REVENI LABS Light Meter Manual

Reveni Labs Light Meter
User Manual and Operating Instructions
Revision: 2
Date: 2020-08-01

Revision: 1 –2020/04/17
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Layout and Features
Key Features
Ambient reflective metering
Integrated flash/accessory
shoe mount
Bright and crisp OLED
display
Simple controls and menu
Aperture or Shutter priority
mode
Exposure compensation in
1/3 stops (-2 to +2 stop
range)
Single LR44 battery
EV Display feature
45-degree cone sensor field
of view
Left and right lanyard/strap
holes
Dimensions: 0.92(22.5) x
0.86(21.8) x 0.71(17.8)
inches(mm)
Weight: 9g incl. battery
Technical Data
Shutter speed range
Aperture range
Film ISO range
EV Range:
1hr –1/8000th sec in 1 stop
increments
F0.7 –f1024 in 1 stop increments
ISO 1 –ISO 12800, see “Setting
Film ISO” for full list
EV 2 –EV 19.5 in 0.1EV
increments (@ISO 100)

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Getting familiar with your meter
The Reveni Labs Light Meter is intended for easy attachment to the
top of a camera via the flash/accessory “hot/cold” shoe mount. This
is a common feature on top of many cameras made in the past 100
years. The precise dimensions of the shoe vary from camera to
camera so if initially if the fit of your meter is tight, it will “wear” slightly
over the first several uses and become more free-moving. This is not
a problem as there are integrated lever springs to ensure the meter
does not fall out of the camera mount.
Off-camera, the Reveni Labs Light Meter works just as well, and can
be aimed manually at the subject to be metered. The meter has
lanyard holes on both sides of the screen, to allow it to be attached to
a neck strap or leashed to the camera for added security.
Battery
The Reveni Labs Light Meter uses a single alkaline LR44 (A76,
AG13) coin cell which is commonly available. Expected battery life
for a quality coin cell is approximately 5 hours of total use, equating to
several thousand readings with a 5 second time-out. Reveni Labs
recommends to only use high quality name brand alkaline cells in the
meter.
Do not store the Reveni Labs Light Meter for long periods of time with
the battery installed. The standby life of an installed battery is
approximately 1 year.
The battery must be inserted with the Positive (+ marked, flat side)
down, otherwise the meter will not work. The battery holder is
designed to prevent the battery from making contact if inserted
upside down.
DO NOT insert the battery directly into the opening without the
battery holder, as damage may occur if the battery is inserted
upside-down.

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It is recommended that you carry an additional battery with you in its
original packaging, and do not carry any battery without a covering in
a pocket. If the battery contacts become shorted by a metal object
such as keys, it can cause burns or possibly start a fire.
Low Battery
If your Reveni Labs Light Meter does not turn on, or the screen
flashes but does not remain on after the Power/Sample button is
released, the battery is likely too low. Waiting for the battery to
“recover” can sometimes get additional use from it, however it is
recommended to replace with a fresh battery once this begins to
happen.
Dispose of drained batteries in accordance with your local laws.
Physical Care
The Reveni Labs Light Meter is designed to be rugged and sturdy,
and should not break from regular use. It is not intended to be
exposed to excessive moisture such as direct raindrops, or operated
by wet hands. There is the possibility of permanent damage if it is
exposed to water. If the meter does get wet, remove the battery and
wait for it to dry or place inside a sealed container with uncooked rice
to absorb the moisture.
Dirt can be wiped off with a slightly dampened cloth or dry brush.
Dust can be blown away with a dry blowing device such as a
compressed gas duster or puffer bulb.
Take care not to strike the screen with any object, as it contains glass
and may crack or break.
Do not dismantle your Reveni Labs Light Meter as there are no user-
serviceable parts inside.

