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Everything posted by Tom_Kline

  1. I am not sure what you are referring to. I use Seacam housings that feature a fitting for a ball in the center-top of the housing. I use this mainly for attaching a camera pole in my stream shots. I use the same fitting for focus lights when scuba diving.
  2. There are two sets each consisting of two parts. One part is for the viewing lens. It slides onto the post of the RM4 lens control interface unit (the gizmo that couples the shutter speed and aperture settings and fits into the bayonet mount of the lens - there are 4 different versions for the 4 different RM housings) in such a way that when you flip the lever on the outside of the housing the viewing part swings over the viewing lens on the camera. The cu lens that goes over the shooting lens is a simple piece of glass that fits in the holder on the same lens interface unit - it swings in too. They have not been made for decades so it takes a lot of searching to find one.
  3. At least theoretically any lens set to f/8 will transmit the same amount of light. Differences that occur are mainly due to differences in transmission of light by glass which is less than 100% as part of the light gets reflected, mainly at glass-air interfaces. Type of lens coating (from none at all for lenses made prior to the 1950s to the most recent coating types (very old uncoated lenses can be adapted to m43)) has the most pronounced effect on transmission. The number of lens elements as well because more lens elements results in less transmission - multi-coating as enabled far more lens elements than the past. The only practical way that we as photographers can detect differences in light transmission between two lens would be to take two identical exposures, one with each lens, and compare the resulting histograms in Lightroom or some other software (even the back of the camera could work but the graphs are tiny). I would be more concerned with differences in autofocus ability between these lenses and this would depend on your camera model.
  4. Since you have the tapered port the best option would be to either get the dedicated wet diopter lens that Seacam sells for it or get the Seacam 67mm adapter for the port and use one of the many 67mm wet diopter lenses available on the market. If you go for an internal (dry) diopter you will need to have enough room between your 100mm lens and port glass for the diopter to fit. Diopters are actual lenses so thicker than filters which are flat. As well you will get fewer lens aberrations if you buy an achromatic diopter which are thicker still (and more expensive). Wet diopters can be removed during a dive whereas you are stuck with an internal one for the dive.
  5. I bought items from Wetpixel member friendlyfish listed on these sales: https://wetpixel.com/forums/index.php?/topic/68839-fs-seacam-wideport-macro-port-port-extensions-gears-nikon-105-macro-lens/ https://wetpixel.com/forums/index.php?/topic/68838-fs-nauticam-to-seacam-port-adapter/ Items arrived well-packed and just as described.Transaction went very smoothly. Seller is an excellent communicator and highly recommended. Thank you Mark!
  6. To get 270 Watt-seconds, i.e. 270 Joules, output for the same batteries one will get about half as many shots. There is something called the first law of thermodynamics. https://en.wikipedia.org/wiki/First_law_of_thermodynamics
  7. I suspect the light output is going to be similar given how much juice one can get out of 8 AAs. Buy two more strobes for a total of four to gain one more stop. If you can do with less angle there is the option of the reflector accessory for the Retras.
  8. Looks like it uses AAs which has advantages as well as disadvantages: https://www.backscatter.com/Isotta-RED64-i-TTL-Underwater-Strobe It might be better to compare this with Retras. It is still at pre-order so not likely to get any user feedback.
  9. Phil such a camera would be more than way cool though I would not mind if the VF articulated all the way to 90 degrees (or 0 degrees depending on your reference) so that one could look straight down through it as well as at 45 and horizontally.
  10. I have done the pre-focusing thing as well in the dark but then a subject of different size will show up... I have not used the 3D AF. With Canon I have used what is nicknamed the ring of fire, which is auto point selection of all the AF points but only in S mode in spite of Canon's suggestion this is for static subjects. Their auto point in AFC is more like 3D in that one has to start with an AF point on the subject which is not possible for me (remote control shooting without looking through the VF). I use release priority so one has to get a feel for how fast this works to start the AF earlier enough via remote control. Nikon has something like this since the D4 which is what I have been using with both the D4S and D800. I have tried this in both AFS and AFC but use AFC for the most part. I used the D2X for quite a few years and for that I chose the row of AF points run horizontally. Nikon dropped this but something similar is back with the D6.
  11. Up to six divers are tethered to the boat: three starboard, three port. The tether consists of a down line that is about 15m long and has a dive weight (~ 2kg) at the bottom. A jon line of about 1.2 m length connects the diver with the down line. The jon line has clips on either end for clipping onto the down line and the diver. The only lights are those held by the divers. The DM orbits the divers (i.e. is not tethered). The boat may or may not have a drogue deployed from the bow. A parachute is used for the drogue.
  12. I have relied on AF for most of my salmon UWP. They move fast when doing interesting behavior such as spawning and fighting. Most of my rejected oof images are do to the subject moving out of the AF rectangle - to the left or right of it.
