Intro
Half-and-half (or split) air/water is very special and always appreciated by every eye because it is mixing two very different worlds on one single image. There are many creativity options, like for every kind of image, but in this case, the two environments add many possibilities.
To shoot these images, a wide fish-eye lens is necessary, such as the Nikon 10.5mm or if you prefer, a zoom lens like the Tokina 10-17mm
Glass Dome Ports
Half-and-half Lofoten underwater and divers Zodiac
Glass ports are excellent for underwater photography. They are even better for half–and-half (split) pictures as the water drops slide down from the air part of the dome. However, you will not always be able to get rid of all the droplets.
Glass dome ports are quite expensive. You must be very careful since it is very hard to fix any scratch on them; scratches will be visible on the pictures.
Acrylic Dome Ports
Woman free-dives in Greece – Split image showing a sail boat above the sea
Acrylic ports are also high quality and they are less expensive. It is harder for the drops to slide along the acrylic than glass. To avoid the droplets on half- and- half pictures, you can put a motorcycle windshield rain repellent on the dome. This kind of product is easy to find. By google-ing motorcycle windshield rain repellent, you will find many of brands manufacturing the product.
Small scratches are usually not visible underwater on an acrylic dome port because acrylic has almost the same density as water and water will fill the scratches. If you still want to remove them, use a product like Novus.
Be careful not to scratch the inside part of the dome port as these scratches will be visible on your images.
Photoshop
This picture in the Dead Sea was a challenge as the sea was rough, the salt was really hard and sharp and the water drops very sticky on the dome port
Even when using glass ports or acrylic ports with rain repellent, you still may have some drops on the pictures. These can be erased with Photoshop‘s Healing Brush Tool and/or the Clone Stamp Tool.
Remember: The best pictures are always the ones without corrections or as few as possible. Many photo competitions don’t accept image modifications, so always try to get rid of the droplets during the shoot rather than letting the small voice tell you that you’ll still be able to erase the drops using photo-editing.
Half and half or split-water photo rules to remember
There is a difference in focus between the air and underwater. The best is to focus on the underwater subject, using a high aperture like f/16 or f/22.
Because the light is different above and under the water, it’s important to choose an aperture that won’t burn the clouds or any other subject above the water. The best is to use a larger aperture, such as f/16. The bracket option on the camera is always useful for several images with a stop difference at each shot.
To avoid under exposure underwater even though the exposure is fine above the water, get as close as possible to the underwater subject and use strong strobes to light it properly. I use Ikelite strobes but there are other good brands that manufacture strong flashes.
To avoid over-exposure above the water, some underwater photographers use half neutral density filters.
The pictures here under were both shot at F16, 1/80. The first one is properly exposed above and below the sea level and the second one is over-exposed above, burned by the sun, while the exposure is good underwater.
Half-and-half or split image correctly exposed above and below the sea level sky
Half-and-half or split image with over-exposed sky