Jump to content

uw_nikon

Member
  • Content Count

    164
  • Joined

  • Last visited

Posts posted by uw_nikon


  1. Crop in the view finder.

    (the closer to full frame in the original image the better)

     

    Zoom with your fins.

    (less water between lens and subject = better image quality: sharpness, color, detail, etc.)

     

    Shoot the lens you have mounted.

    (not the one you _wish_ you had mounted)

     

    Minimum image dimensions depend on what's spec'd for the competition.

    (some comps request the RAW file; looking for camera skill instead of image editing skill)

     

    Many competition judges can tell if an image has been cropped by 30% or more (Depth of field, Image quality, etc.).

     

    Most of the time, the final image matters more than whether or not it was cropped to achieve the image.

     

    Take Care,

    ChrisS


  2. Maybe, check your DIY port wiring.

    Also, try connecting one strobe only to your housing and shooting some land test shots (full manual: ISO 100, f/11, 1/100s, 60mm macro).

     

    -I think, for TTL to work with two strobes: one has to be wired "master" and the other "slave" for camera/strobe communication to work correctly. (that's what the old "film" y-cables do)

     

    -how are the housed strobes connected to the housing?

    (a y-cable or two separate sync cables. If two separate sync cables, the ports have to be wired like the y-cable)

     

    Take Care,

    ChrisS


  3. Assuming you mean the Sony PMW-EX1, I don't know. It depends on the data rate of the video you're going to record _and_ what you expect the machine to do while you're editing. (if you're just logging your footage and saving it to an external hard drive, firewire 800 should work fine.)

     

    You might be more bound by the number of processor cores (2), the slower front side bus (800MHz), and RAM (4GB max) when compared to a MacPro 2.8GHz: 8 cores, 1.6GHz frontside bus, 8/16/32GB depending on how much $$$ you want to spend. There are always tradeoffs when using a portable.

     

    Take Care,

    ChrisS

     

    for the EX1, eSATA necessary? Can I run a new MacBook Pro and some FW800 externals?

  4. eSATA = external Serial ATA

    basically, the cable connectors are beefed up for secure external connection when compared to the internal connectors.

     

    wikipedia link to SATA

     

    There are some nice eSATA RAID boxes out there for relatively little money. But, you also need an eSATA RAID PCI card to run them. (I saw one at the SF Macworld show in January for $695, 4 hot swappable bays and the RAID card, I think it was 2 terabytes, 4 500GB drives.)

     

    The old ATA is a parallel and its xfer speed is limited because it's hard to keep the parallel data lines in sync with each other.

     

    Take Care,

    ChrisS

     

    can someone explain eSATA drives to me?

  5. You can calibrate your laptop screen with the HW discussed in other recent threads.

     

    Calibrated monitor vs. Print done on a calibrated printer.

     

    Main problems:

    -the monitor is projecting light at you

    -the print is _reflecting_ light at you (the question becomes what light source is illuminating your print? full spectrum 5000K is probably what's expected for correct viewing)

    -also, screen gamut (range of color) and printer gamut overlap; but, it's not a 100% overlap. You're generally lucky if you get 85% (and pay lots of $$$ if you want higher color gamut for either monitor or screen)


  6. Technique has far more to do with quality images than high end equipment. (The nikon 105VR is an extremely sharp lens.)

     

    You don't say what is bad about your images' focus:

    -depth of field/plane of focus

    -point of critical focus

    -just plain out of focus

     

    My macro technique:

    -camera set to "single servo" AF

    -use the center five AF areas (I shoot the D200 also)

    -half press and hold shutter release (this establishes focus and then _locks focus_ until you fully depress the shutter release)

    -recompose the shot with critical focus area(s) "in focus" (making slight adjustments in camera to subject distance and point of view to get the image you envisioned)

    -take the image by fully pressing the shutter release

    -repeat as necessary

     

    Take Care,

    ChrisS


  7. Add another 1TB SATA drive for a boot drive. (boot drives don't need the extra speed expensive SAS drives give you.)

     

    Use the four SAS drives as an array (hopefully, supported by a RAID card).

     

    The question of which RAID config (four drives as RAID 0 1.2TB volume or four drives as RAID 10 600GB volume) depends on how much space you need and how much time you have to reconstruct your editing work if the RAID 0 config goes bad while editing.

     

    You could configure the four SAS drives as RAID 5.

