By Underwater360 | snapshot.canon-asia.com
Compact cameras are a great way to get started in underwater image capture. They are small and relatively inexpensive, with the ability to add accessories that can expand the capabilities of the setup for advanced users.
The First Step: Camera Setup
The underwater environment has many unique properties that can hinder image quality. Water absorbs light, and does it across the spectrum as depth increases, from red to yellow to finally, the blue spectrum. This means that underwater, everything tends to look more monochromatic cyan blue or green, depending on the conditions in the water you are in. Digital cameras can adjust white balance (the white point of any image) to counter this effect to a point.The PowerShot G7 X Mark II has an underwater scene mode/underwater shooting mode specifically for underwater stills, found under the SCN mode. This automated setting mode is specifically made for underwater scenes in mind and will correct white balance compensating for the light spectrum absorption to a point, while still retaining control over auto-exposure and flash modes. This setting is best for JPEG shots for easy output and minimal software editing for those starting out with underwater photography or want a quick and simple output.The PowerShot G7 X Mark II/WP-DC55 combo requires the camera to be set up to optimise image quality. For beginner enthusiast shooters, auto-exposure modes Av or Tv may be easier to use. Set the Ring Function button to STD to control the Mode settings (e.g., Av in Av mode). You can control exposure via the exposure compensation dial (top dial): +/– exposure darkens or lightens the image. For JPEG, one can also use the underwater setting for White Balance for better results.For the highest-quality still images, it’s best to set the camera for RAW image capture, where white balance is not set and gives the best resolution and colour output from the camera. It does require shooting in Manual (M) mode for optimum control of the camera. Set the Ring Function button to SWAP Ring Function, which allows you to switch between Tv or Av when turning the front control ring. Use the step/continuous selection lever setting for tactile feedback and better precision.With the PowerShot G1 X Mark II/WP-DC53 in M mode, it is imperative you set the function assignment of the Rings and Dial properly. The inner step ring has to be set to ISO/Tv/Av for full control. One can cycle through each function using the +/– buttons. For each mode, the inner step ring function should be set to ISO/Tv in Tv mode or ISO/Av in Av mode to maximise the camera’s capabilities. The PowerShot G1 X Mark II does have an underwater stills mode under the SCN as well.
When shooting underwater video with the PowerShot G7 X Mark II, you can make use of custom white balance (WB) by taking a shot of a neutral foreground subject (like a grey card or just pointing towards the sun at whatever depth you are at) and then using the custom WB function to achieve the correct white balance. Alternatively, you can use the underwater WB setting, but custom WB is the most accurate. The PowerShot G1 X Mark II can be set to have one-push WB: Set the shortcut button for custom WB and use it on a neutral foreground object like a grey card or point at the sun.I would suggest using Tv at 1/100, if shooting Full HD at 50fps, and 1/50 for Full HD at 25fps for the PAL setting; and 1/120 for Full HD at 60fps, and 1/60 for Full HD at 30fps for NTSC. In Asia/Pacific (except Japan), PAL would be the natural setting.It can be daunting to remember which button to push for what setting. Starting in Av mode would probably be best, especially when using flash. Then you can work your way to more complicated modes and settings to make your images shine.
The most important thing in preparing the housing is to first remove and check the O-ring for any dirt, dust or hairs. Using clean fingers and a clean, lint-free cloth, work your way around the O-ring and wipe it clean. Check the O-ring groove on the housing as well. Then apply a little silicone grease to the O-ring (enough to lubricate but not excessively so) and reinstall the O-ring. Always check both sides of the housing for any impurities before closing the housing.As an extra precaution, test the locked housing in a bucket of water, making sure you point the lens downwards. The WP-DC housings are transparent so it’s easy to tell if you have a leak or not. Always keep the housing out of direct sunlight.These plastic housings are positively buoyant and require the optional WW-DC1 weight system if you are not adding any accessories like external strobes. Canon recommends three weights to keep the housing neutral.As your skills improve, you will want to add accessories like external strobes, which will alter the weight of your setup. You will have to adjust as needed.