The Asahi Pentax Digital Spotmeter has remained a popular choice since Ansel Adams popularized them with his zone system. He also used the previous analog meter that was replaced by the Digital Spotmeter, the Pentax Spotmeter V.
Where to Buy a Pentax Digital Spotmeter
Like with most used photography gear, eBay has the biggest selection and best prices. There is a large price range, with the Pentax Digital Spotmeters in excellent condition going for a large premium.
Check current prices at eBay.
Alternative Spot Meters
- Under $50 - Soligor Digital Spot Sensor, or Soligor Spot Sensor II. The Spot Sensor II will require getting lucky on an auction.
- $125 - Gossen Ultra Spot Meter
- $200 - The Minolta Spotmeter M or Minolta Spotmeter F.
- $350 - Asahi Pentax Spotmeter V
- $600 - Sekonic L-858D-U
With the exception of the Sekonic, all the light meters will have to be purchased used.
Spotmeter Batteries - 4LR44
A 6V, 4LR44 battery powers the meter. They are widely available and used in cameras like the Canon AE-1, as well as dog shock collars.
You should be able to easily find them in stores. Buying them online does save money, especially if you plan on keeping a spare battery with you.
There is no built-in way to check the battery. If the LED display does not light up with an EV reading, you need to replace the battery.
Measuring Range: (100 ASA) EV 1-20 (EV 20 is displayed as "0".
Measuring Angle: 1°
Measuring Distance: From ~1.5m to infinity.
Measuring Method: Spot measuring of reflected light.
Exposure Readout: Red digital LED display.
Photosensitive Cell: Silicon Photo Diode.
Scales for Calculating Exposure
Shutter Speed, 1/4000 sec. - 4 min.
Aperture, f/1 - f/128
EV Number, 1 - 19-2/3
IRE, 1 - 10
Size (DxHxW): 44mm x 144mm x 83mm
Weight: 258g with a battery installed.
The viewfinder is a decently sized pentaprism. The measuring angle is 1 degree. EV readings are displayed on a red LCD at the bottom of the viewfinder. Unfortunately, the display does block a large portion of the viewfinder.
40.5mm filters can be used on the front of the meter. The eyepiece is able to be adjusted and fixed into place with a locking ring.
Compared to the Minolta Spotmeter F, both viewfinders are similar in size. The EV display in the Minolta's viewfinder barely takes up any space, letting you see significantly more.
The Pentax Spotmeter V has an enormous viewfinder that dwarfs the size of the digital Pentax and Minolta meters. That comes with the disadvantage of being larger and it is an analog meter.
Shutter Speed & Aperture Scales
Around the front lens are two rings to calculate camera settings based on a given exposure reading.
The front dial is used for ASA and shutter speed. There is an ASA index, ASA scale, and shutter speed scale.
EV is set with the second scale, which will align aperture values with the shutter speeds on the other dial. There is an aperture scale, EV No. scale, IRE scale, and IRE standard index. (Institue of Radio Engineers)
Originally the light meter came with a vinyl case. There is a wrist strap and 1/4" tripod mount on the bottom.
Pentax Digital Spotmeter Manual
A PDF version of the manual can be found at Butkus.org.
An original copy of the manual can usually be found on eBay.
Zone VI Modified Meters
Fred Picker, the publisher of The Zone VI Newsletter, modified some light meters. The goal of the modifications was to improve the accuracy of the meters when used with black and white film.