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ChrisRoss

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ChrisRoss last won the day on February 16

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About ChrisRoss

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    Great Hammerhead

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    http://www.aus-natural.com

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  • Gender
    Male
  • Location
    Sydney Australia

Additional Info

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    Australia
  • Camera Model & Brand
    Olympus OM-D E-M1 MkII
  • Camera Housing
    Nauticam
  • Strobe/Lighting Model & Brand
    INON Z-240

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  1. I'm assuming the slave is off behind the divers so further from the camera which means the light needs to travel through more water. If it is twice the on-camera strobe to subject distance the amount of filtration by water will be about equal. Beyond that point it passes through more water. On processing there a few tricks you can apply - first on my monitor I see an overall green cast in the lit portions, a very slight curves tweak will fix that but you still have green in the deep shadows. If you have full photoshop you can use a selective color layer and adjust the blacks - add 6-7 points of magenta and the green will go away - it won't become blue but it's no longer green. You can also add a lot of magenta to the greens. It's a one minute fix in full photoshop. Other programs you could probably do it working on curves through a shadow mask.
  2. I believe the change to the dome port II was an enlarged lens opening to accommodate bigger lenses. The Canon 11-24 was specifically mentioned. Zen also has a larger version the DP-120 -1124 for the same reason. The spec sheet says the Nauticam has an ID of 109mm. The diameter of your GM lens is 88.5 mm so I would hazard a guess that you should be fine with either version. The 11-24 lens has a diameter of 108mm according to the specs. Finding the full dimensional specs of domes seems to be like uncovering a state secret for some reason.
  3. There's no reason the other domes wont work with another 16-35mm lens you just have to work out the port extension if it's not listed on the port charts. The Nauticam port chart lists both the 16-35GM and 16-35 FA lens and it shows the GM lens using 10mm more extension than the FA lens. The ZEN Port chart also lists both lenses and shows the GM lens requires the 35.5 mm N100-N120 adapter and a 70mm N120 extension which is exactly the same set of extensions as the Nauticam 230mm dome. The Zen port chart is here: http://www.jaredparsons.com/portchart/zen-only/by-combination-group/nauticam-n120/
  4. The issue with 15mm dome depends on how it is setup with the dome in question. Adding extension places the lens further back in the dome if the lens is setup with the barrel mostly inside the extension then adding some extension means it is more likely that various parts of the dome are going to end being in the field of view and it will vignette. The 230mm dome port has a hood and this is a likely source for vignetting. Whether it does so or not you would have to test. The good thing about vignetting is it is easy test in the shop. There is is really no benefit in using the big dome with a fisheye lens apart from not needing a second dome to accommodate your fisheye lens and the bigger dome makes it more difficult to get in close for CFWA shots.
  5. The strength of the pulse does not change only the duration - maybe the white BG is producing a flash duration that is too short for the protocol to cope with? Maybe try a different subject or move back from it?
  6. The issue being addressed is related to the field of view and how much closer the dome's virtual image is to the sensor plane than the centre. The field of view of your lens is the same as a 16mm lens on full frame and it it is dealing with the same size and shape as that lens virtual image on any given dome. The problem in the corners is due to not having enough depth of field to get the corners sharp. DX will be better with this as the magnification to achieve a given field of view is less so the depth of field is better by 1.5 stops compared to full frame. All assuming the lens is positioned properly in the dome and really only talking about the shortest focal length. A rule of thumb for a rectilinear 16mm lens is f16 for full frame f11-13 for DX and probably f8 for m43 to get the corners looking acceptable. The S&S lens is a field flattener it brings the corners into focus and can reportedly do two stops better than a bare lens so for DX it should improve the image so you can use f5.6-6.3 if f11-13 is your limit currently. Whether you can or not depends - if you already use a 230mm dome on DX the corners may be really quite good already and you could do better still. Some lenses may not be so good in the corners on land and adding the native lens abberations to the depth of field issue means the corners can't improve as much. Some lenses will also have some field curvature natively - on land this is covered up by the depth of field but your starting point is not so good and adding on the issue with the virtual image means the problem is worse on that lens. You see many wide lenses that need to be stopped down 2 stops or so to be at their best in the corners. A good starting point would be to establish the aperture limit that you are happy with on your current setup.
