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#378077 Winter musings

Posted by dreifish on Yesterday, 04:07 PM


Maybe you can read that from the metadata of the file. I do that in Sony Vegas Pro with an extension called Show Recording Data, but you there would be other free tools to do it outside of Vegas like EXIF Viewer(?). I guess maybe Adobe apps (Lightroom? P Pro?) show it in the file properties.


As to the main question, it's very difficult at the moment to make recommendations. I'm not happy with the GH4 for run-and-gun style underwater shooting, which is what I do, for many reasons. I badly want to go to Raja Ampat but I actually turned down a trip this coming February partly because I thought I would be frustrated by the camera. And I think that would be true for most of the "stills" cameras that have video features.


On the other hand, the GH4 is great for tripod-based macro video, once you've worked out a working focus procedure. So it depends what you want to shoot.


The camera that interests me most for wide angle is still the Sony Z100 in a Gates housing with a SWP44 lens that Josh Jensen shot this with. A 4K 60p ENG camera with a built-in lens, ND filters, proper auto-focus, nice white balance, proper zoom, worldwide support etc.. But it's so old now! Maybe we'll get a Z200 one day. Who knows...



Fully agree on this Nick -- I'm not sure how much of it is the camera/housing/lens/lights combination as opposed to Josh's obvious mastery of it and whatever post-production he's doing that makes the difference, but his  footage is excellent -- both in terms of colors, sharpness, focus, and stability.  Aspirational I would say.


I'm not convinced it could be replicated with a Sony A7RII, GH4, or other similar DSLR setup, including a housed Canon 1DXII ($11000).


Of course, the Z100 ($4500 new, $3750 used) + gates housing ($7250) + SWP44 lens ($4300!) at $15000+ starts to put you firmly in Sony FS7 ($8500 body + $6400 aquatica housing + $2000 dome = $16900 + lenses) or even Red Raven territory ($10k body, $10k nauticam housing, 2k dome = $22000 before lenses). And, from the specs, it's a larger, heavier camera setup than the FS7 or Red Raven.


Which begs the question -- why did Josh pick the Z100 over an large sensor, interchangable-lens raw-capable FS7 or Red setup? I'd be curious to hear his answer. Perhaps it's the versatility of the 20x zoom-through par-focal lens with the SWP44 port allowing you to go to a full 110 degrees at the wide end. That sure would be sweet to have for run-and-gun type shooting. Does it outweigh the benefits of RAW recording and the higher dynamic range of a large-sensor camera? I don't know. Perhaps for his work, it does. I'd be really curious to hear Josh's take.

#378010 Color Correcting Purple Water

Posted by dreifish on 21 October 2016 - 05:10 PM



It's actually a pretty easy correction using the blue color vector in the 6 vectors panel of Color Finale Pro plugin for FCPX, pushing the hue of blue from magenta towards cyan and increasing the saturation a bit. I do the same thing with the HLS panel in Lightroom for stills, so I suspect something similar can be done in Adobe Permiere or DaVinci Resolve, but I'm not experienced enough with that software to explain. Here's the exact correction:


First, adjust the blue vector, which fixes the water column:


Screen Shot 2016-10-22 at 8.58.33 AM.png



Then fine-tune white balance with the color wheels. 


Screen Shot 2016-10-22 at 8.58.43 AM.png

#376888 Sony a7s II underwater use -- All parameters

Posted by dreifish on 10 September 2016 - 04:53 AM

Well the deep shot is so defective with its magenta color that I don't think anything could help it.  The question is, if it had been shot in a sLog profile, would it be easier to correct?


Thanks for taking the time to do that.


No, it would be even harder to correct. SLOG is meant to solve issues with dynamic range -- i.e. a very contrasty scene where the brightest part of the image and the darkest parts of the image are more than 7-8 stops apart. The scene you filmed isn't one of those situations. It's easy to tell -- just put up the histogram when recording the video or a waveform monitor in your video editor. Most likely, when shooting with no picture profile, you'll find that neither your blacks nor your whites are clipping. So you can easily represent all of the image in 7-8 stops of the standard no picture profile. All SLOG will do is compress those 7-8 stops of contrast into 3-4 instead.  


