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Dave S

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Everything posted by Dave S

  1. Hi Jean, Is there any news to report on the Tokina 16-28mm testing? Also, more generally, is there currently a zoom gear sized between 18722 and 18723, and if not, would Aquatica consider producing one specifically to fit this lens? Similarly, assuming your initial 75mm ideal extension calculation is correct, would Aquatica consider producing a new extension to suit this lens? Thanks.
  2. Hi Jean, I've just returned from overseas, and had a chance to accurately measure my 16-28mm with callipers, alongside the Canon 24-70mm f/2.8. The two lenses have the zoom ring the same distance from the bayonet shoulder, but the 16-28mm zoom ring is smaller than the 24-70. (74.5mm diameter for the 16-28mm, compared with 83.5mm for the 24-70mm.) I had been hoping the 18723 ring for the 24-70mm would fit the 16-28mm, but from those measurements it looks like it will be too large. Is there any zoom gear sized between the 18722 and 18723? Also, could you please tell me the length of the standard macro port (18428) and the low profile macro port (18429), in terms of distance from the bayonet mount to the glass? I'm also trying to figure out whether I'd be able to use different lenses behind one without needing many different extensions. I.e. Using the 28mm or 50mm primes, or adding a teleconverter to the 100mm macro, I'd like to try to calculate whether I'd get vignetting due to the port being too long, or have the lens hit the glass due to it being too short. Thanks.
  3. Hi Jean, I received the housing today, and while the port and extension look good, the 18722 gear unfortunately doesn't fit on the zoom ring, even with the gear's o-rings removed! Is there a larger size gear you could recommend? About 2mm wider in diameter would be perfect. Thanks.
  4. Sorry, you're right, that measurement is an error. It should be about 95-100mm.
  5. Hi Jean, Here are my measurements of the lens. All length measurements are taken from the shoulder of the bayonet mount - the circular metal face that presses against the front of the camera when the bayonet is secured. Could you please let me know if these change your guesses about which extensions and gears would be appropriate? Length (bayonet shoulder to end of non-removable lens hood): 135mm Diameter at front (lens hood): 90mm Bayonet shoulder to rear end of zoom ring: 23mm Bayonet shoulder to front end of zoom ring: 40mm Diameter of zoom ring: 75mm And one extra measurement, the aperture diaphragm appears to be at about 121mm from the bayonet shoulder when zoomed to 16mm. Thanks!
  6. Thanks Jean, much appreciated. I'll be receiving the lens before purchasing the housing, so if it would help, I could provide some accurate measurements of the lens when I have it. (External measurements would be easy, diaphragm position a little more difficult.)
  7. I'm considering getting an Aquatica housing for my 5D mark II with a Tokina 16-28mm f/2.8 lens, but this lens isn't included in Aquatica's current lens charts. Has anyone tried housing this lens yet, and if so, are there any currently available extensions and zoom gears that are suitable for it? I haven't purchased the lens yet, so can't measure it, but it looks to be very similar in size and shape to the Nikon 24-24mm f/2.8, or a little similar to the Canon 16-35mm f/2.8. Aquatica extension 18458 and zoom gear 18722 with the 14-24mm, or extension 18457 and zoom gear 18708 with the 16-35mm. I'm tempted to just try getting the extension and zoom for the 14-24mm and hoping they fit, but obviously this is quite a gamble. Jean, if you could comment on this, it would be greatly appreciated! Thanks.
  8. Dave S

