Owner's Manual

Using the Field of View Reducer for Small Leaf Applications:
The field of view reducer (FOVR) accessory reduces the sample chamber area from 63.6
mm
2
to 19.6 mm
2
, roughly 30 % of the original size. Field of view reduction errors were less
than 5 % for all leaves tested using the steps below.
1. To use the reducer you must calibrate the meter without the reducer installed. Installing the reducer prior to
calibration results in the error message:
2. Install the FOVR carefully by gently pressing it into place on the meter body side of the sample chamber.
3. You are now ready to make measurements on smaller leaves. Important note: If the meter turns off (preset
Auto-off in 4 minutes), you will need to remove the FOVR to repeat steps 1 and 2.
4. To remove the FOVR, carefully use a needle to depress the foam washer and pick out the FOVR from the
sample chamber (see image below).
Converting from µmol per m
2
to mg per m
2
:
The leaves of higher plants include a mix of both chlorophyll a and b in about a 3 to 1 ratio (Parry et al., 2014).
Chlorophyll a has a molar mass of 893.5 grams (g) per mole; chlorophyll b is slightly heavier at 907.5 grams per
mole. The typical weighted average mass of both types of chlorophyll in plant leaves is very close to 900 grams per
mole (this is equivalent to 900 micrograms per micromole; or 0.9 milligrams per micromole).
The reading(s) in µmoles per m
2
can be converted to units of mg per m
2
by multiplying by 0.9. For example, a
reading of 400 micromoles per m
2
is approximately 360 mg per m
2
.
The reverse conversion from mg per m
2
to micromoles per m
2
can be done by multiplying by 1.11 (1/0.9). For
example, a reading of 350 mg per m
2
is approximately 388.5 µmol per m
2
.
!! Warning !!
Clean Sample Chamber!