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uw_nikon

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Posts posted by uw_nikon


  1. The reason the "fixed" version became very noise/pixelated is the original image has way too much blue in it. There's not much red or green data for Photoshop to pull out. Look at the histograms for each color channel. Blue will be pretty strong (data acrossed the whole histogram or maybe a big lump to the right). Green and red will be under exposed (lump or spike on left edge of histogram only)

     

    Why so much blue?

    -depth (water filters color quickly in this order: red, orange, yellow, green, blue, indigo, violet)

    -too much distance from camera to subject (loose of contrast and detail beyond 6 feet/2m)

    -too much distance from strobe to subject (water eats about one f/stop per foot/30cm; beyond 4 feet/122cm strobes quickly loose their ability to restore color/contrast and detail gets muttled by the water)

     

    For better future shots,

    -use a wide angle lens or wide angle adapter so you can get within 4 feet/122cm or so of your subject

    -use a wide angle strobe (or two) to provide light and restore color, contrast, and detail

    _or_

    -use a magic filter (to cut down the blue light; Alex Mustard's magic filter) when shooting without strobes

    (some camera's allow you to set the white balance by shooting a picture of a white slate at depth)

     

    get low, get close (get closer), shoot up

     

    Take Care,

    Chris

     

    (edit: added the histograms of the original image with comments)

     

    <snip>

    I did work on the pic a bit and it got better, but very noisy/pixelated. I was wondering if one of you guys would be able to do a better job.

    <snip>

    post-6274-1170537395_thumb.jpg


  2. Since it's mostly buttons and knobs you're actually concerned about, Try this:

    -dunk your housing for about 15 to 30 seconds

    -pull it from the rinse tank

    -then use a plastic spray bottle to gently flood each of the buttons and knobs while you work them

     

    Also, avoid using compressed air to blow out the water remaining around the buttons and knobs. You can easily blow water past the first o-ring which means possible corrosion trouble.

     

    The number one rule of underwater photography on a boat is:

     

    _Never_ leave you housing in the rinse tank unattended.

     

    (if the next UW photog rinsing their housing is not paying attention, they'll bash the stuffing out of your housing, strobes, etc.)

     

    Take Care,

    Chris


  3. Open the help file for Photoshop CS2 and search for "Obtaining custom profiles for desktop printers". (a profile calibrated to your printer _and_ the paper you're printing on could fix some of the problem.)

     

    Cameras, monitors, and output devices (printers) have different color spaces which can make it hard to exactly match what you see on your calibrated screen to what prints on your printer (the bright fluoresent greens might be outside of your printer's color space). Printed images will appear differently in different lighting situations (sunlight, fluoresent, incandesent, etc. will all make the inks reflect differently).

     

    Take Care,

    ChrisS


  4. Video editing is probably more bounded by:

    -hard drive speed (xfer to/from RAM to hard drive)

    -available computer RAM

    -processor speed (applying filters, color correction, etc to each frame takes processor power)

     

    A decent (current middle of the road) ATI or nVidia video card with 256MB of memory on-board will do a great job for video editing. Just make sure your monitor supports 1080 HD resolution (1920 x 1080) or larger. (note: some video editing SW can use the video card (graphics processing unit) to do realtime work on video streams; also, both ATI and nVidia are doing work to allow programmers to use their GPUs as massively parallel general purpose computing devices which could enable some very wizzy stuff in the future; mostly supported on their higher end GPUs)

     

    Take Care,

    Chris


  5. Aquatica's ports use extensions for different lenses:

    105mm af-d = flat port used for 60mm + an extension ring (one more o-ring to worry about)

    17-35mm af-s = 8" dome port + an extension ring

     

    Many plastic glues actually fuse/weld the two plastic parts together. Making them as strong as a single piece of the same size.


  6. -A full-frame nikon digital camera, 16MP+, 100% view finder coverage, in a d200 body.

    -Aquatica d200 housing w/view finder magnifier

    -housing/strobes/arms balanced and about 1#(500g) negative in saltwater

    -a dual channel manual strobe controller (full, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, off; half or 1/3 stop increments), LCD display, two 1"(25mm) rotary dials to adjust strobe power (easy to use with cold water gloves), independant of the housing, input = nikonos standard, 2 outputs = connections to strobes, (not necessary but could be useful for macro: allow digital TTL pre-flash with old film TTL UW strobes), microcontroller controlled, powered by 2 AA batteries which allow 100+ hours run time

     

    ports (with extensions where necessary) and lenses:

    8" dome port for wide: 17-35 AF-S, 18mm, 24mm, 35mm f/2, 16mm fisheye

    flat port for macro: 60mm micro, 105mm AF-S micro, 200mm micro

     

    Strobes:

    a pair of ike SS200s

    a pair of ike SS50s


  7. When shooting ambient light only:

    -stay shallow, get close, get low, shoot up (you should be at the subject's eye level or lower)

    -have the sun at your back (which puts light on the front of your subject)

    -get your buddy to carry a 8x10 18% gray card, take pictures of your buddy holding the gray card at a few distances (and maybe a few different depths) You can use the 18% gray card to quickly adjust color in Photoshop.


