Adventurer

Don’t underestimate the DOF issues this optical category produces, once you move the concept to a full frame sensor. If you compare land based 28-60mm DOF to a 10mm lens, the latter will give you 130 FOV and more DOF sharpness. This water contact optic category that throws the image into the distance enjoys an excellent reputation for compact cameras, microfourthirds and previously camcorders, because they crop in on the center part of the optic.

I can get access to a D-Pro and wonder if that one is also in the fast or slow strobe category. I think you can derive some insights from the D-Max, so I am curious about your readings on that one. Also interested in the Kraken KRS160, if anybody has values for that one.

Here is one of your practical applications @Phil Rudin as asked above. Also as previously mentioned faster light gives you crisper (sharper) subjects in photography. I must thank @DreiFish for putting so much work in his answer. He illustrated it very well with his example pictures and I could not have it explained better. Especially point 6. and 5. in his initial answer are very worthwhile reading. I hope 🙏 less people skip over that too fast 😎😉 To me strobe speed ( and I do not mean recycle time with that ) is just as important as strobe power (GN, Ws etc).

Sorry - I must apologize for reading to quick. That part is valid and DreiFish is right. He correctly explains the difference. However the readout speed of your camera sensor must be able to keep up with the strobe, if it’s really fast.

no you cannot. what you described is a test for x-sync speed, not flash duration. you are all mistaking the effect of shutter speed for flash duration. please try to get your head around this another time. I know it’s counter intuitive and may be difficult to sort out. If you have a fast moving subject you can freeze it in your frame with a very fast and strong strobe, even if you expose for 3sec or bulb. There is no need to discuss x-sync speed or new fancy global shutter or HSS for this, it is not the application and irrelevant.

You could have lowered that ISO and would have received nicer blues 😎

I do not agree Wolfgang. Keep in mind the following. When you try to photo water droplets you will find that your shutter must be set to bulb to archive this. The flash will freeze your foreground. The sharpness of your underwater imaging subject is largely also accounted to bringing fast light to the table. You will observe a pleasing “crispness” if successfully mastered with the right gear. More than 10 years ago I had a lot of issues with Subtronic and Ikelite strobes which had round flash tubes. These were very slow as @Chris Ross pointed out correctly. Occasionally this resulted in an unpleasant movement halo in front of fast moving subjects (a lot of pelagic animals and fast movers such as dolphins and sharks). When I switched to system strobes or other uw strobes that used xenon flash modules (in German: Stabblitzröhren) the problems disappeared. Also my macro shots got crisper.

Hello Sergio, as far as I understood you are talking about the ambient light. The part in the picture your strobes cannot reach, correct? It would be good to know, if you also changed settings upon ascent. ISO and/or shutter speed need to be re-evaluated whenever the ambient light changes. Different water depth is such a change. You should be able to archive nice blues at any water depth. The color temp of your strobes and auto-wb has a minor influence, too. But I recommend not to focus on that part too much.

Dear forum members, in another thread here we gently touched the question of having fast light. While everybody is currently still talking about guide numbers and color temp, I would like to raise awareness about flash duration and flash peak values and energy. This is a very old video about a Canon 580 EX II where you see the setup and measurement curves that can be done. As all of you want to know what the most powerful and best underwater strobe in the market is, this is an interesting approach. Years ago I have been involved in such a test. Maybe a member has the equipment to go for such a setup and can publish the results. Here is the video on youtube: How to measure Flash Duration

Today my Marelux 30mm Extension Ring finally arrived, thanks to hydronalin Germany. So I re-did the test and also optimized the chessboard straightness with a leveling tool. To me this F11 picture just looks great and I think that I almost nailed the right position with 30mm extension ring. 35mm was the computed optimum when leaving the BK7 glass out of the equation. That missing computation should allow you to go shorter up to 10-15mm on large domes. So averaging in data collection errors and some other mistakes it’s worthwhile to finalize all with a practical test setup in the garden. As I had slight vignetting with 35mm in the corners (see above) the 5mm less just seem right and I am glad. As we often talk about “curved virtual images” behind domes I thought it’s interesting to observe this practically. I was able to sneak my phone camera perspective in from the top, which shows you very well the curved chessboard on the dome below the waterline. I hope this helps others here to optimize their dome setups and get maximum IQ out of them.

Wowzer! That shot is fantastic and exactly the style I like. I was thinking about getting away with just one Apollo for shooting comfort but this makes consider me two apollos.

my condolences - another great one gone

The sharpest lens in APS-C Sony is the Sigma 16mm. It can be utilized behind a dome. The maximum f-stop is F16 but that's not a big issue. In fact not raping your aperture will improve IQ substantially. In your country Hydronalin has published extensive videos on A6000 A6300 A6500 A6400 with Fantasea Housings. Most stuff from the videos can be applied to Seafrogs and Nauticam housings as well. You will find the videos on their facebook page, not on youtube. The videos can be found and watched without having a facebook account.

