Pool review of Subal’s new prism live view finder PS-30 along with a comparison of video lights from Subtronic, Keldan and Hartenberger
Once I had written lengthy reviews about Subal’s housing for the Nikon D7000 and a comparison of different strobes and how they work while diving I started to investigate further. Since Nikon’s D90 and Canon’s still much acclaimed 5D Mk II, high-definition video has increasingly been incorporated into smaller simpler cameras and has become a standard feature.
This was one of the most revolutionary steps in photography, similar to the advent of digital photography 10 years ago, autofocus some 20 years ago or the SLR revolution in the 1970s.
Since I began underwater photography I had always kept an eye on underwater videography as I was fascinated by all the different and mostly large housings that were around. The most interesting steps in videography that have occurred in the last few years were the introduction of HDV combined with hard disc/solid state recording that made things a lot easier in terms of storage, handling, video editing, etc. The Full HD resolution of 2 megapixels (1920 x 1080) gives a bright, crisp cinema-like resolution at your home TV.
However, for us underwater photographers with our heavy, bulky housings, domes and strobes the idea of having to carry another complete setup for video, underwater optics and lights was a big turnoff that made it difficult to do serious videography and photography on the same trip.
This changed in 2008. The Canon 5D Mk II was a huge step forward incorporating video and the potential of using all the available lenses in the EF universe. It was so good that Hollywood filmmakers put aside their precious gear and started using a photo camera that every enthusiast could buy for 2.000 €.
Nikon was the first to introduce video in an SLR, but the D90 featured a resolution half of the Full HD specification, being 1280 x 720. In addition, the video function only worked in full automatic mode. This made it good for occasional videos but not for serious stuff. With the professional Nikon D3s you could vary the exposure modes but still had to live with the 720p resolution. This has changed with the introduction of the D7000 which finally has 1920 x 1080p (The p is for whole – non interlaced - frames which is usually called progressive scan, the other being i for interlaced). Interlaced is a decades old standard that is still used in broadcasting today, but p is considered superior for video and film-makers).
Subal has produced am optional exchangeable prism live viewfinder for the monitor of the camera that is essential for live view and video. I overviewed the housing here and Wetpixel included it in their comparative review of available D7000 housings here.
Large viewfinders that provided a comfortable view were a neglected piece of equipment during the 90’s. Seacam was the first to introduce a large angled viewfinder in 1998 with Subal being the first to provide a straight viewfinder. The introduction of video literally screamed for a new generation of finders and monitors that was finally met this year when almost all major providers of underwater imaging equipment introduced external monitors. Although Subal exhibited an external monitor at DEMA 2011, they have also produced a prism viewfinders for use with the camera’s own monitor.
The Subal ND-7000 housing has a removable monitor back plate that allows the user to switch between the three viewfinders (standard, straight and angled) used for photography and the PS-30 used for video, all it needs are some screws that can be changed within a minute. If you switch on the monitor in order to check the settings a whole new viewing experience is awaiting you with the PS-30. The prism shows a 1:1 picture of 100% of the 3” monitor angled at 30 degrees. This means that you don’t have to move your head or the camera housing to switch between shooting and reviewing footage. Just look down and you see all the information from the monitor, look straight and you see your model, shark, wreck whatever. All that’s moving is your eyes.
On the first day of my review I met with some friends that were doing model photography in the pool. I started filming them and also did some videos with the model which was a nice and relaxing session. Doing that I found that the PS-30 is also useful for model/fashion photography in pools. First of all you can check all the data with the info button and the monitor, then you can focus on your subject, and after that you can review the picture. Again, this can be done without moving your head or the housing. This ability is superior to anything I’ve seen before. I guess that the PS-30 can be used for wreck photography as well or other photo-applications where a fast AF is not so important. I will investigate the matter further and provide results as soon as I’ll dive with it in the sea.
To put it plainly: The PS-30 is a specialist tool for unrestricted HDSLR videography that can also be used for some photography, but not for all due to Live View’s relatively slow AF performance
The PS-30 is currently only available for the Subal ND7000 for Nikon’s D7000. It is planned to incorporate the back plate into future Subal SLR housings.
