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H2Oplanet

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Posts posted by H2Oplanet


  1. Aqua_Soul,

     

    It is difficult to determine the root cause(s) of degraded metals without actually inspecting, testing and evaluating the components; however, as you can tell, that doesn't stop many of us from trying. Metal failure occurs predominately through corrosion, fracture and wear. In my opinion, corrosion is misunderstood more than other forms of materials degradation. Assuming that your problem is pitting due to exposure in marine environment(s), I am fairly comfortable with and confident in the following comments/questions/suggestions:

     

    1. I agree with Bob's comment above. Have you asked the manufacturer-of-the-housing if they know of similar problems with their product(s) and if they are will to evaluate... with hopes that they will repair or even replace?

    2. You might consider visiting corrosion forums for further input...MarineCorrosion.org out of the UK is a good source but often very technical.

    3. Generally, I would recommend you take action very carefully after weighing your options. It would be relatively easy to damage the housing well beyond its current state.

    4. Based upon the limited information gleaned from your posts and observation of your photos, I would recommend the following:

    a. Do not try to "locally" anodize the housing unless you are comfortable doing so and/or you solicit help from someone who is. It's not simply a matter of cleaning out dirt, debris and corrosion products followed by local application of an acid. Anodization is an electrochemical process. There are different types of anodized coatings and they are produced primarily by two methods: chromic acid and sulfuric acid. They produce a relatively thick, tenatious oxide layer that protects the underlaying base metal, aluminum alloy in this case. In my opinion, if re-anodizing is required, you need to match the process that was used originally and blend in a manner that you don't disrupt regions adjacent to the pits. Areas that presumably have retained integrity of the anodized layer.

    b. Initially, I would not add sacrificial anode(s). They are relatively easy to install but care must be exercised to prevent other problems (e.g coating disbondment at the point of attachment, etc.). Furthermore, they only preclude corrosion during immersion. Most of us expose our housings to "alternate immersion" service. Consequently, even if the housing is protected via sacrificial anode, pitting can/will proceed while the housing is in spray-and-splash or even marine atmospheric conditions (like one often experiences on the deck of a boat even if you fresh-water rinse upon surfacing). Above the water's surface, a sacrificial anode can only protect the basemetal for a distance of approximately 1/4" (6mm)--radial distance from the perimeter of the anode. If you do pursue the sacrificial anode route, I would recommend zinc over magnesium (advantages include less probability of coating damage and lower consumption rate of anode itself).

    c. Initially, I would focus on locally cleaning the pitted areas followed by an organic coating. Ideally, you'll want to use a system similar to your original coating whether it be enamel, epoxy, etc. Unfortunately I can't provide a specific cleaning procedure but I suspect there are many reliable solutions available online. I would suggest you only clean to the degree necessary (remove debris and any white powdery corrosion product). Should not rely solely on the unaided eye but rather use a magnifying glass or microscope at low power.

    d. If "c" above does not mitigate the pitting then you may need to proceed to anodizing and/or installing a sacrificial anode(s)

    e. Again, whatever actions you take you obviously want to make sure you do not do "more harm than good". If repairs are not done properly, you can aggrevate the surface and accelerate attack at/near the existing pits or elsewhere.

     

    As for the cause of your pitting problem, there are several possibilities. I can't say with a high degree of confidence; however, I will provide the following comments:

     

    --it is likely that you had defect(s) in your original coating system. Organic coatings (paint) often have "holidays" even if applied correctly. For aluminum housings, the below laying anodized layer is the next line of protection from pitting and other forms of corrosion. Without a painted overcoat, the relatively brittle, anodized layer can be damaged, mechanically in a variety of ways which provides a path for pitting of the basemetal (typically due to crevice corrosion via a "differential oxygen cell" mechanism).

    --although less likely, you may have had a housing with some form of surface metallurgical defects (e.g. shrinkage porosity, gas porosity, non-metallic inclusions, etc.) In this case, the defects may have precluded the expected protection from anodizing and coating.

