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frogfish

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Everything posted by frogfish

  1. Craig, I appreciate your message. I think this discussion is performing a useful service for anyone who is considering the AF-S 12-24 zoom lens, particularly until more manufacturers come out with clear advice as to which dome(s) the lens will work with and in what configuration. Used with the FE2 dome, the 12-24 has certainly impressed me as a valuable tool for wide-angle work. I would say that it outperforms my 20 mm prime lens with the older SWB dome by a considerable margin. Like you, I would not want people anyone discouraged from considering the AF-S due to premature judgments based in incomplete or inappropriate tests, but I agree completely that the matter of which domes and configurations (extension ring, diopter) work and don't work needs to be sorted out. I'm not completely convinced that tests of the lens with a diopter are an accurate indication of underwater performance, given that in an above water test, the camera is shooting a grid in a flat plane, while underwater in a dome, the camera is actually shooting the virtual image, which is a section of a sphere. In any event, I did some quick tests with the camera out of the housing and the +2 diopter mounted, at the closer subject distances you suggest. The camera was hand-held, so there probably some problems that are primarily due to my inability to hold the camera plane exactly parallel to the subject. Test 2189 - 12-24 zoom w/ +2 diopter. Zoom power: 24 mm. Distance: approx. 30 cm/12' (subject to sensor plane - the front of the lens is approx. 17 cm./6.5" from the subject. Test 2192 - 12-24 zoom w/ +2 diopter. Zoom power: 12 mm Distance: approx. 30 cm/12' (subject to sensor plane - the front of the lens is approx. 17 cm./6.5" from the subject. Test 2194 - 12-24 zoom w/ +2 diopter. Zoom power: 12 mm. Distance [closest focus or near]: approx. 24 cm/9.5" (subject to sensor plane - the front of the lens is approximately 18 cm./7" from the subject). Test 2198 - 12-24 zoom w/ +2 diopter. Zoom power: 24 mm. Distance [closest focus or near]: approx. 24 cm/9.5" (subject to sensor plane - the front of the lens is approximately 18 cm./7" from the subject). I certainly see a degree of rectilinear distortion in these images, though I don't understand why the distortion is restricted to one side of the image in two of the examples - perhaps this is the result of my failure to hold the camera perfectly level. Again, however, I think the level of distortion would be tolerable for most of the underwater subjects that I am likely to be shooting at very close focus distances with this lens underwater. And, as I said earlier, I'm not yet persuaded these tests are really indicative of what the performance through a dome underwater will be. I'll try to shoot some close tests in the pool the next time I have the 12-24 lens on the camera in the housing. Robert Delfs
  2. Craig, Very interesting. It sounds to me like the optics on the Nexus 170 mm dome and the Subal FE2 dome must be very different. If you can get good results with the 170 dome and no diopter, but experience pincushion with the +2 diopter, then I'd have to say - don't use a diopter. (What does Nexus say?) I certainly don't dismiss Lee's observations that the 12-24 used with diopter and the SWB dome produced unacceptable pincushion distortion in their tests. My disagreement was with their conclusion - that the 12-24 lens was intrinsically unsuitable for use with external diopters, and hence for unsuitable for use underwater. While they tested a variety of diopters and extension rings, all the tests of the 12-24 lens they carried out used the SWB dome. The people at Subal were very clear that the 12-24 zoom would not perform acceptably with the SWB dome. (That is the reason I bought the FE2 dome when I acquired the housing and the 12-24 lens, even though I already own a SWB.) I'm qnow uite satisfied that the +2 diopter does not represent a problem with the 12-24 with the FE2 dome. But it seems clear that this diopter power may not be appropriate when the lens is used behind other domes. Indeed, it seems clear that some domes will not work properly with this lens under any combination of diopters (Iincluding none) and/or extension ring lengths, and the Subal SWB dome that Lee and Al used in their tests would appear to be one. Since I have no intention of ever using the lens in the dome in air (or with a diopter in air), how the lens performs under those conditions is not really relevant to any of my concerns. But I will try to shoot a smaller grid at 12 inches the next time I have the housing set up. Robert Delfs
  3. I very much agree with Paul's assessment that the 2.0 EX converter is a big improvement over the original. The interface could still be much improved. One thing in particular I'd like to see would be better linkage between the gray picker and manual color temperature and color settings. As it stands, these are separate modules. If you use the gray picker, you can't fine-tune color temperature up or down. The gray picker seems to be able to come up with color temperature settings that are not accessible on the manual controls. You can zoom in the preview window of the converter, which I don't think was possible before. Being able to adjust ISO sensitivity in 1/6 stop steps is also a big improvement. The EXIF extractor is particularly useful for editing, as the preview windows for RAW files aren't really big enough. Before, you had to convert the RAW files to TIFF before you could get a better look at the image. I haven't used any other converters except EX 1.0 and LE, so can't comment on the quality of conversions relative to other programs, except to say that the EX 2.0 files look very good.
