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Rui_Guerra

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Rui_Guerra last won the day on November 22 2013

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About Rui_Guerra

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  1. Not entirely correct. I have here the Nikon 16-35 f4 and it changes the position of the from element, getting 9mm shorter when going from 16mm to 24mm. From 24 mm to 35 mm it moves out the front element for about 6mm. So there should be other things to consider and not just if it changes or not the front position element while zooming. It also moves a lot (around 30 to 40 mm) the position of the rear element while zooming in from 16 to 35 mm (maybe this compensates?). Nauticam recomends a 90 mm extension. Do you have any comparation test shots where you've based your decision about the extension length? I use an 80mm extension, just because that's what I have here (although image quality is very good, with the normal limitations of FOF and dome ports - using a big 230cm).
  2. I'm glad you mention this Adam, because I'm shooting video with a very similar setup: RED Weapon 6K, Nauticam Weapon LT housing, Nikon 16-35mm f4, 230mm dome port, but with a 30mm+50 mm extension (total = 80mm, instead of the 70mm you mentioned). Nauticam suggests in it's website that we should even use a 90 mm extension: https://www.nauticam.com/pages/port-charts Have you noticed any lower image quality in the corners with your 70mm option in any conditions? I'm asking this because I was even considering to update my extension to the recommended 90 mm, although I don't thing that a 10 mm increase will make any visible improvement (I'm vey happy with my setup so far). Another different story is light. Although the 16-35 f4 is an amazing lens, for video in some situations a faster lens is needed. So I'm looking for the options and one that comes to my mind is the Nikkor 17-35mm f2.8 (1 stop faster) or even the Sigma Art 18-35 f1.8, although with a narrower FOV and only usable from 20mm to 35mm (to cover the RED bigger then traditional S35 RED's sensor). But opening the aperture to 2.8 or 1.8, brings again the question of corner sharpness of dome ports (although only in the cases where we have some parts of the subject/scene in the corners). Which bring us to the WACP alternative. But then we need to seed a comparation test chart at this wide open apertures with a WACP and a big dome. That is the kind of comparation that could make it clear how many stops we really gain with the WACP, so each of us could decide to make the additional investment or not. Another question: is the WACP completely rectilinear, even at 130º? Besides the high price, it's also a very heavy piece of equipment (not very travel friendly), so it's not easy to just jump in and buy it. And we also need to buy the N100 to N120 adapter and (maybe) some specific extension ports.
  3. I'm also with you since I'm also a user of RED 6K. Much more info is needed with other lens combinations. In video, we need all the light that we can and there are many times where we need to shoot wide open (depending on the lens that could be f4, f2.8 or even wider). So far the recommendation emphasis had been in a slow 3.5 - 4.5 lens, which is of limited use for video work in less then ideal light conditions (if we have ideal light conditions, we could use smaller apertures, so no real need for the WACP). In my point of view, it's biggest usefulness is where the dome ports start to fail, at wider apertures, let's say from f5.6 and wider f-stops. So we really need to know how it performs in the f2.8 range and even f1.8 or f1.4. I know that in the real work we don't shoot test charts but to see the sharpness in the corners, we need that someone goes to a pool, shoot at a flat test chart in a pool's wall, at wide open f-stops, both with the WACP and a big dome (for example a 230 cm), and post the photos. Only then we can really see the improvments and how many stops do we gain in sharpness. Shooting reef corals and real underwater scenarios is nice, but doesn't provide us with objective data.
  4. Hi all, Anyone have used this brand, specially the powerful options in the 25000 - 30000 versions? Are they reliable and according to the specs? http://www.bigbluedivelights.com/products-detail.asp?Product=218 Thanks!
  5. Is this available to buy? Price? What kind of batteries are those (LiIon rechargeable? What charger? Thanks! Best Regards?
  6. The problem with the Sigma 15 mm FE is the front part (around the glass) and not the outside part of the lens. Since that area it's not mat, when we try to do some backline shoots with the sun in the picture one can see the parallel lines in the reflection inside the dome (I use the Subal DP-FE). I'm surprised that not every people that use this lens doesn't have the same problem. Or maybe they still not noted it... Although in photos its possible to use PS or LR to fix it, a major problem is when shooting video. It will ruin completely the footage :-( Until now I wasn't able to find a good solution. I've tried to glue some mat tissue but it came loose. Permanent ink (like Edding 3000) is not mat enough. And since the lens is metal painted black, its not possible to sand paper that area either. Anyone have another sugestion? Thanks!
  7. Hi all, thanks for the answers. I do take my video job seriously. For years I've used regular topside tripods (Gitzo) and ball heads underwater. Caring them underwater its not a problem (although I admit that some times a lift bag will be very handy..) But now, after 15 years of use uw, my Gitzo head (ball head) needs to be replaced. I have disassembled it many times to clean it, and thats why I wonder if that will be possible with a fluid video head and, if not, how long will it last. Many times I've used them in situations where a small / dedicated uw tripod will not work due to its limited size/high. In some very limited situations I've used a monopod, but most of the time, I need a tripod so a head is a must. TLC tilt/shift head looks good but I'm not sure about the smoothness of the movement. And i don't need the legs. But, anyway, I will look more carefully at this option, especially because of it's corruption free constrution. ULCS looks too small for the kind of gear I need to put on it (DSLR housing + external monitor + arms and two lights). Cheers,
  8. Hi all, I wonder if someone have already tried any tripod fluid video head underwater, form smooth pan/tilt camera movements? If so, what brand and model have provided the best results/durability? First of all, do you think it his really necessary a fluid head to achieve that level of camera movements smoothness, or, since the rig is underwater, a regular (no fluid inside) pan/tilt head is enough? My main concern is about how long will a fluid video head survive in the salt water conditions, maintaining it's fluid movements. I'm considering, for now, a Manfrotto MH055M8-Q5 ( just for the ability to shoot both photo and video in the same dive) or a dedicated fluid head like the 503 SERIES. But of course I would like to hear any other suggestion that you might have... Thanks! Cheers,
  9. Yes, how is this project? I'm very curious too...
  10. Are you sure?!?!?!?! I'm not sure if you are making a statment or posing a question, thought. I use Subal equipment for a long time and (as in any other brand) the underwater weight of the 8" dome vs the 60mm flat port are quite different... Cheers,
  11. Red filter can ne benefical to both photo and video in conjunction with custom WB to mantain blue water color and prevent it to become grey/dull. If you need to use flash/video lights for the foreground (while using the filter) you need to put a cyan filter over the light so subjects will not become redish.
  12. Hi all, The Nikon 10,5 is one of the sharpest fisheye lens in the market, and much sharper then the Tokina 10-17. Many full frame photographers had to stop using the Tokina in high resolution cameras like the Nikon D800 (I know it's a FX lens, but you can use it for circular photos at 10 mm). Being a fixed lens and a faster then the Tokina (f2.8 vs 3.5-4.5) it's hard to believe that it focus slower. Depth of field of both wide open, will of course be slightly less in the 10,5 since you'll be using f2.8 vs 3.5 in the Tokina. Cheers,
  13. Hi Thetrickster Yes, there is a way to correct WB in FCPX. You can use a free plug in named RT Color Balance or you can do it without the plug in: Cheers
  14. gecko1 : Just send an e-mail to Subal because it's possible to change the back of the dome or buy a Subal adapter type3-type4. Everithyng have a solution :-) Cheers,
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