After further testing over the past two days, I've basically found no situations where you NEED more than 7-8 stops shooting ambient light underwater. Think about it -- all those particles in the water strip away contrast resulting in a very flat image. That's why the most important rule of underwater photography/videography is to get as close to your subject as possible. The only situation where the scene has greater contrast than that is if you're shooting directly into the sun AND you're trying to preserve detail in the highlights AND the shadows (as opposed to just silhuetting whatever you're shooting against the sun). How often do you find yourself doing this with ambient light underwater?


SLOG only helps you preserve more luminance detail. It does not help you preserve more color detail. In fact, because it compresses the luminance range, it actually preserves less color detail. So no.. color correction of SLOG footage is never going to be easier than color correction of non-slog footage. 


I will try to post some more of the tests I've done, including some UAWB tests in the 10-12 meter range and using all the different picture styles to see which creates the best colors over the next few days (or weeks.. I have a busy week next week). In the meantime, I'll leave you with another screen grab from a video shot today. No picture profile, picture style standard, 3m, underwater auto white balance. 20160910-.jpg

#376826 Sony a7s II underwater use -- All parameters

Posted by dreifish on 08 September 2016 - 05:06 AM

Any password ?? Cant download...

Oops.. updated the link with the decryption key. Should work now?

#376811 Sony a7s II underwater use -- All parameters

Posted by dreifish on 07 September 2016 - 08:09 PM



I am leaving for a one-week trip to Grand Cayman next Thursday, and am up for conducting some tests.  Will be diving 2 tanks a day for 6 days, so I will have some time to review footage in the eventing.  


Dreifish, what would the advantage be of a Cinegamma setting?  You had be convinced to leave picture profiles alone for the future.  It certainly makes life easier.


Geo, I think you'll be quite happy sticking to no picture profile for your Grand Cayman trip. You can acquire very nice footage in this mode underwater.


The Cinegamma settings allow you a bit more control about how the camera records highlight and shadow information. Some of them will allow you to capture slightly more light-level gradations in the highlights or shadows areas of the image before those areas clip to pure white or pure black. That's the theory. It's not as much extra gradation as a log gamma curve (e.g. SLOG2 or SLOG3) would allow you to capture, but it's more than you get using the no picture profile settings. They also have the advantage of letting you use the Rec709 color space (which is the color space you'll be outputting your video in for TV/web use) rather than the SGAMUT color space that you're forced to use with SLOG. This means you won't have weird color shifts that you need to fix in post as you would with SLOG. 


In practice, there's some disadvantages and things to consider:

  • You need to post-process your footage to get the best out of it. Like with SLOG, you're squeezing more dynamic range into the same 8 bits of luminance data. The camera records all light levels from 0 - 255, with 0 being black and 255 being white. Cinnegamas and SLOG give you the option to try to squeeze in 10 or 12 stops of dynamic range into those 255 levels, rather then the roughly 8 stops you get with no picture profile. This will end up producing a video file that has less contrast initially. So to get the same "pop" you'll need to boost the contrast in post processing. No picture profile lets you use the video files as is, without this extra step, so it's a distinct advantage if you have tight deadlines or you don't want to spend loads of time color correcting the footage.
  • You trade detail in the midtones for extra detail in the shadows/highlights. Because you're squeezing in more information into the same 255 levels, you'll get less levels to represent the midtones -- which is usually where your subject is. So instead of having 255 levels to describe the black-to-white gradation of a manta's belly, for example, with cinnegamas you'll only get, say, 128, because the other 128 are now being used to record the gradations in the shadows of the coral the manta is hovering over, and in the sunrays. These are details you would otherwise lose clipping. So by choosing a cinnegama or slog profile, you're basically choosing to emphasize detail in the highlights and shadows at the expense of  midtone detail. Now, there may be scenes where this is the right choice, but, overall, I think it's rare that you need more than 8 stops to showcase the underwater world well. Do you really need that much detail in your sunbursts? Or in the shadows? Or would you rather use that data to make your main subject look better?