  4. I'd written: >>Adding a second strobe doesn't increase the range of illumination. SeeDave replied: >I need to think about this more. If the transmitted light of a strobe falls off like Energy/r^2, shouldn't twice >the energy give me twice the illumination? I grant that when the distance r gets "big" the falloff is fast, but >two times teeny is still bigger than teeny, right? When two strobes are used, they're normally positioned out to both sides inorder to illuminate a broader area, so they don't act as a single-point source. But even assuming that you strapped two big strobes together to increase the illumination, you don't get anything like twice the range. The conventional formula for using two identical strobes with the light superimposed is: f number = 1.4 x (Guide Number for a Single Strobe / Distance) I'm don't believe that this formula necessarily holds true underwater, where the exponential light fall-off as distance increases is much sharper than in air. But even if it did, all this would give you is one additional stop of aperture, or an equivalent 1.4x increase in range at the same f-stop. Say, from 5 to 7 feet. The image of sweetlips and divers (which James kindly linked in) does illustrate how sharp the illumination drop-off is with a medium-tight aperture - it was probably f/11 but I'm not sure. This was shot with a 20 mm lens on a F801s, so it's essentially the equivalent to the Nikonos 15 mm. The sweetlips are very close. Actually, the problems with the strobe illumination on that image are more profound than James' comments may suggest. I was having serious problems with my strobes on this trip (like most trips these days). If you look at the image, it's clear that the left strobe didn't fire at all. All the strobe illumination is coming from the far right, creating very unnatural-looking lighting. Had the other strobe fired propertly, the terrible shadows of tails and things would have been smoothed out, and there might have been even illumination across the bottom of the frame, and maybe a bit better lighting of the second school of a different species of fish visible on the far left. Had I known that I only had one functional strobe, I would have repositioned the arm straight up over the housing. That might have been better, but the beam of the single strobe still wouldn't have been broad enough to illuminate the entire frame. Despite these problems, it's still the closest I've come to getting this technique to work. And the missing left strobe does make it very easy to see the fall-off in light from the right strobe across the frame. (How do people make quotes appear in nice boxes, by the way?)