  7. Here's an article: https://indopacificimages.com/chinchorro-crocodiles/ It's in Mexico, but the priciples should be similar looks like he used the Tokina 11-20mm from the EXIF data.
  8. I'm perfectly happy diving with a 700 lumen dive torch with a 60° beam, mounted on the cold shoe of my housing - at low power it has 2-3 hours burn time and uses the same batteries as my flashes. With my normal exposures of around 1/125 @ f8 ISO250 it does not show up in my shots. A nice low tech solution. This is the torch: http://www.inon.jp/products/le_light/lf1400s.html you can get a YS adapter to attach to a YS cold shoe mount. The design of the o-ring seal is particularly good, I never get any water or grit on the o-ring due to the outside o-ring on the body of the torch - unscrew - inspect o-ring - change battery - rescrew. I generally use the supplied diffuser to soften and spread the beam. If you can't find a European retailer this guy in Japan is very good: https://www.uwdigitalcamera.com/store/ and I can recommend dealing with him.
  9. For travel the volume is often a deciding factor - large domes are more difficult to travel with. The size of the dome required for a 16mm full frame equivalent rectilinear wide lens scales with the sensor size as does the required aperture. You now have an alternative to big domes in the WWL and WACP from Nauticam - but these are heavy and expensive. Because the aperture scales, flash power also scales with sensor size. Fisheye lenses though are pretty much the same dome size whichever format you choose. Here's my rig in a carry on size backpack. It contains top row: 4"Zen fisheye dome, Pany 8mm fisheye , Oly 60mm macro. olympus 12-40, Pany 7-14. Middle row: 60mm macro port, 2 x INON Z-240, Zen 170mm dome. Bottom row: Nauticam EM-1 MkII housing - camera inside spare batteries. Laptop in sleeve underneath. In selecting your camera you might also like to consider battery life; the GX9 is CIPA rated for 260 shots while the EM-1 MkII is rated for 440 shots. I can get 3-4 dives out of my EM-1 MkII.
  10. Another data point here: Issue is trying to use the single fibre optic port to trigger two strobes and it's not working. It is a different version of the housing so check if the housing you are looking at uses this same arrangement. Also check port availability. With luck you may find a user who can comment from experience.
  11. it's 0.5x "equivalent" magnification including the 2x crop factor.
  12. In general the WWL is limited to 28mm full frame equivalent field of view so would vignette between 12 and 14mm on the 12-35. Also it is not suitable for the larger diameter fast f2.8 lenses I assume because the entrance pupil is too big for the WWL to function as designed it can only feed the fully corrected image into the smaller entrance pupil of slower lenses. I suspect it also changes length too much so performance will be compromised at the wide end with the lens further from the port. An additional concern is lack of a flat port that will fit the lens, for example ignoring the length for now, the focus gear of a 12-40mm f2.8 Oly lens (similar in size to the Pany) will not fit through a 60mm macro lens port I have at home. I would suggest you research which particular 14-42 is the best one to use with the WWL.
  13. The 12-40 is I think still the better UW option at least from the close focusing standpoint, the 12-45mm gets 0.25x magnification at 23cm MFD while the 12-40 is 0.3x at 20cm. I use the 12040 in a 170mm Zen dome and image quality is great all through the zoom range. What would be interesting to me would be 10-40mm zoom with similar max magnification. those extra 2mm would extend the versatility quite a bit.
  14. The Oly fisheye is a little better than the panasonic. I have the Pany 8mm and it's a nice lens, the corners are a little prone to purple fringing and not quite as sharp. It may be connected to Panasonic using a different cut off filter on their sensor to Olympus and the Olympus letting through wavelengths in the violet that the panasonic lens is not corrected for - I don't have proof of that though. You do need to focus on the closest part of your composition with the fisheye even if that is in the corners to place the depth of field properly . Also need to watch the corners, very easy to get a stray diver there if you are not paying attention and they will look very weird - so the shot is for the bin. For wrecks you would need to watch your corners closely I would imagine, depnding on what is in the corner the distortion could stretch out what ever is there and look odd ruining the shot. Getting in close is a skill that will take time to acquire in my experience.
  15. Might get some good prices on the EM-1 MkII now the replacement is out - if it's close the 1-mkII would be a better option than the 5-MkIII if only for the much bigger battery, the better housing options have been covered already - the 1-MkII housing is really quite nice to use with the shutter and back button focus setup.
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