    --also possible but not probable (and you are in the best position to know this) is that the housing experienced some very fine mechanical damage (hitting edges, sharp pointy object striking the housing, etc.

    -- Pitting (particularly when crevice corrosion is an issue) can occur very quickly with passive film former (e.g. aluminum alloys, stainless steel alloys, etc.); however, depending upon the residual thickness of your base-metal, specific location of the pits, etc. your damage may not be urgently significant. Again, unless you go about repairs methodically and with care you could cause more harm than good.

    --The role of dissimilar metals in your problem is easy to overstate. Aluminum and Stainless Steel are often successfully used in combination for Marine service regardless of the specific stainless steel alloy. The potential difference (driving force for dissimilar metal corrosion, a.k.a. "galvanic corrosion") of aluminum and stainless steel is typically acceptable particularly when the stainless steel component is small relative to the aluminum component (as is the case with most UW housings). The reasons include (a) a favorable anode/cathode ratio and (b) a phenomenon known as polarization...I will not get into this topics unless you are interested:)

    --The role of stray-currents (the often used term, Electrolysis, is a bit of misnomer and erroneously used even by chemists, metallurgists, etc.--rarely does the corrosion engineer talk in terms of "electrolysis"), is unlikely for your problem.

     

    Sorry for the long-winded response...please let me know if you would like further input...Good Luck!

     

    Scott


  2. Ren has forwarded the image to the Marine Science Department of University North Carolina @ Wilmington. They, in turn, passed it on to a Mr. David Johnson (Curator/Ichthyologist, Division of Fishes, National Museum of Natural History) who suggests it may be a "monkfish" (Lophius sp.?)... anyone else have an opinion?

     

    Scott Marshall, P.E.

    www.H2O-planet.com


  3. post-4226-1238613230.jpg

     

    My buddy, Ren Chapman, shot some video of this critter earlier in the week (see attached "frame grab" image). It was about the size of a quarter and was found in ~20' of seawater offshore here in Wilmington, North Carolina. It had streaming tentacles and seemed to "flare up" and hold its ground rather than retreat when approached. To me it looks like a postlarval form of a lionfish. The water column was filled with myriad species of jellyfish...could it be that these guys mimic jelly's in early stages for protection? As you are probably aware we have been "invaded" by Lionfish over the last few years here on the east coast so it would make sense if it were indeed a species of Lionfish; however, tropicals begin to move into our area via the Gulf Stream this time of year and I'm often surprised at what we see this far "north"... Appreciate any comments/information...cheers...

     

    Scott Marshall, P.E.

    www.H2O-planet.com


  4. As I understand it, the charging/discharging of battery cells is very similar to corrosion cells in that both are electrochemical reactions. Gas is emitted at the cathode (typically hydrogen for corrosion cells in marine environments). With a "fast" charger, the kinetics probably increase such that more gas is produced quicker??? Again, I have no direct experience with battery technology per se but significant "exposure" to corrosion technology (particularly, marine corrosion).

     

    It seems the larger objective (regardless of charging type and cell type) is to provide a way for gases to dissipate while avoiding an ignition source. PRC's post on this matter are practical, enlightening, interesting, and helpful. thx

     

    Scott

    www.H2O-Planet.com


  5. Let me be clear that, I THINK that this killing was unmerited. My opinion is based upon reading everything I could about this incident, looking at all the stills and video made available, speaking directly with DJ about it and lastly weighing my personal experiences with Tigers (3 weeks with numerous Tigers at Tiger Beach and one scary encounter at night in the Marshall Islands).

     

    I believe DREW and several others have guided this thread in a very productive way. The opinions, experiences, perspectives and testimonials shared on this site and others will hopefully educate others that may someday be faced with similar decisions. I only hope the outcome will be different more often than not.

     

    That said, DJ is a friend and a fellow photographer. He has a significant understanding of the ocean and it inhabitants honed by a formal education in Marine Science and countless hours in and around the water. I know him as a kind and rational person with an extremely strong appreciation for conservation and the environment. Given the same set of circumstances I may well have made the same decision to document the experience photographically. That said, I suspect I would have used the images in a different manner.