  5. More on liveaboards in Indonesia... Most of the liveaboards I know here in Indonesia cost considerably more per day than land-based diving., unless you happened to be staying at an Aman Resort. Paste, you'd mentioned that the Wakatobi Resort is above your budget - I'm not sure what their costs are, but I think it would be hard to find a good liveaboard that costs any less. Some of the top tier boats (Pelagian, and Komodo Adventurer, a new catamaran) are now charging US$300 a day. Others (such as the Kararu boat) are less, but most still in the $250/day range. Evening Star II was even less expensive, but I understand that operation may be shutting down soon. All these boats I've mentioned are mainly operating in Komodo area most of the year, but this winter several will be rebasing to Rajah Empat (West Papua) over December-March, which is the rainy season in the Bali-Komodo area. There is a lot of enthusiasm about the diving in Rajah Empat, and if demand is there some boats may start operating there more of the year. Another interesting possibility is to find a transfer trip, when these boats are rebasing. Most of the transfers to and from Rajah Empat involve roughly two-week trips between Sorong and Kupang (West Timor), which include several days diving in the Rajah Empat area, plus numerous stops in the Banda Sea (including Banda Islands) and Alor region. Some of these sites can be quite spectacular, and are difficult or impossible to get to any other way. As I'm sure you're aware, there are a lot of factors to be considered in selecting a live-aboard. Safety should be number one, particularly if you're looking harder at the lower-cost operators in order to reduce costs. The fact that a boat is less expensive doesn't mean it isn't safe, but I think it's worthwhile to look into what type of vessel, its condition, safety and communications equipment on board, etc. before putting your money down. If you're a photographer, then it's important that the boat be "photographer-friendly." Most are, but some aren't. Protected space to work on cameras adequate for as many photographers as will be on board, rinse tanks, charging facilities, etc. Another issue is the style of diving and sites. Some boats cater primarily to macro photographers, do mainly macro sites. Others are more into wide-angle stuff, big pelagics, drift dives, etc. If you have strong preferences in the kind of diving and/or photography you do, you won't be happy if the philosophy and operating practices of the people running the obat lie in a different direction. Robert
  6. I'm with MikeO - I've never understood why low-volume masks suddenly became the hot new thing, but if I had to guess, I'd say "marketing." My favorite mask used to be the huge Mares thing (I can't remember the name now) with two extra windows on the sides and two more on the bottom, angled down. Ugly to look at, and very high volume, but very comfortable, and the bottom windows (with plain glass) made it much easier to read small numbers on a wrist computer with a small display (like the unimportant ones that tell you how many minutes you're supposed to stay at what depth to avoid bad things happening). Or figure out which way a pygmy sea horse is facing. I'm shortsighted and use prescription panes in the main lenses, so it's sometimes hard to see things that are small. The side-windows sound like a gimmick, but they weren't. They were actually angled back slightly, so when you looked sideways, you could actually see a bit behind you. Particularly nice if you're buddying with a diver who needs keeping an eye on. Unfortunately, there was an intrinsic problem with the design - the frames tended to crack. I went through two before I gave up. I think Mares doesn't make them any more. If they brought it back with the design flaw fixed, I'd buy another in a minute. My main mask for the past couple years has been the Mares Liberator. Black silicone. Medium-volume, reasonably comfortable. My backup mask (which I take with me on every dive in a pocket on my harness) is a BigEye. I don't like it as much as the Liberator. One reason is that the design seems to trap bubbles more easily, particularly if the mask is angled at all downwards. My primary second stage is quite small, but this doesn't seem to be a problem with the Liberator. The key issue with a masks, as far as I'm concerned, is fit. Since some faces are broad, others narrow, with differently shaped and curved foreheads, temples, cheeks, etc., the mask that fits me perfectly may be terrible for you, and vice versa. There's certainly no one single "best" mask for everyone. If a mask doesn't fit right, then it will leak, and a leaking mask will ruin a dive. Robert Delfs
  7. I think the answer depends a bit on what you want a liveaboard for. I understand that there are some liveaboards based in Manado at least part of the year, and I've heard there are also now 2 or 3 boats offering dives in the Lembeh Straits. I think some boats based in this area occasionally go up north to the Sangihe Islands (but I haven't heard much good about Sangihe Isls.) Given what can be done based in a resort (KBR or Lembeh Resort) in the Lembeh area, or in Manado/Bunaken area from any of the many operators there, I think you would want to know where a liveaboard in North Sulawesi would be taking you that (1) you can't get to using day-boats from the resorts, and (2) are places you really want to go. With respect to 1, keep in mind that some of the Manado operations have fast, long-range boats (or at least used to) that can cover a lot of the less heavily dived sites between Manado and Lembeh, if that's what you're interested in. If you want to combine your diving in north Sulawesi with a liveaboard trip, I'd be more inclined to look at other prime areas in Indonesia that can only (or best) be dived from a liveaboard.
