Re: Pinhole Light Meter

Honestly I don't know. I suppose I developed it because I could and I
wanted / needed it to assist me in getting more accurate exposures for
some of my more complex shoots. Obviously it would be great if I could
make money doing what is in reality a hobby but realistically I'm not
sure that's possible.

I have 5 OLED displays on order and will probably get a couple of PCB's
made for some Version 2.0 prototype's. I will be dropping the LED
indicators. They just aren't useful. I have built up a small cache of
ILEX No 3. Synchro Electronic shutters from eBay for about US$20 each
and Lenox Laser are interested in making up a pinhole adapter for them
and Melles Griott 04 IES 213 shutters which are far more robust affairs
that the UntraThin Melles Griott I have connected to my custom Zero
2000.

I'd be interested in having somebody along to work out glitches if they
paid their way. i.e. paid cost for components, actually used the device,
and made useful comment to improve it. The main microcontroller is
re-programmable. Perhaps one person just using the light meter and
another using the whole system. It will take me a couple of weeks to
work out compinent costs.

The biggest cost at the moment is the IR cut filter which you can see on
top of the light sensor. It's a Sirius Optics NIR1 filter but the Baader
UV/IR Cut Filter appears technically better. The IR cut filter currently
costs US$59 with a US$20.00 adapter from
http://webcaddy.com.au/astro/adapter.asp. The light sensors I use are
designed to function with the Hoya CM500 or Schott BG18 or BG39 filters
also. These make the light sensor's response similar to that of the
human eye / film. If anyone knows where I can get such a filter on the
cheap that would greatly cut the overall cost.

If it becomes a big stumbling block I was thinking of just buying a
sheet of the stuff from Schott and cutting it myself with some Schlott
Opalika diffuser. One route I'm exploring is that there are people who
actually specialise in removing IR filters from digital cameras for IR
photography.

To answer another email: I can't see the Shutter Driver box getting much
smaller than it currently is because of the 6 AA batteries it needs. You
could probably power it off a 9V battery but my calculations indicate
the current draw would be too big. As it is the 6 AA batteries provide a
very useful approx 30 hours of power.

For the light meter the size limitation is primarily the screen. To make
it any smaller would also make it quite fiddley. I had envisaged having
it on a separate tripod or sitting next to the camera pointing at the
scene, a piece of 18%grey card or being held by the photographer. I
quite like it in a rectangular box for that reason - because it can be
sat next to the camera.

All the best

John
----- Original Message -----
From: "andy schmitt" <aandy@comcast.net>
To: <pinhole-discussion@spitbite.org>
Sent: Friday, August 04, 2006 11:15 PM
Subject: RE: [pinhole-discussion] Pinhole Light Meter

> John
> I love it. Are you thinking about manufacturing them or are you going
to
> post the details? I also don't think size is as important as
functionality.
> Is the box on the side the shutter control?
> Thanks again & have a great weekend?
> regards
> Andy Schmitt
>
> -----Original Message-----
> From: owner-pinhole-discussion@spitbite.org
> Sent: Friday, August 04, 2006 1:03 AM
> To: pinhole-discussion@spitbite.org
> Subject: [pinhole-discussion] Pinhole Light Meter
>
> Hi
>
> I have been taking Pinhole Images with a Zero 2000 Pinhole Camera for
about
> 7 years.
>
> To improve the exposure accuracy of my images I have created a
prototype
> specialist Light Meter especially for my Pinhole cameras. One of its
more
> unusual features, and the main one I wanted, is that it integrates or
sums
> incident light over the exposure time. Thus a creating perfect
exposures in
> variable lighting conditions (sunsets, clouds, multiple flashes, etc.)
. The
> f/stops I use are f/45, f/48, f/55, f/128, f/138, f/158, f/176, f/216,
f/235
> but they are just programmed into the microcontroller. Film ISO/ASA
rating
> (ISO 3 to 8000 in 1/3 stop increments). I user Fuji Provia F100 which
> appears to have negligible reprocity but that could easily be
programmed in.
>
> It also functions as a Timer, Normal Light Meter and via its TTL
output and
> a battery powered prototype Shutter Driver I created it can control
shutters
> like the ILEX No 3. Synchro Electronic Shutter (which you can buy off
eBay
> for US $20) or Melles Griot 04 IES 213. I currently use it with a
heavily
> customised Zero 2000 Pinhole Camera and "UltraThin"
> Melles Griot 04 UTS 203 Electronic Shutter.
>
> Here are some pictures of the functioning prototype
> http://www.flickr.com/photos/92561604@N00/sets/72157594223607004/
>
> I'm kind of wondering if it's worth taking this project further, would
> anyone else want to use such a device?
>
> All the best
>
> John
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Received on Fri Aug 4 15:28:33 2006