I have a 75-200mm telephoto zoom lens which claims it can be used as a macro lens. However, I’ve never had much luck. Granted, my optics are cheap optics. But, for you SDopers in the know, can a telephoto zoom lens ever perform down at the Macro level??? Or, should I look into getting fixed-focus Macro lenses, if there are such a thing? (At best, I have those screw-on lens filter diopters, but is that the same thing as Macro?)
(My apologies if this might border on IMHO. The factual question rests contained within my post is: Are there fixed-focus Macro lenses?) - Jinx
The term macro is used very loosely and in the case of your 75-200mm zoom lens I’d wager it has a closeup mode but no true macrom mode.
That said, what “bad luck” are you having? Closeup work causes some problems such as limited depth of field. As you increase the magnifcaiton ratio - ratio of subject size to image size on film - the depth of acceptable focus gets very thin. You also lose a little light too. A lens at a 1:1 magnification makes an image two stops darker than when set to infinity. This is sometimes called the bellows factor.
A quality fixed macro lens is probably best. something in the short telephoto range l ike 105mm is versatle. I’ve got a second generation 55mm micro nikkor. It will go to 2:1 by itself and 1:1 with an extension tube. For greater magnification you usually get a better image with the lens backwards. I mount it on a bellows attachment with a pair of reversing rings that convert the filter ring to a bayonet mount and vise-versa on the bayonet end.
Screw on diopter correction lenses will help you do closeup work but you’ll not have as good an image as with a prime macro lens.
True micro/macro lenses are disigned differently optically, too. It’s not just about getting closer.
A micro lens gives a fairly flat field curvature. That’s the plane of focus bending away from or towards the subject in relation to the film plane. Center to edge sharpness is kept nearly equal, too. Both improve at about 2 stops down from max aperture. This is VERY imprtant for flat work reproduction.
For 3D subjects, it’s a little tricky to balance a fast enough shutter speed to reduce wind shake or or other subject movement, and a small enough f-stop to compensate for the reduced depth of focus as you get closer. DO use a tripod. Sometimes, flash is a good tool. Allows small f-stop and the flash speed stops the action. Off the film plane flash metering is very handy, but if you’re using a K-1000 like in your other post, you’ll have to get out a macro exposure calculator (some good books and data guides have them).
Again, just practice. Even a cheap macro zom can get a nice shot of a flower or whatever if you use your other techniques, too. Like selective focus, proper background, good image placement, relative camera position, yada yada.
I’m assuming that your zoom lens has a small tab or button, which, when activated, places the lens in “macro” mode.
Note: Nikon calls its macro lenses “Micro”, thereby screwing up the term “microphotography”, but that’s another matter…
Your zoom lens, when in macro mode, probably has a fixed focus distance, as well as length - move the subject or the lens closer together/further apart until the image is in focus.
Then get a real macro lens - much easier to work with.