Greetings,

I just acquired a 67 outfit (90MM, 200MM, 45MM, 105MM, tripod, body) two days ago. It appears to be in good working order and I will run tests this week. I should mention the equipment is used and belonged to a pro, so it was used A LOT but well maintained.

I got a simple manual on the camera, but no information about using the leaf shutter on the 90MM. I have figured out how to fire it with the focal plane open, but I'm confused about the U/S switch. Also, how would I use it to sync flash at higher speeds and why?

Thanks in advance for advice from some of you experienced 90MM LS users.

-- Rick Dawson (wadric2@swbell.net), January 03, 1998

Answers

Last question first, Why higher sync speed?

The P67 body syncs the flash at a maximum shutter speed of 1/30 sec. This is the fastest speed at which the shutter is completely open, allowing the flash to illuminate the entire frame. At faster speeds, the rear curtain is closing before the front curtain is completely open. This results in a moving "slit" that exposes the film, and would not allow a flash to illuminate the entire frame. Faster flash sync speeds are often required to balance flash illunimation with ambient light. The most common example is fill flash used in outdoor people photography. For example, an outdoor portrait. You need to shoot at f8 to limit the depth of field. The meter says 1/125 at f8. With a sync speed of 1/30, you can't use a flash for fill.

U/S switch. I don't know for sure, but I've been told by several sources that U stands for usual and S for special. I know of photographers who tape the switch in the U position to prevent accidents.

How? Make sure the switch is in the U position. Set the camera shutter speed for 1/8 or slower. Plug the flash into the pc socket on the lens. Set the lens shutter speed as desired. Cock the leaf shutter by rotating the ring on the front of the lens. Aim, focus and shoot. The leaf shutter must be cocked after each shot, winding the camera does not do it.

Reportedly, the S position can be used to make multiple exposures. but I'm not sure how. With the lens in the s position, you can lock the mirror up, and cock and release the shutter multiple times. the shutter is released by pushing the lever toward the u.

I hope this helps, Jim

-- Jim Sabo (jsabo@vss.fsi.com), January 12, 1998.

Just an addon to the 90 2.8 LS usage answer. The shutter speed for the focal plane shutter must be set between clicks (between X and 1/1000). At this setting it will remain open when fired until shutter speed is moved to a click (referred to sometimes as the 'Time' setting). Instead of sliding the leaf shutter switch from 'S' to 'U' to make multiple exposures, it is easier (and steadier) to thread a standard cable release into the leaf shutter socket. Leave the switch on 'S', fire the first exposure with the focal plane shutter, then just recock and fire the leaf shutter as many times as desired with the cable release. The mirror will be up and the focal plane shutter open, so battery is being depleted.

-- (jshupe@kfv.com), March 18, 1998.

OOPS! My addon answer applies ONLY to multiple exposures with 90 LS lens. Focal plane shutter is set at 1/8 or lower for regular LS operation. The 90 LS can also be used as a normal lens with the Focal Plane shutter by simply not cocking the leaf shutter.

-- (jshupe@kfv.com), March 18, 1998.

I too have a 90mm LS lens. The "U" is for usual and the "S" is for special. I phoned Pentax and they sent a copy of the manual for the lens at no charge. The above instructions are correct. I recommend contacting Pentax and getting the manual.

-- Gary Struckmeier (aenelson@wvi.com), June 11, 1998.