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Choose a manual light meter for difficult lighting conditions

The built-in light counters inside the cameras cannot deal with all light conditions, especially in the presence of extreme contrasts, and here comes the role of the separate manual counter, which is held by hand to help achieve a more accurate exposure under all circumstances.

It happens with most themes that counters
The implicit exposure refers to a correct exposure, but these meters may be deceived by scenes that contain exaggerations of light or darkness, or what exceeds the normal rate of light or shade. by hand. If we had a roll film camera without an implicit counter . A separate photometer becomes necessary.

It should be noted here that most hand-held meters are, like implicit meters, working by measuring the light reflected in the subject, and their special appeal lies in its essence as a style appeal - that simply put, with a hand-held meter, we can easily make decisions for individual areas of the subject, although many Of the manual meters, it is also characterized by facilities based on alternative methods of taking optical readings.
Most of the modern meters, for example, have a light diffuser that can be placed on an “eye,” so that it allows taking light readings of the event, ie readings of the strength of the light falling on the subject actually, and reading of this kind is usually impossible with an expression through the lens (TTL) in a camera (SLR). .

Made of opaque plastic, this diffuser is usually dome shaped to accommodate all
The light falling on the face of the subject. except if
Some meters contain a flat diffuser, as the meter with a flat diffuser has a narrower reception angle and can also tell us the relative strength of a number of different light sources.
It is possible to use some meters with an accessory, to take local readings - readings from very small areas of the subject. There are a few large, expensive meters, such as the Pentax Spotmeter, designed for this type of expression in particular with a local meter, look through A viewfinder that displays a wide view of the subject, but the reading is taken from a small circle in the center covering an angle of a few degrees. It should be noted that spot readings are ideal for taking accurate exposure readings from small spaces, and from a private distance, such as a brightly lit figure on a remote, poorly lit stage. Use location meters with caution because they are calibrated based on the fact that the location to which they are directed is typical of moderately bright lighting.
Among the other facilities available in the more complex and elaborate meters, we find links for taking exposure readings, either for copying or for enlarging. With just a few meters, we can actually take readings from the camera's gritted-glass focusing screen, although this feature is usually only used with large-bodied, wide-screen slide film cameras.

The rarest features we can find are flexible fiber-optic (*) drivers - in-situ readings of areas of the subject that cannot be accessed without them - and adapters for taking readings from microsquees and telescones. There is a meter, the Gossen Luna Pro, that can be converted into a color and temperature meter or a flash meter, and a few meters, such as those in the Calcuflash and Vivitav LX series, can be used to read normal light and flash together.
With the availability of the facilities of a series of alternatives like this, we may find the task of selecting a counter somewhat confusing and confusing, and if we do not have an urgent need that calls for the availability of a particular feature, it may be easier to choose a counter based on sensitivity and cost, and these two elements both depend in part on the type of photographic cell that is used based on the counter.

Cell types:
Photocells in light meters come in three main categories: selenium, cadmium sulfide (CdS), and silicon photodiode (SPD). The most important of the three are the selenium cell counters. This is because these do not need batteries, last for a long time, and are characterized by a color response similar to the response of the human eye. However, these meters do not respond to weak light levels and tend to become less accurate with the passage of time. However, their low price and simplicity make them ideal to support an implicit meter, including one of This type, the Weston has become a classic, and when I go to a remote location where there is no way to get batteries, a selenium cell counter may prove very valuable.

However, when additional sensitivity is required to express low light levels, we need either a CdS meter or an SPD counter. The first counters must include a battery, but they can come in exceptionally small and sensitive, but unfortunately they are sensitive to red light to an extent. A little more than usual.
It also responds rather slowly and has a memory effect that makes it exaggerate by reading the levels of weak light when we calibrate it after a short time after its optical calibration for a bright scene. From here, it is no longer surprising that the (SFD) counters replace the (CdS) counters now, as the first is as sensitive as the second. It has no memory effect.
It is worth noting that the (CdS) and (SPD) cell counters are not only expensive to operate, but also expensive to purchase. Unless we plan to do a lot of nighttime photographic work, the extra sensitivity may justify the cost, and although we may have to make adjustments for reciprocal failure (*)—the loss of layer speed in effective sensitivity during very long exposures—the CdS counter will work. The SPD, at least, can give a reading in conditions in which many other meters do not respond at all, but the sensitivity varies even among the (SPD) meters, and it is recommended that we check the meter to make sure that it gives it the level we want.