     

    At the end of the day, I believe that this is a healthy discussion and hope that it will continue without the attacks that serve no useful purpose but rather alienate, polarize and put strong personalities on the defensive.

     

    Cheers,

     

    Scott Marshall

    www.H2O-planet.com


  6. Thanks for the suggestions everyone... always amazed at the experience base on this site. In addition to topside and snorkel shooting, it is apparent that a day trip on SCUBA to Ni'ihau has potential for fun and productive shooting. I understand that the monk seals are endangered and protected... do operators/enforcers permit approaching these animals... In general, how well do the monk seals respond to divers/snorkelers? :):blink:


  7. I will be in Kauai for two weeks visiting my son and I will have significant leisure time for shooting topside and underwater. I plan to bring a wide range of lenses (8mm to 500mm), 2 cameras (1Ds Mk II), tripod, and one housing. I will not be bringing SCUBA gear so I will be limited to shallow UW shots and split shots (snorkeling only). I will be staying in the Princeville area and hope to day hike around fairly accessible areas of the island. Given that information, any subject and/or location recommendations?


  8. Jeremy,

     

    Not sure it is a Nikon/Canon difference but I believe that my images with Canon cameras have a slightly different texture and color relative to similar (subject and condition) images I've seen from fellow Nikon photographers. To me the RAW canon files (I shoot 1Ds Mk II) generally appear to be (1) little less saturated, (2) more of a soft "matted" texture and (3) from more of a soft "pastel" pallet directly out of camera. Again, it is extremely subtle.

     

    Perhaps this is due to factors such as (1) CMOS vs CCD, (2) camera settings, (3) display type etc. I use Apple monitors (non-glossy option) both with laptop and desktop units. Perhaps my aging eyesight plays a role.

     

    Depending upon subject and conditions, my preference alternates.

     

    Anyone else notice this difference? Alex, we've shot the same subjects on the same dives (you Nikon, me Canon) is this my imagination??

     

    Cheers,

     

    Scott


  9. Ghost, I am a fan of pretty much all things SEACAM except their strobe arms. The arms are robust but too negatively buoyant. The clamps are very cumbersome to work; this makes strobe placement more difficult than it needs to be. In addition, they are extremely expensive (like all SEACAM products). I much prefer my ULCS systems.

     

    Furthermore, I am not a fan of STIX system predominately because the threaded fasteners (screws) that secure the ball-ends frequently back off. Many have suggested "band aide" fixes for the STIX fasteners (e.g. lock tite) but it seems to affect the ability of the user to add/remove floats which, in my mind, was the real advantage of the STIX system. If John can remedy the fastener problem than I think that this system has very good potential.

     

    Lastly, I know many UW photographers that love TLC products. I have never tried TLC personally.

     

    Hope this helps... :D


  10. Thanks for the good information guys...just want to clarify a few points and that may better explain the intent of the thread...

     

    I have swum and photographed over 30 species of sharks. Most of these experiences have been "chance" encounters although some have been "baiting" and/or "chumming" situations. They include very close encounters with Scalloped Hammerhead (rebreathers), Great Whites (cages), Mako (scary spear fishing incident), etc. So, at the end of the day I am asking about "chance encounters" and "baiting" situations.

     

    Again, questions were conceived after reading so much about covering the white colored STIX arms (converting color from white to black) and after reading the following on Jim Abernethy's website: Please do not bring any white or yellow dive gear, especially fins, mask, gloves, or wetsuits with a large amount of white or yellow.

    If the white arms are of concern then why not the shinny strobes and the shinny stainless attachments/inserts within the housing?

     

    I will be joining Jim and many others this summer and I respect their experiences and opinions but I just wanted to expand the conversation from dive gear and strobe arms to other equipment that may/may not increase risk...

     

    Lastly, I have never been in the water with many of these species (Great Hammerhead, Tiger's, Oceanic Whitetip, etc.) and I am excited to get as close as these animals will allow but I do want to minimize unnecessary risks...want to stick around to see my 3 and 4 year olds grow up...Thanks again for your thoughtful replies!

