Turn your Leica-meter... into an incident Leica-meter!
Eugene J Lee
11.6.10
This hack is so easy it's actually kind of funny. Take your lightmeter (potentially ANY lightmeter), cover the sensor with styrofoam. Tweak the thickness of the styrofoam so the meter is accurate. Ta-da.
no, the funny bit is how long this write up is now.
Long story short, I got two (!) Leica-meter MR s from fellow RFFr Fred R. This is surprising because I thought I was going to get one, and the MR is
actually worth more than $10 (I've seen working MR-4s for over a hundred...).
So, I cut a rectangle of styrofoam out. Forced it into the metering aperture. Done. Well, kinda.
You'll notice that LR-44 batteries don't really fit in the battery chamber. Yeah, yeah, you could get the proper batteries, but hey, LR-44s are sooo cheap. To make the bottom contact fit, I put a circular metal plate for the battery to sit on. I also put a bit of paper to wedge the battery against the + contact. This was later changed to a wooden crescent, because the paper is a little fiddly. It's important to have these two bits- otherwise the battery might not make contact, or the battery might short out (good for reducing that 1,5v to 1,35 v!).
MR hack-it by
rokka~!, on Flickr
The other problem was that the meter was off anywhere other than sunny 16, maybe 2 stops off indoors. I thinned the foam a bit, and now the meter is
kinda accurate. More on this later.
How thin? I took off ~0,5 mm. It's kind of agak-agak, you'll have to see what works for you.
The hackering by
rokka~!, on Flickr
This is (kind of) important- Don't mess with the needle zero! The middle ranges won't line up. To correct for the voltage difference, change the ASA. The battery check position corresponds to sunny 16, so just change the ASA so that sunny 16 lines up with the needle. It should work okay.
You can go in there and mess with the resistors to make it work with 1,5 v if you want to. I didn't bother- it's alot of mounting/dismounting of the top cover... and taking the top cover off is a fuss.
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SO- how does it work? It works okay. The Leica-meter is kinda nice, it's coupled and all that. It makes your camera bigger though. Which is kinda lame. Oh well.
There are a couple problems with the incident-mod, one being that you need to point the meter towards the light source (pinholes ahoy!!!), and that for some reason, the low end of the high range and the high end of the low range don't agree. The first issue isn't that bad, you ought to know when it's sunny 16 anyways, and the second issue, well, it should be okay with negatives (+/- 1 stop) and might even go away when the voltage is actually 1,35 v.
But I have a few gripes with the Leica-meter itself- the battery door is made of some thin plastic that is easy to break, and the scale is actually very easy to misread. At the extremes of the scale, the bars are thin (because the needle moves in an arc), and the needle is pretty thick. This can lead to a reading error of +/- 0,5 stops, maybe worse. Don't bother trying to get half-stop precision at the low end of the scale.
Again, this should be okay with negative film.
I've been using the incident Leica-meter for a few weeks, and the negatives look okay. It's not going to replace my Lunasix, but it's better than guessing... for now.
Oh, and tape up that top plate.
Linear Mode
