Adjustment Of The Soft Focus Effect; Depth Of Field; Other Functions; How To Attach The Softness Control Discs - Mamiya Sekor SFC 150mm f/4 Instructions

1. Set the lens aperture at f/8.
automatically.
3. Focus.
4. Set the lens to the desired aperture.
5. Return the depth-of-field preview lever to its original position by slightly
pressing it in the return direction. The lever will then return automatically.

Adjustment of the Soft Focus Effect

The degree of soft focus effect varies depending on whether or not the Softness
Control Discs are used and in accordance with which of the three Discs is used. The
amount of effective softness, however, will also depend on the type of subject,
distance, lighting conditions, the amount of enlargement given the negative, the
concept, personal Iikes, etc.
1. When not using a Softness Control Disc
The soft focus effect varies depending on the aperture used. At full aperture (f/41
the softest effect is obtained. The effect is less at f/5.6 and completely disappears at
f/8 or smaller apertures to produce a normal sharp image.
2. When using a Softness Control Disc
There are three different types of Softness Control Discs, each with a different
diameter hole in the center.
Discs. The f-value of this lens changes according to the Disc used. When the No. 1
Disc is used the effective lens aperture is approximately f/5; for the No. 2 Disc this
value is approximately f/5.6; and for the No. 3 Disc it is approximately f/6.3.

How to attach the Softness Control Discs

1. Remove the front lens barrel by rotating it counterclockwise.
2 . Slip the disc to be used over the rear end of the front lens barrel.
3. Put the front lens barrel back into place and tighten by rotating it clockwise.
Depth-of-field
The depth-of-field and the degree of softness can be easily checked by stopping
lens down to the preset aperture by operating the depth-of-field preview lever.

Other functions

All other functions such as removal and attachment of the lens, operation of
mirror lock-up, etc., are the same as for standard Mamiya-Sekor lenses.
the