My Adventures with the Ziess Nettar 515

2005 R. A. Suomala

My son, Mark, and his wife, Becky, came to visit Arizona this January from their home in New Hampshire. They usually come here to do some high intensity bird watching and to visit with us old folks. I suspect the weather has something to do with this migration. Becky inherited a camera from her mother's father (Becky's grandfather), one of the Turner clan. They brought it along because of my interest in old cameras. It turned out to be a Ziess Nettar Model 515 (s/n J23186) which was purchased new by her grandfather in 1938. The camera has a three element, uncoated, f/4.5, 75 mm, Nettar Anastigmat lens and a Kilo shutter. The Nettar cameras were a low cost alternative to the top of the line Ikonta cameras. While the construction of the Nettars was relatively economical, the high quality of workmanship and simplicity meant that they almost always worked and were easy to fix if they did not work.

This particular specimen was in fair shape with the following problems.

1. Someone had taped the leading and trailing edges of the pressure plate down to the inside of the camera back (yuck). Evidently the masking tape that was initially used gave up so copious amounts of black electrical tape were added. I have no idea why this was done (Maybe when film is run through it will all be revealed). The electrical tape came off fairly easily but did leave small amounts of adhesive behind. The masking tape adhesive was another thing altogether. This stuff is a real challenge to remove. Masking tape was originally developed to mask off areas during the spray painting process. It was never intended to be left in place but rather stripped off immediately after the paint had dried. In fact if you leave it on for any period thereafter it will probably leave some gummy adhesive behind. Fortunately a firm in Arizona has developed a relatively non-toxic, citrus based, biodegradable solvent that removed the adhesive with out damaging the paint or plating. The product is De-Sol-it â and is made right here in Arizona by Orange-Sol Household Products (1-800-877-7771). The solvent was applied to the adhesive residue with Q-Tipsâ . Several applications were required and some light scrubbing with the Q-Tipsâ helped. I tried to avoid getting it on any of the leatherette covering or in any places where the solvent might migrate into areas from where it could not be easily removed. Finally, when all of the adhesive had been dissolved and the excess solvent wiped off, a light wash down with isopropyl alcohol removed any remaining solvent/adhesive.

2. The shutter did not operate in the speed range from 1 to 1/10 second. The self-timer was inoperative. To fix these problems the front focussing lens element and its mount were removed by first removing the small stop screw and then completely unscrewing the mount. Since this is a single lead thread there is no need to make any index marks for re-assembly. There is a very thin nut plate used to secure the shutter faceplate and speed indexing cam plate. This nut plate has two notches that are intended to accept a spanner wrench but the nut can be turned by judicious use of a small blade screwdriver (providing you don't let the screwdriver slip, ouch!). Once the nut, faceplate and cam plate are removed you can see the timing escapements that control the slow shutter speeds and the self-timer. Each of the two escapements has a toothed wheel that rotates against a sort of hinged flapper. An extremely small amount of Break-Freeâ CLPâ , cleaner, lubricant, penetrant (MIL-L-63460, available at most gun shops, shake well before using) was applied to the perimeter of the wheels and the problem was solved (Note-professional camera repairmen usually use NyOil which is available from Micro-Tools www.micro-tools.com). The rest of the shutter mechanism was left dry. Most between the lens shutters are better left that way. The shutter speeds were checked and are as expected quite proper except at the high end. The following lists the speeds and corresponding error in f-stops.

1 sec 0.01 stop fast

1/2 sec 0.22 stop slow

1/5 sec 0.04 stop slow

1/10 sec 0.48 stop fast

1/25 sec 0.13 stop slow

1/50 sec 0.37 stop slow

1/100 sec 0.38 stop slow

1/175 sec 0.62 stop slow

Not too bad for a 67 year old shutter that has probably not been used for at least the last 25 years. One clue to when it was last used is the metal film spool found in the camera. When was the last time 120 size film was supplied with a metal spool? The fast 1/10 speed was tested again and it is still fast. Probably always was. I decided not to adjust the shutter speeds. It is less of a bother to simply open or close the aperture a half a stop. Probably ignoring it altogether would still produce acceptable results.

