I searched this web site and photo.net, but I couldn't find the lens limitations for wide angle and telephoto. Do I calculate lens limitation for telephoto based on bellow extension? In this case, it's like around 300mm lens for telephoto. Is this correct? I've a Pacemaker Crown Graphic 3x4 with knob 2x3 roll film back. Also, can Pacemaker 2x3 lens boards fit Pacemaker Crown Graphic 3x4? I've checked Midwest Photo Exchange and Brooklyn Camera, but I didn't find any used lens board for 3x4. I couldn't find Columbus Camera online at all. Does this mean I've to make my own lens board for 3x4? Thanks.

According to Graflex (graphic Graflex Photography 11th ed) the minimum flange focus is 1 5/8" for a 3x4 crown. which means you can focus a 65mm lens at infinity.

the longest lens Graflex suggests for the 3x4 is the 10" Tele Optar. This is a true telephoto meaning when focused at infinity the bellows draw is about 7"

If you used a normal 10" lens it would focus at infinity with 10" of bellows draw and you would have any close focus as the 3x4 has only 11 1/4" of bellows.

I'm afraid your stuck looking for used 3x4 boards. Each format used a different size and since 3x4 is a dead format, nobody is willing to reproduce new boards for it.

Columbus Camera Group is NOT a single store but a grouping of several in Columbus, Ohio.
This link to an auction of theirs has a means to contact them.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1356834374