Extension Tubes or Macro Lens?

What's the advantage of a macro lens over a normal lens plus extension
tubes?

Edward Holt wrote:

What's the advantage of a macro lens over a normal lens plus extension
tubes?

You can't focus to infinity with an extension tube so a macro is handy
in the field.

Macro lenses have flat field for technical work.

Macros are optimized for closeup with regards to all the inherent
compromises in lens design like abberations & such (complex stuff g).

"Edward Holt" wrote:

What's the advantage of a macro lens over a normal lens plus extension
tubes?


In general, the optics of a macro lens is optimised for close-op work.
The optics of a normal lens are optimised at infinity.

Having said that, it is possible to get good results with some normal
lenses used with extension tubes. It depends on the lens.

Paul Furman wrote

Edward Holt wrote:

What's the advantage of a macro lens over a normal lens plus
extension tubes?

You can't focus to infinity with an extension tube so a macro is handy
in the field.

Macro lenses have flat field for technical work.

Macros are optimized for closeup with regards to all the inherent
compromises in lens design like abberations & such (complex stuff g).

IMX the major practical downside to tubes vis-a-vis a macro lens was
having to change tubes in the field to cover the same magnification
range as a macro lens. It's quite possible to get more than adequate
results using tubes with a good lens.

--
Hil