Pentax Camera Operating Instructions Manual page 33

PENTAX T'A'' LENS.
T o s e t t h e l e n s i n t h e A p o s i t i o n , m a t c h t h e A - i n d e x ( g r e e n l i n e ) o n
t h e a p e r t u r e r i n g t o t h e o i n d e x m a r k w h i l e d e p r e s s i n g t h e a p e r t u r e
a u t o l o c k b u t t o n . R e l e a s e t h e b u t t o n t o l o c k t h e l e n s i n t h e A
p o s i t i o n .
To release the lock, rotate the aperture ring towards aperture scale
with the auto lock button depressed.
A (autol setting
Programmed AE mode
Shutter-priority AE mode
T h e f o l l o w i n g m o d e s a r e a v a i l a b l e w h e n t h e l e n s i s s e t i n t h e m a n u a l
f -stops:
f/number setting Aperture-priority AE mode
Metered Manual mode