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Everything posted by uw_nikon

  1. Yes, one foot (30.48cm) of water sucks up about one f/stop of strobe light.
  2. Another solution: -mount adhesive backed velcro (hook-type) tape to bottom of housing and back of dome port -use velco tape (15mm x 200mm, loop-type) to keep the dome port from rotating by sticking it to the back of the dome and wrapping to the velcro patch on the bottom of your housing
  3. Looks like some kind of cowrie. Their mantles often cover their entire shell.
  4. Shell: advantages: fast drying, packs small and light, buoyancy change only from air in suit disadvantages: (for most shell suits) no stretch in suit material so they have to be cut looser to allow full range of movement which usually means big wrinkles and more drag when moving through water Regular neoprene: advantage: less expensive compared to compressed neoprene or good quality shell suit, material stretches so suit fits more like a wet suit which means little drag in the water, some insulation in case of major leak. disadvantages: buoyancy change from air in suit and gas in neoprene (behaves more like a wetsuit for buoyancy; could require more lead), long drying time, heavy, bulky to pack. Compressed neoprene: advantages: material stretches but has very little buoyancy change due to material compression, suit can be cut fairly snug (meaning few wrinkles and fairly streamlined in water), tough durable material disadvantages: heavy, a little bulky to pack, long drying time, expensive
  5. Well, skimming through "Adobe Photoshop CS2 Studio Techniques by Ben Willmore" (p.134) Offset and laser printer use LPI (lines per inch) instead of DPI (dots per inch) LPI Use 133 Magazines and brochures 150 high-end mags and high-quality brochures 175 annual reports and high-end brochures To calculate image DPI needed for printing associated LPI multiply by 1.5 for lots of detail _or_ multiply by 2 for image to look smoother So, 350DPI is in the ball park. If your images aren't big enough, you can use strair-step intepolation to up the resolution of your images. (there are many tools that do this.) Color space matching and compensating for printing color changes could be more of a problem than image resolution. (talk to someone who knows the printing process and can explain what you need in plain english) Take Care, ChrisS
  6. My guess is that the polycarbonite plastic is not strong enough and thick enough to allow a 1/4-20 tapped hole. Even if you tapped a 1/4" thick piece of stainless steel and anchored that to the top of the housing you would probably run in to the same strength of plastic compare to strength of aluminum problem. One solution I've seen is use flat bar stock stainless steel to bridge between the housing's handles and tap a 1/4-20 hole in the top center of that. Take Care, ChrisS
  7. General tips: 1. avoid bullseye composition (don't put your subject dead center of the frame) >>shrimp, gobie in brain coral 2. fill the frame >>shrimp 3. watch your histograms (for correct exposure) and overexposure warnings (blinky blacks) >>gobie in brain coral, box fish over sand 4. use the info in #3 to adjust the power of your strobes (foreground) or shutter speed (background) 5. shoot verticals (as well as horizontals) (remember to move your strobes otherwise lighting won't look natural) >>angel fish 6. get low, get close (get closer), shoot up
  8. USB2 (and USB1.1) use the CPU to move data. Look at: -Firewire (1394, iLink) 400Mbit/s or 800Mbit/s -external SATA (Serial ATA) for xfer speed faster than firewire. -internal SATA Note: if you need very high xfer speeds, you'll probably have to use a two(or more)-drive RAID-0 array. You can run in to drive transfer speed limitations using a single drive. If you're using a portable, you can get PCCard Cardbus adapters to connect Firewire and external SATA drives to your computer. (many portables also have firewire built-in; it looks like ExpressBus 34 eSATA adapters are available also) If you have room in your desktop, go with an internal SATA drive (even if you have to add a SATA card to support it). fast, simple, inexpensive. (or you could do external SATA, a little more expensive: drive enclosure, external SATA cable, SATA adapter card) It really depends on what kind of flexibility you need from an external drive.
