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H2Oplanet

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About H2Oplanet

  • Rank
    Clownfish
  • Birthday 12/12/1958

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    http://www.H2O-planet.com
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  • Gender
    Male
  • Location
    Gulf Breeze, FL, USA

Additional Info

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    United States
  • Camera Model & Brand
    Canon EOS 1Ds Mk II
  • Camera Housing
    SeaCam
  • Strobe/Lighting Model & Brand
    SeaFlash 250's
  1. Best to Jimmy from Siobhan and Scott...moving back to FL from NC...hope to see you soon on the ShearWater
  2. 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
  3. Love the idea...Might also consider expanding to include a protocol for testing strobes and conveying results consistent with pool/field test of others...??? Cheers, Scott
  4. Eric, I will send you an e-mail with a contact that should be helpful... Scott www.H2O-planet.com
  5. Canon 180mm AF is slow relative to 100mm AF...extended working distance of the 180mm is desirable for some subject matter... If I recall optics lessons correctly, the DOF is equivalent/comparable at equivalent magnifcations (anyone confirm/refute)???
  6. 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
  7. 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
  8. 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
  9. 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
  10. Weedgal, Generally, the German made B + W filters are of exceptional quality. As mentioned earlier, they are readily available...I use B&H out of NY... For the +4 Diopter, B + W's designation would be NL-4 ...
  11. 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?
  12. 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?
  13. 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
  14. 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...
  15. 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
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