At 23:20 4/9/99 , John Hudson typed until his fingertips were worn to the
bone, then sent:
>I have came across a three filter set in a photo shop's cut bin. The three
>49mm magnifying filters were +1, +2, and +4 diopters.
>
>Using the +4 filter on my Zuiko 50mm / 1.4 lens [in place of the usual UV
>filter] the closest I could focus was about three inches from a flat two
>dimensional object .... a business card.
>
>Does anyone have any experience of these Vivitar filters and could opine on
>the quality of any photos taken using them as compared say to using a Zuiko
>50 mm / 3.5 macro?
>
>I wonder what the photo performance would be using a +4 diopter filter with
>a 135mm / 3.5 lens?
[snip]
I have had a set of these Vivitar close-up filters for about 20 years. You
didn't state whether or not they came with the instruction sheet which is
written in four different languages.
First some excerpts from the instruction sheet:
--------------------
Die Linsen koennen einzeln oder in Kombination verwendet werden . . .
[Oops, you probably want the English version]
They can be used singly or in combination to provide a range of
magnifications from +1 to +7 diopters, giving an image of up to 2/5 life
size when using a 50mm camera lens.
. . .
When using your Vivitar Close-Up Lenses in combination, best results are
obtained by mounting the lenses on the prime lens with the highest diopter
number lens nearest the prime lens and the lowest number farthest out.
. . .
The following table indicates the recommended maximum camera lens focal
length usable with the close-up lenses.
Diopters Use on lens no longer than
+1 500mm
+2 250mm
+3 = +2 & +1 180mm
+4 135mm
+5 = +4 & +1 100mm
+6 = +4 & +2 80mm
+7 = +4 & +2 & +1 75mm
. . .
The following table provides a handy guide for determining the
magnification ratios for various combinations of close-up lenses and camera
lenses. The figures are approximate and based on the camera lens being set
at infinity. Magnification increases as the focused distance decreases.
Focal length in mm
Diopters 50 55 85 100 135 200
+1 1:20 1:18 1:12 1:10 1:7.5 1:5
+2 1:10 1:9 1:6 1:5 1:3.7 1:2.5
+3 1:6.6 1:6 1:4 1:3.3 1:2.5 -----
+4 1:5 1:4.5 1:3 1:2.5 1:1.9 -----
+5 1:4 1:3.6 1:2.4 1:2 ----- -----
+6 1:3.4 1:3 ----- ----- ----- -----
+7 1:2.9 1:2.6 ----- ----- ----- -----
--------------------------
The greatest magnification occurs when using the +4 on a 135mm or the less
desirable combination of +5 on a 100mm. Purists will tell you extension
rings, bellows or a macro lens is better for macro work (but all are more
expensive).
Points to remember:
1. You are adding more glass and air-glass interfaces so some degradation
in performance is to be expected and be careful of situations that might
cause flare.
2. In general, use as few as needed to achieve the desired magnification
by selecting the combination of prime lens (that you happen to have) and
diopters to minimize the number of close-up lenses required.
3. Keep the close-up lenses *clean.* This will minimize the effect of
point #1.
4. Use a tripod if possible to keep things steady and allow using slower
shutter speeds.
5. You will lose depth of field with increases in diopters. Stop down the
aperture as much as increasing shutter speed allows (unless you
deliberately want a shallower depth of field).
I have used mine on a 50mm f/1.8 and a 75-150mm f/4 zoom with decent
results photographing African Violets. I have not formally tested them for
distortion, resolution or contrast. Aesthetically (and subjectively) the
purple color of the violets did not show any dreaded separation into blue
and red blotches using reversal film (Elitechrome 100) even when projected
to a 50" screen.
I have no formal A vs B comparison with any macro lens, but could not tell
much difference in the results between using these close-up lenses on the
50 and 75-150 versus the macro ring built in to my 35-105 zoom.
Hope this helps you out some.
-- John
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