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Using Your Meter
Please ensure that you are familiar with the operation of your meter
and that it is providing consistent, accurate readings prior to taking
your photographs. Incorrect operation can impact the accuracy of
your reading. Always keep in mind the “Sunny 16 rule” to ensure that
your meter is providing a reasonable reading. This will ensure that
severe exposure errors do not occur.
Sunny 16 Rule
The Sunny 16 rule is a simple estimation scheme to help guide a
photographer in estimating the correct exposure in some lighting
situations. The rule is, in broad daylight, set your aperture to f16 and
set your shutter speed to the reciprocal (1/X) of your film speed. For
example:
Sunny day, ISO 100 film (EV 15): f16 and 1/100 is the ideal exposure.
This method often may reach a shutter speed which the camera may
not offer. In this case, rounding to the nearest shutter speed is
sufficient. In the above example, 1/125 would be the correct shutter
speed choice.
By understanding this estimation rule, you can gain a sense of
approximate correct exposure and provide yourself a “second
opinion” to ensure that your use of the Reveni Labs Light Meter was
correct.
Power
Pressing the Power/Sample button turns the meter on. It will
automatically take a reading and calculate a shutter/aperture pair
based on the previously saved settings. The meter will automatically
turn off after the prescribed time.

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Sample Screen
After taking a reading the meter will display the calculated aperture
and shutter speed. The aperture is always shown on the top line
(denoted with an “f” symbol) and the shutter is always shown on the
bottom line. When exceeding 1 second, an “s” will be shown next to
the time. When under 1 second, the reading is assumed to be “1/X”
with the “1/” implied to save screen space. With speeds exceeding
1/1000, the trailing zeroes are replaced with “k”.
In Aperture Priority mode, an arrow points to the top line of the
screen. When in Shutter Priority mode, the arrow points to the
bottom line of the screen. The value that the arrow points to is the
“driving” value, meaning it is controlling the calculation. The value
that the arrow isn’t pointing to is the “driven” value, which is
calculated based on the driving value and the other meter settings.
Where the arrow points is the value that will be adjusted if the user
presses the Left or Right buttons. The driven value will be
recalculated each time the user presses the Left or Right button, but
a new reading is not taken unless the user presses the
Power/Sample button again.
While the light being measured may have infinite variation, cameras
do not and therefore the reading must be rounded to the nearest

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“stop”. Otherwise the meter would report shutter or aperture values
which the camera does not have available.
What are “Stops”?
A “stop” is the colloquial term for a relative amount of light. Adding a
stop is to double the amount of light being exposed to the film, and
subtracting a stop is to divide the amount of light by half.
Most cameras have their available shutter and aperture settings
dividedq into 1-stop increments, so each adjustment either doubles or
halves the amount of light striking the film.
The ISO film sensitivity system also follows this trend; every doubling
of the ISO number requires only half the amount of light to expose the
film the same amount. Halving the ISO requires a doubling of the
light to expose the film the same.
EV (Exposure Value)
Exposure Value is a common way of quantifying photographic light
levels irrespective of a specific shutter speed or aperture size. The
EV scale is exponential and therefore matches the standard
adjustments of doubling or halving the amount of light as seen by the
film when adjusting either ISO, aperture or shutter speed.
A specific EV number correlates to a specific amount of light striking
the film, and so can be achieved by an infinite combination of
aperture and shutter speed selections. In this way, it is effective at
divorcing the exposure value from the camera itself. Since the same
amount of light will produce a different exposure on a different ISO
film, the EV system has to take into account the film ISO to be
accurate.