3. The camera had been carried in a leather case, which tended to abrade the paint on the corners of the camera body. Once again the gun shop had the solution in a product made by Birchwood Casey â called Super Black ä . This is called an instant touch-up pen and comes in a gloss black grade (follow directions carefully). Some would argue that the camera should be left in the original worn condition but I prefer the somewhat restored look.

4. The front lens surface had some almost imperceptible, light cleaning marks and one very fine scratch near the outer edge. Since the marks were hard to differentiate in appearance from fungus some vinegar was applied to the lens surface. Alas, after carefully washing off the vinegar with distilled water the marks were still there. These probably won't affect the quality of the images but resolution tests will sort this out. NOTE!! Do not clean lenses with your shirttail. In fact if you don't know the correct way to clean lenses leave them alone.

Becky's brother, Ted (another maternal offspring of the Turner clan), and his wife Mary moved to Tucson from Wellesley, Massachusetts several years ago (you don't suppose the weather was a factor?). Ted and Mary invited us all up for dinner so I loaded the Nettar up with some 120 size Ilford Pan F (ASA 50). The bellows were checked for leaks but sometimes the really small ones are almost impossible to see. The frame index marks (black on gray) on the Ilford film backing are really hard to see through the little red windows (maybe it's my old eyes). Since this is a half frame camera (6 X 4.5 cm just like the latest crop of medium format professional digital cameras) the frame number comes up really fast in the second window. The camera has two windows to read the frame numbers because the film manufacturers did not provide numbers on the backing for the 6 X 4.5 format as they do now. Well the pictures were a disappointment. I misjudged the exposure on some interior shots, there was an obvious light leak in some of the shots and there seemed to be a focussing scale problem.

The first problem addressed was the light leak. A light source that could be inserted into the interior of the bellows was constructed using a 7-1/2 watt, 120VAC lamp. With the light source installed and the room darkened the bellows were pushed and flexed and sure enough there was a small light leak at one of the external edges of the bellows. You had to push the bellows just so to be able to see it. Experiments with black silicone RTV (Room Temperature Vulcanizing) rubber sealant indicated that it was just not opaque enough to seal light leaks. Several Internet sources suggested Liquitexâ , an acrylic artist color as a sealant. Liquitexâ is made in England and according to the label the black pigment is made from "Amorphous Carbon Produced by Charring Animal Bone (PBk 9)". Wow! Liquitexâ is available in "Ivory Black and "Mars Black". My local art store (Artistic Creations, Green Valley AZ) suggested that the "Ivory Black" (#1045 244) was probably the more opaque/blacker product. If you would like to see how this material behaves then apply some to a piece of clean glass. A single thick coat dries to a very thin flexible film that can be removed intact with a razor blade. Try multiple coats to see how well it builds up. The Internet sources recommended applying the sealant to the inside of the bellows. Believing that there is no such thing as overkill in sealing things, I also applied it to the outside. Several coats were applied After the sealant was completely dry (overnight with the bellows open), the bellows were closed and opened several times and checked for leakage. The bellows were now light tight. I wondered why there was just this one leak. The conclusion is that the person who used the camera got in the habit holding the camera by hooking the index finger of the left hand around the top when the front was open. Unfortunately the end of the finger and probably the fingernail abraded the projecting fold in the bellows at that single point.

The focus problem was attacked next. Fifty years ago or more when Edmund Scientific was a real experimenter's paradise I obtained a military surplus, gun sight reticule projector from them. This consists of a lamp, a reticule and a collimating projection lens. I have used this successfully to simulate a star (infinite) image. Using a piece of ground glass (actually plastic) at the film plane, an 8X loupe and the collimator, the image appeared to be much out of focus when the focussing scale was set at infinity. The focussing scale is attached to the front lens cell by three, very small, equally spaced set screws located on the perimeter. Backing these screws out but not fully removing them should allow removal of the scale ring. It was finally necessary to back off the projecting infinity stop screw a few turns in order to remove the ring (the screw probably bottomed out on the lens cell). Note! When the lens cell was rotated to achieve focus it seemed a little loose so a very small amount of synthetic, fairly high tack grease was applied to the focussing thread. Once again the gun shop comes to the rescue with Plasti-Lube (available from Champions Choice, LaVerne, TN, their item CC140, http://www.champchoice.com, phone 1-800-345-7179). Professional camera repairmen usually use NyoGel, which is available from Micro-Tools.