  8. eTTL/iTTL or plain old school film TTL: all can be fooled resulting in bad exposure. (especially true with wideangle) Don't let technology govern your images completely. Learn how to use your strobes with manual settings, diffusers, and varying strobe to subject distance. (the hows and whys are important even when shooting TTL)

     

    macro strobes and wide angle strobes are two different beasts

    -macro strobe = small package, ment to work close to your macro port, tight beam angle (60-70 degrees), relatively low power

    -wide angle strobe = medium to large package, ment to be away from your dome port, wide beam angle (100 degrees plus), higher power over entire beam angle

     

    What to look for in a strobe that does both macro and wide angle:

    -manual power settings (1/8, 1/4, 1/2, full) _or_ the ability to use a manual controller with 8 to 10 power levels

    -good beam angle (100 degrees)

    -medium size (so you can place the strobes close to your macro port)

    -decent power across the entire beam angle

    Maybe, look at Sea&Sea ys-120, Ikelite DS-125, or Inon

     

    If you're going to get a pair of strobes, get two of the same strobe.

     

    Digital cameras will trigger older (pre-digital) strobes. You just have to use manual strobe settings. (older strobes don't support the pre-flash required by iTTL/eTTL)

     

    Take Care,

    ChrisS

     

     

    Can anyone give me pointer in regards to strobes. I am looking for unit to connect to my canon 30d prefferably using ETTL. I need some recommendation for a two strobe system that will provide a do everything package ie wide angle and macro, with as few as compromises as possible. I am assuming that the older generation strobe won t work...I could however use them as slaves.

     

    Also is there any resource that reveiews strobes assessing their angle, power. etc.

     

    Is there any strobe that could be considered an industry benchmark

    Thanks for you time. Erol


  9. Making your camera system neutral is a great idea.

     

    But, a compressible/flexible bag has a major problem. It's buoyancy decreases with depth. (10m/33fsw = 1/2, 20m/66fsw =1/3)

     

    Something light and incompressible/rigid would be much better. (i.e., closed-cell high-density floatation foam used in boats _or_ balsa wood shaped to fit under the housing or around the macro port and covered with epoxy _or_ floatation strobe arms, etc.)


  10. Change the color of the diver's hood and wetsuit/drysuit. (red, royal blue, anything other than black)

     

    Shoot test shots in the pool

    variables

    -manual strobe power

    -diffusers

    -strobe to subject distance

    -strobe placement and angle toward/away from subject

     

    Make a shooting plan

    When reviewing your test shots, pay close attention to skin tone

    Make careful notes

    Tweak your best techniques to get what you want (in camera, not in photoshop)


  11. I am looking for any suggestions on what to use to clean the O Ring to keep those nasty hairs and bits off it.

     

    0. Make sure your work area and hands are clean (no hairs, dirt, sand, etc.)

    1. Remove o-ring with plastic pick

    2. Clean the groove and mating surface the o-ring seals against. (q-tip or foam swab)

    3. Use a lint-free cloth (or good quality paper towel) to gently wipe the old grease/lube off the o-ring.

    4. Regrease the o-ring. (no big globs of grease, slick like a fish)(if the o-ring was really dirty, repeat steps 3 and 4)(never set the o-ring down once it's clean and regreased)

    5. Inspect everything closely _before_ reassembling. (use a small light and magnifying glass/reading glasses, if necessary)


  12. Get a mask that fits _your_ face.

     

    Other things to consider for UW photography:

    -black skirt on the mask, instead of clear (no distracting glare from the sides of your mask)

    -low volume (your eyes are closer to the glass and closer to the view finder if you're shooting an SLR.)

    -no purge valve (one less thing to break)

     

    I use the cressi-sub super occhio, a low-volume freediving mask with black skirt. (that's what fits me best.)