Personally, I'm ok with sacrificing a bit of detail in the highlights and shadows to get a picture with more contrast/pop with limited post-processing. Over the years, I've come to believe that a wide dynamic range is really not that important underwater, since we're often working with artificial light (strobes or torches) that fill in the details in the shadows. Does more dynamic range help? Sure it does, especially with careful post-processing to tone-map that dynamic range into the smaller space of you output format. But it has less visual impact than nice colors and nice contrast. 


To give you guys a visual reference for what I'm talking about, here is a short video with two scenes shot using no picture profile, cinegamma 1, cinegamma 2, cinegamma 4 and slog2, in that order. I took this footage yesterday with the A7RII set to UAWB, depth 3m, midday, good visibility. SLOG2 footage is at ISO800, F11. Other footage is at ISO200, F11. No post-processing was done. I also thew in a shot at the end to show what WB: Sunny looks like by comparison to UAWB. 




As you can see, it's not a huge difference between No PP and Cinegamma 1, 2 and 4. SLOG does show a big difference, but that's because of the SGAMUT color space messing everything up. If there's any colorists out there that want to play with the footage to see if you can make the Cinegammas or SLOG look nicer than no picture profile, I'm happy to share it. It's about 144MB in h.264 1080p.  If someone can suggest a web host, I can even put up the original 4k files.

#376725 Sony a7s II underwater use -- All parameters

Posted by dreifish on 05 September 2016 - 06:58 AM

As promised, here is some rough-cut footage shot on my A7RII as part of a series I'm doing on the different dive sites in Komodo National Park.


The first video is shot entirely using ambient light and underwater auto white balance mode, no picture profile. Depth of the site varies from 3-12 or so meters. Some of the deeper shots (e.g. the turtle, lion fish) are shot using a green water magic filter. The shallower shots such as the coral are shot with no filter. Minimal color correction done in Final Cut Pro X.




The second video is shot using two Gates GT14 lights, mostly in Custom White Balance (5200K). A couple of shots, like that of the anemonie and the sweet lips are in underwater auto white balance mode + the lights. No filters were used. 



#376719 Sony a7s II underwater use -- All parameters

Posted by dreifish on 05 September 2016 - 12:28 AM

Ammar, I think you have to be very careful about SLOG2/SLOG3 shooting underwater on the A7 cameras. Because SLOG is NOT raw. What slog is doing is trying to squeeze in a broader luminance/chrominance range in the same 8-bit 4:2:0 100mb/s video container, unlike RAW photos, where a JPEG is 8-bit 4:2:2 compressed image and the raw is 14-bit 4:4:4 (kinda, it's actually the luminance level for each sensor pixel, which you debayer to color information when you process the raw).


There's a couple of important implications to this. First, SLOG2 has a baked-in white balance, just like a JPEG, and unlike a RAW. So whether you shoot with no picture profile or SLOG, you still have to get the white balance right at the time of acquisition. You will have much less flexibility to correct it later than you would with a RAW photo file, or even with a JPEG file (since JPEG is 4:2:2, it records twice as much color information as the video, which is 4:2:0). 


Second, because SLOG is trying to squeeze in a much larger color and luminance range into the same container, you end up using fewer bits to represent luminance/color variation. Which, in practice, means you have LESS room for fine color corrections in post with SLOG footage than with no picture profile footage. Plus, the colors are just off. Now, I'm not a great colorist by any means, but in my experiments shooting the same scene with no picture profile and SLOG underwater, the no picture profile image looks much better both right out of camera and after post-processing -- better saturation, better color accuracy, etc. Yes, you have to be careful to expose correctly for the main parts of the image and you will get some parts that are blown out, but the properly exposed parts will look good -- if you get the white balance right. With SLOG, none of it looks right, and adjusting it in post still doesn't produce an image as nice as the no picture profile image.


I'll try to post a few examples of footage I've shot recently with ambient light (shallow) in UAWB mode and with artificial light (a bit deeper) later this week. After using this camera on 100+ dives, including 50+ video-focused dives, I'd say it IS possible to get very nice footage from it. But you have to get it in camera as much as possible, relying on post-processing for minor adjustments (minor levels and contrast, primarily, rather than color shifts). 


