PREVENTIVE MAINTENANCE FOR LENSES
Text and Photos by Bob Warkentin
What's So Special About the Front Glass Port?
A Unique Problem of 15mm and 20mm Lenses: PROBLEM: White Cloudy Buildup on the Dome Ports
Cleaning Flat Glass Ports 0n 28mm, 35mm and 80mm Lenses
Stupid Mistakes Do Happen: PROBLEM: Scratches on the Flat Glass
PROBLEM: Whoops! The Lens Port Glass Is Crusty With Salt Residue
PROBLEM: Whoops! Small Scratches and Nicks-The Damage Is Done!
PROBLEM: Permanent Spots on Front Glass
PROBLEM: Direct Sun Light and Cracking of the O-ring Around the Flat Glass Ports
Distance & F-stop Knobs: PROBLEM: Servicing the Knob O-rings
PROBLEM: "Ah, ha! Playing With Your Knobs Again"
PROBLEM: Bumping and Wobbling Big Knobs or Add-on Extensions
PROBLEM: 15mm knobs
Optics and Their Optical Coatings: PROBLEM: Salt Water Mist or Droplets on Optical Coatings
PROBLEM: Well, You Got Spots On the Optics Anyway
What's So Special About the Front Glass Port?
In reality, the front ports of the 15mm, 20mm and the 28mm are an integral part of the overall optical system of each lens. The cost to replace a damaged port on these lenses could cost around $100 to $200. The front ports of the 35mm and 80mm lenses are basically flat ports, made from very thick specialty glass. Even so, the cost to replace them could range between $50 and $100. (Photo 1)
But, people some how have got the idea that the front flat or dome glass port on a Nikonos lens is nothing more than just a plain ol' cheap piece of glass to keep out water, period! Therefore, people allow these ports to become scratched or nicked, or they allow a white cloudy residue to build up around the edges of the glass and metal serial number ring that won't clean off, or use God-only-knows-what to clean the glass, causing the surfaces to become damaged (appearing like spots), and so on.
The major problem area of these two lense comes with the improper cleaning of the lens after saltwater use, which results in a white cloudy deposit that forms on the edges of the glass dome at the interface of the aluminum alloy serial number ring. I have seen this glaucoma-like residue extend as far as 3/4 of an inch above the serial number ring on 15mm lenses. (Photo 2)
If you have a lens with this cloudy deposit present, then you have found out that it will not clean off. You probably have also found out that the edges of your pictures are soft and fuzzy. What is it? It is the combination of aluminum oxide (rust) from the lens mount ring and dried salt water minerals.
How did this happen? During diving, salt water collects under this ring. Your conventional rinsing techniques were not sufficient to remove all of the salt water. So, over time, the aluminum metal in this area began to oxidize. Now as the water drains out from around the dome and the two spanner holes in the serial number ring, the salt water also drains out particles of aluminum oxide which together dry out onto the dome glass leaving a permanent white cloudy deposit on the dome.
SOLUTION: "Drain The Swamp" of 15 and 20mm Lenses
To fix the problem is easy, and even while the lens is still mounted to the camera! As soon as you get out of the water, take something like a drinking straw, place it over one of the spanner holes and blow out the water with your mouth. Watch out: keep your eyes closed! The water coming out the other hole usually hits you in the face and eyes. (DO NOT USE A HIGH PRESSURE AIR GUN! Lips and lungs, only!) Note: On old style 15mm lenses, the spanner holes are sealed so this procedure will not work. Therefore, you must constantly inspect the lens and wipe off the drainage.
Now, when you submerge the lens in fresh water (while still mounted to the camera, of course) to clean off and out the salt water, this hidden area will be more easily filled with fresh water. Blowing it out again with the straw should just about remove all remaining salt water (photo 3). You can do this as many times as you want if you feel the need. Also, periodically inspect for drainage and wipe clean with a soft, grit-free tissue or cotton cloth.
For all 15mm lenses, there is also another window to be concerned with. This is the f-stop/distance scale window on the side of the lens casing. While this window is plastic, it too can become cloudy with residue. And just like the dome serial number retaining ring can trap salt water, so can a lot of salt water, sand and grit be trapped between the walls of the metal lens casing and this plastic window. Lots of water, and all around the lens.
