I had a quick google search and didn't find anything definitive, but maybe someone here can tell me off the top of their head with the resolution roadside billboards might be printed at? I'm guessing it's pretty low around the 50 to 100 dpi area but any help from people in the know would be appreciated. I have a prospective client who wants some images for a billboard and wants to know the maximum size my cameras will print to.
Talk to your billboard printer. The ones I've done ranged from 18 - 30 dpi at final print size, depending on the vendor. Do your computations based on 20-30 and you'll be fine. There are also several standard board sizes and if your client is not buying the largest signs, that may make your life a little easier as well.
If you're wanting this information in order to determine the resolution of images your'e providing for a billboard...forget it. You don't need it for digital any more than you needed it for film. Give them the same product a film photographer would give them.
You want to give them an image that when printed to paper at a normal hand-holdable size is sharp viewed from reading distance: An 8x10 (or 9x12) at 300 ppi. If it looks sharp in your hand, it will look sharp on the billboard. You don't need to know what the billboard printer is doing.