  13. Maybe they will respond to new ML APS-C cameras from Canon and Nikon.
  14. Canon may be phasing out APS-C DSLRs as well. Northlight has a timeline of Canon camera introductions here: https://www.northlight-images.co.uk/canon-camera-rumours-and-info/ Need to scroll down a bit - it looks like a spreadsheet with boxes filled in with shades of green. It runs from 00 to 22. Note that last APS-C DSLR intros coincide more or less with the 1Dx3 intro ('19 to early 20). Nikon has currently two APS-C Z bodies and it is rumored that Canon will have APS-C R bodies as well. Canon currently has the EOS-M APS-C line (that is rumored to be doomed). It looks to me like APS-C is far from dead and may even lead micro-4/3 in sales.
  15. Manta dives may be the biggest draw for divers and snorkelers (and a few that have never used a mask and snorkel) to Hawaii. A bonfire is used to attract zooplankton that in turn attracts the mantas. Each boat seems to donate a large dive light to the bonfire that is placed on the bottom pointing up. Originally the mantas were attracted to shore by hotel lights - over a period of decades this morphed into what is done now. Mike Bartick has shown his Anilao set-up in several on-line vids. He uses a drifting buoyed system with lights at various depths attached to a down-rope. BW dives in Kona are not done this way.
  16. The 10.5mm is an AFS lens but uses screw-drive for the AF. There is no nomenclature specific to screw drive AF in spite of the Alphabet Soup nomenclature of Nikkor lenses! I suspect that Nikon has replacements for the D500 and D850 on the drawing board but these may never get introduced due to production capacity limitations. One thing that could go into these hypothetical cameras is live view AF comparable to what is in the Z9 (and of course the sensors to do this). I believe the "killer app" feature of mirrorless is subject recognition with size (mainly the back focus distance; but mount diameter as well in the case of Nikon) secondary. Folks have gone bonkers with eye AF that Sony introduced a while back. This has morphed into a greater range of subjects and may be the subject for future development, maybe even the possibility of training ones camera to recognize a specific subject. This requires greater computational ability - keep in mind that CPUs continue to grow in capability....
  17. I believe "universal trays" are made for point and shoot housings. You should not need one for your housing - it should have both handles (grips) and holes for flash arm base bolts (at the top of the grips). Check the Nauticam web page for these details!
  18. I have started shooting while it was still dusk (note it was twilight for the pic). Twilight periods are rather long at high latitude - just under 1 hour for each of the three phases where I live. The BW dives I have done at Kona have been either shortly after sunset or around 2200, all without bonfires. The 2200 dives are done following the bonfire Manta dives from the same boat. The Manta dives are done from sunset on. With around a dozen boats some start earlier than others and many in the water are just snorkeling.
  19. It is in here somewhere: https://www.youtube.com/channel/UC3Rf_mU-wBuBXas7fBRJrMQ Adam did back to back interviews with Edward Lai not too long ago - check these out first. As well it was discussed here when the WACP-1 was first introduced. Alex mentioned that he used the Nikon 28-70 which I understood to mean the f/2.8 lens that preceded the 24-70 models but was wrong. He corrected me - it was the variable aperture model that uses 52mm filters if I recall correctly.
  20. I have done the same thing - used the Z6 with the excellent 24-70 kit lens for most of my topside shooting last trip to Hawaii (b4 the pandemic). Had the FTZ in case I wanted to use one my macro lenses (which I did not get around to on this trip). Found this on Facebook so here courtesy of Seasport Divers' posting there. Well protected against solar radiation and holding the Z6 off Niihau Island (in the background).
  21. This should work. Keep in mind that plankton are small but animals that feed on plankton will be larger, can be much larger like mantas. You will probably will get some creatures that hide in the sand so this could be very interesting!
  22. There are organisms that are going to be attracted to light at night regardless of depth or salinity so the answer to your question is YES! I have been working on this at a small scale as a covid project - maybe it should be called cigarette lighter (not literally of course) underwater photography. One does not need very much light once it is dark to do this. My main limitation is that once it actually gets dark at night (in Alaska north of 60 degrees latitude), it gets cold rather quickly. Found an example on my HD taken before things froze up. Note that there is still twilight at 8:21 pm on Sept 26 (it looks like this at 3 in the afternoon now!). I used the Retra strobe's aiming light to also be the "bonfire" You can see stuff growing on the bottom of the lake. The stool was so that I could look at the back of the camera once out of the water while all the stuff was still attached to it (it stayed horizontal).
  23. Looks like this will work!! Moving parts will need some maintenance.
  24. Davide, Are you aware of the notched ULCS clamps that allow one to position an arm at 90 degrees. There are several models available. I got these a couple years ago but more are available now - some with notches on both sides of the clamps.
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