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Setting film ISO (film sensitivity or “speed”)
To meter accurately, your Reveni Labs Light Meter must be set to
match the ISO of the film currently inserted in your camera. Be sure
to change this setting whenever you switch rolls or use your meter
with a different camera.
Press the menu button to cycle through menu options. Stop when
the top line of the display shows “ISO”.
Press the Left and Right buttons to adjust the ISO setting up or down
to the desired value. The full range of ISO settings available are:
oISO 1, 3, 6, 12, 25, 32, 50, 100, 125, 160, 200, 250, 320, 400,
800, 1600, 3200, 6400, 12800.
Press the Power/Sample button to save your selection and take a
new reading at the newly selected ISO.
For unavailable ISO ranges, manipulation of the exposure offset
feature can be used to achieve the correct exposure for in-between
values.
Metering Mode
The Reveni Labs Light Meter can perform its calculations based on
two modes; Aperture Priority and Shutter Priority. In Aperture Priority
mode, the user selects the aperture they wish to use and the meter
will calculate the shutter speed required to get the correct exposure.
In Shutter Priority mode, the user selects the shutter speed and the
meter calculates the aperture. This offers control to the user
depending on their desired depth of field (soft background, prominent
bokeh, wide range of focus, etc.) and shutter speed (freezing motion,
blurred motion, etc.) within permissible ranges.
Press the Menu button to cycle through menu options. Stop when
the top line of the display shows “MODE”.
Press the Left or Right button to switch between “A. PRI” (Aperture
Priority) or “S.PRI” (Shutter Priority) Mode.
Press the Power/Sample button to save this selection and take a new
reading in this mode.

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Exposure Compensation
The Reveni Labs Light Meter has an exposure compensation feature
commonly found on digital cameras and cameras with automatic
metering. It allows the user to set an “offset” for the exposure,
adjusting it up or down to account for environmental conditions. For
example, a bright snowy day will cause the meter to read high. This
will make the snow look grey instead of white, and most non-snow
subject matter will become very dark. One solution to this is to apply
an exposure compensation to “correct” for the snow.
A similar thing can happen when metering a dark scene with a
brighter subject, such as a concert stage. The general darkness of
the scene will cause the meter to read high, and the better-lit subject
will become overexposed.
How much exposure compensation is needed is subjective, and so
often a photographer may choose to “bracket” their exposure; take
the photo multiple times at different exposure levels. Often a
photograper will shoot 3 shots; 1 at the metered speed, one at 1 stop
under, and one at 1 stop over. This ensures the photographer has
captured the scene with correct exposure, at the cost of two wasted
shots.
Press the Menu button to cycle through menu options. Stop when
the top line of the display shows “COMP”
Press the Left and Right buttons to adjust the compensation value in
1/3 stop increments. This will cause the meter to trend higher or
lower, depending on actual lighting conditions.
The exposure can be compensated up or down by 2 stops maximum.
Return the value to 0 to remove the exposure compensation.
EV Display
If the user wishes for a more granular lighting readout, they can
select the EV Display feature, which will briefly show the measured
EV to 1 decimal place before displaying the calculated
shutter/aperture. This allows the user to see whether the metered

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value was rounded up or down in order to produce useable settings,
and may influence their setting choice depending on their own
interpretation of the lighting conditions.
Press the Menu button to cycle through menu options. Stop when
the top line of the display shows “EV”.
Press the Left or Right arrow button to cycle between “EN.” and
“DIS.” This will enable or disable the EV display feature.
Time-out
The Reveni Labs Light Meter turns off automatically. The user can
select how long you would like it to stay on for after the last reading is
taken.
Press the Menu button to cycle through menu options. Stop when
the top line of the display shows “T-OUT”
Press the Left or Right arrow to increase or decrease the time that
the meter will stay on, in seconds.
The timer resets whenever a button is pressed, so the meter will
remain on indefinitely if it is being actively used.
Calibration
The Reveni Labs Light Meter comes factory calibrated, but if the
user wishes to adjust it, they can do so. It is not recommended that
the user adjust this value and should use the exposure compensation
feature to make adjustments instead.
Press the Menu button to cycle through menu options. Stop when
the top line of the display shows “CAL”
The bottom line of the display shows the current calibration value.
This will have been set from the factory.
Press the Left and Right button to adjust the calibration value. Each
increment of the calibration value will change the reading by 0.1EV.
It can be adjusted from -20 to +20 in increments of 1.