Pentax Digital SLR (K100D)?

Question

Hey, could someone please tell me how to change the exposure time and ISO on this camera? I have to take pictures of constellations and star trials for physics and I don't know how to operate the camera

Answer 1

Stop your lens down to about f/8 at an ISO of 100.

You will need a cable release you can lock.  This will allow you to set your camera on "B" and lay it on its back, focused at infinity and then open the shutter using the cable release and then lock it down for an hour or so.  Since you are using a digital camera you can check the exposure and adjust the f/stop as necessary.

Answer 2

The ISO is set using the Fn button on the right of the rear LCD screen. This brings up an onscreen menu- use the four way controller above the Fn button to navigate the menus and  select  ISO sensitivity.

Although for long exposures at night I leave the ISO at the lowest setting on my Pentax DSLRs.

Adjust the exposure time by setting the mode dial on the top left of the body to Tv (Shutter speed priority).

Then use the wheel on just above the four way controller on the back of the camera to select the exposure time (shutter speed).

Experiment with different times and check your results on the LCD screen.  

You will need a tripod or something to hold the camera still as you will be using long exposure times and camera shake is a problem.