     

    Scott


  11. I have some follow-up concerns in the wake of the wonderful thread initiated by Cor's review of the Stix Buoyancy Arm System. In this thread, concerns were raised over the possible shark affinity to the white floats. Many of us were concerned enough to change the white color to black via coatings, shrink wrap, etc.

     

    For years, we have heard and read of general concerns that certain shark species are attracted to light colors such as white or yellow. Also, it is commonly stated that Barracuda are attracted to "shinny objects". I have experienced a few incidents that may be pertinent (young sea lion tugging at my yellow mask strap, Silky sharks swooping down and pulling up just short of shinny 1st stage regulators, etc.) but I am interested in others experiences. So can anyone help me with the following?

     

    (1) Are there concerns about other lightly colored and/or shinny photo equipment? Specifically, is the silver finish of Camera Housings and Strobes like SeaCam models a significant problem?? While these surfaces are more of a matt finish than a glossy finish they are fairly reflective...

     

    (2) If there is a concern, has anyone simply attempted to darken the surface via a marker such as a Sharpie Pen? Any other fairly simple solutions that don't have considerable downside?

     

    (3) Are there specific concerns relative to Oceanic Whitetips or Tiger Sharks (I believe that Cor's upcoming trip to shoot these species prompted the concerns about the white floats?)...

     

    Thanks,

     

    Scott


  12. Two Questions:

     

    (1) Can someone explain how best to make a buoyancy collar for a flat port when shooting macro? i shoot macro with the 100mm Canon as well as the 180mm Canon. Just purchased the Stix system and I like the idea of using the collar in conjuction with the buoyancy arms for macro which would allow me to limit arm lengths and reduce bending moments.

     

    (2) You guys got me concerned about Sharks now since there are many species here in North Carolina plus I'm joining JASA/Wetpixel for the Bahama shoots in July. I can use techniques in this thread to cover the white floats with black but shouldn't I really be more conerned with my large, shinny SeaCam housing and the two large SeaCam 250 strobes??

     

    Please advise...

     

    Scott


  13. Are you sure that this damage is not of mechanical origin? Perhaps a ding, wear, etc... Perhaps the corrosion product developed after bare metal was exposed (mechanical damaged initiation)? After now having seen photos, it doesn't look like a crevice corrosion or dissimilar metal problem. For passive film formers (stainless and aluminum) crevice corrosion manifests itself under the crevice former but the damage you show is on a "boldly†exposed surface slightly remote from any obvious crevice. If dissimilar metal contact were a problem it typically would be most significant at a stainless/aluminum interface, which is not what I am seeing in your photo. I see two dings on the aluminum "cold shoe" base somewhat remote from the stainless steel "cold shoe" rail (for lack of a better term). Again, based upon location (corner and edge), it looks like mechanical damage??? Conversely, if this aluminum base is machined from a small piece of cast aluminum then it is possible that you have surface defects that have been exposed in a very short period of time (e.g. a non-metallic inclusion, shrinkage porosity, gas porosity, etc.). However, I believe that the aluminum base is probably a wrought aluminum alloy in the 5000 or 6000 series for which you rarely experience significant surface defects during processing.

     

    Lastly, regarding your question of "inferior quality aluminum" that is doubtful. Without any evidence that your problem is common for your specific equipment, it is doubtful that the original materials specifications were "inferior". Furthermore, inadequate materials substitutions (using materials other than those specified) for high reliability parts are fairly unusual. My staff and I have performed several thousand failure investigations and improper materials substitution was implicated in only a handful of instances. Conversely, poor materials selection is fairly common because most designers rarely consult with materials scientists (metallurgists, etc.) and even more rarely consider input from corrosion engineers. If this is a poor materials selection then more people should start to experience similar damage.

     

    There are just so many possibilities and without looking at the components I am probably just confusing matters for you?!?! Have you spoken with the housing distributor? The OEM??