    -throughput should still be pretty high

    -if a drive dies, the array still works (with degraded performance), and your array can be reconstructed using the checksum info on the other three drives. (I don't know how much space the checksum info takes up; but, I would guess, the array would be over 1TB.)

     

    Take Care,

    ChrisS


  8. A simple TTL test is:

    -set shutter at the sync speed of your strobe (usually, around 1/250 second)

     

    Part A "quench test"

    -fully open aperture (f/2.8)

    -point strobe and lens at a wall about a meter away

    -take a picture

    pass = strobe fires a very short flash and recycles very quickly

    fail = full dump

     

    Part B "subject too far away for your strobe's power"

    -put the dome cover or lens cap on

    -take a picture

    pass = full dump and strobe has to recycle fully

    (I think, S&S strobes have a LED that tells you if a full dump occurred or if TTL quenched it before a full dump)

     

    Correct exposure and TTL are many times mutually exclusive (especially, in wide angle); it can work very well for macro.

     

    Be very careful with the reflectivity of your subject:

    -octopi, moray eels eat up light

    -barracuda, the underside of mantas reflect light back

    TTL generally assumes the main subject has 18% gray reflectivity (and makes stupid mistakes because of it)

     

    Use:

    -histograms

    -blinky black over exposure warnings

    To catch exposure errors and fix them.

     

    Take Care,

    ChrisS


  9. Full = 200 watt seconds

    1/2 = 100 watt seconds (full brightness, half the time on strobe pulse)

    1/4 = 50 watt seconds

    etc.

     

    diffusers do cut the power of the strobe down. (but, not necessarily by a full stop; it depends on the diffuser.)

     

    one stop = half the current light _or_ double the current light

     

    quench = power is cut to the flash tube

     

    when using TTL, you can run into two basic problems:

    -aperture too big and strobe too close to subject = strobe cannot quench fast enough (over exposure)

    -aperture too small and/or strobe too far away from subject = strobe does a full dump (under exposure)

     

    Take Care,

    ChrisS


  10. Doing some fast lookups at BH for lens lengths:

    Tokina 12-24mm zoom = 90mm

    Nikon 20mm prime = 43mm

     

    Lens Length Delta = 47mm

     

    Looking at Ikelite's site for port extension lengths:

    #5510.10 .... 1.300" (3.302cm)

    #5510.16 .... 2.047" (5.200cm)

     

    Port Extension Delta = 19mm

    (meaning the lens _could_ be sticking too far into the dome by 28mm;

    I don't know how Ikelite dome extensions work, I just going off how port extensions work with my Aquatica housing: most primes don't require an extension, zooms and longer primes do require an extension)

     

    With my Aquatica, the front element of the lens is basically even with the front of the dome base. What does the tokina 12-24mm look like when in your Ikelite dome?

     

    Take Care,

    ChrisS


  11. how does the mounting plate work?

    (see attached picture)

    (cap screw threaded into plate, plate screwed down to housing, ball adapter threaded onto exposed threads of cap screw?)

     

    One way you could remove the ball adapter is:

    -clamp the ball adapter in a vice (housing laying horizontal)

    -use a jeweler's saw* to cut the stainless steel cap screw

    -replace cap screw

     

    _or_

     

    (if the ball is loose enough to allow the jeweler's saw to slip between the ball and the mounting plate and make the 90 turn toward the housing)

    -use the jeweler's saw to cut through the plastic mounting plate just inside the two mounting screws

     

    _or_

     

    -use the jeweler's saw to cut the the plate's mounting screws at about the mid-point of the plate's thickness

    -carefully extract the cutoff mounting screws from your housing

    -then replace the plate and the mounting screws

     

    *very fine-toothed blade coping saw designed to cut metal

     

    Take Care,

    ChrisS

    post-6274-1200356778_thumb.jpg


  12. You have a ball adapter like the one pictured in the attachment to this post?

     

    It sounds like electrolysis (differing metals: stainless steel (the threaded stud) and aluminum (the housing and ball adapter) will create a weak electrical current when exposed to salt water). This can erode metal or basically weld them together.

     

    The prevention:

    -use silicone grease on the treads of the stud

    -wrap the stud with a couple of wraps of teflon plumber's tape

    -periodically, remove the ball adapter, clean the stud, and reapply the grease and tape

    -add a sacrificial anode to both parts (back and main body) of your housing

     

    The fix:

    Once you remove the ball adapter, try using white vinegar to dissolve the corrosion (use modeling clay to build a little dam around the stud/ball adapter and fill it with vinegar; let is soak for a few days). You could also try the same trick with penetrating oil.