  9. Are you using a USB2.0 memory card reader or a firewire memory card reader? -USB2.0 uses the CPU extensively to xfer stuff -Firewire is peer-to-peer (so, it uses direct memory access to xfer stuff _and_ very little CPU >> meaning the powerbook probably won't overheat using the firewire memory card reader) Take Care, ChrisS
  10. To set rear curtain sync, hold down "flash" button (next to "D200" marking on left front side of body) _and_ spin the back command dial. Using histograms, Red = foreground (illuminated by strobes) -The general rule is try to make sure it has data across the entire width and tapers off just before it get to either end. -if it's shifted right (large hump of data at right side, not tapered off as it reaches right edge), the image is over exposed (whites/highlights get burnt to pure white) -if it's shifted left, the image is under exposed (blacks/shadows block up and lose detail; go to pure black) You can try this out on land with any lens attached. -set camera to manual -f/8, 1/60, no flash -(optional, set the camera up on a tripod) -look at exposure meter in view finder -adjust shutter speed so image correctly exposed -take a photo -Now, don't move camera from current scene, adjust shutter speed so it reads "-1" (underexposed), and take another photo -Repeat, once more for "+1" (overexposure) Look at the histograms for each shot. (pay attention to how they are shifted left or right) Compare them to each other. Strobe positioning: -many possibilities: http://kelpfish.net/strobe.html -to keep it simple: strobes pointing straight ahead, tuck them in tight to macro port, one on left, the other on right (use edge lighting so you don't illuminated the water between the lens and the subject. This gets rid of most of the backscatter when done correctly.)
  11. When shooting macro, ambient light is almost a non-factor in the exposure. (at least for mostly green water Monterey; for clear blue water, ambient light would/could be a factor depending on depth and sunlight angle) My recipe: -shutter = 1/250th (sync speed of D200; you can always set it slower for creative affects) -aperture = f/22 (or f/16 for dark/light asorbing subject) -rear curtain flash sync (minimizes motion blur due to ambient light. Ghost trails behind direction of travel. I don't know if my ss-200s and D200 actually allow rear curtain sync to work as expected.) -strobe diffused at half power (I'm hauling around two Ikelite ss-200 because my ss-50s don't have adjustable power manual settings) You can use the camera's blue or green histogram to get an idea of how the background exposure is being affected by shutter speed then dial it in. (Berkely White tip #1001) Used mostly for wide angle but could be used for creative macro shots.
  12. There's always beg/borrow/rent lens(es) and port(s) from friends/club members or shops (NCUPS.org, MPUP.org, Backscatter) for a few weeks. (or buy the lens and rent the port) Lenses to look at: wide (in 8" dome) = Tokina 12-24, Tokina 10-17 fisheye, Nikon 12-24, Nikon 10.5 macro (flat port with possible extensions) = nikon 60mm micro, sigma? 90mm, nikon 105mm micro
  13. One great trick with autofocus. -set AF to "S" (single servo) -half press the shutter release to activate AF and focus on your subject >>Once AF locks "in focus," it won't change until you fully depress the shutter release or take your finger off of it. -then you can recompose your shot for critical point of focus and composition
  14. The 60mm is a tack sharp lens. (shoots closer to what a 105mm does on a film camera with the digital crop factor of 1.5x). f/32 on the 60mm moves to f/64 when you're focusing down to 1 to 1 because of the "bellows affect" as the lens lengthens. The aperture stays the same size but the amount of light reaching it diminishes by 2 stops. Going from f/2.8 to f/3.5 could diminish your D70s Autofocus speed a little bit. A focus light is helpful with any macro lens as long as it doesn't spook your subject. The other thing to look at is how many blades does the aperture have (the closer to round, the better the out of focus area will look). hmmm, internal focusing (meaning the macro lens can do 1-to-1 with out a extension tube or meaning the lens length doesn't change?). If you mean the lens length doesn't change, you'll have to look at the new nikkor 105mm macro instead of the 60mm. (another thread covers that pretty throughly) Vinetting with a ring flash. Show an example uw image and maybe a (front view from 45 degrees) picture of the camera in the housing with the ring flash port attached and 60mm lens focused at 1-to-1 and 1-to-6. I've never had a vinetting problem with the 60mm or 105mm (film or d200) when shooting a pair of strobes. I normally shoot f/22 or f/16. (I did notice a different behavior on my d200 compared to my n90s. If you're focused at 24" with f/32 and then focus to 1-to-1 the camera compensates for the bellows affect and still reads f/32; you can dial the aperture smaller to f/57 with the 60mm once you're focused at 1-to-1.) Take Care, ChrisS