     

    Just a few more points-of-information for those interested in marine corrosion:

     

    For copper based alloys, crevice corrosion typically manifests itself just outside the crevice former. Conventional wisdom is that crevice corrosion of copper alloys is due to a “metal ion concentration cell†while stainless steel (and some other passive film formers) exhibit crevice corrosion damage under the crevice former due to a “differential oxygen cellâ€. So, crevice corrosion of passive film formers is particularly dangerous considering you cannot see damage unless components are disassembled (this is why non-user serviceable o-rings scare me particularly with my old Nikonus systems).

     

    Conversely, even user-serviceable o-rings can be a problem particularly if you don’t do a good job of cleaning and drying equipment. I do not maintain my equipment well and have experienced damage to systems that I believe was, in part, due to crevice corrosion. For example: (1) pitting on Nikonus RS cameras where the lens o-ring (crevice former) seats at the cameras stainless steel lens opening, (2) Under clamp o-rings with ULCS arm clamps, (3) metal-to-metal crevices where sync cords mate with housing or camera bulkheads (again many attribute this to dissimilar metal corrosion but I believe it is more of a crevice corrosion problem particularly when the oxide layer (anodized layer) of a female socket (bulkhead fitting) within the camera or housing has experienced mechanical damage such as cracking, abrasion or galling). Regarding non-metallic (e.g. Delrin) male connectors for sync-cords, I believe they generally work better than metal connectors but not because this removes a dissimilar metal but rather it presents a situation where mechanic damage (a pre curser to further, more serious, crevice attack) is much less likely. However, unless you are careful the weakness of the Delrin connectors in my opinion is that they can more easily “cross-thread†…such was the case with my Ikelite cords mating Nikonus RS cameras to Substrobe 200’s.


  14. SCUBA-SI,

     

    It is difficult to impossible to do a root cause failure analysis without looking at and evaluating the failed component(s) directly. Having said that I will attempt to provide some comments that may help with this problem and others of a similar nature involving marine corrosion. I apologize in advanced for the long post but corrosion is a very difficult and misunderstood subject:

     

    1. Localized corrosion in the form of pitting is often the result of "crevice corrosion". This corrosion mechanism often occurs when a passive film former (e.g. aluminum alloys, stainless steels), are "covered" by a crevice former (e.g. barnacle attached to metal, gasket at a metal joint, adapter over a metal seat). Typically, tight, deep crevices are much more of a problem than loose, shallow crevices. For example, if you take an aluminum tube and stretch a tygon tube over its end (inner diameter of the Tygon the same or less than the outer diameter of the aluminum tube) and fully immerse it in natural seawater for a few weeks. Then remove the assembly from the water and take the Tygon from the end of the aluminum. You will notice significant pitting and etching on the outer diameter of the aluminum outer diameter surface. The tighter the crevice (Tygon fit over aluminum) and the deeper the crevice (distance the Tygon is placed over the end) and the longer the assembly is in seawater the greater the depth of attack.

     

    2. Dissimilar Metal Corrosion (a.k.a. Galvanic Corrosion, etc.) occurs when dissimilar metals are in direct contact with another (although a metal wire can connect two metal components that are fairly remote from other). The active metal (the anode) will corrode preferentially to the noble metal (the cathode). This is the basis for cathodic protection which is purposefully placing an active metal in contact with another more noble component in order to preclude corrosion of the more noble component.

     

    Dissimilar Metal Corrosion is often erroneously cited as the reason for numerous corrosion related failures mainly because it is easy to observe that two different metals are in contact with one another and draw the conclusion. Take the same assembly cited in paragraph 1 but slide a stainless steel sleeve tightly over the aluminum tube (specific alloys are important as is anodization but for simplicity sake let's not worry about it). All else being the same, pitting on the Tygon/aluminum assembly will be as significant if not worse than the Stainless/aluminum assembly.

     

    Dissimilar Metal Corrosion becomes much more significant with unfavorable anode/cathode ratios. For example, if you place an aluminum rivet in a copper plate you will get much more attack than if you place a copper rivet in an aluminum plate (all else equal of coarse: size of plate, size of rivet, method of fastening, etc.).

