What size is your Crown? 2x3? I ask because the 4x5 Crown's maximum extension is 317 mm, which is plenty for a 210. I b'lieve the OP was asking about 4x5 cameras. Oh, and by the way, a 4x5 Speed Graphic's maximum extension is around 323 mm. No way can a 600 mm lens be used on a 4x5 Speed.
Originally Posted by PDH
You may be thinking of a modified 4x5 or 5x7 Graflex SLR. Graflex Inc and several other companies made them for sports photographers. See http://books.google.com/books?id=SiE...tha%22&f=false
I've modified a 2x3 Graflex RB Ser. B to use long lenses; the longest I've tried with it is 900 mm. I don't recommend this, internal baffles in the RB that can't be removed vignette badly in portrait orientation with lenses longer than around 250 mm and in landscape orientation with lenses longer than around 500 mm. Not worth the trouble and expense.