As far as I know SUPE and BIG BLUE do not have constant lumen output electronics implemented in their lights, which safes them costs and for you this means less video footage quality during the dive. If you want constant and " true " lumen output you will need to buy video lights from Keldan, Light&Motion, Sealife, Weefine or Kraken. The remote control feature is available with Weefine and Kraken and Wireless on Keldan lights. Note that SUPE has rebranded into FOTOCORE lately.

Entirely possible that the same energy is spread to three tubes each one not at full power which would give better temperature or at least no drop I do not understand that we are discussing in the wrong direction. DreiFish gave these values: Marelux Apollo III = 6808K (at maximum I suppose) Marelux Apollo III MTL = 7092K Difference almost 300K cooler in MTL. As MTL mode reduces the strobe output to recycle faster, I would assume at least the same 6800K or slightly warmer color temp, when following your previous arguments about single flash elements output emitting higher energy and more cooler photons. Do we agree on this point or is there a misunderstanding we can work out? My intuition was that Marelux will evenly reduce the power output on each flash element. --- So if the above is true and agreed upon, DreiFish's measurement on Apollo III might give us a hint that the 3 flash elements do not fire at the same time in MTL mode. Marelux might eventually archive the high recycle times by rotating the 3 elements for light emmission and giving up to maximum output at each element, before the other two take turn again.

Note that Apollo III v2.0 now hits the streets with some minor improvements.

more additions: the weefine and small Kraken strobe ( WFS07 and Kraken KR-S05 ) have TTL and properly adjust the light output automatically, when put in something they call "Sy" mode on these units. Corrections in the google docs file are recommended quickly, before too much wrong info circulates.

Not sure if I understood what you wrote here correctly. They way I read it it‘s a wrong statement. According to my lab experiment and oscilloscope values measured back with Subtronic Pro 160, Ikelite DS160 and Inon Z240, SEA&SEA YS.. some years ago the warmer flash tubes (Ikelite, Subtronic) create their higher power by leaving the light on longer at lower level. This also applies to all other ring flash tubes such as Seacam and OneUW. The peak lumen number you were able to measure from a Z240 was higher than on the much stronger D160 or Subtronic. This gave me and my friends headaches, so we set up time logged testing with an oscilloscope. We then found that the z240 delivered his peak value much faster and the large (warm painted) plasma tube strobes took more time to ignite and needed stay on longer. All that time stuff in milli and microseconds. There are some underwater applications were fast light delivery comes in handy and will result in sharper images.

Lethal stuff 🤣 thanks for putting the work in this and sharing here! update note: afaik the Kraken offers USB-C charging update note 2: INON D200 and Z330 are not available anymore correction: you wrote marilux again 🤣 instead of Marelux question: how did you measure the energy output?

Xenon Strobe tubes and LEDs have a manufacturing variance and tolerance in that range. More closely to the 500k instead of 1000k though. So that offset may come from the component source. Furthermore ambient light might have cooled down your measurement. And as Massimo pointed out correctly full power measurement is cooler than in mid range color temp measurement. This would support your marketing accusation a little bit, if strobe manufacturers did not measure color temp at full output. The latter one however is a very practical approach as most of the users don’t fire at FULL all the time. @DreiFish the Marelux MTL reading freaks me out?!? I cannot really get my head around why a lower strobe power should be the coolest of all 🙏😇 Maybe you guys can up with ideas for this?

Well, don‘t be too harsh with the manufacturers. First, we do know if @DreiFish Spectrometer has been regularly and properly calibrated. Second, has it been done in a completely dark room ( I mean pitch black room ) or outside or living room environment? The ambient light might heavily distort the spectrometers readings. If you want to be precise you need to take it into an Ulbricht Sphere. However I highly appreciate Dreifish‘s home probing. Maybe he can let us more about his test environment? Furthermore I suggest to do multiple measurements for each unit to get an idea about measurement variance and errors.

If you want to go that way and be just super precise and optimized try the following: photo and strobe (white or grey) sand in your desired subject distance and use that white balance reference picture to set the manual wb. This will take the water effect on that particular dive, strobe color temp and diffusers into account. The manual Wb on most cams will include more parameters than just the Kelvin value. I personally would not use the diffussors then unless I have to increase beam angle or want more soft light instead of hard light.

sorry! I did’t know that rule. The video showed the left image of the bs promo pic screenshotted and taken in Adobe Lightroom. Then simply moving the white balance slider to the left until reaching approx 4500K. The result was the image presented on the right 😎 by bs to promote their diffusor.

Hahaha I had not seem that ok than this makes totally no sense „ Look mom, I can turn green water into blue! “ ( now you do not need buy me that $39 diffusor ) 🤪😜

Very smart. You still might have some deviation, depending if the lab conditions or camera changed over time. However,.. could you be so gentle and post the links of the video(s) you watched/sampled to do this and maybe 1-2 monochromed screengrabs to illustrate your method ?