Since I got the Gates GT14 lights, I've also tried to do some shooting with lights in UAWB mode -- the results are interesting. Generally, setting custom white balance to the lights (5200K for me) is better if you're shooting a scene where the lights are the primary source of illumination (subject <0.3m away, depth 20m+). However, if shooting wide angle in shallower depths or where the subject extends beyond 0.5m away, you actually can get decent color shooting in UAWB mode with the lights on. Of course, just like if you were shooting with a red filter and lights, if your subject gets too close to the lights, the red is going to be emphasized a bit too much. So Sony's UAWB mode is not smart enough to dial the red boost down if there's a strong source of warm light in the scene. But for scenes where the lights provide a more limited fill, the overall balance is actually not bad.


When I get a chance (and get the right filters), I'm going to try to put some blue gels on the lights to cool them down and see what results I can get shooting with gelled lights and UAWB mode. I'm expecting this might actually produce the most pleasing images in the 10-20m range, or even below 20m. Above 5 meters, especially with clear water and a sunny day, the UAWB mode works really, really well with or without a filter. 

#374294 Indonesia Diving Location Recommendations

Posted by dreifish on 04 June 2016 - 02:35 AM

Everything Tim said plus I had a great time last November at Ambon. It has a great vibe and the macro critters are excellent all over the bay.


I would second the recommendation of Ambon (I did my divemaster training there, awesome for critters, especially Twilight zone). Unfortunately, I don't think it works with the OP's timeline -- I think most (all?) dive shops/resorts in the area are closed for the summer months and open again only in September/October timeframe.

#374193 Canon 1dx Mark II - Philippines

Posted by dreifish on 01 June 2016 - 09:31 PM



First of all, great work indeed. Well done.


For the macro shots, were these at night, or just selective lighting during the day? If so, what where you using for lighting? And for stabilization?


Also, perhaps I'm misremembering, but did you not use to shoot a Canon 1DC before? If so, do you have any thoughts about the differences/similarities between shooting with the two different cameras? Especially when it comes to 4k quality, white balancing, etc.



#367471 Back to full frame -- A7RII vs. D810

Posted by dreifish on 25 November 2015 - 06:11 AM

I bought a GH4 last August intending to do 4k video after flooding my old D800. Found out I prefer photography. After using the GH4 for a year (Nauticam system), I find that most of the time I take stills. Currently, I shoot underwater every day. I'm based in Thailand and I work on a day boat where I shoot, and sell images to, tourists trying out scuba diving for the first time, doing courses, or just fun diving on our boat. You can see some of my stills at www.andreiv.com to give you an idea of what I like to shoot.


I'm 90% convinced that I should get a full frame camera again to address some of the shortcomings of the GH4. For the past couple of months, I've been mulling about whether to go with a D810 or A7RII setup. I would probably buy two bodies down the line -- one to stay inside the housing, and one as a backup/for topside use.


I'm hoping for some wise guidance to sway my decision. I've highlighted questions in bold/italics. Please also correct any mistaken assumptions I have.  


1.  Gear I Currently Own

  • Panasonic GH4; Nauticam GH4 Housing; Panasonic 8mm Fisheye (w/ Zen 100mm glass dome); Panasonic 7-14mmF4 (w/ Zen 170mm glass dome); Panasonic 14-42mmPZ (w/ 35mm port); Olympus 60mm macro; Nauticam SMC and Inon +6 Diopter.
  • Nauticam D800 housing; Sigma 15mm lens (Nikon Mount) (w/ Nauticam 8.5" Acrylic dome -- needs new acrylic element).; Nikon 16-35mmF4 (w/ port extension for use with 8.5" dome); Nauticam port for Nikon 105mm macro. But no body or 105mm macro -- both were lost in the flood. 
  • Nauticam 45* Magnifying Viewfinder
  • Nauticam Flip Adaptor
  • 4x Sea & Sea YS-D2 strobes with CM Diffusers; Retra LSD Prime Snoot
  • 2x Archon 5000 Lumen Video Lights


