Originally posted by tweet25 my flash is a Pentax AF400FTZ - thanks
The AF400FTZ is a good flash unit I own both the AF400FTZ and the AF500FTZ and I use them on my pentax film bodies. Unfortunately the AF400FTZ is TTL only and your K-r takes P-TTL flashes (the next generation beyond TTL) and it's not backwards compatible as far as the flash being able to communicate with the camera for automatic flash exposure. You cans still use it in manual mode (both camera and flash in manual). The manual covers manual operation on pages 14 and 15, the download link to the manual is below.
Downloads & Literature - PENTAX Imaging USA
Here is a quick summary on how to use it with your K-r in manual, remember, this is a workaround to get you experimenting with an "old school" flash that's not "auto" compatible with you're camera. It may seem like a lot of work, but it will get you some flash pic's until you can get a P-TTL flash for your camera.
-Make sure your camera is in manual
-Set the Zoom head on the flash to match the focal length of the lens. If you're using a zoom lens it will be the number on the zoom ring that lines up with the index mark on the lens. The zoom head setting on the flash will light up on the control panel.
-Slide the zoom switch until the arrow lines up with the zoom head setting.
-The middle switch on the bottom of the control panel should be labeled, TTL AUTO/ H L, the H&L are the manual modes. you will use on of these settings.
-Set the ISO slider at the top of the control panel to match the ISO setting of the camera (manually set the ISO on the camera).
-The H & L markings on the control panel are color coded to match the color coded distance scales on the upper part of the control panel. At very close range you can use the low setting and at longer range us the high setting.
-Once the zoom head and ISO is set, set your camera to it's flash sync shutter speed 1/180th of a second.
-Estimate the distance between you and the subject, look it up on the distance scale. The Yellow scale on top is for the low power setting and the white letters on bottom are for the high setting. The row of numbers in the middle on the "F" line is the aperture (F-stop) that you would set the lens to based on the estimated distance between you and your subject.
-Once you do this take a test shot.
This is how flash photography was done decades ago before any kind of automation, this will get you experimenting until you get a compatible flash unit for you're camera. The above instructions only apply if you have the flash head pointed at the subject, if you want to try bouncing the flash, you'll want to set the flash to high power and open up you're lens my several F-stops and then go higher or lower based on your test shot.