macro functionality refers to how close it can focus -- ie, much closer than most lenses.

 

[Buschmaster]

It doesn't really have anything to do with focal length. You'll find macros from 60mm up to 180mm. Macro functionality refers to how close it can focus -- ie, much closer than most lenses.

Some Sigmas telephotos have 1:2 macro from 200-300, I believe, as well.

 

[cutsman]

So if focusing distance is the big difference... is there any disadvantage to using a macro lens for non-macro purposes?

 

[Buschmaster]

So if focusing distance is the big difference... is there any disadvantage to using a macro lens for non-macro purposes?

None. At least not in the decent macro lenses. I shoot Pentax and a lot of people say they keep either their 50mm or 100mm (same lens different focal lengths) macro lenses on quite often even just for portraits. However, some cheaper macro lenses may not be quite as good with focusing to infinity.

 

[devilot]

OP, thanks for asking this... I've always wondered but was too chicken to ask.

Macro functionality refers to how close it can focus -- ie, much closer than most lenses.

Nice. Is there a non-super-technical way to explain how the physical lens is different to allow for this?

 

[Since '76]

Ability to focus 1:1 (lifesize) images on the sensor or film
A nice flat field (no pin cushion)
Less vignetting (even illumination)

All very useful in copy work as well as close-ups

 

[Lovesong]

None. At least not in the decent macro lenses. I shoot Pentax and a lot of people say they keep either their 50mm or 100mm (same lens different focal lengths) macro lenses on quite often even just for portraits. However, some cheaper macro lenses may not be quite as good with focusing to infinity.

That is true for most macro lenses. One major exception being the MP-E 65mm, which is one of the top-notch lenses for macro photography, but will not focus much beyond 5 inches. The 100, 60, and 180 from Canon are awesome for both macro, and general use.

 

[Clix Pix]

Nikon's current lineup: 60mm, 105mm VR and 200mm f/4 -- all excellent lenses with 1:1 ratio. Each can be used for other purposes as well. The 105mm VR in particular makes a nice portrait lens, too!

 

[IscariotJ]

Nikon's current lineup: 60mm, 105mm VR and 200mm f/4 -- all excellent lenses with 1:1 ratio. Each can be used for other purposes as well. The 105mm VR in particular makes a nice portrait lens, too!

I've just picked up the 105mm VR, and found it's focal length to just right for other types of shots. Sorta like a prime for my D40. Was beginning to wonder if there was any reason not to use it as such....

 

[miloblithe]

I wonder what the lowest magnifaction lens that a manufacture calls a macro lens is? A lot of lenses don't come that close to 1:1 and are called macros by their manufacturers. Seems like anything better than 1:4.