2. Limitations of Current GH4 Setup Driving Desire to Upgrade (in order of importance, roughly)

  • No ability to use a large dome with the 8mm fisheye for split shots. (Action) split shots are hard with the Zen 100mm dome. 
  • 8mm fisheye is too wide at times for environmental portraits of divers. Ideally, I would like a fisheye (zoom) option that covers the 180* to 100* or even 80* FOV range. Or at least a wide angle option with less corner distortion. 
  • Distortion on the 7-14mm in Zen 170mm dome is unpleasant, especially the way it stretches objects towards the corners at 14mm, so I don't like shooting with the lens. Looking back at my old pictures with the  Nikon 16-35mmF4 doesn't show the same problem. Is this because of actual distortion of the lens, or perspective distortion because 7mm is so wide?
  • Not able to use teleconverters (to limit the field of view of the 8mm fisheye, primarily) 
  • Unreliable subject tracking in AF-C for focus & recompose technique. I miss the D800's 3D tracking for macro/fish portraits. 
  • Limited depth of field control for topside images
  • Limited ability to track/shoot wildlife topside
  • Limited manual wide balancing for wide angle ambient light video. I find the video looks a bit brittle, the colors artificial, and the water column too purple. 
  • Noise in ambient-light 4k wide angle video (manually white balanced) at ISO 400+; ISO 800 barely usable. 
  • Can't quickly zoom to 1:1 on the focus point in image playback in order to judge focus?
  • Limited ability to kill the ambient light for shots with black backgrounds (because max flash sync is 1/250, min ISO is 200 and diffraction is an issue past F11--with F22 being a hard limit on m4/3 lenses)
  • Olympus 60mm macro has too tight a field of view, focus is slow. I haven't tried the Panasonic 45mm or 30mm macro options, but suspect the working distance is too limiting compared to full-frame macro options?

2. Things I Like About the GH4

  • Size/weight of the system
  • Being able to compose with either back lcd or EVF w/ Nauticam 45* viewfinder
  • Exposure/white balance preview in EVF/lcd along with focus peaking and zebras. I love being able to see what the background exposure will look like before I take the shot, letting me focus on composition and waiting for the peak of the action
  • Accurate contrast-detect focusing -- no issues with PDAF mis-alignment
  • 8mm fisheye sharpness, close focusing ability inside the Zen100 dome for CFWA/WAM
  • optical flash triggering & TTL with ys-d2 strobes using internal pop-up flash
  • battery life sufficient for 3+ dives without switching batteries


So with that background in mind, let's talk about how the D810 and A7RII would or would not address my wants.


3. Shared advantages of D810, A7RII

  • Full frame sensor -- better noise, dynamic range, color depth, depth of field control
  • Can use a fisheye zoom to cover at least part of the 180*-100* FOV range, though both options seem problematic? D810 can use the Tokina 10+17 + 1.4TC for most flexibility, or the Sigma 15mm + 1.4x TC for a tighter field of view and better image quality than the Tokina. The A7RII with the metabones adapter can use the Canon 8-15mm + 1.4x TC in full frame or APS-C crop mode for ultimate flexibility and better image quality than the d810 w/ the Tokina 10-17 + TC, though you lose a bit of reach at the long end. 
  • Both can use the above  fisheye solution with a large dome like the Nauticam 8.5" acrylic or 230mm glass dome for easier split shots
  • Both have native 16-35mmF4 wide angle option that offer a more versatile field of view range than the 7-14mm on the GH4. Image quality is similar between the two?
  • Both gain at least 2 stops of ambient light control over the GH4 (for black backgrounds) because they have base ISO 100 and lenses can be closed down to at least F32. D810 gains 3 stops (base ISO 64, 1/320 flash sync)
  • Both can use teleconverters -- Nikon natively, A7RII on Canon lenses
  • Both have macro options (90mm on Sony, 105mm Nikon) that have a slightly wider field of view and better working distance than the Olympus 60mm


