Jump to content

diverdoug1

Member
  • Content Count

    412
  • Joined

  • Last visited

  • Days Won

    10

Everything posted by diverdoug1

  1. I had the same problem, but I fixed it by bending the reflector metal strips to a better angle, and now it is flawless.
  2. I have used the Nauticam straight, and both the straight and 45 in Aquatica and Subal. I find the optics comparable. I disagree with divegypsy that an external diopter is a benefit. I like it to be set correctly (a bit harder with initial set up of internal but don't have to worry about it being changed accidentaly). I shoot a lot of supermacro, and I usually use manual focus, so I rely heavily on the quality of my viewfinder optics.
  3. Although the Nikon 105 VR is my favorite Macro lens, if the $899 price tag is too steep, you might consider the Nikon AF-S Micro-Nikkor 60mm f/2.8G ED. It is a great macro lens that you can pick up for about $550 ($150 more than the Tokina but will give you much less headache). If you are shooting DX, you might find the 60mm preferable to the 105mm Nikon.
  4. I was flying from Singapore to Manado on a Tuesday in October, and last week was informed my flight was bumped back to Wednesday. I rescheduled so I could get there on Tuesday, but more expensive. Fly from Singapore to Jakarta on Singapore Airlines, then wait in Jakarta for 6 hours, then fly Garuda Airlines from Jakarta to Manado. Very unhappy with the extra money and inconvenience they have caused me, but nothing to be done.
  5. Fogging should not be a problem. Your strobes may not cool efficiently, so take your time between shots. If you are in a spring with a high tannic acid content, it can discolor the bright-work on your housing. Give it a good soak after use because the solutes in hot springs can cause issues if not rinsed thoroughly. If you have a vacuum leak detector, it may give you a false alarm. Do not remove any o-ring until it has had a chance to cool down. If going in a really hot spring for an extended time period, I would check with the manufacturer. I have used an Aquatica housing in 104 degree water for up to 45 minutes (max depth was about 20 feet).
  6. dpaustex, which housing are you using for your Mark iii? I saw that you were selling the Ikelite housing and wondered what you upgraded to. I am thinking about trying a Hugyfot or going with Aquatica. I already have some Aquatica housings which are great, but I have heard really good things about the Hugyfots as well.
  7. I like my rigs to be negative enough to be able to place them on the bottom and not drift in most normal current situations. This usually is around 2 pounds negative. also make sure that the distribution of flotation is such that it is easy to hold on target.
  8. I am having similar problems. I can't copy and paste to a post.
  9. David, I bought a 2+ diopter with a 82 mm thread from B&H last year. I think it is a HOYA. The optics seem fine and have noticed no extra CA
  10. Don't move directly at your subject, but take a circuitous route
  11. That is no questioon at all , I would take the Audi!
  12. Correct, If the water temperature is not low enough to cause the housing wall to drop to the dew point (18°C in the example) then condensate will not form. In response to Draq's comment, I think there may be a substance called Berrrr-bonne (sp?) manufactured by a Mr. Daniels in Kentucky that will cause you to not care about condensation.
  13. It may be like a Ford or Chevy question. No one common answer.
  14. I tip via my credit card when on a liveaboard because I don't like to travel with big sums of cash.
  15. I know Draq, it is killing me that the '"Walking Dead" is over for the season!
  16. Sorry about that Draq! I will try to clearly answer the 2 questions posted in this thread using what little expertise I have in the area as a hyperbaric physician. I will not get drawn into a pettifoggery once again. Your question if the negative pressure generated by the Nauticam system will make it less likely to flood -the answer is yes, because the o-ring is sucked into the mating surfaces of the housing, preventing blow-by. watboy, your question if an additional benefit of a vacuum system would be that it would eliminate condensation issues , the answer is no. It will greatly decrease them though. If you close your housing at 30°C and 75% relative humidity, condensation will form when the housing wall reaches 25°C. Under the same conditions, If you pump the housing down negative 10 inches Hg, condensation will form when the housing wall reaches 18°C. Starting conditions will certainly modify the results, but not the manner in which you can calculate the benefit. The explanation is below. Condensation forms at the dew point which is when relative humidity (RH)= 100% RH= partial pressure of water vapor (PW) / vapor pressure of water (VP) at a given temp. Vapor pressure of water at a given temp. (VP) is independent of pressure When you decrease the pressure by 10 inches Hg, you are decreasing the pressure inside the housing by 30% Following Dalton's law, decreasing the housing pressure by 30% will decrease the partial pressure of water (PW) by 30% once the temperature equilibrates. Therefore, relative humidity will decrease by 30% So starting at 30°C and 1atm and a RH of 75%, pumping the housing down to .7atm will yield a RH of 67.5% once the housing equilibrates with the 30°C ambient temp. Using the dew point curve we know that at 30°C and 75% RH the dew point = 25°C Using the dew point curve we know that at 30°C and 67.5% RH the dew point = 18°C So after vacuum there will be a 7°C degree difference in how cold you have to get the housing wall before condensate will form. I will be happy to answer any questions not originating from Interceptor.
  17. I am faced with one of 2 possibilites 1. If he's trolling then 2. If he has a comprehesion deficit issue and really belives what he is posting, he has my condolences. Either way, he does not care to understand or is unable, and will continue to argue in esoteric circles. I have, to no avail, done my best to help him grasp what most find to be a fairly easy concept. I apologize for helping to so horribly hijack this thread. If anyone ELSE is still interested in this material, follow the links provided to see the lab set-up we use for our undergraduates, which demonstrates the physical properties described in the preceding discussion. http://www.phywe.com/461/pid/23579/Condensation-of-gases-through-an-increase-of-pressure-andthrough-cooling.htm and a Full discussion of dew point, relative humidity, and how it changes with temperature AND pressure. http://www.youtube.com/watch?v=D_UpZwLFmVY
  18. In a sealed vessel, so the ammount of water molecules contained remains constat), increasing the pressure will decrease the dew point and increase the relative humidity.
  19. Wrong, your assumption that the relative humidity of the housing will be at 65% once it reaches 34 degrees is incorrect. If the relative humidity inside the housing was 65% at 24 degrees, the relative humidity will be lower at 34 degrees (remember, warm air is thirsty air).
×
×
  • Create New...