     

    if the stud is fused to the housing:

    -have a machinist remove (using Bridgeport machine, housing held in a jig, and end mill) the stud from the housing body

    -replace the bad threads with a Helicoil insert

     

    Take Care,

    ChrisS

    post-6274-1200271802_thumb.jpg


  13. What's your budget?

    (Saying you can only afford a single strobe _then_ looking at high-end housings[light&motion, subal] never mind the cost of the camera, lenses, port(s). Tells me you haven't done your research.)

     

    In underwater photography, it's the person behind the camera that _makes_ the image _not_ the fancy camera. (Rats!, my pencil can not draw as well as yours. >> the artist draws not the pencil.)

     

    There are plenty of threads here on wetpixel to answer your questions.

     

    A good choice would be a used D200, an Aquatica housing with 8" dome port, Tokina 10-17 or nikon 16mm fisheye, a single used Ikelite SS-200 on a ulcs 8-8 arm, and a sync cord. You're still talking close to $5000.

     

    Most people won't outgrow that system for many years.

    (camera envy is another story with newer cameras coming out every year)

     

    Take Care,

    ChrisS

     

    So in short - I need a system that Im not going to outgrow too quickly - ie one that i will grow into but not one so technically limiting that it makes my hair fall out. I need a housing rated to depth 70-90m and given the narcosis - easy functionality. The camera technically should be able to produce shots good enough from magazines. My budget can only afford a single strobe, one wide angle and one fish eye lens and ideally one dome port that supports both these lenses. I can still use the above mentioned olympus for macro.

     

    So ...... where Im at is ..... a Nikon either d80 d100 d200 or d300 in a light and motion or subal housing.

     

    What say you ??? And which lenses would you advise for a newbie for WA CFWA and Fish eye......


  14. hmmm...

    Macro without a real macro lens is very limiting. Wet or dry diopters do increase the close focusing ability of a normal (non-macro 50mm) lens; but, a real macro lens is specifically designed for close focus.

     

    f/stop for macro

    -limited by the amount of power your strobes can pump out (when using low ISO 100); I usually shoot f/22 with my nikkor 60mm macro. (note: the lens will do f/32 and the bellows effect pushes that to f/64 when focused to 1:1.)

    -the closer you focus the shallower the depth of field at any f/stop

     

    bottom line = look at either for your camera:

    -Olympus 35mm f/3.5 (relatively inexpensive, ~$165 at b&h after rebate)

    -Olympus 50mm f/2.0 (more expensive; but, faster and more flexible for lighting)

     

    How much are you spending on your Philippines' trip?

    (how many shots will you miss without a macro lens?)

     

    Take Care,

    ChrisS


  15. Be _very careful_ about regulations (even self made ones).

     

    There are plenty of people who will twist them in to unmanageable/very constrictive rules that no one can comply with.

     

    A few years ago, there was a campaign/study done on divers disturbing the kelp in Monterey Bay by Marine Biologist PhD representing the kelp harvesting industry which basically wanted to force divers to stick to underwater "trails" and not touch anything. Why? because divers break a few kelp stipes once in a while. (never mind, that the kelp harvesters clear cut the top of the kelp forest in large areas.)

     

    Take Care,

    ChrisS


  16. The gold lettering is not around the front element* (It's on the lens barrel; therefore, much less likely to reflect back on to the dome.). I have the 10-17. But, haven't shot it underwater yet. If you're concerned with possible reflections from the gold lettering cover it with black electrical tape.

     

    Take Care,

    ChrisS

     

    *Note: some of the Nikkor wide angle primes have white lettering surrounding the front element (24mm, 28mm, 35mm); I have had problems with that lettering reflecting off the dome and appearing in images. Solution: use a black permanent marker to cover all the white lettering.


  17. Two things to try to fix your external DVI monitor problem:

    -zap PRAM (hold down command-option-P-R all at the same time after you hear the startup sound on reboot, wait until you hear the startup sound repeat again)

     

    -reset the PMU (Power Management Unit) You'll have to lookup how to do that on the Apple support site.

     

    Take Care,

    ChrisS


  18. Looks like some kind of scorpion fish. (dorsal and anal fins are poisonous to varying degrees depending on species)

    Very similar to the rockfish (Sebastidae genus) we have along the west coast of the North America.

     

    Take Care,

    ChrisS

×
×
  • Create New...