glasses lens as convertor
I have a few glasses lenses, so I thought to give it a try in practice too, in order to help you guys.
At first I tried various single lenses, and even if the principle stands, the results were totally unusable. I wonder how the doggie photographer managed to make those photos now.
But when I tried two lenses instead, the results were surprising. Particularly using 2 roughly equal convergences, but opposite in sign, gave superb results (+2.25 and -2.5). It's best to orient them as the objective was an eye behind spectacles. Even better, swapping their order inverses the magnification effect. You can even get a lens shift function emulation.
I have to say the projector I used has a rather long throw and the zoom effect I got wasn't very large, perhaps around +-20%. If you need a major change, say 2x or 100%, the results may not be as good. But I feel up to 5 diopters it should work too well considering the price of the investment. And my lenses were only older glass, and not the optically better plastic lenses common these days.
PS There's no reason this shouldn't work for an anamorphic effect too, provided you get cylindrical lenses. Much more compact and maybe better than trophy prisms.
I have a few glasses lenses, so I thought to give it a try in practice too, in order to help you guys.
At first I tried various single lenses, and even if the principle stands, the results were totally unusable. I wonder how the doggie photographer managed to make those photos now.
But when I tried two lenses instead, the results were surprising. Particularly using 2 roughly equal convergences, but opposite in sign, gave superb results (+2.25 and -2.5). It's best to orient them as the objective was an eye behind spectacles. Even better, swapping their order inverses the magnification effect. You can even get a lens shift function emulation.
I have to say the projector I used has a rather long throw and the zoom effect I got wasn't very large, perhaps around +-20%. If you need a major change, say 2x or 100%, the results may not be as good. But I feel up to 5 diopters it should work too well considering the price of the investment. And my lenses were only older glass, and not the optically better plastic lenses common these days.
PS There's no reason this shouldn't work for an anamorphic effect too, provided you get cylindrical lenses. Much more compact and maybe better than trophy prisms.