Do you want to stay P-ttl automatic? If P-ttl you will have to use the 3 piece cable Ole shows in the diagram or 2 P-ttl flashes wireless. P-ttl flashes aren't cheap. We are probably talking $150 up for 1 flash and close to $100 for the dedicated P-ttl cord. There is a Promaster cord that could save you $20-30.
If you don't mind using a flash with its own built in electric eye we can shave the price down. You will need an adapter to set on the K100d flash shoe. This will have a pc terminal on it.These are about $15. The flash will need a different adapter. This will look like a hot shoe with a pc terminal on the side. Another $15 or so. You will need a pc cord to run between them. About $10.
You will then set camera to manual exposure. Use a shutter speed 1/180 or longer and set the Fstop the flash calcultor calls for. With digital you can shoot a shot to see how that looks and go from there.
Things to consider:
1. If you want to put flash on light stand or small tripod make sure flash pc adapter has tripod socket.
2. Make sure older flash has low voltage flash circuit. You can test this with a vom. For digital many say 24 volts or less. Pentax will handle more. If you are unsure about this visit your local camera store. They can help with all this.
If you have more questions just ask.
thanks
barondla
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