A Little Help Please
Posted 19 July 2003 - 08:36 AM
I am a newspaper photographer with 20 years experience as well as a very part-time diving hobbyist. I am scheduled to photograph a story on some underwater archeologists who are currently working off the coast of New Jersey. Since I have gotten quite used to shooting all my assignments with digital Nikons , I would like to try to do the same in this case. I used to own a fair amount of Nikonos gear but sold it off as I started to dive less and less, so I am pretty familiar with underwater photography.
A colleague of mine has offered to loan me an ewa-marine U-AXP aqua housing for this shoot in which I intend to use a Nikon D-100 or D1X with mounted strobe and 17-35 lens. The dive site lies between 30-60 ft. which is within the rated limits of this housing. I am told that for the most part visibility has been quite good at about 20 feet so I plan on shooting mostly available light and using the strobe just for a little fill and extra color.
My questions mostly revolve around the U-AXP housing.
- First of all, is the U-AXP a good choice in this case or should I look into renting something more substantial? If so, what should I rent and where is a good place to rent from in the northeast?
- The instructions for the U-AXP say for diving below "snorkel" depth you should fill the housing with air to compensate for water pressure and increase the rated depth of the housing. What I have been unable to find is any information on how much air to fill the housing with for a given depth. I am assuming that too much air will make the unit too buoyant and difficult to manage, and too little air will collapse the plastic on top of the camera possibly depressing the shutter or other buttons. Is there a giudeline for how much air to fill it with?
- If there is some sort of guideline for a 30-60 ft. dive, then are there also guidelines for the amount of weight needed to counter the buoyancy?
It has been a few years since I have done any diving and I don't want to bogg myself down too much on technical issues related to the camera. My hope is that if the U-AXP is the way to go, my familiarity with the camera will make things much easier. Any other advise, suggestions or recommendations would be greatly appreciated.
Posted 19 July 2003 - 09:06 AM
If you do use the U-AXP you will also need to be concerned with the wide angle lens and the available port. The 17-35 would work much better behind a dome. How do you plan to sync your strobes to the camera? Are you planning to use the popup flash and a passive sync?
I think you'd be better off housing the D100 in an Ikelite (availability?), Sea & Sea, or Aquatica. I think a 5050/PT-015 combination with the wide adapter would be a better choice, too.
- Col. John "Hannibal" Smith
Nikon, Seatool, Nexus, Inon
Posted 21 July 2003 - 01:59 AM
I use a Fuji 6900 and a mounted flash... also 1 ankle weight to help with the buoyancy issue faced at 6-0m - I then hold it against my body else it acts like a lift bag..
A good lanyard or 2 even is essential !!
I generally inflate the bag as much as possible, the air is then forced into the camera as you descend..Note those silica gel pouches are useful as your breath is some what warmer than the water.
My one problem was that at just below 30m the camera really becomes unusable as the plastic casing is hugging the camera so much that only the most basic of shots (ie point and shoot) are then available...
This bit is hard to explain without having the casing infront of you.
another point to look out for - as the camera is joined to the front glass plate of the casing via a metal bar, the body is free to move around - this has the effect of moving the lens to the side of the glass plate.. This means your shots will have the black metal ring in the bottom left or right corner - so after diving in or your first shot, simply check the position of the lens by looking at the housing front on - you should be able to move it around before your descent.
Posted 21 July 2003 - 07:47 PM
I managed to test out the housing yesterday in some fresh water at a quarry using one my company's old D1 bodies (just in case it flooded).
Overall I was pretty satisfied with the housing, but need to do some more testing to get some of the air/weight/buoyancy issues worked out. I started with the bag just shy of fully inflated and two 1.5lb. ankle weights attached to the bottom. At the surface it was a little too positive making it a bit difficult to submerge. At 20 ft. I removed one of the weights resulting in the package becoming surprisingly neutral. At this depth it handled well and adjusting most of the controls on the D1 and SB-28DX flash (mounted on the hot shoe) was pretty easy. At 50ft. the pressure forced the bag heavily into the camera body making it difficult to operate some of the controls including the shutter button, but especially the monitor and delete buttons.
I was also a little concerned with distortion at the edges using a 17-35 considering the housing uses flat glass instead of a dome. Surprisingly the corners of the images are a lot cleaner than I expected. There is some distortion but it is not severe. I am sure it would be much worse if it were not for the D1 CCD being smaller than a 24x36 film frame. The housing comes with an adapter ring that screws into the filter threads of the lens and presses snugly into the band around the inside of the front glass keeping the lens positioned properly, but you do have to be careful it does not slip out.
As much as I would like to rent a real housing for my assignment, budget issues have relegated me to doing what I can to make this housing work since it is a free loaner. My other option is a Nikonos V, but I have gotten very spoiled being able to shoot more than 36 frames at a time and seeing my take right away on the preview screen. I plan on making one more test dive at the quarry before my assignment. I will start with the bag fully inflated with three or perhaps four ankle weights attached. Hopefully the extra air will be enough to make the camera easier to use at lower depths.
Thanks also to others in different topics on this forum for recommending using RAW format in the camera instead of jpeg. Using the Adobe Camera Raw plug-in in Photoshop 7, the colors in my images are much more accurate (especially at greater depths) and easier to control than if I had shot jpeg as usual.