How do we get rid of this salt water? That's right, blow it out your lens. And what do we use? That's right, lips and lungs! But this time I use my mouth directly on one side of the window. Keep your eyes closed or they will become full of salt water and usually some sand and grit particles as it all comes out the other side of the window area.
Since there is only a rubber O-ring in direct contact with every flat port glass as well as no hidden areas on the flat ports for salt water to be trapped as there are on the 15 and 20mm lenses, these lenses are easy to clean from side to side just during the proper fresh water cleaning procedures. I have not seen one that has become cloudy at the edges of the front glass like the 15 and 20mm lenses.
Well, since so many people have the idea that glass is just glass, nothing can stick to it that can't be cleaned off and thus "very easy to clean" just like a diving mask, where do all the ugly looking front glass ports come from?
PROBLEM: Scratches on the Flat Glass
True, with all of the diving and photo equipment that we carry, sooner or later scratches occur. But the biggest single contributor of scratches is the DRIED SALT WATER (salt crystals) itself. These crystals form their own "sand paper". So, when we wipe off the lens port with our dry t-shirt or towel, we are literally grinding these dried salt crystals into the glass and presto: we have made "instant under water use from now on" lenses. Or, we use a previously salt water wet towel and wipe the port vigorously to get off those dried water spots. The salt water in the towel has evaporated leaving behind the coarse salt crystals. Guess what: "sand paper" in another form!
But why doesn't it happen to the glass on our diving masks? Well, have you ever seen anyone "dry" cleaning the glass with a towel or T-shirt? No, of course not. They always are using a liquid like mask defogger, liquid soap, spit and ocean water along with a wet hand or finger. But nothing dry, right? (No, I am not saying to use these items to clean the lens. Just don't "dry" clean the lens. Please read the SOLUTION section below for the answer!)
The next contributors to those fine scratches commonly found on these lenses are, believe it or not, from either tooth paste, liquid window cleaners, or water and vinegar solutions. Man, what humans can do!
Easy! Don't let the salt water dry out on the lens! As I continue to preach, just keep all of your photo equipment wet, even in salt water, until you can properly wash off the salt water with fresh water. Remember, salt water dries out on your body (and your equipment) in 5 to 10 minutes after diving. While it is not usually possible for you to remain submerged in salt water indefinitely in order that you don't have the discomfort of salt water drying out on your body, your photo equipment can remain submerged.
So, carry on board the dive boat an empty plastic trash can. Between the first and second dive, fill the trash can with salt water and submerge your equipment (assembled, of course!) for the duration of your surface interval as well as that long boat ride back. Leave it resting in the "wet" salt water (not drying the air) until you are ready to perform the fresh water rinsing (or pour out the water from the trash can if you are within 10 minutes away from your room and fresh water).
(Warning! For this procedure, the lens MUST be mounted to the camera. Don't be stupid and think you can do this with just the plastic rear lens cap on the lens.)
Lay the equipment submerged in water (fresh or salt, it doesn't matter right now). Let it sit for about 5 minutes, and then while still in this water, carefully and gently wipe your finger over the glass port until you feel salt buildup. Using your fingernail, try to unseat (flick off, not wipe off) the salt crystals. When you no longer feel any coarseness on the glass port, then submerge a cotton cloth into the water and gently wipe the glass using short upward rotating strokes with the cloth wrapped around your finger, advancing to another part of the cloth with each wipe. If you are finished diving for the day, then the water should be fresh. Regardless, the secret here is to do the DRY salt crystal removal in a WET environment (remember the "wet way" that you clean your diving mask glass!).
There ain't nothin' you can do now! But no worries, mate! Since the lenses are used underwater, the water merely fills in the scratch or small nicks during diving and typically does not affect the photo in any way. However, land use (35mm and 80mm) is another story. Your photos will be affected depending upon the size and shape of the scratches. No way to fix this without replacement of the glass port.
I have seen the results of a dried salt water spot cleaned so hard that it resulted in a permanent damage to the surface coating. This is a "gray area" topic for discussion. Sometimes no photo problems; sometimes big photo problems. This time, no easy answer.
On land, you certainly will have photo problems. But for underwater use, you must try the lens to determine if there will be any noticeable photo effects. Photographically you may see a diver in a blue bathing suit with yellow/orange spots. Water may not be able to work its magic this time as it did for the scratches and nicks in the glass ports. Here, you will be forced into replacing the glass port.