The lens cell was rotated (aperture at f/4.5) until the star image from the collimator was sharply in focus. The scale ring was installed with the stop screw against the focus scale index tab (set to infinite focus). The focus was checked at 4 feet (minimum scale distance) using the ground glass, 8X loupe and some newsprint located exactly 48 inches from the film plane. PERFECT!

Now maybe that explains the tape on the pressure plate. Unfortunately it probably made the problem worse. I suspect someone had tinkered with the camera and maybe loosened the three screws in an attempt to get at the shutter. Not a good idea unless you are prepared to correctly set up the focussing scale.

The next step was to shoot some more film using Kodak 100T-Max (The latest version of T-Max100). The yellow backing with very distinct frame numbers on the Kodak make the frame numbers much easier to see than the frame numbers on the Ilford film as viewed through the red windows. The first exposures were made to check focus and resolution. No attempt was made to maximize resolution by using ultra fine grain film and processing to maximum contrast. Just regular film and normal processing. The following equipment was used:

1. Two studio electronic flash units (no flash sync on this camera so all exposures were made using the "open flash" technique).

2. Edmund Scientific version of the USAF 1951 resolution test chart, 24 X 36 inches.

3. Bogen 3040 tripod with a couple of sash weights to anchor it.

After much measuring and agonizing over alignment of the optical axis with the chart a series of exposures were made, one at each indicated aperture. The chart was 60 inches (5 feet) from the film plane and the focussing scale corresponded to the sharpest image on the ground glass.

Using a 40X microscope the following maximum resolution values were observed.

f/4.5 33 LP/MM, center 12 LP/MM, corner

f/5.6 41 LP/MM, center 21 LP/MM, corner

f/8 46 LP/MM, center 29 LP/MM, corner

f/11 46 LP/MM, center 29 LP/MM, corner

f/16 52 LP/MM, center 37 LP/MM, corner

f/22 46 LP/MM, center 46 LP/MM, corner

Some of the softness at f/4.5 can probably be attributed to film flatness or lack thereof. Overall these are quite acceptable results for an uncoated, three-element lens. Obviously images taken with this lens will exhibit less contrast than those taken with modern, multi-coated lenses. Some artists actually prefer this softer contrast. Maybe that explains the art community's love of the images made with the ridiculously inexpensive Holga camera (Check out some of Imogen Cunningham's ethereal pictures taken with early, uncoated lenses).

Mounting the camera on a tripod presented a small problem. The tripod thread is in a bushing whose surface is about 2 MM above the bottom of the camera body. This makes it difficult to secure the camera to a tripod with enough friction to prevent rotation about the axis of the mounting screw. The solution to this problem was to place a neoprene O-Ring around the bushing. The O-Ring that worked best was 15/16 X 3/4 X 3/32. These are available at most hardware stores in the plumbing section.

Using this camera I had to remember many old lessons. Using my Nikon 8008s (soon to be an antique also) with its automated exposure and focus requires little in the way of attention to detail. When using a view camera I never have a problem remembering focussing, setting the aperture, setting the shutter speed, cocking the shutter, inserting the film holder, and removing the dark slide. But somehow when using a relatively small, hand held camera I now seem to forget to focus, cock the shutter and advance the film. These are things I always had to do 50 years ago, but seem to have forgotten (My first camera was a Kodak 3A, Autographic 116 with a Rapid Rectilinear lens).

One thing that has drawn my attention to old cameras is the satisfaction derived from putting them back to work. Sixty-seven years ago each of the component parts of this camera was carefully handled by people who were proud of their craftsmanship. No automation here. Maybe old cameras are just inanimate objects but somehow when they are restored to working condition they seem to come alive and I even imagine they feel warmer to the touch. I simply don't get that sense of intimacy with modern film cameras containing electronics and certainly not with digital cameras. Sort of like the difference between a Bugatti and a Hummer.

USE OLD CAMERAS!!