cheapest basic 8X10 lens
Posted: Mon Jul 18, 2011 7:09 pm Etc/GMT-1+01:00
I am building a right angled camera obscura thing at work on thursday, basically it will be as follows:
square wood box
pin hole in the 'front' side
mirror internally at 45deg
opaque perspex (ground glass effectively) top
the idea being you point it at your subject, stick a bit of paper on the top and a dark cloth over your head and you can copy the scene onto your paper. it has to be quite portable.
I guess the internal optical length will be about 20-30cm so I'm looking for a cheap lens in that kind of length to substitute for the pin hole to give me a brighter image.
any suggestions, the budget is very limited, they are moaning at £10 for the mirror I'm wondering about things like tescos reading glasses or trying to blag a single lens from specsavers in town etc (I think i need about a +4 dioptre lens).
any help or suggestions?
square wood box
pin hole in the 'front' side
mirror internally at 45deg
opaque perspex (ground glass effectively) top
the idea being you point it at your subject, stick a bit of paper on the top and a dark cloth over your head and you can copy the scene onto your paper. it has to be quite portable.
I guess the internal optical length will be about 20-30cm so I'm looking for a cheap lens in that kind of length to substitute for the pin hole to give me a brighter image.
any suggestions, the budget is very limited, they are moaning at £10 for the mirror I'm wondering about things like tescos reading glasses or trying to blag a single lens from specsavers in town etc (I think i need about a +4 dioptre lens).
any help or suggestions?