Don't use chemicals like window cleaners, vinegar, etc. to clean the glass ports. Only water or a genuine liquid lens cleaner, and a soft tissue, cloth or cotton swab, even a wet finger. The secret here is that no cleaning should be done DRY.
All to often I have seen lenses with their respective cameras that were in good working condition except that the O-ring around the flat glass port of the lens was dry-rotted, cracking, and even leaking water. Since none of the other camera or lens O-rings were cracking (flat, filthy, worn out: yes, but not cracking!) it is obvious that prolonged direct exposure to direct sun light destroyed this O-ring
No, don't use a #15 sun block lotion. Just "stick it where the sun don't shine"!
This is one area of the overall Nikonos system that has one of the best all-around O-ring seats. Best from the standpoint of being an O-ring contained operational point that can continue to function water tightly year after year even if the rest of the lens suffers from massive amounts of human neglect and poor cleaning.
In the photo cutaway, the O-ring pocket is obviously small, and the knob itself has on its end an extension the diameter of the pocket (photo 6) which in essence seals the "top of the jar" from debris to get in. Of course water can get into this area, but the volume is so small that the residues left behind are likewise very small. The result: an O-ring area that can last for a long time before replacement is required.
PROBLEM: Servicing the Knob O-rings
While the lens housing must be completely disassembled for this procedure, this is the least of the problems.
Unfortunately, the aluminum knobs are held onto the gear axles with tiny (stainless) steel screws. And we all know what that equation equals: [steel screws + aluminum knobs + salt water + 1 week of use = "concrete"]. To remove the knobs from the lens casing for a demanding individual, you simply apply the hacksaw tool and presto: almost instant separation cutting right through the knob and gear.. Since new parts (knobs, gears and screws) in addition to the O-ring as well as a lot of labor are needed, this ain't a cheap procedure. So if you really have money to burn, I've got the fire.
As explained in the opening paragraph of this section, the O-ring pocket is well protected and enclosed. I have not (yet) seen a lens which has leaked from a knob O-ring unless the knob or knob/gear axle assembly was loose and could be wobbled (through the O-ring), or where the knob/gear axle had been bumped and was bent or that the metal O-ring pocket was pitted.
So just by performing your good after-diving cleaning procedures to all of your equipment, you will keep your knob O-ring in good condition.
Regardless of your desires to be photographically creative under water by bracketing each shot, the knobs were not designed for you to rotate 360 degrees. As your hand twists the knob in a direction illogical in the mind of any red blooded Vulcan (or even that of Nikon), you notice that the knob now turns very freely, or that the indicators are not changing, or the iris does not open or close, or the lens' optics do not move. You have either stripped every tooth off of the gear itself, or have cut a channel into the axle itself (common on 20mm's) from the locking set screws which hold the knob onto the axle.
Ah, knowing not the word "defeat" and adding to it the concept of "there's a first time for everything", there quickly appears like almost magic a box of jeweler screwdrivers. Soon the surgeon's tools are skillfully dissecting the screws from the knobs. When all have been loosened,the knob is forced against the side of the lens case as the screws are re-seated. In eager anticipation, the first timer tests the knobs only to realize that the "operation" to correct for this looseness only further loosens the feel (and wobble) of the knob and gear axle.
SOLUTION: Don't Dive The Lens
There isn't anything you can do yourself except profit from your mistake. The lens must be fully disassembled and rebuilt to correct your "great ape" strength or your "field surgery".
As the old saying goes, "when you stick out your neck, someone may chop it off". Well, the same is true for the knobs on a Nikonos lens. The bigger the knob, or the longer the knob add-on extension, or where the knob sticks out determines how much of a target you will have for bending and expensive damage. Adjustment knobs are certainly a necessary part of underwater photography, period! The bigger the knob the easier it is for you to grab and turn, but not necessarily on the axis of the O-ring (better known as wobbling the knob).
First, don't use those add-on extension knobs unless you are forced into it by having to use thick gloves. If you have to use them, remember to be ever mentally aware that your hands can cause the knobs (and the gear axle which goes through the O-ring) to be rotated off center thereby causing water leakage past the O-ring To eliminate leakage of water every time you adjust the f-stop or distance of your lens, tell yourself to "push in on the knob and then rotate it on axis".
For the 15mm lens, the knobs themselves are large, and when the lens is mounted to the camera as everyone does, one knob extends below both the camera as well as the camera tray. What a perfect target for destruction, EVEN WHEN JUST MOUNTING TO A CAMERA TRAY!