    Aquatica

    Where are you located, and where are you willing to post to?
  9. Sorry, you're out of luck. I asked Ikelite about this recently, and here's the response I got.
  10. Thanks jlyle, good to know they're sensitive, but I'd be using it for a remote strobe inside caves and wrecks, so would sometimes need enough cord length to position a strobe around a corner with the EV sensor in view of the on-camera strobes. If they're anything like the slave sensors built in to my Inon strobes, line of sight will still be required.
  11. Thanks, sounds like the Ikelite sync cable extension might be useful in that case.
  12. So I'm considering getting a DS51 with manual controller to use as a remote strobe, but I have a few questions for anyone that owns the EV controller. 1) What is the length of the cord that goes from the EV controller to the strobe? 2) Is this cord a normal sync cable, or is it different, or not removable from the controller unit? Thanks!
  13. I've recently bought a pair of 2nd hand Inon D2000 strobes. I'm not sure which version they are, but they're optically triggered only, they have no sync cord attachment. They came without the magnetic screw-in switches. Now, I'm using a Canon G10, and normally run it in manual mode. In this mode, the camera's internal flash is also manual, and so has no pre-flash. I'm also using the strobes in manual mode, and finding that the output of the strobes is extremely low, even when set to full power. When I change the camera to Av mode (using TTL flash, with pre-flash), the Inons suddenly behave properly. So, I'm assuming that the Inons are expecting a pre-flash from the camera, and putting out a weak initial flash, followed by a full-strength 2nd flash, in order to trigger any other optically-slaved strobes that expect a pre-flash. Now, what I'm wondering is, will replacing the magnetic screws (if I can find them or build a replacement) set the strobes to fire on a single flash, rather than a double flash? The diagram on the back of the strobes (image attached) isn't very clear. Thanks!
  14. Ok, ok. Sorry, I didn't think there was any SLR housing capable of accepting 67mm wet filters. "Achromat" means a design using 2 lens elements to reduce chromatic aberration; it's not a coating. I'm not sure how well that Subsee magnifier would work, as it looks pretty small, and I would suspect it'd be too small to be used with an SLR lens. The Canon close-up lenses (for dry use) are apparently acromats, although I'm not sure about the Inon or Epoque. An achromat normally requires 2 lens elements, but that may be different underwater. The Inon has 2 glass lens elements, but I suspect that underwater it might be the case that the air gap between them acts as a single element, while the glass-water barriers cause very little refraction. The Epoque has 4 glass elements, so I'd say it certainly could have greater potential for correcting chromatic aberration.
  15. I might be able to answer that one. When you say you're using it with a "Nikon 105 lens", do you mean a 105mm SLR lens? And if so, are you using the Inon either inside a housing or on land (directly attached to the camera lens)? (I ask because I wouldn't expect it to fit on the outside of an SLR housing.) If you are using it attached directly to the lens, then it's conceivable that the chromatic aberration (purple fringing) is occurring because the UCL-165 is designed to be used wet. Or possibly it just introduces CA whether used wet or dry. Either way, for dry use (including inside the housing), I'd be more inclined to suggest a Canon 250D close-up lens for use with a 105mm lens. Unless your lens diameter is too large for the 250D (max 58mm), in which case you might only be able to use the weaker (but stackable) Canon 500D, or a lower quality close-up lens from another manufacturer. But for dry use, the Canons are the best close-up lenses out there, AFAIK.
  16. I'm wondering which of the Epoque or Inon close-up lenses is appropriate for a Canon G10. (Ikelite housing, don't worry, I'll find a way to attach it.) So, a few questions: 1) Epoque don't give a power or focal length for their lens, but it's apparently stronger than the Inon UCL-165 (which has a focal length of 165mm). Does anyone know what the focal length or power/dioptre of this lens is? 2) Has anyone used the Epoque with a Canon G-series (7, 9, 10, whatever) camera, and if so, how does it go? Does it limit the min-max focus distance range too much to be useful? (Assuming shooting nudibranch sized stuff.) (Zoomed-in macro performance is about the same, without close-up lens, across the Gs, I think. The G10 focuses closer than the 7/9 when zoomed in, but also has a shorter max focal length.) 3) Does anyone know how strong the Epoque is compared to two stacked Inon 165s? The lens comparison and advice given by Marine Camera sort of suggests that an Epoque would be appropriate for a G-series, as AFAIK they don't focus closer than 12 inches when zoomed in. Thanks!
  17. Uh, the strobe in that picture is definitely overexposed. How much brighter would you expect it to be?
  18. Assuming the intent is to increase contrast (as colour filters are used for in surface B&W film photography), why bother? Seems to me that if shooting digital, this would be hugely inferior to (and more expensive than) shooting in colour and then adjusting the individual colour levels (or using other techniques to adjust contrast) before converting to monochrome. Which issue of UWP was this article in?
  19. Guide number is a measure of flash illumination. The DS-51 has a surface guide no. of 17, making it almost 4 times more powerful. (The guide number doubles when you multiply the strobe power by 4.) 9m is very weak, and would probably only be useful for macro. I use a YS-27DX, which is great for a simple slave strobe, and that has a guide no. of 20m.
  20. http://www.ikelite.com/af35/autoflash.html Short, bubble arms that are an integral part of the strobe and it only has a surface guide no. of 9m @ ISO100. Looks terrible IMO.
  21. The 165 offers plenty of flexibility... When you want to focus further away, you take it off!
  22. Ok, here's the results of my test. I hand-held an Ikelite W20 wide angle lens in front of my Canon A630 in WP-DC8 housing. Without WA lens, at widest (35mm) zoom: With WA lens, at widest (35mm) zoom: Without WA lens, zoomed to 46mm to remove vignetting: So it definitely gets me a lot wider, even after vignetting is removed by cropping or zooming. I noticed the corners were quite soft, but I'm not sure whether this is to do with depth of field, quality of the wet-lens, my holding it unevenly, water on the lens, or something else. I'm convinced, and am now going to buy an Inon and build a 67mm screw thread adapter from a stepping ring. I'll post results of that once I get it all together.
  23. As long as it's a wet lens (as opposed to a lens designed to be used in air or inside a housing), I think it should produce a proper image. The only concerns would be how to attach it, and whether the rear element (or more specifically, its image circle) is large enough that you won't get significant vignetting. Do you mean Tokina? They make lenses for SLRs (and other interchangeable lens cameras). AFAIK they don't make wet lenses. No, as long as the lens is designed to go underwater, it should work almost the same in air and water. (But of course will be wider in air than water if it has a flat port, due to diffraction.) With a wet-lens, you should be able to focus normally. Set it as wide as you can. If you get vignetting, then either zoom in, crop the image later, or use photoshop to clone out the vignetting. I think the wet lens should be mounted as close as possibly to the front of the housing. Did you forget to set it on the 2nd post also? Click the "Options" button on the first post and then "Track this topic".
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