  8. James, About 4 feet away - I didn't measure. I'd just come back from some mola dives, hadn't used much of the card - too much work uphill finning to do much shooting. The camera and housing were set up, and there was still enough light for the autofocus to work, so I dropped into the pool with mask and snorkel and took a few shots of the with the zoom cranked all the way in to 12 and all the way out to 24. I wasn't worrying much about focus, as long as the shot was clear enough to show the extent of rectilinear distortion, and aligned close enough to true horizontal that I could reproduce the image aligned and as close to full frame as possible, without a lot of rotating and cropping. Also, I was shooting at 1/30 (no strobe, to avoid strobe reflections off the tiles, late afternoon). I suspect the softness in focus is more a matter of camera movement at the slow shutter speed. I don't think there is any problem with close focus using this lens, dome and diopter configuration at much closer distances than this. (See image below.) But the 2X diopter was of course still on the lens from the dive. My position is that, with this dome, this diopter should be on the lens at all times. The comparison between the pincushion problems so dramatically evident in Craig's tile tests vs. mine suggests that the Subal FE2 dome, in combination with the 50 mm extension ring, may work better with the 12-24 lens than the configuration Craig used, which I infer was the Nexus 170 mm dome plus 25 mm extension ring, no diopter. But it's not clear to me whether the problem with Craig's test shots is primarily related to the dome optics, size of extension ring (i.e., alignment with lens nodal point), presence/absence and/or choice of diopter, or some combination of the above. In any event, I feel even more confident now that the Lee Paterson/Al Burton conclusion (that "the design of the 12-24 AF-S lens precludes the use of optics in front of the lens" due to unacceptable pincushion distortion") on the MCD website page Craig cited can be dismissed out of hand. My test pictures were taken with a +2 diopter. The discrepancy can probably be attributed to the fact that Paterson and Burton tested the 12-24 with the Subal SWB dome, which is not suitable for any lens this wide. Subal's position, I believe, is that the only the FE2 dome (on a Subal rig) can be used with the 12-24 and other super-wide (< 18 mm) lenses. Image taken with 12-24 zoom lens at a distance of about 2.5 feet (from the barrel sponge).
  9. The problem with neoprene wetsuits for camera systems is the same as the problem with wetsuits for divers - it compresses at depth, giving up more buoyancy the deeper you go (and the more you need it). Since as divers we like to keep warm, and prefer flexibility, we're pretty much stuck with neoprene or something like it for suits. My current camera rig is fairly neutral, but I experimented with various approaches to adding buoyance to my older, heavier, film rig. Including lengths of PVC pipe, sealed at both ends, taped to the strobe arm sections. Which sort of worked. But the best thing I've seen for this is marine-grade foam, which is very rigid and does not compress at depth - or at least not until past 200 meters, at which point the issue is probably irrelevant. It cuts easily with a saw or surfoam tool, and pieces of it can be taped to your housing and/or strobe arm segments. Certainly doesn't require precision cutting or clothes-making skills. It's cheap enough that you could throw it away at the end of a trip if packing space is at a premium and cut new flotation pieces when you get home. And if you do decide to pack it up and take it, at least you won't have to hang it out to dry with the wetsuits, booties and other water-absorbent gear.
  10. Let me throw in my $0.02, while being well aware that we all find it wasy to recommend whatever it is that we use. I've only ever used UltraLight arms, but (unlike my experience with strobes), I've never had reason to second-guess that decision or wished I'd invested in another system. One of the strongest arguments for Ultralight (which probably also applies to TLC) is that this is a modular system. Whatever segments, clamps and connectors you get for your present system, you will almost certainly be able to adapt and use them on any future underwater camera system you may acquire. I started with a single strobe, with two longish segments for wide-angle and a single short arm segment for macro, basically duplicated all of that when I acquired a second strobe, and now also have a variety of ULCS connectors I use for my Ikelite light meter and various night dive/aiming lights etc. It's not cheap, but very well-designed and engineered, and built to last a lifetime.