4. Nikon D810 Advantages

  • COST. I can convert my existing, D800 housing for $650, the camera body itself is $800 cheaper than the Sony, I already own all the lenses/ports except the Tokina 10-17 and Kenko 1.4x TC. Overall investment around $4000. 
  • Best flexibility controlling ambient light underwater (base ISO 64, 1/320 flash sync)
  • Slightly better DR at ISO <200. 
  • Better subject tracking in AF-C 3d tracking mode
  • Slightly longer reach using Tokina 10-17mm + 1.4xTC vs A7RII with Canon 8-15 + 1.4xTC
  • Can shoot 6 frames/second in DX mode vs only 5 for A7RII (with native lenses - 3 with Canon lenses)
  • Can be used to shoot wildlife topside (better autofocus, many longer lenses)
  • More rugged, better weather-sealing than Sony
  • Has a 60mm macro option for fish portraits
  • Excellent battery life that will last at least 3 dives
  • Pop-up flash allowing optical flash triggering with TTL
  • Great ergonomics topside -- the camera just feels right in my hands
  • Better selection of native lenses, primes and zooms, at more reasonable prices than the Sony primes


5. Nikon D810 Concerns

  • No 4K video; video white balance for 1080p underwater poor. Would need to keep GH4 system if I want 4k video (undecided).
  • AF-S less accurate than Sony/Panasonic because it's off-sensor PDAF
  • No electronic viewfinder; no focus peaking; no live exposure preview; no zebras; have to review LCD after each shot for exposure
  • No ability to shoot at arm's length using back LCD; must have face against the viewfinder.
  • Unacceptable image quality with the Tokina 10-17 + 1.4x TC?
  • System is about 2kg heavier than Sony, 3kg heavier than Panasonic. 


6. Sony A7RII Advantages

  • Great 4k video, both in full frame and APS-C crop, great versatility (it's essentially both a full frame and APS-C camera in one). No need to keep the GH4 system.
  • Widest AF-point coverage; complete frame covered when shooting in APS-C mode?
  • Accurate AF because PDAF points are on sensor and used in conjunction with contrast detection
  • Full viewfinder image when shooting in APS-C mode; 
  • Better DR/Noise at ISO 200+, where most wide angle shots will be taken
  • EVF with focus peaking, live exposure preview, zebras
  • Able to shoot/compose at arm's length using back LCD
  • Only 1-2kg heavier than Panasonic; lighter than Nikon. 
  • Can use adapted Nikonos water-contact lenses for best image quality, smaller size
  • Can adapt pretty much any lens (great for things like Canon tilt-shift lenses, unusual lenses like the Venus Laowa 15mm 1:1 Macro Lens)
  • Has wifi, can be controlled over wifi


7. Sony A7RII Concerns

  • COST. Would have to invest about $10k for body, housing, adaptors, ports, zoom gears, 8-15mm lens, teleconverter and 16-35mm lens. That's $6000 more than the D810 system. Could recover maybe $3500 of that from selling the D800 items I have. Cold also recover $5000 or so from resale of GH4 system. 
  • Subject tracking no better than the GH4 (in other words, not reliable enough to use, unlike Nikon's 3d tracking)
  • No native fisheye option. Not clear how well the Canon 8-15 + metabones adaptor would work as substitute. Sony 28mmF2 + fisheye converter lens is bulky and heavy, not as good image quality as the Canon 8-15 behind a dome? Sony 28mmF2 in flat port with Nauticam WWL-1 seems to have good IQ, and a FOV roughly equivalent to the Sigma 15mm + 1.4x TC? However, that option doesn't allow for a large dome port for split shots.
  • No native 50mm or 60mm macro lens for fish portraits
  • The white balance for ambient light video is just as problematic as the GH4 and requires red filters
  • Not great for wildlife topside (lack of lenses, evf, slower FPS).
  • No pop-up flash -- need Nauticam flash trigger or electric sync cables; no option for TTL
  • Battery life may not be sufficient to last 3 dives, requiring switching batteries on the boat
  • Weather sealing is not as good as Nikon's / the GH4
  • Ergonomics are not as good topside as the D810


