Blitz or flash freely translated into the flash. This is one accessory that is widely used in the world of photography. Its main function is to illuminate (mencahayai / illuminated) objects to the lack of light exposure well. But later began expanding its use to produce artistic photographs. However, flash photography is one thing to be learned. Most of the readers must have often used the flash well and getting good results also, but this paper will discuss the basic knowledge required to use the flash correctly. Correct in the sense in theory can be accepted and justified in terms of using a base that can be explained scientifically.
Using the flash is not merely a flash lit it, directing the camera and click and be a single photo and beautiful light, but there are things we need to know for the sake of getting good photographs and correct it. Whether we look at digital cameras as art or technology, the flash still is a means of simplify, optimize, and enhance creativity.
Meters, Aperture, and Shutter Speed
Photography briefly defined as the science is often painted with light. In conventional photography using film, we ‘paint’ with light in the film layer. Term is to burn the movie permanently using light with a certain intensity. The intensity of light entering the film or CCD / CMOS digital camera should be right. Excess lighting will cause the results of washed-out photos (commonly called over-exposure/OE) and lighting will cause the results of the dark images (commonly called under-exposure/UE). So how to get the right light?
We know what is called lightmeter in the world of photography. Lightmeter some built-in in the camera body and some are handheld. We usually use is the built-in lightmeter it. We use to measure lightmeter reflective light that comes into our lens (if TTL) and the processor will determine whether the camera is in accordance with the type of film cameras installed in us. In the auto mode or programmed auto, the camera will automatically find the right combination of f / stop and shutter speed (explanation follows). In the aperture priority mode (A / Av) the camera will use the f / stop which we select and determine the appropriate shutter speed. In contrast, the shutter speed priority mode (S / Tv) the camera will use a shutter speed that we choose and determine the appropriate aperture. In manual mode (M) we will have to determine the right combination is guided by the camera meter.
Aperture or shutter opening is wide hole opened by the camera to allow light inside. Usually symbolized by the number f / stop. This figure is actually the result of a multiple of sqrt (2). Commonly used is usually started from 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, ff. To keep in mind, the greater the number the smaller the opening. Because it is usually written as the denominator fractions such as f/1.4, f / 2, f/2.8, f / 4, f/5.6, f / 8, f/11, f/16, f/22, and so on. Aperture is also associated with DoF (Depth of Field) or the space that we can sharply defined as a room in front and back of objects that are included in the range of focus. DoF is itself influenced by 3 things are:
1. f / stop where f / greater DoF would provide a wider (more and more regional focus).
2. Distance of objects where objects are further focus will cause the DoF is also widening.
3. The use of telephoto lenses where the lens will give a narrower DoF than a wide angle lens (wide angle).
Shutter speed or aperture is the length of the shutter curtain is opened to allow light inside. This figure is symbolized by a second unit and the increase / decrease in the form of multiples of ½. Example: 30s, 15s, 8s, 4s, 2s, 1s, 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, 1/2000s, 1/4000s, and so on. The slower the light coming in more and more.
As measured by the camera’s meter the incoming light intensity is. If the meter shows the lack of light then we can reduce the f / stop or slow the shutter speed. Conversely if the meter shows the advantages of light then we can expand f / stop or speed up the shutter speed. One thing to remember is that the slower shutter speed the more likely the object blurred by hand movement, camera shake or movement of the object itself.
Blitz and GN
To divide / classify blitz, there are several classifications that can be used. The first, based on the availability of the camera flash is divided into the built-in flash and external. Built-in flash from the camera itself while the external flash is a flash attached additional cables or hot shoe to the camera. In addition, we also can divide by the type / brand of camera. We know the dedicated flash and non-dedicated flash. Dedicated flash flash is made specifically to use certain features within a specific camera. Usually the camera manufacturer-specific flash out also for the camera range and can use features such as TTL, slow sync or rear sync, etc.. While non-dedicated flash has the general functions of most of the camera alone and can be used regardless of the type / brand of camera. Flash this type usually require a lot of computation because the flash is already dedicated’ve got the information from the camera lighting so that does not require additional settings again. There are also flash output power (GN) can be arranged and some are not able to (fixed GN). We’ll tend to talk more about the flash non-dedicated, non-TTL, and fixed GN.
In using flash photography, we will not escape from the calculations related to the intensity of light reflected back from objects that we cahayai. Therefore, we will see what is often called the GN (Guide Number) or flash power. In short we can say if flashnya powerful, it will be one object with mencahayai lighter and can reach more distant objects.
GN is basically a simple calculation of flash power. There are 2 kinds of writing GN using a different calculation of unit m (meters) and feet (feet). Normally in Indonesia, we use the count to m. This is one of the considerations are also due to flash with the same strength, the number GN m and different feet away. In addition, GN is generally written for the use of film with ISO / ASA 100 and wide angle (35mm/24mm/20mm).
GN is a product of the distance from the opening (f / stop or aperture) in certain conditions (ISO / ASA 100/35mm/m or ISO / ASA 100/35mm/feet). For example, if we want to use flash to photograph a person standing at a distance of 5m from us using a 35mm lens and we want to use f/2.8 then we need to flash GN 14. Calculation commonly used is usually just find the right aperture for a particular blitz. For example, the GN 28 will flash to photograph the object is 5m that we will use f/5.6.
GN is only a guide for photographers. Not set in stone. Which affected a few. One of them is the ISO / ASA is used. Each 1-stop increase in ISO / ASA will cause GN increased by sqrt (2) or approximately 1.4 times (or the farthest distance multiplied by 1.4) and 2-stop improvement in ISO / ASA will cause GN increased 2 times (or the farthest distance multiplied by 2 ).
Film SLRs vs. Vs. Prosumer Digital Camera. DSLRs
One thing to remember is that the film cameras and digital camera is different. In the digital camera itself, there is a difference between pocket camera (in this case is usually able to use additional flash is the PDC / Prosumer Digital Camera)) and Digital SLR (DSLR). The first difference, of course, in terms of the proportions of the sensor / film to the lens. Because the digital camera sensor smaller than 35mm film, then we’ll be stuck on a long comparison of different lenses. To obtain a similar angle as 35mm, so the camera with a sensor 1/1.8 “will use the lens of about 7.5mm, D100 will use a 24mm lens and 10D will use a 20mm lens. This is the effective length of the lens to start the calculation using the flash GN.
Second, zooming. At the PDC, zooming will cause a change f / stop is slower (large numbers) and so also with the use of consumer zoom in SLR / DSLR. For example, we know f/3.3-f.5 lens 35-70. That is, the largest opening is f/3.3 at 35mm and the largest opening is f/4.5 at 70mm. This certainly will affect the object being photographed.
Use the zoom on the camera is usually coupled with the use of the flash zoom head. Telephoto lens / zoom to narrow the angle and zoom lens coverage on the flash head to narrow the dispersion of light that flash in other words increasing intensity, so they can reach further. Zoom head position and the telephoto lens on the wide positions would cause a part of the photo is not a light or familiar with the term vignet. Zoom head in wide positions and telephoto lens in position will cause a flash of light can not reach the remote object (after all, it’s worth a telephoto lens? For photographing objects that far?). In addition it also happens if we attach a 35mm lens on DSLR and then we do a flash calculation using the calculation remains to SLR is usually because the angle is equivalent to 50mm or more (depending on factors pengalinya). Actually there are no significant problems that arise, but we are ‘wasting’ the light in vain.