carried out some exposure steps for Kamra #3 Bulb. Although the bulb has a focal length of around 100mm, the aperture opening is Ø25mm or /f4.0. 3 test print exposures were done. Rated with light meter at eye level, f2.0, 2.8, 4.0 the most accurate and ideal is between /f2.0-2.8 the bulb does collect alot of light and causes alot of flares and adds diffusion / soft focus
digitally inverted from the negative print. focal length estimated at 100mm. aperture opening at /f4.0 which is about Ø25mm, strobe light rated at f 4.0 at eye level (power output at 2.5). today all kamras have finally been tested with printed exposures. what a benchmark! project completed!
Going through some testing, using a spherical aqua lens, first patented by Thomas Sutton in 1859. here using a light bulb filled with water, an estimate of /f4.0 aperture opening.
light meter rated /f 8.0 for the custom combination lense 100mm on -0 shutter ring (which is rated at f 4.5). about 2 stops under to get a well exposed image. (positive image digitally inverted)
the custom-made combination of lenses & aperture/ shutter ring rates the exposure at double step under. also tested positive papers which are also rated at least double steps under too, ASA 1-2
while preparing kamra #4 woodie for processing, was mixing the chemicals in the box when the front tripod leg started to move and slip. the kamra's mounting came off from the fall and the 12kg box smashed the tripod's leg into pieces :( have to fix this another day. but in the mean time i need to find other surveyor's tripod too. anybody got any?