This is a good lens. Have one in SL66 mount. The 180mm is said to be better (well it is better if you look at the MTF charts), but that does not mean that the 150mm is bad. I search Ebay quite often for Hasselblad gear and you can get a 180mm CF for 500 Pound if you have some luck. The 180mm is said to be much longer physically and heavier. For handheld work consensus seems that 150mm is better suited. Then there is also a 160mm CB Tessar. Some people say it is bad but I have seen wonderful pictures made with it. It is also rather light. I have seen this for about 300 Pound used (but beware: dealers often list it at unreasonable prices). The 150mm is better in picture quality though. If it is in good working order I think you canīt get wrong at that price.