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About davelew

  • Rank
    Wolf Eel
  • Birthday 05/20/1975

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  • Camera Model & Brand
    Olympus EP-1
  • Camera Housing
  • Strobe/Lighting Model & Brand
    Inon D2000, Inon S2000
  • Accessories
    ULCS strobe arms and base
  1. I had a chance to borrow a Nikon AW120 recently for a dive where my SLR gear was left at home. For a shallow dive in the Florida Keys, at 20 feet with bright sunlight, this was a surprisingly capable little camera. I could zip it into a pocket in my BC, forget I had a camera with me, and then pull the camera out when I saw a yellow stingray posing. Set at 24mm with the flash turned off and the underwater mode, I couldn't figure out how to change any other settings. Although I would have liked better sharpness and contrast, I'm actually pretty happy with this picture. It's not publication quality, but I think it's acceptable for web viewing, and certainly the best composed image I have taken of the species.
  2. I'll repeat what MarkHerm said. Photography is an advanced diving skill, not something that most new divers can do safely or easily. The problem with fixing white balance in post-processing is that most cameras don't allow you to set the ISO to one value for red pixels and to another value for blue or green pixels. Water filters out most red light in a couple feet, so an exposure for proper reds is going to completely overexpose the greens and blues, while a proper exposure for blue is going to underexpose the reds. The E-M5 has a great dynamic range for such a small sensor, but most natural light seen when diving has hundreds of times more blue light than red light, and the E-M5 can't compensate for that (no camera can, to my knowledge). Unfortunately, the human brain is wired to respond to reds, and most of the best underwater photos have red in them. Needing red in photos and not having much red light underwater is one of the big challenges of underwater photography. There are four main ways of dealing with this problem: 1. Bring your own light in the form of underwater strobes. Inon and Ikelite are two popular brands. Alex Mustard has done some work which, I believe, shows that Inons are slightly better for cold water and Ikelites are slightly better for warm water, but both are excellent choices. The main drawback to using strobes is the short range of strobes underwater, but since the water column degrades image quality, you generally need to get close to your subject anyway for a good photo, so this isn't much of a drawback. 2. Put a red filter on your camera. This cuts down on the green and blue light, letting proportionally more red light in, at the cost of reducing the total amount of light, which means higher ISOs (with more noise), slower shutter speeds (with more motion blur) or wider apertures (loss of sharpness and DOF) are required. Since this balances the red, green, and blue channels of the camera before the signals go the A2D converter, it gives pretty good quality as long as the photo is properly exposed to start with. 3. Using the white balance option on your camera. Some people will bring a white slate or wear white fins, and take a photo of the white reference underwater to set the white of the camera. This tends to cause problems with the red in photos. Think of a camera that normally assigns a value of 0 to 999 for the redness of every pixel. Now imagine that all the reds are 0 to 9, so the camera multiplies each red value by 100 to get the full range, but it ends up only having 10 shades of red instead of 1,000, so the reds end up looking really weird and banded, not smoothly varied like the other colors that use the full of numbers from 0 to 999. 4. White balance in post-processing. This is about the same as #3, with the same drawbacks. It helps to shoot RAW in order to do this, since JPEGs lose some of the image information. In practice, most photographers use a combination of #1 and #4. Many photographers have dual strobe setups, with two strobes on arms in order to get the distribution of light they want.
  3. Thanks-- that looks exactly like what I saw.
  4. Just out of curiosity, what makes you certain? I actually considered E. crucifer, but rejected it because of the lack of a prominent mouth (or whatever you call the center region of an anemone without any tentacles).
  5. I have no idea if this is how they are doing it, but here's a way to get 3D through a dome port: have the axis of both lenses pass through the theoretical center of the dome. The trick is that the two cameras can't be exactly parallel to each other (or, if using a beam splitter, they can't be exactly 90 degrees off from each other). If you want the cameras pointed at the same subject, and that subject moves to a different distance, you would have to move the cameras as though on a curved track (both rotating and translating them).
  6. I use some Nikonos lenses on a micro-four-thirds camera (Olympus EP1) in a one-of-a-kind experimental housing. The EP1 has a higher crop-factor than the NEX cameras, 2.0 instead of 1.6, but it's lower resolution so the pixel size is probably similar. Here are my opinions: The 80mm is REALLY hard to use. I usually try it with the Nikonos close-up adapter for supermacro, but the depth of field of a 160mm equivalent lens along with manual focus is problematic, at least for me. I believe that the lens is sharp, I just haven't gotten any supermacro images in focus yet. Here are the closest: P5040991.jpg by davelewinn, on Flickr P5040978-2 by davelewinn, on Flickr The 28mm lens is OK, maybe a little better with the closeup adapter, but nothing great. This is my best shot with the 28mm: P5030857.jpg by davelewinn, on Flickr The 15mm Nikonos lens is the only one I regularly use. It is more than sharp enough for a 12 megapixel sensor on a 2.0 crop factor camera, which is pretty astounding for a lens that age. Here is an example of a shot I took to try to later identify the beaded anemone, which shows what the 15mm is capable of even on a crop sensor camera: Turks and Caicos by davelewinn, on Flickr Personally, I find myself using a modern fisheye lens with autofocus and a dome port more than the Nikonos lenses. As frustrating as autofocus sometimes can be, manual focus is even more frustrating.
