about macro lenses

it can sound a little bit supid, but what macro lenses is for? is it only for

macro photos? what is the difrence between normal zoom lenses?

They're optimized for close-up (up to half size on film), but may be used as a "normal" lens.

Macro lenses are able to focus on objects very close, projecting their image close to (1:4, 1:2, ...), at (1:1), or larger than (2:1, ...) life size onto the film. Most macro lenses are optically optimized to do this with floating element(s) to correct image distortion, focus plane curvature, etc.<p>

Zoom lenses move elements around to modify focal length. Macro is more a function of focal distance (focus on close objects) than focal length (which affects angle of view). To further confuse matters, some zoom lenses do have limited macro capabilities.

so what advantage do macro lenses have in macro photography? and if they have some in macro, so in normal photography thare should be some disadvatages, isnt it?

if i use macro ring, does that normal lense which i use with it get the same characteristics?

Macro lenses typically will allow close focus and 1:1 reproduction ratios. A zoom lens with 'macro' is not a true macro lens. It typically does not allow 1:1 reproduction, it often does not allow extremely close focus, and since it also has to function as a normal zoom lens, it is a compromise design that is optically inferior to a true macro lens for macro use.

 

If you want to take 'real' macro shots - of a bee in a flower, for example, a lens with real macro capability is required.

 

You do not have to buy a dedicated macro lens, though.

 

You can use spacers - these move the back of the lens away from the camera body and allow closer focusing.

 

You can use a macro teleconverter, which performs two functions - it moves the rear of the lens away from the camera body to permit close focus and magnifies the image (to make it closer to 1:1 reproduction).

 

You can use a 'bellows' especially designed for macro work.

 

You can use special lens filters, which are often (and incorrectly) called 'diopters' to magnify and allow closer focus.

 

All of these (except the zoom-with-macro-feature) will give you something resembling true macro capability. Some methods provide better results than others, and usually a dedicated macro lens will give the best possible results, but it is also usually the most expensive route. If shooting macro is something you have an interest in, you might try one of the less-expensive methods first to see if it is something you want to do often enough to justify spending the money for a dedicated macro lens.

 

But a 'macro' feature on a zoom lens is next to worthless. It just does not do what you think it will do.

To build a little on Wigwam's well-stated explanation, a true Macro lens is optimized to give a flat field at close range, from about 1:15 magnification down to 1:1 (life size) or greater. Flat field is essential for copying documents, but less important for photos in nature. Macro lenses are often much sharper than standard lenses, owing to their relatively simple design, again at close range. Some have special, moving elements (e.g. the Nikkor 55/2.8 AIS and others) which give sharp results at both close and normal distances.

 

Many zoom lenses have a "macro" setting, which merely allows close focusing without any special compensation. Results vary from pretty good (Nikkor 28-105/3.5-4.5 AFD) to fuzzy at the edges. Most are limited to a magnification of 1:4 (1/4 size), which is close enough for casual use. Actually, 1:4 would cover perhaps 80% of macro photography applications, including flowers and mushrooms.

 

Extension tubes are inexpensive, and work very well with prime lenses, and especially well with long prime lenses, like a 180/2.8 or 300/4. Long lenses give a long working distance - good for things that crawl or fly. If you use extension tubes on zoom lenses, you lose the coordination of zoom and focus.

 

Less effective but inexpensive and easy to carry are closeup lenses (or filters), which allow you to focus more closely by effectively shortening the focal length of the lens. The plus side is that they work with zoom lenses and do not require a compensating increase in exposure.

 

"Closeups in Nature" by John Shaw is a good read for more information and examples.

If there are any significant disadvantages they are the relatively high price and smaller maximum aperture compared to common prime lenses of the same focal length. Otherwise a macro lens will do just fine.

Some macro lenses, such as the old Micro Nikkor 55/3.8 non-AI, have excellent optical characteristics for close up work, but do a terrible job of resolving images focused at "normal" (maybe 10-ish feet to infinity) ranges. This where the modern floating element design comes in. The modern Micro Nikkors and Pentax Macros all use floating elements and render sharp, flat field images from very close to infinity. I suspect that almost any modern macro prime (non-zoom) is probably very good. If they all prove too expensive, or if there is nothing compatible with your camera system, you can probably rig something up with an enlarger lens and bellows. Enlarger lenses are specifically designed for close-up, flat field work. They are essentially macro lenses without automatic diaphrams or focus helicoids.