Blurryeyed Loc: NC Mountains.

If you are considering this purchase a macro lens will introduce you to a whole new world that you probably never realized existed right in your backyard, there is one consideration that you might want to note, a macro lens is very slow focusing when used as a normal telephoto, for me the close focus ability of the macro is worth the trade off, but some people find this to be a great irritation.

jerryc41 Loc: Catskill Mts of NY

It's like a microscope vs a telescope. If you're really into photography, you should have several of each.

gvarner Loc: Central Oregon Coast

In addition, a macro lens is designed to be sharp clear to the edges and is commonly used for portraits too.

Bob Boner

I use the Sigma 150mm macro. The increase focal length lets me photograph some insects that fly away when I get close enough with my 100mm.

amfoto1 Loc: San Jose, Calif. USA

Many (most) macro lenses actually are a specialized type of telephoto lens. Previous responses are correct. To summarize:

Macro lens 60mm to 105mm...
1. Focus much closer (6 to 9 inches) to be able to achieve full 1:1 magnification.
2. Optimized for flat field (edge to edge, corner to corner sharpness) at very close distances.
3. Typically uses "long throw" focus (both manual & AF) which is slower but emphasizes precision because depth of field becomes shallow at short distances.
4. Few have larger than f/2.8 aperture. Plus macro lenses often feature and are optimized to use especially small apertures (f/22, f/32) to increase depth of field.

Short telephoto 60mm to 105mm...
1. Don't focus particularly close or try to achieve more than approx. 1:5 or 1:6 mag.
2. Often are optimized for six to ten foot working distances. Not flat field (Google "field curvature").
3. Some have short throw focus for speed. But not all, some more portrait-specialized lenses also are long throw.
4. Often have one or two stops larger max aperture (f/2 to f/1.4) in order to more strongly blur background. These lenses may be optimized for wide open or near wide open shooting, too.

quote=jerryc41]...If you're really into photography, you should have several of each. [/quote]

How true!

I use Tamron 60mm f/2 (crop only), Tamron 90mm f/2.5 (vintage, manual focus), Canon 100mm f/2.8 and Canon 180mm f/3.5 macro lenses. I also use Canon MP-E 65mm which is an ultra high magnification "super" macro (up to 5x life size) and often use 45mm and 90mm Tilt Shift lenses for close up work.

On the whole, I don't like to use macro lenses for portraiture. To me they can just be too sharp and make somewhat "clinical" looking images at non-macro distances. An exception is the Tamron 60mm f/2 (crop only) which works pretty well thanks to its larger aperture. But for portraiture I also use non-macro 50mm f/1.4 (on crop), 85mm f/1.8 and 135mm f/2.

imagemeister Loc: mid east Florida

To be vary concise, macro lenses are generally optically designed and optimized for close up work and flat fields with reproductions of 1:10 to 2:1 - and some even going to 5/6:1 ! - but most still CAN be focused at infinity. In order for this optimization, their f-stops are smaller - generally 2.8-4. Their focus speed is generally slower because of the longer travel and greater accuracy required.

Standard telephoto lenses are physically shorter than their actual focal length, are optimized for focus at infinity, with max aperture on the order of 1.8-2.8 and their closest focusing generally 1:5. with great focus speed.

..

Architect1776 Loc: In my mind

Macro lens 1:1 magnification capability with exception of some 50mm Macros that go to 1:2 but come with a 1:1 extension tube.
Telephoto is not capable of 1:1 or 1:2 magnification.
Same angle of view though on a FF camera.
Also an 80mm Telephoto could possibly have a larger aperture.

bodiebill

Thanks for all the professional information--it has really added to my knowledge of Macro Photography.
You have all been kind and gentle in answering my question.
BodieBill

RWR Loc: La Mesa, CA

Focused at infinity, internal focus lenses perform no differently than any other on a bellows or extension tube. Extension determines reproduction ratio, move the camera/lens combination in or out to focus.

Apaflo Loc: Anchorage, Alaska

Notice that Nikon, as just one example, ceased to sell extension tubes when they began producing macro lens with Internal Focus.

With close focusing macro lenses the primary benefit of Internal Focus designs is that astigmatism can be controlled at both infinity and at 1:1 focusing. That could not be done with a unit focus design. That benefit is not maintained when extension tubes are used, hence Nikon stopped selling extension tubes, due to degraded performance, for use with their macro lenses.

RWR Loc: La Mesa, CA

I tested a Tokina 100 f/2.8 ATX AF (old version, 1:2, internal focus) on a bellows from about 1:4 to 1:1. From my admittedly unscientific observations, astigmatism seems to affect mostly the edges with the lens wide open, and is greatly improved by stopping down, til you reach the point where diffraction starts to deteriorate everything. For most three-dimensional subjects, corner definition is generally of little concern anyway.
For magnifications greater than 1:1 I either use a reversed lens or stacked lenses, so cannot comment on macro lens performance at those ratios.
Edit: I often use extension tubes with a couple of internal focus zoom lenses in the field for closeups (usually 1:2 at the most) of three dimensional subjects, mostly at f/11-f/16.