Mamiya C330 close-in exposure compensation

Autonerd · Dec 14, 2020

I've been shooting with a friend's C330. The camera has a pointer for parallax correction and exposure compensation. According to the manual, if you meter at 1/125 and f/11, and the pointer indicates 2, you open up one stop (1/60 @ f/11 or 1/125 @ f/8). If it's at 3, you'd be at 1/125 and mid-way between f/8 and f/5.6.

But wait a sec -- isn't that increasing exposure by one stop and 1.5 stops, respectively? You're opening up by 1/2 the value of the pointer -- so why is the 2 not a 1, and why is the 3 not a 1.5?

Aaron

pbromaghin · Dec 14, 2020

I can't remember if there is a 1, but
1 = 1/2 stop - half again the light
2 = 1 stop - 2 times the light
3 = 1.5 stop - 3 times the light
4 = 2 stop - 4 times the light

MattKing · Dec 14, 2020

Actually, the instructions (see below) make it clear that the exposure compensation indicator is set up to indicate exposure factors, not stops.
That means that it indicates changes to the length of the exposure, not the aperture.
You need to multiply the exposure time by the factor. It is a linear function when you work that way.
If the meter indicates one second, and the indicator in the viewfinder says 1.5, you need to use 1.5 seconds.
If you want to work in stops, you need to recalculate using square roots.
The manual:
Compensating exposure:
As distance between the lens and film increases. image brightness on the film is
reduced even though aperture size remains the same. Consequently, it is necessary
to increase the exposure.
The figures on the focusing screen left side indicate the exposure factor. Compensate
the exposure after reading the figure indicated by the pointer while focusing.
For instance. assuming that the correct exposure value measured by an exposure
meter is 1/125 sec. at f/11, compensate the exposure as follows:
If the pointer indicates 2, 1/125 sec., f/8
or 1/60 sec., f/11
If the pointer indicates 3, 1/125 sec., between f/S and f/5.6
or 1/60 sec., between f/11 and f/8

dabsond · Dec 15, 2020

I have always followed the built in chart on the side of the camera bellows. Works well for me.

benjiboy · Dec 15, 2020

The close-up exposure requires a transparent exposure compensator plate that fits in the cameras folding viewfinder above the focusing screen that gives the correct exposure factors for close up exposure. compensation with the 55mm lenses

Marco Gilardetti · Dec 15, 2020

Same goes for exposure compensation on filters.

I fully agree with the original poster that this is absolutely dumb, silly and confusing. Of all the things that changed in photography over the decades, this one, which was one of the less intelligent to begin with, survived absolutely untouched.

MattKing · Dec 15, 2020

The system works well if you are used to using filter factors.
If you are used to working in fractional stops, the system is a challenge.

Sirius Glass · Dec 15, 2020

I always considered the scales a big plus for the C330. It encourages buying the Paraminder, using a tripod and take photographs of flowers.

Autonerd · Dec 15, 2020

MattKing said:
Actually, the instructions (see below) make it clear that the exposure compensation indicator is set up to indicate exposure factors, not stops.
That means that it indicates changes to the length of the exposure, not the aperture.
You need to multiply the exposure time by the factor. It is a linear function when you work that way.
If the meter indicates one second, and the indicator in the viewfinder says 1.5, you need to use 1.5 seconds.

Well, that makes sense! Thanks.

Mamiya C330 close-in exposure compensation

Autonerd

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dabsond

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Marco Gilardetti

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Sirius Glass

Autonerd

Mamiya C330 close-in exposure compensation

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