First, don't forget to use only the single hole (not the channel hole) in the camera tray (of the Nikonos flash) to mount your Nikonos V with a 15mm lens. Otherwise, the tray will cause the lens to be seated on its main mounting O-ring at an angle and will probably cause the lens to flood.
Next, if you really are smart and want to further protect your $1200 investment, for about $0.89 you can build a combination handle and knob protection bracket and attach it to the bottom of your tray. Simply buy a 3/4" wide metal brace at the hardware store, along with a 1/4x20 bolt about one inch long, and a 1/4" washer, lock washer and wing nut. Bend the brace. Cut off the head of the bolt and file off the rough surface. Screw the bolt into the bottom of the camera tray by hand, set your just made "handle" over the bolt through one of its already drilled holes, and secure it to the tray with the washer and wing nut. (Photo 7) Presto: not only do you have a handle to hand your camera rig up to the guy on the boat when getting out of the water, but also a guard protecting the lens knob from getting bumped underwater, on the boat, in a rinse tank, and other places.
Unless your lens should ever be flooded, only the rear optical group of any Nikonos lens is ever in danger of being permanently damaged by salt water from every day use. This is an all too frequent problem and one that will really ruin your photos. (Photo 8)
PROBLEM: Salt Water Mist or Droplets on Optical Coatings
We all know (I hope) NOT to remove the lens from the camera in the rain, or with a dripping wet face, chin, hair or hands (including those other wet divers around us) or where there is a lot of salt spray while the boat is under way, right? But do you remember from previous articles in Ocean Realm that water will remain in the O-ring grooves for up to seven days after diving, even though the outside is bone dry? And did you realize that when removing the lens from the camera, you can cause a vacuum of air to occur around the wet O-ring of the lens that will cause the water to become a spray mist of salt water that will be sucked right onto the unprotected optical coating of the rear optics? And, salt water will eat optical coatings!
First, wait a while, while everyone around you dries out, including yourself (however, remember that the camera and lens will be in the trash can staying wet in the salt water). After removing the camera/lens from the trash can and towel drying the excess water off the equipment and your hands, point the lens downwards, SLOWLY unscrew and remove the lens DOWNWARDS from the camera. Set the lens face down off to one side and just set the rear lens cap over the back of the lens for now. With camera still in hand and pointing downwards, towel dry the silver colored lens mount ring on the front of the camera, regardless if you are mounting another lens for more diving that day, or you have completed your cleaning procedures and are disassembling everything for over night dry out. Now for the lens setting patiently off to the side.
If you are on board a boat that you must leave, then take the edge of the towel and run it around the still exposed edge of the O-ring (the lens cap was NOT pushed down over the O-ring initially, remember?) to pickup the excess water. Now, push down and lock the rear lens cap and it is ready to be transported, but NOT PUT AWAY YET for good! Remember, it is still salty!
Back at your room, the dismounted lens must have a proper final fresh water cleaning. So, remove the lens from the rear lens cap just as though you were removing a lens from the camera (downwards, etc. just like above). That's right, the rear cap fits tight enough that if you were to pull it off of the still wet O-ring too fast it would cause a salt water spray to be sucked onto the rear optical coating. Remount the lens onto the camera and perform the final fresh water cleaning. (Please don't be foolish enough to believe that you can submerge a lens in water using the plastic rear lens cap as a water tight seal) If there is no more diving for the day, you can now dismount and set the lens face down on the table and this time just let the rear lens cap loosely rest on the lens while the O-ring and channel dry out over night.
Like front ports above, don't just dry rub to optics, even with a soft cotton swab. Use a liquid lens cleaner and a lot of lens tissues or cotton swabs. And DON'T pour the lens cleaner all over the optics! Apply it to the tissue or swab, and then apply the moistened tissue or swab to the optics. One wet wipe; then dry wipe; then throw it away and get another tissue or swab.. But don't keep wiping the wet one over and over again. It could have picked up a crystal of dried salt and could scratch everything. If you decided to pour the cleaner onto the optics, then the cleaner will get under the metal lens retaining ring and just when you think all is clean and dry, it will leak out, dry, and give you weird looking pictures. Control the liquid you use!
Reprinted with permission from Bob Warkentin's Southern Nikonos Service Center, Inc.
9459 Kempwood, Houston, TX 77080 713/462-5436