Yashica Twin Lens Reflex Guide - Focal Press January 1964
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Zone Focusing
With action subjects and similar occasions where you want to shoot quickly. determining sharp zones even with the depth
of field indicator wastes too much time. There you need prepared settings covering given near and medium distance
ranges that you can easily memorize and set on the camera. The zone focusing table (p. 65) gives such settings; then you
only have to worry about keeping the subject within that zone while you shoot.
With landscapes and views You sometimes need depth from infinity to the nearest possible point. Thus by stopping down
to f11 and focusing on 25 ft. you get a really extended zone from infinity down to about 12 ft. But don't use this setting if
you want the maximum sharpness in the far distance; in that case focus on infinity.
Close-up Work
The Yashica reflex focuses down to 3½ ft. and covers a subject field of about 23 x 23 in. at this distance.
For work at still nearer distances close-up supplementary lenses have to be used. Two identical lenses (i.e., matched in
focal length) are required, one for the viewing lens and the other for the taking lens; they should be obtained as a matched
pair, otherwise the focusing on the screen will not be exactly the same as that on the film.
For the Yashica reflex models with bayonet lens mount special bayonet-mounted close-up lens sets are available
consisting of one lens that fits over the taking lens and a second one with a built-in wedge to fit over the finder lens. The
wedge compensates for the finder parallax, ensuring that the reflex screen shows the same field as the camera lens will
reproduce on the film. Place the finder close-up lens into the bayonet mount on the camera finder lens in such a way that
the engraved red circle on its rim shows to the top.
The Yashica Close-up Lens Set I permits focusing distances - measured from the back of the camera body to subject - of
23¼ in. down to 17¼ in. on the 2¼ x 2¼ models and from 23½ in. down to 15¼ in. on the 1 5/8 x 1 5/8 models.
The Yashica Close-up Lens Set II permits focusing distances - measured from the back of the camera body to subject - of
18¼ in. down to 14¼ in. on the 2¼ x 2¼ models and from 16¼ in. down to 12 in. in the 1 5/8 x 1 5/8 models.
For cameras which accept a push-on lens mount, the normal close-up lens pairs - obtainable from photographic dealers -
should be chosen in appropriate push-on mount of 32 mm. or 28.5 mm. diameter (according to camera model) fitted with
+1 or +2 diopter close-up lens pairs.
The +1 diopter lens pairs permit focusing distances - measured from back of camera to subject - of 43 in. down to 24 in.
on the 2¼ x 2¼ in. models and from 42 in. to 23 in. on the 1 5/8 x 1 5/8 models.
The +2 diopter close-up lens pair permit focusing distances - measured from back of camera to subject - of 24 in. down to
16 in. in the 2¼ x 2¼ model and 23 in. down to 17 in. in the 1 5/8 x 1 5/8 model.
With the push-on close-up lens sets you have to allow for the finder parallax (this is only compensated for in the bayonet
models by means of the built-in wedge) by allowing for a strip of the image on top that will not actually appear on the
negative. The depth of this strip becomes the larger the closer the focusing distance. While at 30 in. it is about 1/10 of the
screen height, it will increase to about 1/5 at 18 in.
No change in exposure is required when using close-up lenses, but you should stop down in order to increase the depth of
field which, at such short distances, is extremely shallow. Whenever possible, f8 to f11 should be chosen. See also close-
up lens table on page 69.
