Asahi Pentax Digital Spotmeter - Vintage Exposure Meters

By Nathaniel Stephan
Last Updated: November 16, 2020
Pentax Digital Spotmeter

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

  1. Under $50 - Soligor Spot Sensor, Soligor Digital Spot Sensor, or Soligor Spot Sensor II. The Spot Sensor II will require getting lucky on an auction.
  2. $125 - Gossen Ultra Spot Meter
  3. $200 - Pentax Spotmeter V
  4. $350 - Asahi Pentax Digital Spotmeter
  5. $600 - Sekonic L-858D-U

With the exception of the Sekonic, all the light meters will have to be purchased used.

Spotmeter Batteries - 4LR44

Pentax Digital Spotmeter Battery

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 with you.

There is no built-in way to check the battery. If the LED display does not light up with a reading, you need to replace the battery.

Digital Spotmeter Specifications

Pentax Analog vs Digital Spotmeters
Size comparison against the Pentax Spotmeter V.

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

ASA, 6-6400
Shutter Speed, 1/4000 sec. - 4 min.
Aperture, f/1 - f/128
EV Number, 1 - 19-2/3
IRE, 1 - 10

Dimensions

Size (DxHxW): 44mm x 144mm x 83mm
Weight: 258g with a 4LR44 installed.

Pentax Digital Viewfinder

Pentax Digital Spotmeter Viewfinder

The viewfinder is decently sized. 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 your view.

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.

Pentax Digital Spotmeter Eye Piece Adjustment

The closest digital spot meter in terms of price is the Minolta Spotmeter F. The 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, so it is best suited to landscape photography.

Shutter Speed & Aperture Scales

Pentax Digital Spotmeter Exposure Scale

Around the front lens of the Pentax Digital spot meter are two rings to calculate camera exposure 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)

Additional Features

Pentax Digital Spotmeter Case

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.

Zone VI Modified Meters

Fred Picker, the publisher of The Zone VI Newsletter, had a service that would modify a Pentax digital spot meter to be used with the Zone System. The goal of the Zone VI modifications was to improve the accuracy of the meters when used with black and white film.

There is more information about the modifications on the Pentax Spotmeter V page, on FredPicker.com and a Photrio.com forum thread.

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