The other day at work I browsed the local auction site and saw a Yashica C, got me thinking about my need to get into medium format photography. The thing about medium format is that you really do need a light meter....erm well if you really want to do photography you need one too, but more so with medium format cause the film is big. And local bloke on the adventure motorcycle forum offered me his Rolleiflex 2.8 Planar - drooooooool!
This got me thinking about designing a building a Arduino powered, small OLED screened, with a few dials and maybe a small toggle switch (I love old electronics with dials and toggle switches like the WW2 gear). I plan to make the dome fitting standard to some light meter I will still decide upon.
The unit will be pretty basic, should measure spot and incident light. It will have two modes (for now). First you select your film speed via a dial. Now you can either enter the shutter speed you intend to use or the aperture you intend to use (shutter priority or aperture priority). Then take the reading and it shows you the EV number, plus either your shutter value or aperture value (dependend on which prioroty you select). It should have another function which I think will be a second button where you take the reading and it shows you the EV number, shutter speed and aperture.
Thing is I can't figure out exactly (nor find info really except what type is used) what sensor they use. I have two choices (the third, selenium offers to little power but its the way most meters worked 40 odd years ago), digital or CdS (think its Cadmium-Sulfide Sensor). I don't really mind which one as long as its pretty sensitive as I want to be able to program/use the meter in very low light as well which very long (5 minutes and more) exposures.
Can anybody assist with what component I should be looking for in say the RS-catalog. I did find photo-sensors and the like but honestly I have no clue what I am looking at.
The rest is pretty much equations. Take reading, add setting(s), run equation and voalla!
Thanks to all who help.
P.S. I am looking at these parts but really I couldn't say if its what I'm looking for since I am getting to know electronics through arduino (links to the SA division)
http://za.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6548097 http://za.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0539836 http://za.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6548918