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Hi, I use a Centon MR20 - it is non-dedicated, inexpensive and works a treat. I also occasionally use my 25 year-old Yashica Medical 100 DX if I don't need the extreme magnification of the Contax bellows unit. Keep an eye on ebay - the Yashica lens is a pearl and still pops up from time to time. Only issue would be replacement lighting units - you'd need to check how often it was used - that's why I rarely use mine! I have also wired up a couple of TLA 20s with heavy diffusers in the past.