If you’re into serious underwater imaging you will discover very soon that beside camera, lenses, housing, domes and viewfinders you’ll need something to lighten up the blue darkness of the sea. This is especially true for photography where strobes are a must. With video it’s also possible to use red filters. Combined with the white balance function of the camera you can certainly achieve pleasing color, and some fishes and pelagics are scared by strong lights. But there are drawbacks with filter use. It works from a depth of 5 m to a maximum of 20-25 m with the best performance shallower than 15 m. Below this depth there is not enough natural light. Beside from that you can loose up to 2 f-stops of ISO and it’s very difficult to combine it with video lights. Video lights (without filter) are suitable for all other applications including caves, wrecks and macro.
New LED (light emitting diode) video lights are constantly evolving getting smaller while retaining the power of HID (high intensity discharge) or high power halogen bulbs.
Hartenberger Mega Compact D2 Video.
Back in the 90s serious video lights weighed over 3 kg. For example a Hartenberger 128 (that is still available today) had a burn time of less than 50 min at a power consumption of 100W with halogen bulbs. The reason why halogen lights are still around is their very warm color temperature of 3.200°K that is suitable for wide-angle and gives pleasing red colors.
Around 10 years ago halogen was largely replaced by HID bulbs. The main advantage of HID is its higher efficiency. A 35 W HID gives you the same amount of a 100 W or more halogen bulb which means that the size of batteries could be minimized leading to smaller dive- and videolights.
I bought the Hartenberger Mega D2 some 10 years ago since I was fascinated by its modular concept. The Mega can be operated either as a halogen light or as an HID and there are options for a dive light with a narrow beam or a video light with a wide beam (though not as wide as with LED). You can choose between traditional exchangeable NiMH batteries or opt for a higher capacity LiMn. On the backside there is a multifunction display that shows power level and battery capacity in minutes(!).
The 35 W HID combined with LiMn batteries is good for an 80 minute burn time. The Mega D2 Video is also the only light in this review that is positively buoyant. With the hood on it is about 500 g positive; which is quite nice. That said, this is also a disadvantage for travelling, since the light weighs 2,4 kg and measures 250 x 118 mm and hence very bulky. Also, the HID bulb gives an uneven narrow light beam of less than 60° that can not compete with the even and wide distribution of new LEDs. And HID is only dimmable by 75%, the color temperature being 4.500° K. The switches can be operated with gloves on and there’s a safety switch. Hartenberger now produces LED lights that are quite powerful (63 Watt), have some color correction built-in in order to produce warmer colors, but seem to rely on a narrow beam of 60°.
Keldan Luna 8-VA CRI.
When you compare the Keldan to the Hartenberger you’ll immediately notice the huge improvements in light technology during the last 10 years. The Keldan weighs 1,1 kg. The manufacturer claims an output of 65 W and uses a Li-Ion battery (that has a higher capacity than LiMn, but is rejected by other manufacturers as unsafe) which lasts for 55 min at full power. The Luna features a LED battery capacity display that is nice to look at.
The most significant feature of the Keldan is an acrylic domeport behind an opaque diffuser which helps the distribution of light more evenly to a circle-like pattern. When comparing the light pattern it certainly is more even than the Hartenberger, showing a circle of around 90° as claimed by the manufacturer, around this circle is a corona which stretches for approximately 120°, quite nice. The whole video light is well-engineered and thought out. The purple finish looks great, but might not be to everyone’s taste. Keldan also produces some useful accessories for their lights, a 50° reflector for illuminating objects further away, a LED module for UV-fluorescence imaging, and some brackets. The battery pack is interchangeable as are the LED modules, so it’s possible to switch the more color accurate CRI version to the more powerful FLUX and vice versa.
