| Author | Message | ||
     Glenn Tinkerer Username: Glenn Post Number: 859 Registered: 07-2006 Rating: N/A |
The only Helioprint lenses I have experience with are Process Lenses - I suspect your lens is a 150/1:9 example. Note the ':' and not as you quote '.', meaning the lens is f9 and certainly not f1.9! Around ten years ago, the world was awash with used/surplus process lenses as the printing industry ditched their traditional methods and went over to digital scanning techniques. When used at their optimum aperture these lenses offer extreme sharpness - in many cases although a lens has aperture detents for values from say f8 to f22, only one position will have an actual value engraved against it. On many lenses this will be for the f22 position, thus marking the optimum operating aperture. The downside in adapting these lenses for general large format photography is the difficulty of mounting them in a suitable shutter. One finds that the internet around 2002 was full of DIY solutions aimed at using these very cheap, but optically superb lenses, on large format cameras. Your lens will offer optimum coverage on 7"x5", the corners on a 10"x8" will certainly not be perfect |