I'm not a photographer, but I'm pretty sure that the Freedom Chair would be perfect.
http://www.dwr.com/product/workspace...ortby=ourPicks
"The grandaddy [sic] of the ergonomic revolution, Diffrient, 78, has spent his career emphasizing the ?the human factor? when designing an object. The first volume of his breakthrough book, Humanscale, was published in 1974, altering the way in which industrial designers approached projects, urging them to consider usability as much as they were considering aesthetics. Diffrient's Freedom chair, first presented in 1999, became a quick hit among purveyors of design and aching-back office workers alike?eight years later, it's still considered to be on the forefront of comfort and style.?
http://www.humanscale.com/about/news.cfm?newsid=70