The Keldan is quite bright, but compared to the Hartenberger and the Subtronics the light is bluish and by my opinion is more like 5.500° K than the manufacturer’s claim of 5.000°K. Actually this is Keldan’s CRI version, there is also a stronger FLUX version that seems to be even more blue. This is normal with all LEDs: the brighter, the more bluish. The Keldan is not heavy, but due to its’ form might be fragile for transporting, the acrylic domeport is prone to scratching and the purple finish comes off quite easily. The on/off switch works well with gloves on, the light is dimmable from 20% to 100% in 5 steps and there’s a safety switch. Keldan has presented a new version of the Luna 8-VA a few weeks ago with a light output increase of 10%.
Subtronic Video and Video NG
The Subtronic Video was introduced some 2 years ago. Back then Subtronic offered only head/tank combinations, but due to customer requests, introduced an integrated video light. The Video has 42 W output with 60 min burn time but if you opt for the tank/head combination you’ll get 90 min due to larger capacity batteries. Compared to the Keldan the Subtronic has a more compact and sturdy appearance that is luggage friendly, and its robustness will certainly appeal to tec-divers. The front side features 6 band like LEDs in a 16:9 arrangement that give some 110° very even light distribution with a sharp fall-off. The color temperature is 5.000° K which gave the warmest color temperature of all LED lights.
On the downside there is only one switch to alter the intensity in 5 step increments and offering direct access to 100% power. Below is a S2 (derived from the robust S6 strobe connection – a joint development of Subtronic and Seacam) connection to charge the batteries.
In November 2011 Subtronic has modified its lights with new higher power LEDs and an output of 56 W. This light is called Video NG (new generation). Due to the higher power output the burn time has decreased to 45 min for the integrated light and 65 min for the tank/head combination.
The only feature missing with the Subtronics is a battery capacity display. Subtronic has explained to me that all their battery packs are interchangeable and usable for strobes or lights but since they have different capacities it didn’t make sense to incorporate battery capacity display. However for the integrated video light this feature will be available by spring 2012.
Both Subtronics produced the most even light distribution and the widest beam of all contenders. The lights are well-built and rock solid. The finish is alloy which masques scratches that will come with everyday use. But for those who dislike silver there is also an option with a black finish that looks quite cool and includes strobes, lights, battery-tanks, arms and clamps. The black finish is also the most stable of all color anodized finishes according to Subtronic.
In order to compare all lights efficiently and while in work I decided to make a short video which happens to be the first one I ever did. For the model work in the second part of the video I used integrated video lights since it allowed me to change them comfortably. I used one Keldan and one Subtronic on each side, so if you favor a light from one manufacturer but already own another one you can use it simultaneously without any problems, especially if both are LED and have a similar color temperature.
Video Light Comparison:
As you can see from the video clip, each light has unique characteristics that will certainly appeal to one or another videographer. My personal opinion is that most lights have become way too bluish during the last 10 years. So I prefer LED-lights with a warmer color temperature that gives more pleasant results in blue water. One can also argue whether a wide beam of over 100° is suitable for all applications but these lights provided me with more than enough light to illuminate the pool wall from a distance of 2 meters, so I think that they can handle almost all applications in underwater videography.
With the merging of photo and video in a single camera/housing new possibilities and challenges arise for the demanding underwater afficionado.
The Hartenberger Mega D2 Video was purchased by the reviewer, also the Subal ND7000 with ports and arms. The Keldan Luna 8-VA CRI was supplied to the reviewer by Nautica (underwater photo shop) for the purpose of the review. The Subtronic Video and Video NG were supplied by Subtronic for the purpose of the review. The prism finder PS-30 was supplied by Subal for the purpose of the review.
About the author: Andrej Belic started diving some 10 years ago in cold Austrian lakes. Before that he already did some travel photography so he immediately engaged in underwater photography constantly improoving his skills. He learned rebreather diving with trimix and started to wonder why there aren’t a lot of good rebreather divers who are also proper photographers. After that he experimented with cave and deep wreck diving with air as a diluent. From 2008 to 2011 he was training apnea and free diving. For next year he is planning to experiment with underwater video and rebreathers. You can find his pictures here. More information will be presented in spring 2012 at the relaunch of the website.