30 seconds is not very long, if you are going to just use your camera on trails then the RS pir has both 5 sec and 30 second and that is all you will ever need. If you are going to set this camera up on something like a feeder then 30 seconds is no where near long enough for a delay ,the camera would run through a roll of film in less than 15 minutes.
If this is you r first camera I would suggest that you don't add a timer,it complicates things and the regular camera cam seem intimidating as it is.
build a camera using jesse's front page and hook relay through pin#2 on IC. you will have both delays(chime andalarm),then you can branch out for bigger and better on Cam # 2
Trust me there will be a CAM #2,there will probably be a cam#10