  15. I have an D200 Aquatica housing. It's about two pounds negative underwater with the flat macro port and 12-12 ULCS arms with Ike SS-200 strobe pair. (heavy at the macro port) With the 8" dome port, it's a little less than a pound negative with the same arms and strobes. (the dome wants to float up). Weight of the water that the camera system displaces minus Weight of camera system dry equals Buoyancy It's really a matter of making the system slightly negative underwater and balancing it (so the system doesn't change postion when you let go of it; i.e., rotates port up for dome and port down for macro). James documented making a floation ring to balance the macro port. To balance a floaty dome port, you can add a small weight to the bottom of the port's hood. Take Care, ChrisS
  16. Maybe, something like this? http://www.custom-surf-wake-photography-un...p?housing=lunar Take Care, ChrisS
  17. Ah, the lotto approach to photography. I've entered one-day beach dive photo competitions (with film and digital categories). Many of the digital entrants shot 200+ images in 3 or 4 dives; one entrant shot almost 500 images. (the only digital shooters that consistantly place normally shoot around 50 to 150 images and have practiced extensively) The problem is most of the photogs are just shooting snapshots/grab shots. Even if the photographer gets a winning image (mostly, just blind luck for the lotto photog), they don't know how they got it and couldn't repeat the shot. A good photographer will produce good to great images with their practiced/finely honed techniques in a very consistant manner (if they can find subjects to shoot). The photographer's eye = Technical: focus, exposure, lighting (know what your equipment can do and cannot do) Artistic: Composition, Peak of Action, Point of focus, Lighting for affect (All of which can be learned, previsualized, planned, and practiced) The instant feedback of digital is a _huge_ advantage over the old days of shooting slide film (where if you're lucky, you get to see slides the same day you shot them). Use all digital's advantages (instant feedback, histograms, 100+ shots/dive) to improve your technique every dive. DON'T just shoot the same old "broken" snapshot over and over. Look at you images critically, make a list of errors, rank the errors, work on fixing the biggest error, when it's fixed, fix the next biggest. (repeat until you've fixed all errors) Take Care, ChrisS
  18. If money is an issue, look at a pair of used Ikelite Substrobe 200s or Sea&Sea 350s. (don't forget to get a good set of strobe arms) TTL generally is not that useful for wide angle and manual strobe power control (with feedback from your camera's LCD and histograms) will produce better results. Take Care, ChrisS
  19. It's normal. The water pushes the o-ring toward the inside. (see attached GIF) Take Care, Chris
  20. http://www.lynda.com/search/?q=final+cut+p...amp;btnG=Search You can get a yearly subscription to their online courses for a fair price. Take Care, Chris
  21. When using a multi-button mouse, right-click has been around since Mac OS X 10.0 (in 2001).
  22. The big differences between shooting with one strobe and shooting with two strobes are: -gets rid of harsh shadows (the second strobe can paint/fill them with light) -flexibility: many different light methods with two strobes _or_ turn one off/point it away from your subject and you're shooting with one strobe (visualize how you want to light your subject, practice and experiment, then continuously work on improving your lighting technique) Note: get a good pair of strobe arms, balance your camera system so it's about 1/2 to 1 pound (250g to 500kg) negative in the water. Hand holding a single strobe isn't a good idea for fragile reef areas because you don't have a hand free to do the two fingered balancing act against the little dead spot in the coral and can easily crash into the bottom doing a fair amount of damage. TTL for wide angle shots probably won't give you good exposure results with any consistancy. Shoot with manual strobe power settings and use the red histogram dial in the exposure for the foreground. Then use the blue histogram and adjust the shutter speed to dial in the blue water background. (something I learned from Berkley White) Take Care, Chris
  23. You could try: Nikon 35mm f/2 AF-D (inexpensive, very fast, sharp, no zoom) or Nikon 17-35mm f2/8 AF-S (flexible, fast, maybe able to find good deals used, many people use it for sharks) Take Care, Chris PS, I wish nikon made a 40mm macro lens (I want the same functionality of the 60mm on a film camera).
  24. If the front element of the lens moves in/out when zooming*, it could be a problem if the nodal point of the lens moves also. *(the 17-55 has internal focusing; so, I don't think its front element moves in/out when zooming) I have used the 17-35 with good results behind the 8" aquatica dome. (no problems, no diopter) Take Care, Chris
  25. I use a pair of Ike SS200s connected via a TTL cord to my Aquatica D200 housing. No problems. (note: the sync port on the Aquatica d200 housing has 5 pins. Only 2 are connected: fire and ground) All my strobe exposures are Manual via: -power dial on strobe (1/8, 1/4, 1/2, and full) -adding/removing diffusers (2/3 of a stop) -changing strobe-to-subject distance (roughly 1 stop per 30cm/1 foot of water) I don't know if the Ikelite D200 housing allows you to use nonTTL mode with Ike's pre-digital strobes.
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