Pentax DS Operation Manual - Page 181

Notes on [Using Aperture Ring] 179 Appendix Aperture Ring Use When [Using aperture ring] is set to [2 (Permitted)] in [A Custom] menu (p.101), the shutter can be released even if the aperture ring of the D FA, FA, F or A lens is not set to the s position or a lens without a s position is attached. However, the features will be restricted as shown in the table below. The camera operates in c (Aperture Priority) mode even if the mode dial is at e or b when the aperture is set to a value other than s. Lens used Capture mode Restriction The aperture remains open D FA, FA, F, A, M (lens regardless of the aperture ring only or with auto diaphragm accessories such as c (Aperture Priority ) mode position. The shutter speed changes in relation to the open aperture but an exposure error may occur. In the auto extension tube K) viewfinder, [F--] appears for the aperture indicator. 6 D FA, FA, F, A, M, S (with diaphragm accessories such as extension tube K) Manual diaphragm lens such as reflex lens (lens only) c (Aperture Priority) mode c (Aperture Priority) mode Pictures can be taken with the specified aperture value but an exposure error may occur. In the viewfinder, [F--] appears for the aperture indicator. FA, F Soft 85mm FA c (Aperture Soft 28mm (lens only) Priority) mode Pictures can be taken with the specified aperture value in the manual aperture range. In the viewfinder, [F--] appears for the aperture indicator. When depth of field is checked (Preview), AE Metering is switched on. Exposure check is possible. All lenses a (Manual) mode Pictures can be taken with the set aperture value and shutter speed. In the viewfinder, [F--] appears for the aperture indicator. When depth of field is checked (Preview), AE Metering is switched on. Exposure check is possible.