From: Winnipeg, Manitoba, Canada
Registered: Nov 2012
posted February 13, 2015 11:22 AM
thanks to you all, I now know the significance of 'f' on lenses (The lower the 'f', the brighter it is)... I am now interested in inches and mm as related to throw distance. I think I might have a clue but it's always a better bet to go by our veterans, anyone ? Thanks in advance and hope you all are having an awesome weekend !!!
From: Aldershot, Hampshire, UK
Registered: Nov 2013
posted February 13, 2015 03:35 PM
Elyas, An easy way to relate the lens focal length to the throw distance and picture size is to remember the ratio of the throw to the picture width. For example a 2 inch (51mm) lens on a 16mm projector has a throw of 5.2 times the picture width. A throw of 15 ft gives a picture of 2.88 ft wide with this lens. The ratio for a 1 inch (25mm) lens is half of 5.2 ie 2.6, so a 15 ft throw gives a picture 5.77 ft wide.