If you have no idea what split photography is, please, read our article Secrets of Split Photography.

Now when you know some facts about split, let’s turn to the theory. As you should know from your physics lessons, as soon light gets into the sea water, it changes its nature. Sea water is almost 800 times denser than air, that is why sun rays are refracted, absorbed and are partly filtered. In air sun rays are spread equally and rectilinearly, but when they get in the environment which has a higher refractibility (air refractiblity is 1 point, water refractibility is 1,33 poit) light rays bend and create a magnifying effect.

As a result, even with optimal lighting conditions and high water transparency, the level of illumination under the water is one f-stop less intensive than above the water. Early in the morning and at the end of the day, when sun rays fell on the water surface at an angel, this difference is even higher, it reaches 3 f-stops. Thus the best time for split photography is from 10 am to 2 pm, when the sun is high in its zenith.

So we found out that the level of illumination of two parts of a split is different, even if the conditions are ideal. It means that it is impossible to set an ideal exposure – either the upper part will be overexposed, or the bottom part will be underexposed.

SOLUTIONS

GRADUATED FILTER
In conventional photography this problem was solved with the help of a graduated filter. This filter makes less visible the difference in illumination level of the two parts. The disadvantage of this method is that one has to divide the shot in the center, as it is impossible to change the position of the filter under the water. Read more about Neutral Density Filter

RAW FORMAT
In digital photography the solution is much easier. RAW format helps you get good results. An ideal exposure for split photography in RAW format is when the upper part is a little underexposed and the bottom part is a bit overexposed. You will correct it in the post-processing.

VIRTUAL PICTURE
There is one more secret of a split. When we shoot with a wide-angle lens, we use a spherical port as well. Under the water a spherical port forms a kind of additional ‘lens’ above the main one. As a result we can see a picture above the port (about 30-50 cm above), which is called a virtual picture.

Remember about this peculiarity of a spherical port when you choose a wide-angle lens. It should be able to focus closely; otherwise you won’t be able to focus underwater.

MAGNIFYING LENS
If a wide-angle lens focuses on a virtual picture underwater, then any subject above the water which is situated farther than 30-50 cm will be out-of-focus. To solve this conflict, use a magnifying attachment. Usually it is a filter put on the lens. Part of this filter is transparent, and the other part is a magnifying lens. In this case you also have to divide you image 50×50, to ‘hide’ the line of a magnifying lens and ordinary glass.

FISH-EYE
If you don’t want to divide your image 50×50, you’d better use a fish-eye lens for split photography. Use a small aperture and you will get a wide depth of field, which allows both the virtual picture and the above-the-water scape to be well in focus. Read more about fish-eye lenses.

Technorati Tags: digital photography, photography tips, split photography, underwater photography, landscape photography, digital camera review

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In the current post we will discuss one more widely used lighting technique so called ‘LIGHT PAINTING’. The example of this technique you can see on the picture below.

To create the same effect you need a mobile source of light that will be directed at a single detail of your composition, while the rest of the composition will be in the dark. This mobile light source is called Lightbrush.

LIGHTBRUSH is a photographic tool that helps to control light and apply it exactly to the area you want. It looks like a box, which includes a mobile daylight source connected to an optic fiber cable. You can attach different light shapes to this cable. Thus lightbrush allows you to illuminate each element of the composition and put accents where you want them to be.

CONVENTIONAL PHOTOGRAPHY

Although ‘light painting’ technique may seem an easy photographic method, in practice it involves much experimentation. The most difficult part is to find correct exposure, which is not easy as you shoot in darkness and thus need a long exposure. Though, the rule ‘the more light is the better’ doesn’t work here, there is always risk to overdo it. Take your time to experiment with exposure.

Lightbrush is an interesting tool that opens many photographic opportunities, but it also costs money. A professional lightbrush with a set of attachments of different sizes may cost about a thousand. Besides, you are unlikely to find it in your local shop. But a budget photographer can easily do it her/himself. Use a halogen or krypton flash attached to a tube with an adjustable socket outlet. It will work as a good lightbrush.

DIGITAL PHOTOGRAPHY

In digital photography, light painting technique is not so widely used due to the need for long exposure times and multiple exposures, which is not always possible with digital cameras. Maximum shutter speed in a compact digital camera is 8-16 sec (30-60 sec in more expensive cameras), while you often need 2-3 minutes exposure for good results.

However, it doesn’t mean that light painting is impossible in digital photography. Use a maximum exposure time possible in your camera and add a finishing touch in Photoshop.

PHOTOSHOP

Actually you can create light painting effect in Photoshop only. Use Photoshop brushing between dark/light and difused/sharp layers. Apply more diffusion on several of the layers to create a strong light painting effect and less diffusion to receive soft effect.

If you want to learn more abut Brushlight tool, join the discussion at Photo.net: Light Painting with a Broncolor light brush.

Interested in more lighting techniques - read Portraits Lightning Schemes