A Guide to using the Nikon Coolpix 8400 underwater

By Dave Harasti (www.daveharasti.com) - Last updated 10 May 2005

I have been playing with camera's underwater for about ten years and a couple of years ago I went digital and purchased the Nikon Coolpix 5000. After two years of playing with the CP 5000 underwater and being fortunate enough to obtain some decent shots I made a decision to upgrade to a new system. The primary reasons for wanting to upgrade the CP5000 was because of the shutter lag delay, slow write times for raw files and I wanted more pixels so I could enlarge images to A3 size with minimal resolution loss. Plus all my photography buddies were upgrading to bigger and better cameras so I had to keep up!

After much deliberation I ended up choosing the Nikon Coolpix 8400 as my new camera. One of the key factors in my decision was the announcement by Ikelite that they were in the process of developing a housing for the camera. My CP5000 is used in an Ikelite housing and after 400+ dives with the Ike housing it still functions as new. I've never had a problem with it over the past two years so hence I had no hesitation in purchasing another Ikelite housing.

My first use of the CP8400 was in late March 2005 on a 5 day dive trip to the Coral Sea out of Cairns onboard Taka III. I received the Ikelite housing and camera the day before I left for the trip so unfortunately didn't get a chance to test it out at my local divesites in Nelson Bay. The trip was a big learning curve with the camera and I managed to get a couple of worthwhile shots that can be seen here. Since these images have been displayed on my website I've received many emails from photographers asking for tips on using the CP8400 underwater. Hence I have developed this guide to hopefully provide some useful tips and tricks and make it easier for those using this system first time round…

As I continue to gain experience with this camera underwater I will update the guide with any additional information that I consider to be worthwhile.

The Camera

The Nikon CP8400 is an 8 mega pixel camera with a 24mm lens. This lens is currently the widest on the market for the pro consumer digital cameras and makes it ideal for underwater use. I won't go into detail on the camera functionality as there are several excellent reviews on this camera that have been written by photographers with far more experience than me. The following websites have useful information:

This camera is well suited for underwater use; the 24mm lens allows you to get closer to your subject. The closer you get to the subject the less water in front of the camera which equates to a cleaner sharper image. It also allows you to capture large marine life such as sharks and Potato Cod without having to move back to fit the animal in. Additionally, by getting closer to the subject it allows more sufficient use of artificial lighting such as external strobes. The auto focus is quick and the shutter lag is minimal; the shutter lag is a significant improvement over the lag of the CP5000 and other digital camera's that I have used such as the Olympus c5050 and Canon S50. It is however not as fast as a digital SLR camera such as the Nikon D70 or D100.

To get the most out of this camera underwater you need to use the camera in manual mode. By using manual mode you gain complete control over shutter speed, aperture, ISO, white balance etc which gives you much more creativity with your images. If you use the camera in automatic mode underwater you will not utilise the full potential of the CP8400 and the images will more than likely lack quality. Automatic settings may be suitable if you are just starting out in digital underwater photography so that you can get used to the whole process however the sooner you master the manual controls the better your images will look.

There are two small constraints with the camera that need to be worked around when using it underwater:

This camera produces noticeable noise at a ISO of 200 or above. I found that shots including blue water (or even blue sky) had a lot of noticable noise which would reduce the quality of the image. Many of my earlier shots were disappointing because of the noise factor however I managed to 'rescue' some pictures by using the Photoshop plugin 'Noise Ninja'. I would not shoot with an ISO of higher than 100 for underwater as you will be disappointed with the quality as a result of excess noise.

The CP8400 has a new image setting which will save images as 'Extra fine jpeg'. The extra fine setting will save images at a size of approximately 4-7mb. If you take an average size of 5mb a 1GB compact flash memory card will hold approximately 200 images. I would recommend using a high speed compact flash card with this camera (such as Sandisk Ultra II or III) and 1GB should be the minumim size. Images can be produced at a resolution of approximately 3264 x 2448; this resolution size is suitable for printing images up to A3 size. Experimenting with a Lexar 1GB compact flash card (80x speeed) I calculated the following write times for the highest resolution:

I do not shoot in Tiff mode as the write time is extremely slow and the files that are generated are very large, almost double the size for a RAW file. I occasionally shoot the CP8400 in RAW mode if I find a worthy macro subject that you can spend time with. As it takes 8 seconds to write a RAW file to the memory card it's a bit difficult to use shooting moving subjects such as fish and sharks as you will probably only get one shot. The benefit of shooting in RAW is that the image is captured without any in camera editing and you have much greater control in adjusting exposure or white balance using programs such as Adobe Photoshop or Bibble. Regarding white balance, I recommend that you leave white balance set to auto however I sometimes shoot with a 'cloudy' white balance as it help increase the colours in the underwater images.

I have found that the battery in the Coolpix 8400 will last for at least 150 minutes, easily long enough for two 'standard' dives.