     

    Dissimilar Metal Corrosion is most problematic in full immersion conditions (assembly immersed in seawater for "long" periods of time). In alternate immersion conditions typically encountered with underwater camera systems, the dissimilar metals only see an electrolyte (seawater) for short periods of time. In the absence of seawater electrolyte, corrosion is nil/negligible. So if you rinse your system you will see little/no attack while in atmospheric conditions. If your system is not rinsed, a consistent salt mist is present, etc. then you can see some degradation above water but damage is limited to ~6mm (1/4") from the dissimilar metal juncture (interface). This limitation is due to the thin film electrolyte on the metal surfaces which results in high ohmic resistance and thus lower current density (corrosion damage is typically directly proportional to current density).

     

    3. Electrolysis is a misnomer relative to corrosion. Corrosion is degradation by electrochemical reaction(s); Electrolysis is the dissociation of water.

     

    4. Stray Current corrosion can be a problem when DC currents (and/or rarely with AC currents) enter and leave a metal component. Damage is seen where the current leaves the metal component. These types of failure tend to be very difficult to evaluate and mitigate. I am not qualified to comment much on stray current corrosion.

     

    Now, on to your specific problem… I would guess that the primary mechanism for pitting is crevice corrosion. There may be some aggravation by dissimilar metal contact particularly if the aluminum adapter has a small nick(s) in its surface that damaged the hard anodized protective "film" (I assume that your hot-shoe is stainless steel?). Again, very small areas of exposed, bare aluminum are much more of a problem than if the entire surface was bare. This is the result of large current density (current densities on the order of pico amps per square centimeter are significant).

     

    Since you experienced significant pitting in a very short period of time, it is also possible that stray-currents were contributing. I have little/no expertise in this area and it is difficult to imagine a source. Certainly the hot-shoe directly on the camera sees currents when the strobe is fired; however, most if not all housing hot-shoes are not "live" and are simply used to attach components such as spotting lights. Any one else think of a way that stray-currents may have entered and discharged through the adapter??? Keep in mind that a salt bridge can carry significant currents from one metal to another.

     

    Camera housings are generally cast aluminum with small stainless steel “inserts/attachmentsâ€. Generally, this is an acceptable materials combination; however, design, workmanship, specific alloys, etc. are important to preclude corrosion issues.

     

    Lastly, I believe the folks at ULCS use hard-anodized 6061 aluminum alloy. This material is successfully used in many components subject to marine “atmospheric†conditions (seawater mist, above waterline). A good example is window frames in oceanfront homes. The material generally does pretty well in alternate-immersion service but is marginal in full-immersion service (not regarded as marine grade where high-reliability components are concerned).

     

    So, I would recommend that (a) you avoid a very tightly fitting adapter (this may not be possible with your specific parts), (B) make sure the housing hot-shoe/adapter juncture is rinsed topside, © somehow verify that there is not a stray current problem and (d) minimize relative motion between the hot-shoe and the adapter. Relative motion can be the result of (a) differential thermal expansion of the hot-shoe and the adapter, (B) galling type wear when sliding the adapter onto the hot-shoe, © abrasive wear if salt and or corrosion products develop in the crevice between the hot-shoe and the adapter, (d) handling the system by anything attached to the hot-shoe, etc.

     

    Again, sorry for the long post. Hope this helps in some way.

     

     

    Oh and bye the way, sacrificial anodes (typically zinc alloy) on the housing are of ZERO use at the surface. Furthermore, the system spends so little time in immersion conditions (perhaps 5 hours a day for 100 days a year even for the most prolific underwater photographers) that, in my opinion, they are of little value.


  15. Eric, I concur that "Bird's Underwater" is an excellent operation and they do get out early (many other operators get to sites shortly thereafter which is very annoying since they "drop off" numerous people); however, IMO it is much better to stay near a site (e.g. Three Sisters) and go in and out of the spring on your own (swim or Kayak)...this way you can avoid the crowds and get more time with the subjects...also, there are some Natzi operators that yell at photographers who breath hold for photo's...they claim that violates regualtions and that you are suppose to stay at the surface snorkeling??? If you go out alone (when operators aren't there) then you avoid their interference...furthermore, the light is not usually optimal at 0630 (sun too low)...

