Shooting The D4, Autofocus and LiveView/Video.

Waiting for the brand new D4 to be passed down to you in the water certainly quickens the pulse. I’d like to tell you my heightened awareness is the result of having the latest imaging tech at my (gloved) fingertips. But it is more to do with taking a $6000 camera (not including the lens or the rest of the kit) underwater! That is a lot of money to loose in seconds to one small leak. I’ve done thousands of photographic dives and I have never flooded an SLR (film or digital), so it was hard to shake the paranoia that my inevitable appointment with that disappointment had simply been waiting for my first trip with the D4. Luckily the camera survived!

There is a serious point here. To quote an old oceanographer’s saying “only put equipment in the water that you can afford to use”. Accidents will happen. When choosing an underwater camera you must be certain it is one you are comfortable using underwater AND risking underwater. I remember Peter Rowlands telling me he stopped using the Nikon F5 underwater because he could never relax into his photography with such an expensive camera at risk. Although as friends of Peter will know, he has similar palpitations when it is his round at the bar!

As I covered in part 1 of this lengthy review, there are not many advantages to big housings, but if there is one it is handling in the water. The extra displacement of the Nauticam NA-D4 makes it very light and easy to use in the water. Its bulk is much more of an issue out of the water than in it. Below is some brief footage of me shooting the housing in a shallow canyon in North Iceland, which shows how light the camera is in the water. Here I am using the camera without strobes and buoyancy arms, although I do have a strobe arm across the top as a place to mount my dive computer.

Autofocus.

I mentioned in the first section of this review that one of the features that impressed me straight away about the D4 was the autofocus. I feel that it was a really significant step on from the D3. I should qualify that I haven’t used the D3 as my main underwater camera since 2008 and have instead used a D700. On paper the D700 has the same AF system, but it is generally accepted that the big pro bodies will drive that system slightly faster because of more powerful batteries and processors. That said, the step on with the D4 is much larger than the small difference between the D3 and D700. I also believe that the D4 improves AF speed and low light performance over the D3 more than the D3 did over the D2.

It used to be easy to understand Nikon autofocus performance. Nikon calls its AF systems Multi-CAMs and the higher the number the more power (apparently the number approximately represents the amount of contrast sensing elements in the AF system). The first Multi-CAM most of used on digital was the 900 in the D100, D70 and S2. The D200 had the 1000. The F5, F100 and D1 had the 1300 and the D2 and F6 the 2000. Finally the D3, D700 and D300 had the 3500. The bigger the number the better the AF.

Well that used to be the case. The D4 and D800 also use the 3500 and the D7000 uses the 4800, which despite the higher number can’t quite match the 3500 in the D3 or D300. Furthermore, although the D4 has the same 3500 as the D3, its autofocus is significantly improved. Understanding Nikon AF performance is now more than a numbers game.

I see several reasons for the improvement in the Multi-CAM35000FX between D3 and D4. First the camera’s processor that drives this system is faster. Second AF is not just the responsibility of the Multi-CAM and data are also fed in from Nikon’s Advanced Scene Recognition System, more of which in a minute. And third the Multi-CAM35000FX from the D3 series has been recalibrated for the D4, with new sensors and new algorithms.

Most noticeable is how well the system works in low light and in low contrast conditions, which is particularly beneficial underwater. 15 of the D4’s 51 AF points are even sensitive down to f/8, beneficial when using teleconverters or macro lenses (whose virtual aperture increases when we move close). Nikon states that the AF detection is fast and accurate down to -2 EV, which means nothing to me, but they say that is about the physical limit of human visibility through a viewfinder. To test it, I went outside and took a photo of our house in the dark, when I couldn’t even see the windows clearly. The camera focused and at high ISO the camera could “see” many times more than I could. Deep wrecks watch out!

Underwater the D4’s AF is addictively good. I prefer shooting macro on DX and used the D7000 most of the time during these shoots for my macro. Scotland and Iceland were assignments, not trips focused on camera testing. But the more I used the D4’s AF system the less I wanted to swap back to the D7000. On paper the D800 shares its AF system with the D4 and I’d expect it to also offer a significant step on from the D3.

One of the biggest technical changes in the D4 is the introduction of a 91,000 pixel sensor (“Advanced Scene Recognition System” in Nikon speak), which performs many functions including exposure control, determining white balance, dynamic range optimization and improving AF performance. This replaces the 1005 pixel sensor of the D3 (which was actually introduced with the F5 in 1996). In underwater reviews we don’t tend to spend too much time on metering because most underwater photographers shoot on manual for camera exposure (some using TTL flash for macro). It is a mistake to think of the ASRS (it is hard not to type ARSE) as just a control for metering.

One of my favourite AF modes is 3D tracking, first introduced on the D3 camera. You can read more about it here in my 2008 D3 review. This system is designed to precisely track the subject (in continuous servo autofocus, AF-C) should it move around the frame after you have focused on it. Since the D3, this system has used the colour and brightness signature of the subject to track it in the frame, but with the ASRS upgraded from 1005 to 91000 pixels, it can now recognize detailed patterns too, promising even better performance.

This system is excellent underwater, not just because our subjects move, but because we do too. When shooting macro we can never hold the camera completely still (unless you want to wedge it into the marine life, which some photographers sadly still favour) and as a result the subject moves around within the frame, particularly with longer macro lenses. 3D tracking really helps keep it in focus. The other major use comes when we want to recompose. The easiest way to shoot a subject off centre in the frame is to focus it in the middle of the frame and then recompose and allow the 3D tracking to follow it to your desired position.