  11. I did some quick test shots in the pool with the 12-24 this afternoon after coming back from a dive. I see a very small amount of pincushion in the horizontals at the top and bottom of the images, but it seems to be less noticeable than what Craig found, and is well within my tolerances for almost any kind of shooting, and certainly acceptable (to me) for underwater. I believe the divergences on the verticals in 2nd and 3rd image are due to my not having held the camera perfectly level. There is very little visible divergence on the first image. These were taken with Subal F2 housing, FE2 dome port, from a distance of about 4 feet, at minimum, maximum and an intermediate zoom power. No strobe. Taken from roughly about 3.5 feet from the wall - the tiles are about 3" x 3". The first two images were rotated slightly (less than 0.5 degree) to align a horizontal with a guide in Photoshop, then cropped in by a few pixels. They're 99% of full-frame. (The third image turned out to be perfectly aligned on the horizontal, so was not cropped at all - 100% of original image.)
  12. You're right - it works. When I slide the mouse cursor over the diver picture, I get a pop-up that says "Wetpixel Forums", so I assumed that just took you to the top of the forum page too, not to the main page. Not a big deal anyway.
  13. This is a bigger topic than you might imagine. Printing (whether on your own ink jet printer, preparation of an art print, or submission to a publication, etc.) means conversion to CMYK color space, even if you don't explicitly invoke this step yourself. CMYK has a different (and much more restricted) gamut of colors, as well as limitations in inking. There may be colors in your RGB image that are not printable in CMYK - look for an explanation point (!) in the information palette when you scan around the image in RGB or LAB. Things with weird names and acronyms like dot gain, GCR and UCR get invoked, and it turns out have huge implications for how a printed version of your image will actually look. None of these are trivial. Resolution is another issue, but it's not the case that, for printing, more resolution is better - sometimes the opposite is true! And there's also aspect ratio. Your original digital image might have an aspect ratio of 1.5:1. You might want to crop this differently to display it on the web, and you definitely will want to crop to a different aspect ratio if you're printing on A4 or US-standard paper sizes and want to make maximal use of the printable area available from your printer. You'll want to set the pixels/inch setting to 72 for images you are using on the web, but for printing you will probably want to go to 200 or higher. As for me, I try to do all editing at the maximum resolution/file size the original image has. Images for the web get converted to 72 dpi and a maximum size of 800 pixels on the longest side - usually 800 x 535 for an uncropped image. To print, I go back to the original large file, set dpi to somewhere between 200-300, and crop the image to fit on A4 paper. Robert Delfs
  14. Just my $0.02, but I've noticed that if you have the forum page bookmarked, or even if you're there, there's no way to get to the main (home) page except to manually edit the URL command address line in the browser. The "wetpixel" at the far left of the navigation line at the top of every page doesn't actually take you to the main page, but rather just to the main forum page.
  15. There will be alternatives to land-base diving in Irian Jaya at or around Christmas. Several Bali-based liveaboards will be in the Rajah Empat (Sorong/Irian Jaya/Papua whatever) area in that period. December-March is the deepest part of the rainy season in the Bali-Komodo part of Indonesia, so a number of operators are rebasing to Sorong during all or this season. The transfer trips (usually two stages, Bali to Kupang (Timor) and then Timor to Sorong, then back again) are also worth looking at, particularly the Kupang-Sorong or Sorong-Kupang trips, as these generally include diving in Banda Sea and Alor region as well 5-6 days in Rajah Empat area. These include Pelagian, Sea Safari (the Kararu boat), and Komodo Adventurer (a new boat which Larry Smith (formerly Pelagian, and before that KBR, and before that...) is now associated with), and that's just the ones I know about. I think there's a good chance at least one or two other boats might be in the area as well.
  16. I agree that test images of grids shot with different dome and diopter combinations would be useful. The tiles in the little splash pool we have here aren't as colorful as the ones in your image, but may serve. What distance did you shoot the tiles from?
  17. I'm very interested (but a bit surprised) to read Craig's post about "unacceptable" pincushion distortion with the 12-24 with a diopter and the Lee Paterson/Al Bruton article from MCD website concluding that the lens' design "precludes the use of supplemental optics in front of the lens" I haven't run tests on grids in a pool, but I also didn't find this problem with any images taken with 12-24. (Fuji S2 Pro, Subal FE2 dome, +2 diopter). I did find BARREL distortion on a couple of images when shooting very tight with the 12-24 opened to widest zoom power, but the subject was a barrel sponge and I didn't find the effect objectionable. As I understand it, Subal is NOT recommending use of the SWB dome (which Paterson/Bruton used for their tests which found pincushion problems with the 12-24 zoom lens).
