Deep sea camera employing one 100 watt- 
Figure l. 
second electronic flash light source and two 35mm 
cameras with Hopkins F-11 lenses for stero use. 
The object on the center of the framework is an 
experimental "sonar pinger'', a sound device for 
positioning the camera the proper distance above 
the ocean floor. 
Figure 2. 
of the M.I.T. swimming pool showing distortion 
obtained when an ordinary camera lens is used 
behind a flat glass window underwater. 
A photograph of the tile on the side 
The success of the lens was very im- 
portant because of the high quality of the photos, 
but the need for a faster lens was felt so that 
pictures could be taken farther off the ocean 
floor. Under sponsorship of Woods Hole Oceano- 
graphic Institution, Professor Hopkins next de- 
signed an F-4.5 lens for underwater use. The de- 
sign was completed in August, 1960, and these 
lenses with an optional shutter are standard on 
all EG&G underwater cameras. The new lens will 
not fit old model EG&G cameras without a longer 
pressure case, but the longer cases are available. 
280 
Figure 3. A photograph taken using the new 
Hopkins F-4.5 underwater lens. Compare the par- 
allelism of the tile lines with those in Figure 2. 
The'data chamber''on the right is an internal part 
of the camera and records, date, time, and depth 
of each picture. The "data chamber" in the camera 
has been found to be invaluable in preventing the 
accidental switching of films. A small photo is 
taken with each photograph of pressure (depth), 
time on a 24-hour basis, and written in longitude 
and latitude information as well as the ship, 
date, etc. 
In April, 1951 plans were being made 
for the June, 1961 cruise of Woods Hole's Research 
Vessel Chain to the Puerto Rican Trench. Chief 
Scientist J. B. Hersey needed a camera that would 
take pictures showing a fairly wide continuous 
strip of ocean floor at depths of 20,000 feet. 
This was to be the first use of the new F-4,5 lens. 
In order to get the cameras farther off 
the ocean floor, a special camera rack was used 
which placed the light closer to the bottom than 
the cameras. The new rack is shown in Figure 4. 
This new rack reduces the light source-to-bottom 
distance, thus increasing the illumination of the 
subject. The camera was wired such that it took 
pictures at -second intervals with a light source 
output ratings of 50 watt-seconds. Two of these 
camera assemblies were used, and hundreds of 
photographs were obtained. A sample photograph is 
shown in Figure 5, 
The results of the Puerto Rican Trench 
expedition indicated that still more light should 
be used. Consequently, a new lighting system was 
designed and two assemblies were built. The new 
system consists of the same framework as is shown 
in Figure 5. In place of the one, six volt, 50 
watt-second light source are two, 24 volt, 200 
watt-second light sources giving a total rating of 
400 watt-seconds. This increase by 8 fold in the 
light permits the use of wider angle reflectors 
to produce more even lighting. (The 24 volt light 
sources were originally designed for the bathy- 
scaphs FNRSII Trieste and Archemede. No batteries 
or automatic cycling controls are used since the 
lights are normally powered and controlled manually 
from inside the bathyscaph.) The automatic control 