Meter sensitivity:
The maximum sensitivity of an exposure meter is traditionally given as the exposure value (EV) of a film of 100 aza. Each exposure value is simply an expression of the many different combinations between shutter speed and aperture that are required to give a correct exposure under certain lighting conditions. For an exposure value of 10, for example, the exposure will be 1/30 second at / 5.6 or 1/60 second at / 4 and any combination of these two numbers, from here the sensitivity of the meter in terms of the exposure value becomes simply that correct exposure To the darkest conditions he can deal with.

While we find a few TTL meters on SLR cameras that can operate at -6 EV - the equivalent of two minutes at f / 1.4 or a similar exposure, most of them cannot handle exposure values.
Optical transmission of one - one second at 1.4, for example. Some of them do not work under 3 (EV) - a quarter of a second at f / 1.4. Rather, there are selenium cell counters that do not work even under 6 (EV) - 1/30 at f / 1.4.
As for the (CdS) and (SPD) meters, on the other hand, they give no less than 2 (EV) in a typical way - 8 seconds at F 1.4 - and some of them give a quality of - 8 (E) - eight minutes at F / 1 4, - although for exposures of this length one should take into account commutative failure.

When you test the sensitivity range of a meter, we have to be deceived by the gradations on the dial of this meter: they do not indicate the capabilities of the meter. For example, the scales in some meters indicate exposures ranging from one hour to 1/5000 of a second.
And from F / 1 to F / 128, while many exposures in this field are not only impossible to practice, but their measurement may be far from the ability of the meter.
Hence, comprehensive measures of all values ​​have little practical value, and it is much better to have a range of reasonable values ​​that are clear and understandable, even in poor light conditions, rather than a series of numbers that we never use.

Measurements and presentations
Most of the selenium cell counters remain in a state of permanent readiness to work and we do not need to be in the running state to take the reading: the (CdS) and (SPD) counters on the other hand. It must be set to this operating state to take each reading, and it often stops automatically after a minute or so to conserve battery power.

In both selenium cell, CdS, and SPD counters, the reading is often given by a random number or light value. In order to find out the different possible exposure locations, this optical value must be placed on the computer disk, in exchange for the appropriate film speed.

This may be the measure of the film's speed in the meter, which is the same as the DIN (DIN), but it is increasingly relying on the aza alone only these days. The range of the given values ​​can sometimes be extreme - one meter shows any number from 0.05 to 800,000 aza - but these extreme speeds have little practical value because we rarely need a location for a film speed exceeding 3200 aza. Lower values ​​may be possible with print paper and slow copy film, which fits into a much more restricted area. Ease of site setup, a reliable lock and clear, legible numbers are more important than critical values.
What the meter displays comes in two main forms, standard and digital. On standard displays, the reading is indicated by a needle moving on a measuring disc. As for the digital displays, they give a real number that appears from a window, either in the form of a light-emitting diode (LED) or a low-contrast liquid crystal display (LCD). It should be noted here that the LED is bright and can be read in the dark, but it depends a lot on batteries. As for the (LCD), it needs a much smaller amount of battery power, but it is not brightly radiant.

Unlike the standard type. We find the digital displays, and they display values ​​up to the nearest third stop only, and are filled with smaller differences, but they give the reading in clear, easy-to-read numbers on a continuous scale. It also has a memory that can store a reading for later retrieval. In some counters, it is possible to update this memory every second to allow slow detection of the scene. There are a few counters that are distinguished by servo-controlled calculator disks (*), where the light value is transmitted to the calculator.
Automatically even give an exposure value like this, but this is a luxury in fact.
It is possible for the counter displays to take other forms in addition to the standard and digital forms, but these alternatives constitute only a small percentage in the market.

As is the case with all photographic equipment of all kinds, the final choice of a photometer must be a compromise between personal need and financial ability, as a selenium cell counter is cheap and reliable. It works well in good lighting conditions, and in poor light conditions we need the additional sensitivity of the more expensive SPD meters, and with the intention of using it at night, it should contain a clear number display (LED) as well as the light diffuser is a valuable accessory for taking light readings for event (*).

From here before we make a purchase. We have to make a careful decision with preferences, but whatever the decision, we will find that the light meter - which is held in the hand - not only helps to determine the correct exposure, but also fills with feelings of attachment to photography ⏹