My father-in-law has asked for my help in selling his Rolleiflex that he purchased new back in the 50's. The lens is a Zeiss-Opton Tessar f2.8 80mm. The body and case show clear signs of wear but he had it serviced about 5 years ago but didn't take any photos with it. I tried to look on eBay but it could be worth anywhere from $300 to $2500. What are the factors that determine value.? Are there any other places than ebay to sell? Any help would be much appreciated. Oh - in the last picture of the case - in the little case on the strap is a Rolleinar 1 closeup lens - except it is kind of dirty.