Technical terms E - H

 

exposure time

The photographing exposure time defines the period of time in which a photosensitive medium, which may be a film in analogue photography or a CCD / CMOS chip in a digital camera, is exposed to the light for exposure / recording of an image.

 

flashlight

In photographic technology, flashlight is a lighting device which provides the necessary subject or object illumination at the moment of taking a photo by means of a flash of light. The flash of a flash unit only shines for a few fractions of a second, so synchronizing with the shutter speeds of the camera is no problem. The important parameters of a flash unit are the color temperature and the guide number. The higher the guide number of a flash unit, the greater the possible illumination for the subject. There are many different technical versions of a flash unit, but basically you can differentiate between internal and external flash units. External flashguns usually have a much larger guide number. What does that mean in practice? If an internal camera flash is not strong enough to illuminate a subject, use an external flash because these flashguns have more power.

 

Gimp

A free, good and also extensive photo editing program.

 

GPS

GPS means Global Positioning System (GPS) There are two types of GPS once the freely usable and once the military GPS. It's basically one system. But where is the difference? The freely usable GPS is accurate to a few meters. The military GPS is accurate to a few centimeters. In the case of free-to-use, there is also the fact that it does not work in some areas, such as near restricted areas and military training areas. Nice to see that in the area around Munster here in Germany. There are some free roads that lead through the military training area because there is no pure GPS. It works only with a clear view of the sky. Now a clever person can say: "My navigation system in the car also works there and in the tunnel". This may well be because with good Navis maps are stored and the devices have gyro sensors that remember when a car z.b. turns or changes direction. Thus, these devices estimate the speed. Based on the data, the GPS then continues to operate in such areas or in the tunnel. However, with much worse accuracy.

 

Grain or film grain

The grain is a photoactive coating on the plastic strip of the film used to be the carrier material celluloid which is also a plastic compound. The celluloid has replaced the glass plates and was the foundation for today's films. This photoactive layer consists of silver salts such as silver nitrate and other silver compounds. This coating can be finely and roughly applied to the plastic strips. The coarser the job, the more photosensitive the film.