For wide angle photography I tried a few different modes and in the end concluded that AF-C Auto Area mode just worked. You point the camera at scenes and the focus is spot on. This mode incorporates face detection priority, but I didn’t find this a problem with model shots, this mode tended to always reliably focus on the foreground subject. Although I would like to test this in more typical normal diving conditions (than I had in Iceland and Scotland) before concluding it works everywhere. We don’t want scenic shots where the camera decides to focus on the models face in the background, leaving the foreground blurred.

In particular, I was impressed by how the Auto Area focused with the rectilinear wide angles, which require precise focus for sharp corners and sharp subject. Dome ports create a curved virtual image underwater, where the corners of the virtual image are closer to the camera than the middle of the frame. Auto Area detected this and would generally show in the viewfinder that it was focusing on a foreground subject around the thirds of the frame. Focus on the middle of the frame and the edges will suffer.

I also tried shooting with 9 point Dynamic AF. I just left this activated in the centre of the frame (the multi-selector was not connected on the NA-D4). This works fine with fisheye lenses where there is enough depth of field to hide minor focus issues. It was problematic with wide rectilinear lenses, where focusing in the middle of the frame would cause softness in the subject towards the edges of the frame. The example below is sharp on the body of the wolf fish, but out of focus on the head, which is both closer to the camera and also more towards the edge of the frame. It shows how critical focus is with FX cameras behind a dome port, despite the fact this was shot with a wide angle lens stopped down to f/14. If you favour this mode it is important to move the focus point over the closest point of the subject.

I won’t go through all the focus options as this review is already super-sized and also these modes are carried over from the previous generation of cameras. A couple of new features worth a quick mention are the ‘focus+release’ option in AF-C, which will only let you take the first photo in a sequence when focus is confirmed, but then fire off the rest of the sequence even if focus cannot be confirmed. This could be useful both in pelagic action shooting and macro. The other feature is a minor one, but useful. Custom setting a10 makes the camera remember focus points separately for vertical and horizontal compositions. So if you are shooting both on a certain subject you don’t have to reposition the point each time when switching.

In conclusion, the D4’s AF is superb. As a starting point I suggest using 3D tracking for macro and AUTO Area for wide angle.

Video and Liveview

I must start this section by saying that I am not a videoist. However, as publications increasingly go online there is more and more demand for stills photographers to have some video skills to provide video snippets to go alongside features as extended content. The trend that I see is not for NHU level productions, but fly on the wall/behind the scenes stuff. I actually find the GoPro pretty much covers this need, but I admit a video capable SLR gives more possibilities.

I am not going to comment too much on video, simply because I feel I am not qualified. I am sure many more knowledgeable people will have the chance to shoot the camera underwater soon and will be able to give quality feedback. And as with any aspect of the review, please add your thoughts below, which are helpful both for me and for other people who read this review now or in the future.

Now they have released the D4 and D800, Nikon are happy to admit that they were seriously left behind on video, when Canon released the 5D Mk2. The general impression seems to be that Nikon have now closed that gap and the new D4 and D800 are comparable to any HD-SLR on the market.

The Nikon party piece is uncompressed video from the HDMI port, which should be easy enough to feed through a housing, although the Nauticam NA-D4 I used wasn’t set up for it (not that I have an external recorder either). Nauticam have plans to cater for this feature and I am sure other housing manufacturers will too.

The camera also offers three image areas of full HD video: FX, DX (1.5x) and CX (2.7x), which will be advantageous for underwater shooting allowing sequences featuring wide, medium and tight shots to be filmed on a single dive, even if using a fixed focal length lens.

Liveview is not just for video and stills shooters may find times when they need to hold the camera at arms lengths and prefer to use the screen, rather that the viewfinder. On the D3 liveview was slow and clunky, both to activate and use. The D4’s liveview is much more akin to a modern compact. Autofocus is better than you’d expect and shutter lag is minimal. It is very useable and is activated with one push button.

In liveview and video the autofocus works well, but I still wouldn’t leave it on when shooting video underwater. There are just too many objects floating around that can easily distract it. One solution is to use AF to find focus and then switch to MF before you start shooting. Although the more elegant approach is to assign AF to the AF-ON button, that way you can use this button (or paddle on the NA-D4 housing) as a push to focus when you need to and the camera will not get distracted the rest of the time.

It is hard to demonstrate how well the live view autofocus works on the D4. Below is the best demonstration I have managed so far. This is shot in an indoor pool, with no lights apart from the daylight coming in through the window. Obviously you would not want this type of focusing in the middle of a video, but if using liveview for stills this sort of focus performance is very acceptable. That said, it looks much worse on video, than when you are behind the camera doing it. I’d strongly suggest trying it next time you have a D4 or D800 in front of you.

The improved liveview stills mode looks particular well suited to polecam work. With a polecam you could use the liveview feed (via the HDMI port) to see precisely what the camera is seeing and then when the subject comes into range, fire off a series of frames (the camera will keep shooting if you keep your finger down on the remote trigger). Only when you take your finger off the shutter will the images then replay on the monitor. Ethernet and iPhone/iPad is the other option for polecaming, which would be better for remote camera work, where you could control the system from somewhere dry.

Next comparison and conclusion…

(1) Introduction.
(2) Camera and housing overview: Part 1 D4 camera.
(3) Camera and housing overview: Part 2 NA-D4 housing.
(4) ISO, image quality and shooting FX
(5) Autofocus and shooting experience (macro and wide, stills and video).
(6) Comparisons with other cameras and conclusion.