8 Wildhorse Contestants

  • I could just stick with the GH4 and buy the WWL-1 to use in conjunction with the 14-42PZ as fisheye-zoom of sorts. This would cover the 130/120* to roughly 80* field of view, eliminating the need for the 7-14mm, which I dislike? Cheap option-- only $1200 investment. BUT this wouldn't address the lack of a bigger dome port for split shots, noisy 4k video, purple white balance, limited depth control topside, limited wildlife shooting ability. Can anyone thing of some solutions, especially for using a bigger dome on the GH4?
  • Go with an APS-C option like the Nikon D7200 or Canon 7DII to avoid the lack of a native fisheye zoom on full-frame. But does a dedicated APS-C camera really offer any advantage? -- after all, both the D810 and A7RII can be shot in APS-C crop mode with comperable image quality, and once entire system costs are computed, there is a minimal cost saving in going with the D7200 or Canon 7DII over the full frame bodies. 

  • r4e likes this

#366491 A "universal" DSLR housing??? Heard of this company?

Posted by dreifish on 26 October 2015 - 06:43 AM

Hmm... three new members chime in to laud the housing, all from Italy, all within hours of each other, and all three with just one single post? Does noone else find that a little.. suspicious?

#366387 Is the sony a7r2 (w/Nauticam) worth the money? Any experiences w/this equipment?

Posted by dreifish on 22 October 2015 - 05:12 PM

True, full-frame should provide you much better detail&dynamic range than m4/3. However ports and optics are at least as important for the resolution as the sensor. Regarding AF: true, DSLR-s are leading here. However mirrorless is coming up tremendously.



After looking at several reviews and browsing through a big pile of forums I concluded that the A7sII should be the coming king of UW foto+videography.

4k video on the 7rII is crippled by the faulty binning algorithm when shooting full-frame. Super35 is usable, however that crops ~half the sensor.

As for stills, in most waters I dive, I doubt that the added resolution of the A7rII would materialize, probably I'd also need a perfectly focused nikonos lens for that too and someone, who filters all slit and sh&@t from the water...


OTOH, the 7S family is an absolute low-light winner, ISO 12800 is usable and provides a dynamic range you see at ISO 1600 in case of the OMDmk2... This means those filter assisted manta/whaleshark shots won't look washed/noisy anymore.


Full frame will require larger domes/port, obviously, especially for wide angle rectilinear lenses. The (size) difference between a 170/180mm dome and a 230mm one is very noticeable, and significant for travel.


That being said, assuming equal quality domes, the optics (e.g. lenses) on full frame have an inherent advantage because of the size and pixel density of the sensor. A bad lens on full frame will still resolve much more detail than a great lens on m4/3 or APSc. Even when the sensors have equal megapixels, because of refraction. Check out the DXOMark lens sharpness tests sometime -- the Nikon 105mm macro resolves 12 megapixels on detail on the APS-C d7100 sensor. The same lens, however, resolves 19 megapixels on the full frame D750 sensor. And both sensors are 24megapixel sensors. That's just physics at work. Boost the resolution (e.g. pixel density) of the sensor, and you get even more detail. Same lens on the D810 resolves 21 megapixels of detail (which shows that it's actually not such a great lense, since the best lenses on the D810 can resolve 30+ megapixels according to DXO).


For comparison, the olympus 60mm macro only resolves 10 megapixels on the Olympus EM-1. So going from micro4/3 to full frame gives you twice the resolution. Now, you may argue that the water between your port and the subject dissipates much of that advantage, but, in my own experience, having worked with both systems, you can still see a difference. Especially with macro.


As for the A7RII, I really want to like it -- I agree with you that on paper it looks like the perfect hybrid photo/video camera and I would love to upgrade to it from my GH4. However, for underwater use, I have two major concerns:


1. The white balance for ambient light underwater video. According to Backscatter's review, you need a red filter to properly white balance. And even with the red filter, the results to my eye look too purple and fake. Compare the wide angle footage in Backscatter's review with underwater 4k footage shot on the Canon 1DC -- the Canon white balance and colors are much more pleasing, in my opinion. Since I think the GH4 does underwater macro video (with lights) equally well to A7RII, and my main reason for upgrading would be better low light performance and colors for ambient light wide angle video, the A7RII's limited white balancing ability and questionable underwater colour science makes me hesitate. I'd like to see more underwater wide angle footage from the A7RII.


