JoeV
13-Mar-2010, 12:40
Folks;
I putting together an 8"x10" nested box camera that uses a single-element meniscus lens, salvaged from an industrial photo-lithography machine. The lens is convex on one side and slightly concave on the other, about 4" in diameter, with a focal length around 10.75".
I've initially mounted it in the camera with the concave side facing the subject, and have initially used a 3mm aperture, located about 1" in front of the lens, in order to get a wide DOF, as a kind of "hyperfocal" setup, requiring minimal focusing for landscape images.
http://farm5.static.flickr.com/4051/4423318639_0275fa4425_o.jpg
http://farm5.static.flickr.com/4060/4423318675_54ee72c590_o.jpg
The initial test photos, subject matter not exactly thrilling (of my desolate winter-time backyard) indicate that the lens is pretty sharp, corner-to-corner, at F90, but I'd like to improve its performance if I could.
http://farm5.static.flickr.com/4040/4423778886_e0be317221_o.jpg
Is there an optimal location for the front aperture? Like the front nodal point? And how would I, in actual practice, go about testing for this point?
I am also planning on using this lens wider open, for fuzzy-edged portrait kinds of images (notice how I avoided the use of the term "bokeh" ... oops).
Thanks for your help.
~Joe
PS: The test image was exposed onto a preflashed grade 2 paper negative, hence the washed out sky.
I putting together an 8"x10" nested box camera that uses a single-element meniscus lens, salvaged from an industrial photo-lithography machine. The lens is convex on one side and slightly concave on the other, about 4" in diameter, with a focal length around 10.75".
I've initially mounted it in the camera with the concave side facing the subject, and have initially used a 3mm aperture, located about 1" in front of the lens, in order to get a wide DOF, as a kind of "hyperfocal" setup, requiring minimal focusing for landscape images.
http://farm5.static.flickr.com/4051/4423318639_0275fa4425_o.jpg
http://farm5.static.flickr.com/4060/4423318675_54ee72c590_o.jpg
The initial test photos, subject matter not exactly thrilling (of my desolate winter-time backyard) indicate that the lens is pretty sharp, corner-to-corner, at F90, but I'd like to improve its performance if I could.
http://farm5.static.flickr.com/4040/4423778886_e0be317221_o.jpg
Is there an optimal location for the front aperture? Like the front nodal point? And how would I, in actual practice, go about testing for this point?
I am also planning on using this lens wider open, for fuzzy-edged portrait kinds of images (notice how I avoided the use of the term "bokeh" ... oops).
Thanks for your help.
~Joe
PS: The test image was exposed onto a preflashed grade 2 paper negative, hence the washed out sky.