Ikelite Housing

As usual Ikelite has come up with the goods with their housing for the CP8400. When I first saw the housing I was surprised at its size, it was much smaller than I thought it was going to be. It's actually slightly smaller than the housing for the CP5000 even though the CP8400 camera is larger in size than the CP5000 camera. When putting the camera into the housing you need to pull out the AE Lock to slide the camera into place. The housing with camera weighs approximately 2.5 kgs.

The Ikelite housing provides complete control of the CP8400 and all camera features can be accessed with the push of a button or the turning of a dial. The housing is moulded of corrosion free clear polycarbonate, which allows inspecting the o-ring seal and making sure all the housing buttons are touching the camera buttons correctly. Being able to look at the o-ring seal is one of the best features of the Ikelite housings as it's reassuring to see the o-ring is actually in place and working. I suggest dipping your camera in water briefly (1 or 2 seconds) before commencing a dive to ensure the housing is sealed correctly. The housing is rated to a depth of 60 metres, which is more than adequate for recreational diving.

The Ikelite housing comes standard with two handles and a baseplate. I know some photographers remove the baseplate to create an even smaller profile however I leave it on as I find it's useful to rest on the bottom to steady your shots as well as making it stable when kept on land or on a boat. Additionally, I have drilled a hole at the rear of the baseplate and put a stainless steel shackle through it that allows me to clip it off on my KISS rebreather whilst descending or hanging out on the deco line. An excellent feature with the two Ikelite arms is that they allow quick release of the strobes at the touch of a button; much easier than having to manual screw strobes to a baseplate.

The recommended retail price for the CP8400 Ikelite housing US $750 and the optional dome port for the Nikon WCE-75 Wide Angle Lens is available for rrp US $250


I use dual Ikelite DS125 strobes with the camera. One strobe (the primary) is connected via a sync cord with a manual controller whilst the second strobe is operated with the Ikelite TTL slave sensor. The second strobe is set to TTL to slave off the primary strobe giving equal flash output from both strobes.

The built-in flash of the CP8400 can be used for underwater photos however its range is limited so an external light source is recommended. A bulkhead is included with the housing to allow use of optional sync cords and external strobes. TTL is not currently available with the CP8400 just yet as the camera utilises the newest Nikon iTTL flash control. Ikelite is currently in the process of finalising their new strobe development to allow Ikelite strobes to shoot in TTL. However, when I was using the CP5000 which has full TTL capabilities I still preferred to shoot the strobes manually using the 10 power settings on the Ikelite manual controller as it gives much greater control over the lighting in your image.

When you have a strobe connected via sync cord you must have the internal flash of the CP8400 popped up otherwise the external strobe will not fire. Fortunately you can turn the internal flash off through the menu settings (Select Menu Items / Speedlight Options / Speedlight Control / Internal off). When using the sync cord make sure you turn the internal flash off. If you are running the strobe with a slave sensor you obviously need to leave the internal flash on to trigger the slave on the external strobe. Use the external diffuser that is provided with the Ikelite housing to prevent the internal flash affecting the image.

Macro Photography

Macro photography is one of the best forms of underwater photography to get good instant results. The key to macro is to get as close to your subject as possible and make sure that you take several images whilst bracketing your shots. Some tips for using Macro on the CP8400 are:

1/1000, F6, ISO 100, Spot Metering

1/500, F6.8, ISO 100, Spot Metering

1/1000, F7.7, ISO 50, Spot Metering

1/1000, F7.7, ISO 100, Spot Metering

1/1000, F7.7, ISO 50, Spot Metering

Wide Angle Photography

The 24mm lens gives excellent coverage however it is possible to get greater coverage utilising the optional Ikelite port with dome lens that allows use of the WC-E75 Nikon wide conversion lens. The design mounts the lens in the port without using the conversion lens adapter tube. This allows the camera to be removed and installed freely in the housing without removing the wide angle lens.

Some tips for shooting wide angle with the Nikon lens:

Additionally, you can attach external wet lens such as Inon and Epoque to the front of the Ikelite 8400 housing however there are limitations with the use of these lens compared to the Nikon lens. There are generally problems with vignetting using these lens (black shading in the corners) and the optics are generally not as sharp or defined as the internal Nikon lens. If you already own an external wide lens than I'd try it out on the housing but if your in the market for wide angle coverage I'd suggested purchasing the Nikon WC-E75 wide angle lens utilising the additional Ikelite domeport.

1/250, F4.3, ISO 100, Matrix Metering

1/250, F6.4, ISO 100, Matrix Metering

1/250, F3.6, ISO 50, Spot Metering

1/250, F4.5, ISO 100, Centre-weight Metering

If you are in the market for a top of the range pro-consumer digital camera then the CP8400 can be considered an excellent purchase. It is a step up from the Nikon CP5000 and the Olympus C5060 and is an excellent alternative for those that don't want to outlay the cost on a digital SLR underwater setup.

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