2. The focusing system underwater, especially focus tracking. As I mentioned, I absolutely love Nikon's 3D tracking in AF-C mode for shooting macro photos, and I always get frustrated with the GH4's autofocus system in similar situations (the tracking usually can't pick up a fish's eye, so you have to manually move focus points around). From what I can gather, the A7RII's autofocus tracking isn't as good/flexible/versitile as Nikon's implementation. And it doesn't work in low light (just like the GH4) meaning you need to use a focus light. Focus lights can be a significant disadvantage when working with skiddish creatures like mandarin fish. 


All of which leaves me at a loss for what to do. I want to upgrade to an A7RII, but I think a Nikon D810 is still a better choice for photography. And for video, Canon has more pleasing colors underwater, which, IMO, makes a bigger difference than resolution for wide angle video. If you absolutely need a camera that can do both great underwater 4k video and photos, AND you shoot wide angle video, then the Canon 1DC might be a better choice than the A7RII, budget allowing.


If you just need macro video or underwater video where artificial lighting will dominate (e.g. inside caves, deep wrecks) the GH4 is probably a match for the A7RII on the video front since you can shoot at low ISOs. 

#366375 Is the sony a7r2 (w/Nauticam) worth the money? Any experiences w/this equipment?

Posted by dreifish on 22 October 2015 - 06:35 AM

What are you upgrading from? Are you happy/unhappy with the image quality of your current set-up?


IMHO, full-frame is overkill for underwater. The main advantage of full frame cameras is that they are better at gathering ambient light in low-light situations, but assuming you are using strobes, this is not really an advantage underwater. The image quality differences between FF, APS-C and m4/3 is really minimal for underwater shots, especially for macro. Before jumping into FF, think about costs, bulk and available lenses. If I was starting from scratch, I probably would go m4/3. If you look at the best underwater shots from m4/3 (i.e., Oly, GH4, etc), I don't think you will find a perceptible difference between those and the best UW shots taken with FF.


Mirrorless vs. DSLR is a very interesting and debatable question. Advantage of Mirrorless is: less expensive, less bulky, same image quality. Advantage of DSLR is better AF (although that advantage is fast disappearing, I think many of the best mirrorless cameras have more or less caught up). Another advantage of DSLR is better lens availability, but that advantage is also disappearing. Another advantage of DSLR is better battery life, assuming you are using mainly the optical viewfinder rather than live view. For me, the advantage of smaller form is more important than better battery life. 


I would perhaps go out on a limb and say 2015 is the year that mirrorless caught up and surpassed DSLR, at least for underwater. 

Having shot both a Nikon D800 full-frame system and a GH4 underwater, I think there are real differences between the two, both when it comes to image quality and ergonomics/usibility.


For macro shooting, the D800+105mm macro produces much more detailed files than the GH4 + olympus 60mm. And the tonality is more pleasing. For wide angle, the differences are a bit more subtle since you can shoot the GH4 at wider apertures than the full-frame camera, but I think they're still there, especially when it comes to dynamic range. This can be noticeable when you have large gradations in illumination in different areas of the picture (shooting portrait orientation on a wall dive, for example). 


The biggest difference for me though is the autofocus system. The D800 3d tracking is sooo much faster and more accurate for focus & recompose work with moving subjects than any of the equivalent "lock-on" modes I've tried on the GH4 and the Olympus OM-1. Perhaps the new Sony A7RII comes closer--I'd be interested to hear from someone who has shot the A7RII and a Nikon full-frame underwater.

#342738 For Sale - Inon Float Arms & LD & 67MM lens holders

Posted by dreifish on 02 February 2014 - 03:33 PM

The arms have sold.


Lens holders now $12.50 each or $40 for the lot + shipping.