My canonet does iso 1600

[douwe]

I adapted a canonet ql19 GIII, so it can shoot film at iso 1600. The idea is really easy. Like most shutter priority fixed lens rangefinders, the canonet has a ring with little holes in front of the lightmeter. Changing shutter speeds turns the ring, and changes the amount of light that reaches the lightmeter.
I changed the position of the ring, so that the hole corresponding to 1/250th of a second now corresponds to 1/500 of a second. This is quite easy, because you only have to drill one hole in the ring, and you can change it back if needed. (see pictures)
In this way, iso 25 will change to iso 50, and iso 800 will change to iso 1600.
You lose the iso 25 setting, and you lose correct metering for 1/4th of a second. I don't use the latter speed very often because I don't use a tripod very often.
The metering seems to match my lunasixF, so this seems to be a nice trick.
I intend to change some of my more precious cameras as well. I think it will work for a konica auto S2 and S3, minolta 7SII, canonets, but not yashicas.

Have fun!
Douwe

 

[bcostin]

That's a good idea. Did you need to enlarge the opening in the meter aperture slots, or was it already the right size to meter correctly at ISO 1600? I may have to try this.

I've thought about deliberately using a battery of the wrong voltage to skew the meter, but I suspect the voltage difference would not be linear, especially as the battery ages.

 

[douwe]

I only drilled an extra hole in the ring, right next to the original one, as can be seen in picture 2. (7 o'clock position.)
The beauty of this approach is that the meter doesn't have to work outside it's intended range, or with an inappropriate voltage. You just let a larger amount of light reach the sensor. No problems with electronics whatsoever!

Cheers,
Douwe

 

[alkos]

Great stuff, douwe! I've just modded mine, works like a charm! (checked with contax G2 - all exposures ok...)

 

[douwe]

Good to hear it works Aleksander!

I'm going to try the same trick with my konica auto S3, just as soon as I finish the roll inside... (Too many cameras...) I don't really like the look of the canonet pictures you see, that's why I modified it first...

Cheers,
Douwe