Pentax ist - Manual (Page 144)

142
CUSTOM FUNCTIONS
[CF17] Enabling shutter release with the aperture ring set to
other than the position
• Custom Function number [CF17]
• Setting number
[1] . . . .Disables shutter release if the
aperture ring is not set to the
position
[2] . . . .Enables shutter release
✍
MEMO
• When the custom function number [CF17] is set to [2], the shutter can
be released even if the aperture ring of an attached lens is not set to
the
position. However, the features will be restricted as shown in
the table on page 143.