  13. Even if you get a strobe that does digital TTL, learn to use it in manual mode.

     

    This isn't the dark old days of slide photography. Where you had only 36 exposures, no feedback until the silde film was developed, and very unforgiving exposure latitude (correct exposure _or_ trash can). With digital, it's very easy to shoot with your strobe(s) and camera set in manual mode. (instant feedback, histograms, visual over-exposure warnings. All on the camera's LCD)

     

    TTL can be fooled.

     

    Assuming macro:

    -Get in the pool with some stuff to shoot (small toy plastic lizards/frogs/insects) and a few different materials (a dark colored piece of cloth, the white pool bottom, something close to 18% gray) for backgrounds.

    -bring a metal yard/meter stick with you (to eliminate guesstimation)

    -Set strobe to manual full power

    -Set shutter speed to the maximum sync. speed of the camera

    -Set aperture to one stop below the smallest aperture setting (i.e., if smallest is f/32, set it to f/22)

    -hold you camera at a fixed distance to the subject

    -shoot a series of pictures: strobe at 1', 2', 3', 4' from the subject

    (pay attention to the histogram, what the image looks like on the LCD, over-exposure warnings, etc.)

    -shoot the same series again with the diffuser mounted on the strobe

    (how did the exposures change? what happened to the shadows, detail, color saturation?)

     

    -change backgrounds and shoot another series the same two sets again

    -change subjects

    -etc.

     

    Latter

    -play with lighting positions/angles

    -composition


  14. I have the Ikelite digital UW light meter and a housed D200 (yes, the 4 channel histogram is very cool for judging exposure).

     

    I think, there are a couple of reasons to keep it.

    -flash calibration (or just checking the output of your flash units)

    -ambient light meter (sanity check for tricky wide-angle situations)

     

    Take Care,

    ChrisS

     

    We'll be moving from film to all digital in a few months.

     

    Using Nikon D-200s, is there any reason to keep Sekonic or Ike u/w light meters?


  15. A great starter lens is the nikkor 60mm micro AF-D f/2.8. (I kind of wish nikon made a 40mm micro lens for their digital cameras because the 60mm is a 90mm equivalent with the digital crop factor.)

     

    For wide angle, look at the 12-24mm or the 16mm fisheye. (nikon makes nice glass; but, other companies make similar lenses for less money)

     

    As with any lens, spend time learning what it can do _and_ what it can't do. Pick a subject on land and shoot a few hundred concept shots within 4' of your subject to get an idea of what shooting the lens underwater would be like. (4' is about the maximum distance your strobes can be from a subject for color, you quickly lose contrast and detail beyond about 3' in water)

     

    Take Care,

    ChrisS

     

    Photography plans include simple macro, fish shots, and probably the occasional head & shoulders type shots of divers. Diving would be caribean trips (bonaire) and NC coast diving which includes some 10' viz green water. Any suggestion appreciated.

  16. I don't think the Sekonic Marine Meter II (L-164C) would be very helpful for uw video.

     

    All video cameras have a built-in light meter. The main problem for uw video is white balance (the water filters out color, the deeper you go the less spectrum you have). I don't do uw video. But, other club members do and they use a white slate (8" x 10", A4) and the white balance button on the camera to do uw video without artificial light. Hold the slate flat toward the lens at the distance you're filming and press the white balance button on the camera. (the camera then adjusts the color input levels to match its model of balanced color by cutting out blue and green while leaving red untouched). This works well in clear water.


  17. I use the UWtec SmartCOM (a console with quick disconnect and compass).

     

    Likes: readable display (nice UI, show info you need while diving), long battery life, good ergonomics (relatively small size, compass mounted at top and angled for easy reading), built-in screen guard, easy download of dive data via IrDA (mac & PC), good algorithm (also see dislikes)

     

    Dislikes: alarm beeping on ascent (very slow ascent rate for last 30 feet/10m; the alarm doesn't go off very often for me; but, can/will go off if you swing the console up to look at it), the software(JTrac) for my mac could use some user interface/features tweeking


  18. Use single servo auto focusing mode (my method with the 60 and 105mm, I've never used manual focus; I normally shoot in Monterey so I usually have a focus light mounted on the housing, aim it so the edge of its beam illuminates what I'm trying to photograph, and turn it on only if the AF is hunting too much)

    -half press the shutter release (result: camera achieves and locks focus)

    -keep the shutter release half pressed

    -recompose the composition

    -move in/out slightly to get the critical focus just right

    -fully press the shutter release (result: image captured)

     

    or

     

    Use continuous auto focusing mode:

    multiple combinations (read the manual and practice shooting land macro shots)

    -closest subject priority

    -use (all AF points, wide AF pattern, single AF point)

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