Scott Jones did a lot of work on the subject. See these relevant threads:

http://www.largeformatphotography.in...ead.php?t=4361
http://www.largeformatphotography.in...ead.php?t=4404
http://www.largeformatphotography.in...ead.php?t=4440
http://www.largeformatphotography.in...ead.php?t=4537
http://www.largeformatphotography.in...ead.php?t=4572
http://www.largeformatphotography.in...ead.php?t=8370