     

    Bird's rents out a home right at "Three Sisters" but I understand that they now only rent it long-term (3-months?)...other homes are available and most have Kayaks that are part of the deal...the key is to avoid holidays (Thanksgiving and Christmas) and to get there when a cold front is moving through or has just moved through (October and November are optimal)...

     

    PS: I am interested in going again this year...I have a 3-year old daughter with a wetsuit (as wll as good swimming skill) and I want her to "model" with the Manatees... anyway, we are hoping to spend a few weeks at Crystal River...let me know if you are interested in splitting lodging expenses (me, my wife and daughter as well as a pro-photographer friend of mine from Boca Raton)...


  16. Mike, Perhaps I did overacted a bit...maybe alot...

     

    Typically, I do enjoy and appreciate the comments and images of yours and Alex's...

     

    But, ...What could be more amusing than the irony of an American implying that a Brit and a Canadian might be arrogant?

     

    Bye the way, thanks for turning me on to the series "Trailer Park Boys"...now that's funny...remember Cocos a few years back???

     

    No hard feelings... :)


  17. Didn't think that this forum was for the benefit of "professionals" only...this thread has been very helpful to me and I appreciate the excellent responses...If it's not relevant to the pros so be it...

     

    And since we've been diverted off-topic and the thread appears to be hijacked I'll go off in the new direction for a minute...

     

    How many "real" professional underwater photographers are there in the world? My guess is less than 5 people in the world actually earn the majority of their income strictly from shooting still images underwater (stock and location shooting)... the rest supplement their income with work as dive instructors, equipment repair, selling equipment, writing books, teaching seminars, etc....others made money in unrelated occupations or inherited big trust funds...

     

    Maybe I'm just being defensive, but it seems like there are several instances where so called pros come off as arrogant and jealous at the same time... I'm not sure why...It is indeed a funny world...

     

    I know a few of professional photographers who resent serious amateurs...many times the source of this resentment is that serious amateurs are sometimes willing to sell their images at bargain rates which dilutes the pool that true pros drink from to sustain themselves...perhaps this is one reason that there are so few "real" pros??? As I see it if a pro can't distance himself from the amateur then, well, he isn't a pro and he needs to find some other means of income...

     

    I just don't see any problem with the pro or amateur who has the means and desire to buy the best photographic equipment available so that they can optimize their chances at the best of images...

     

    I have so much respect for so many of the photographers (pros and amateur) that frequent this site and I am amazed at the images that are being captured...and anyone that truly makes a living with his camera is an amazing talent...anyone that makes a living with a camera system that is "less than the best" is a God... :D;) <_< :):o


  18. "Great Stuff" from everyone...I appreciate the thoughtful responses...

     

    Bmyates, I agree that "balanced neutral bouyancy" is very important and I have been impressed with my Subal system for most setups including macro setups which don't have quite the bouyancy of wide angle due, in part, to the dome port bouyancy...Years ago, I experimented with my RS systems through a variety of modifications in attempts to not only obtain neutral bouyancy but also to avoid bending moments...I acheived the former but not the later...the constant torque on my wrists coupled with the extra components led me to abandon the quest...in the end, I decided to compromise and get into the gym to bolster the bicepts...

     

    Alex, I appreciate the comments regarding fast "reloading" and I certainly have been happy with the performance of Subals mounting system: "quick release plates".

     

    As a follow up, would my dual S6 sync cords be interchangeable from Subal to Seacam? This is a relatively minor cost issue but every little bit helps...

     

     

    Lastly, and I can move this to the "lighting" section if preferred...are the expensive Seacam Flashes "good functionally" and "reliable"? I have had a few a few problems with my housed Canon 550's with the Subal systems...Again, I'm not here to bash Subal; on balance, it has been wonderful...just looking to compare and contrast so that I can make an informed decision...

     

    Thanks Again...

     

    Scott Marshall

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