| ||||
|
 This Light Meter is designed for pinhole / zone plate / pinhole sieve or other forms of high f/stop and or low Film ISO cameras. It uses the unique technique of integrating or summing the light energy it receives over time. When exposing it can therefore indicate when a perfect exposure has been obtained even in the challenging conditions of variable outdoor natural lighting. When measuring, it works like a normal light meter and shows the approximate exposure time required. By altering ISO speed, film reciprocity characteristics or f/stop, after a measurement, the effects of changes to those parameters can be seen. In Timer Mode it accurately times exposures from 1/100 of a second to 17 hours 59 minutes 59.99 seconds. Via an optional PICKit 2 its record of up to 60 exposures (Flash count and exposure time) can be downloaded from its EEPROM to a PC in csv form suitable for import into a number of other programs. With the Shutter Driver it can control a wide variety of electronic shutters via its TTL level BNC output socket. I am currently using Melles Griot 04 IES 213 http://www.mellesgriot.com/ and ILEX No 3. Synchro Electronic Shutters. It can also trigger a wide variety of studio flash units via its 3.5mm mono socket. The main box measures 130 x 68 x 41mm with the addition of the sensor the height goes up to 95 mm. The light meter is powered by 1 9 Volt battery which can be changed by opening the front. Controls
Activate Button (RHS Red) - Activates the electronic shutter (if fitted) or flash (if attached). Summing incident light for a perfect exposure in Light Meter Mode. Times the exposure in Timer Mode.
Measure Button (LHS Black) - Measures the exposure time needed.
Select Button - Select which parameter the rotary encoder controls. Parameters include:. Exposure number provides an easy reference for the current film frame and also is the index to the table of stored internal EEPROM data of exposure times and flash counts. Reciprocity Characteristics Manufacturer reciprocity characteristics for the following films are built into the meter.
User Interface A loud piezo buzzer chirps on start-up, after measurement and for 3 seconds after exposure. A bright OLED or LCD display saves power and provides a display clearly visible in the most demanding of lighting conditions. You may change the displays brightness or contrast by turning the 10K Ohm pot on the back board of the light meters PCB when the case is open.
Variables are selected by pressing the Select button until the variable you wish to change is highlighted by a flashing cursor underneath it. Variables are changed by rotating the encoder clockwise or counter clockwise. If a variable reaches its software controlled maximum or minimum it will not increment or decrement. Values and operating mode persist after the unit is switched off. You can also ascertain the effect of reciprocity characteristics, f/stop and Film ISO on estimate exposure time after a measurement by selecting the variable and changing it. Measurement is initiated by pressing the Measure button in light meter mode. The sensor will read the incident light for 4 seconds, give a short beep, and indicate approximate exposure information. Integration / exposure or Timing is initiated by pressing the Activate button. Integration continues until optimal light energy has been received by the sensor. Timing until the countdown is zero. A long 4 second beep indicates the end of both processes. Pressing the activation button during exposure will fire the flash again until the desired exposure has been achieved. Connectors Female BNC TTL out to shutter driver, +5 Volts indicates shutter should be open, O volts indicates shutter should be closed. Female 3.5 mm flash trigger socket suitable for high trigger voltage flash circuits. Internal 6-pin ICSP header to allow connection to PicKit 2 USB or similar devices. Optional 9 Volt power in. Sensor head. Has a standard 1.25" filter thread on the end. Downloading Exposure Data You may attach the PICKit 2 to the ICSP connector inside the Integrating Light Meter to download the EEPROM data to your PC as a hex file. Useing the Integrating Light Meter’s hex2txt utility you may convert the EEPROM data file into meaningful text. Download the hex2txt utility here. (Size 9Kb)
Response Curve The addition of a IR cut filter will remove the photodiode spectral response to wavelengths above 700 nm. I use the Sirius Optics NIR1 filter.
 This unit is designed to drive the ILEX No 3. Synchro Electronic or Melles Griot 04 IES 213 from battery. This particular model is intended to operate Solenoids with a nominal operating voltage of 24V (the most common ILEX / Melles Griott voltage I have found – approx 130 Ohm coil resistance). Utilising state of the art DC-DC conversion technology it can provide 30 hours of continuous use from 6 AA batteries. It can be modified for solenoids with other nominal operating voltages. A push button provide standalone 'B' type operation. i.e. whilst the button is pressed the shutter will be opened. A BNC socket takes TTL level input, +5 Volts opens the shutter, O volts closes the shutter.
I actually consider these light meter to give me a competitive advantage to my commercial pinhole photography but I also need to recover some of the staggering development cost.
If you want to buy one email me at The price US $288 for the light meter. I’m afraid any form of hand built boutique custom electronic for niche applications costs way more than the mass market stuff assembled in factories exploiting people in the poorer parts of the world. As they are hand built I may have to make your order prior to delivery. If you require an f/stop other than those listed in the specification just tell me before you buy the light meter. The software is stable but I will probably add some kind of indication for the estimated number of flashes required for flash metering and allow the reviewing of previous exposure times via the rotary encoder on future models. If you buy a light meter, and your willing to sign a non disclosure agreement you are welcome to view and change the assembler source code. You will require a PICKit 2 for programming or similar. Such access will also allow you to create custom reciprocity characteristics. This light meter does not come with the IR cut filter. I can supply these at US $70 per filter but experience indicates that the metering is usually within 1/2 an f.stop without it. Additionally shutter driver units for ILEX No 3. Synchro Electronic or Melles Griot 04 IES 213 shutters may be bought for an additional US$ 125 and ILEX No 3. Synchro Electronic Shutters may be bought for an additional US $35 with .5m lead and DIN connector. US $45 for a good looking one. I usually remove the fronts as shown on above. New shutters can be bought direct from Melles Griot You could probably obtain a similar shutter for US $20 by searching on eBay. You are probably best off buying the IR cut filter, if required from astronomy shops. Or for US $59 + US $5 shipping http://www.webcaddy.com.au/astro/adapter.asp which is where I get them. Postal options I recommend are: Insured Express Courier International: US $43.00. 2 to 4 business days or Insured Air Mail: US $19.40. 3 to 10 working days according to AusPost More information relating to the development of this light meter can be found on www.f295.org An example of an image taken utilising my custom Zero 2000 show above.
| ||||
|
Page 1
Page 3
 648.jpg)