An aquascape has lifecycle, after mature, it will decline. The only way to keep the memory is to take a photo when it is mature. Usually, people just use the existing light source of the tank and use a handy camera could have an acceptable picture because of preset exposure and color correction is very sophisticated on the market, but for a professional requirement, we still prefer a flashlight with light box as light source instead of tank’s light.

There are some restriction of using the tank’s light to take the photo:

HQI almost the strongest luminosity among all other light sources for planted tank. However, photo taking use HQI, the shutter speed can only be adjusted to 1/60s under ISO200 with aperture F5.6 for a correct exposure. If using this setting to take the photo, it is hard to freeze the fast swimming fish, as a result of a blur image. If adjust the aperture to F4 or lower, the depth of field is too short and cause out focus. If adjust the ISO, there may cause noise at the image. The case even worse if not using the light source as strong as HQI or use traditional film camera.
2) Color temperature: The color temperature of HQI close to sun light, so we can use the “Sun Light” white balance setting but still a little bit warm; fluorescence light easy to cause a greenish mood. It is more difficult to control if there is more than one type of light source. The digital camera control system can make an overall adjustment, but if you want to fine tune, we still have to spend a lot of effort to adjust in order to get a desirable result.
3) Luminosity different: It is a critical issue on aquascape photography. Since the luminosity of the light source is not powerful enough, so we have to put the light source as close as the water surface, as the result, the luminosity between water surface and bottom are various. When we use the water surface exposure reading as standard, the bottom part would cause under exposure. (see picture 1)

▲ Picture 1
a. Length from light source to the plant top = 10cm
b. Length from plant top to the substrate surface = 30cm
c. Length from light source to substrate surface = a+b = 40cm
Length proportion = luminosity proportion
a : c = 10 : 40 = 1 : 4
The luminosity and distance is an inverse proportion, the longer distance, the less luminosity receive, so the luminosity receive at a is more than c. From the picture, the plant top is over exposure and lost all the detail, but the substrate surface is corrected.

The benefit of using flashlight:

1) The flash rate on a flashlight is very fast, handy size can bomb to the correct luminosity within 1/1000s, professional studio light can also up to 1/500s or above. This is suitable for aquascape photography. We have to aware the camera flash synchronous speed are different. Most of handy model can only synchronous to 1/60s or 1/125s. The latest model can up to 1/250s
2) The flashlight luminosity rate is very strong so we can use small aperture to get a desirable depth of field. Even aperture number set to F16 –F22, the shutter speed still can keep 1/250s.
3) We don’t have to worry about the flash color temperature issue, because human sense the sun light white is about 5700K and most of the flash color temperature range is between 5700K to 6000K.
4) As mention before, the luminosity received not only depends on the light source rate, but also the distance between. The longer distance, the less luminosity will be received. Use light box can produce a smooth even luminosity because the height of the box extend the distance between the light source to water surface and substance surface so reduce the ratio difference. (picture 2)

◄ picture 2 A. Length from light source to the plant top = 50cm B. Length from plant top to the substrate surface = 30cm C. Length from light source to substrate surface = a+b = 80cm Length proportion = luminosity proportion A : C = 50 : 80 = 1 : 1.3 From the formula above, the different between A and C is very closed compare with 1:4 without light box. If we can produce a light box with double height or higher, the gap will be close and get an even exposure and rich picture.

Use flashlight tackle most of difficulty of aquascape. One more area I have to emphasis. By using flashlight, we can use hand held to capture the tiny fish on a faster shuttle speed to avoid vibration. Use smaller aperture extend the depth of field, so as tolerance the focus. By using ISO 100-200 could guarantee the picture quality can be achieved.

▲ Snap shot

▲ Schooling fish

▲ Macro

 Using flashlight with light box still have some inconvenience, because it is difficult to have a ready make light box in the market, so we have to DIY one suitable size for our tank. Since the flashlight is reflected in different angle on a closed box before reflected to the tank, so if the box is leaked, the strong light will lighten the outside environment and reflected on the tank surface. For sure, there is some inconvenience and money and time spent on the project, but when we have a good photo, we still worth to do so…

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