It depends on what you're shooting of course. I found that my 35 mm macro is great for shooting earings, but terrible for necklaces. You've got about 2 inches of clear space to work with.
That’s the problem You’re so close that you no longer have room
to adjust the lights, and any high polished areas on the earring
will surely show you a reflection of the camera. Also, even with
the exceptional quality of today’s lenses, at a macro setting,
any 38 mm or other wide angle lens is going to have at least some
detectalbe spherical abberation. And working so close, in
macro mode, you loose the depth of field advantage that wide
angles normally give you with normal distance shots. A longer
lens solves these problems. You just have to be sure that the
macro mode is actually a useful level of magnification. Look for
the reproduction ratio. Many longer lenses have a macro mode
that’s only 1:4 ratio. Not enough for smaller items. A lens
made to actually be used as a macro as it’s primary function,
rather than as a telephoto most of the time with a convenience
macro function added on, will generally be able to deliver a 1:1
reproduction ratio. That means the image on the film is the
same size as the actual object at full magnification. Few
jewelry objects need to get that close. My Vivitar Series One
Macro, for example, goes from that all the way out to infinity,
giving me a range of magnifications allowing everything from a
clear shot of just an earring post all the way to a good shot of
my house… And even the earring post will have me working from
almost a foot away from the post, leaving room for lights,
tripods, etc.
If you have really steady hands you can hold the telephoto turned backwards up to your camera.
Huh? You’re tryong to hold the lens manually just in front of
your camera? Not only is it not real steady, at best, but it’s
not light tight either. Also, reversing rings are designed for
use not with telephotos, but with the standard 50 mm lens, for
when you’re working at such a close distance that the distance
from the film to the focal plane of the lens is greater than the
distance from that plane to the object. The lenses are designed
so that they are corrected for distortion with the distance from
the focal plane of the lense to what’s in front of it being
longer than that behind the lens. If you’re working very close,
turning the lens around works to not only allow the lens to
focus closer but also to again correct the distortions involved
with close up work. With most telephotos worthy of the word, the
working distance in front of the lens will be greater than the
distance behind the focal plane even at closest working
distances, so reversing the lens then makes no sense. If you
need to get closer with a telephoto (as with a normal lens) you
don’t need a reversing ring, you need simple extension rings.
These can be simple screw ons, in which case automatic exposure
functions of the lens no longer are coupled to the camera, as
with the reversing ring, or you can get extension rings that
include the couplings, so your automatic diaphram (f-stops) still
work. Extension rings are, in general, a fine way to get close
focus, better than add on “diopter” lenses that fit in front of
the lens.
Hope this helps.
Peter Rowe