  7. There are some 3D printers that use a laser to selectively sinter titanium or brass powders into a solid metal of any shape, and then let you shake off the excess powder that wasn't sintered. Those would probably be interesting for camera housings, since the sintered metal is strong and watertight. The main issue is that 3D printing doesn't leave smooth surfaces, there are voxels (the 3D equivalent to pixels) around 0.1mm or .004". For many uses those voxels are OK, but that sort of rough surface tends to cause problems with o-rings and sealing-- think of lots of sand on every o-ring surface, and what that would do to seals over time.
  8. A couple of reefscape photos from French Cay, in the Turks and Caicos Islands, last week: Turks and Caicos by davelewinn, on Flickr Turks and Caicos by davelewinn, on Flickr
  9. I have a D90 (basically the previous generation of the D7000) and an OM-D E-M5. I find that, when running out the door, I tend to grab the OM-D. The Nikon has slightly better dynamic range, slightly faster focusing, and I'm more used to the Nikon shortcuts to adjust settings. My impression is that lenses of the same quality are cheaper for the Nikon, but smaller and more portable for the Olympus (for example looking at good-but-not-great fast normal primes, the Nikkor 35mm f/1.8 is US$200, while the Panasonic 20mm f/1.7 is US$300), but it's really hard to compare lenses of similar quality. The OM-D is smaller and easier to carry around for those times when I'm not photographing, and that single fact outweighs the minor performance advantages of the Nikon. The one area where the OM-D significantly outperforms Nikon is with the image stabilization, but that's not much of an issue underwater. An added advantage is that, with either the 60mm macro or the 8mm Zuiko fisheye and MMF-3 adapter, the OM-D is splashproof so a minor housing leak won't be an issue. I don't know if there's another splashproof fisheye lens for the MFT mount, I own the four-thirds 8mm so I just use it with an adapter. In the end, I'd get the OM-D. It's more fun, and image quality is similar. My only advice is to get it without the 12-50 kit zoom. I find that lens to be awful, even compared to other kit zooms. I never thought contrast would be an issue with a modern lens, but the 12-50 has such poor contrast that images often appear to be blurry.
  10. This should be an easy one for you guys, I don't have much anemone knowledge. Last week, I saw what looked like a segmented worm at first nestled in some fire coral and writhing with the surge, in the Turks and Caicos islands in the Caribbean. It only looked like a worm from far away, when I got closer it looked like some sort of rock anemone or carpet anemone, only I've never seen a carpet anemone with branching tentacles, and I didn't see the center of a rock anemone, just lots of edges folded over each other. Here's the best picture I got of it: Turks and Caicos by davelewinn, on Flickr
  11. I don't use a Hugyfot housing, I use an experimental housing with a check valve and the ability to pump a vacuum to test seals and avoid fogging. On my housing, I use a Mityvac hand vacuum pump, available at auto parts stores for bleeding brake valves, or from Amazon: http://www.amazon.com/Mityvac-MV8000-Automotive-Test-Bleeding/dp/B00265M9SS/ref=sr_1_1?ie=UTF8&qid=1352839522&sr=8-1&keywords=mityvac+brake+bleeder I wonder if that would work for the Hugy housings? It takes about 40 squeezes for me to get to a 50% vacuum (15" of mercury on the pump's pressure dial) which is a little tedious, but not too bad.
  12. The fast burst rate (continuous shooting at 60 frames per second) of the Nikon V1 seems interesting for macro. No more worrying about getting the right part of the critter in focus, just start moving and fire off a burst! Of course, this would require a video light instead of a strobe (or naturally lit macro), but it does seem like an interesting niche use, assuming the Nikon "1" macro lens is decent.
  13. If I were buying a compact UW camera right now, I would look very closely at the Olympus XZ-1. It has an f/1.8 lens, RAW support, ISO6400, the ability to control most camera functions with two dials (in aperture priority mode, one dial controls F-stop, the other dial controls exposure compensation, which seems like a nice system). It also has an underwater housing that looks like it has the quality of Olympus' dSLR housings, as opposed to most compact housings. The only drawback I see to the XZ-1 underwater is that the lens only goes to 28mm wide, not 24mm.
  14. The Olympus XZ-1 which was just announced (along with an Olympus underwater housing) also looks interesting. I have no idea about the shutter lag on it, but the f/1.8 lens should allow for fast autofocus.
  15. I've always been surprised that Olympus SLRs aren't more popular with underwater photographers, since Olympus seems to support their SLRs and EVIL cameras with housings better than Canon or Nikon. The E-620 with Zuiko 50mm lens, PT-E06 housing, and PPO-E03 port seems like a fantastic and low price macro setup, at least on paper.
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