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segal3

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Posts posted by segal3


  1. A small sampling of some subjects...(apologies for the vertical nature of this post :D ).

    All photos are uncropped.

    sol06mac1.jpg

    Whitestriped Pygmygoby (Eviota guttata)?

     

    sol06mac2.jpg

    A curious mix of color

     

    sol06mac3.jpg

    Pygmy Seahorse (Hippocampus denise) - I cut off the tail :)

     

    sol06mac4.jpg

    Soft coral crab (Hoplophrys oatesii)

     

    sol06mac5.jpg

    Can't be sure of the species, but it is a decorator crab, that much I know :D.

    Everything seemed to run from the light on the night dives...

     

    It's nice to see more members planning to visit the area!


  2. Those burrows are guarded by a creature so foul, so cruel that no diver yet has fought with it and lived! Iv'e seen the bones of full fifty men lie strewn about its lair. So, brave divers, if you do doubt your courage or your strength, go no further, for DEATH awaits you all with nasty, big, pointy teeth!

    One, two, five! (Three sir!) Three! ;)

     

    Gerard - Mantis shrimp are generally found circumtropically with some extension into temperate regions (there is at least one well-known species off the California coast).


  3. Thanks guys - the garibaldis make good contrasting subjects.

     

    John - I was out on the Spectre to Anacapa this last Saturday. Boat was packed, nearly 40 people, and many of the beginning/new certification divers who loved nothing less than to swim into a shot from behind and to attempt to glide mere inches off the bottom without stirring up the sand (note, attempt :glare: ).

     

    Water was nice though, a warm 64F or so ;).


  4. Hey guys -

     

    It seems that in the current POTW "Soft Coral", a number of entries have been submitted that are not in fact soft corals (despite their appearances). Without singling out any specific image, anemones and cup corals are Hexacorallia and Scleractinia, respectively, and the latter would be an excellent submission to the upcoming POTW "Hard Coral".

     

    This is a great motivation for everyone to learn the species names and classifications of the subjects in their images. Unfortunately, those images that currently are ineligible for voting will be disqualified.

     

    Good luck in future Photo of the Week Competitions!


  5. Granted, this was shot at ISO200 f2.8 with a 1/2 second shutter.
    Hey Rand -

     

    I'm curious about the ISO being so low...just blanked (hey, it happens :blush:) or intentional? I thought ISO400-800 or so was fairly good on the D2X.

     

    Looks like good vegetation cover...


  6. Wide-angle lenses have a very large depth of field as compared to telephoto lenses.
    This is actually a common misconception :lol: - they can have the same DOF under certain conditions.

     

    An excellent article that ties all of this together is Understanding Depth of Field on Reichmann's Luminous Landscape website. Be sure to look at some of the linked pages in the article as well - if you try to work out the math once or twice it should come together. Just plug-in all the numbers and see what you get for a few real-world examples.

     

    The focal length is a function of the lens alone - no other part of the camera. The short of it is, is that as sensor size decreases, DOF increases (assuming constant field-of-view and f/stop). Note that, as mentioned, you must use the f/stop number in the equation, not the aperture diameter for each lens.

     

    Herb can jump in here :lol:


  7. The DOF is a property of the image created by the optics and has NOTHING AT ALL to do with the sensor.
    Hey Bart - Not quite so.

     

    03c06867e117c2af4ff8cd7be670d1c4.png (Source: wikipedia - DOF)

     

    Where f is the focal length, N is the f/stop, P is the pupil magnification, m is the magnification, and c is the circle of confusion.

     

    The circle of confusion is different for various sensor sizes - for example, the CoC of 35mm film is ~0.029mm, CoC of the 20D is 0.019mm, of the D70 is 0.020mm.

     

    Changing the camera sensor size, in turn, changes the DOF for a given focal length, aperture, and lens.


  8. A selection of scenics from this year's trip to the Solomons...(they're all in Adobe RGB)

     

    An unnamed dive site:

    sol06wa1.jpg

     

    sol06wa2.jpg

     

    Lumalihie Passage:

    sol06wa3.jpg

     

    Totalave Island:

    sol06wa5.jpg

     

    Lots of nutrients in the water, so visibility typically wasn't exceptional, save for a few sites.


  9. ...not the other way around.

    _MG_5546_44w.jpg

     

    This interaction was slightly difficult to shoot. The supermacro setup was on, so most of the time the subject filled too much of the frame. Only with my arm stretched way out could I back off far enough - never thought that'd be an issue :P

     

    Anuha Island, Solomons


  10. I don't think Matt was looking for a critique
    I wasn't? Come now, I'm always looking for a critique - the majority of the time that I ask for one though I rarely get anything useful. :rolleyes:

     

    I think this balance is part of a new technique I'm working on (with some fair amount of difficulty in getting it right). This one turned out, but as everyone notices, the aesthetics of the picture are lacking.

     

    A different site, but same day (for those in the area, Three Sisters at Santa Cruz Island). I think the fish from the first photo really needed to make a showing here :unsure: :

    _MG_5881w.jpg

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