  18. My name is Robert, and I'm a government relations consultant. Originally from California, but have been living and working in Asia (Hong Kong, China, Japan) for more than 20 years. We're currently living (but not working) in Bali. I certified as a diver at Maumere Bay in Flores in 1993. All our diving has been in Southeast Asia. My first underwater camera was an MX-10 (which I still have). I went to a housed (Subal) Nikon F801s in 1999. I've just acquired a Fuji S2 (also Subal-housed), and have just taken it on its first trip. I've got some images online on my website (www.tabula-international.com), mostly film scans, but it also includes the first pictures I've taken with the new digital camera.
  19. I use a Halcyon SS backplate and their single-tank (27 lb lift) wing, and love it. the main things I like are reduced drag (even compared to a wing-style Seaquest Balance, my old BC), much easier trim, and a significant reduction in total weight (including backplate) needed on a dive. Maybe I should repeat "reduced drag" two or three more times, as I believe that is by far the most important advantage of this rig for u/w photographers. My wife uses the Halcyon aluminum backplate with the same wing, and also loves it as well. We also both use it with their storage pack to hold a SMB (submersible marker buoy). We only dive single aluminum tanks, tropical Indo-Pacific, so this wing has plenty of lift for our needs. The one big downside with the SS backplate is travel weight, so I was very interested to read on this thread about the Koplin/Oxycheq "dog-bone" travel plate and immediately went to check their website. According to the travel plate weights 1.0 kg (2.2 lbs), which is about the same as the Halcyon (and most other) aluminum backplates. A light-weight single tank adaptor (also cut away) to go with the dogbone plate weights another 0.5 kg., which takes the total weight 3.4 lbs. (about 1.55 kg). That's only 2.6 lbs (or 1.2 kg) more a full stainless steel backplate (6 lbs, or 2.7 kg). The dogbone plate looks neat, but the only reason I'd ever leave my stainless steel backplate behind would be to save weight on a flight. ,So it seems it would make more sense for me to get a STA-less aluminum backplate for trips, and save as much weight as possible. The other drawback of the fishbone design I see is that I wouldn't be able to stow my SMB in the Halcyon storage pack, which bolts to the backplate, meaning I'd have to carry it externally. I carry the largest SMB I've been able to find (the OMS 10 foot sausage), which would be quite awkward to carry externally and would probably add a lot of drag, so this is not a minor consideration. In any event, if you're still diving with a wrap-around vest BC, or even a "wing-style" BC like the Seaquest, you owe it to yourself to try out a backplate and wing sometime, particularly if you're in the market for a new BC. But if all available funds are already committed to buying new camera gear, on the other hand, then I'd strongly suggest postponing that test-dive. Robert Delfs
  20. I don't think you ever had a reply to the query about the adaptor on the Japanese website, or the exchange rate. Clicking on the item I think you're referring to ("Hi-speed 32 bit Cardbus Adaptor (CF32A), CF Card / Micro Drive compatible), the following page does apparently say the price purchased direct is Yen 5,400, which would be about US$46 (at US$1=Y116), presumably exclusive of charges for shipping outside Japan. Robert Delfs
  21. I've been in touch with Subal regarding using the 12-24 mm lens with the new Fuji S2 housing. They've only had one lens in their shop just long enough to take basic measurements, but I was told that the lens will require the EXR-50/3 extension ring and preferably the DP-FE2 dome port. (They did not say that the DP-SWB will not work, but that the DP-FE2 will offer superior optical performance.) It's still unclear what diopter will provide optimal performance. Lens/port configuration for the S2 will be identical to the D10 (for Nikon D100). I'm hoping that they will be able to get a zoom gear done in time to ship one together with the new S2 housing.
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