Bummer !

I know realize that ALL the lightmeters work correctly. Which means, the one in the Mamiya 6 MF camera body, as well my external Minolta ones, and the myLightmeter app. They all agree. But THOSE lead to 2-3 stops underexposure with the Mamiya 6 MF

How is that even possible ? (It didn't do this earlier). And remember, the shutter with this camera, is on each lens, not in the camera.

I really can't figure this out... As a way to circumvent the problem, I have set the ISO on my Mamiya 6 camera at ISO 100, when I use a ISO 400 film. The thing is, that I've never encountered such severe underexposures in any of my cameras before. I just doesn't make sense, why the Mamiya 6 of all, would underexpose 2-3 stops ?

The shutters seem to work. I got by feeling, how 1/8s, 1/15s, 1/30s and so on feels like - but the shutter speeds feel normal.

So, what could it be ? No, the exposure compensation wheel is not false set. It is on 0. The ISO I set two stops lower, because all my films where severely underexposed... But why ? If the light meter works ! When the shutter speeds work... what could be that persistent problem of -2 to -3 stops underexposure.

The lightmeter in the camera, which is external, not measuring though the lens, I always cover above with my hand, kind of shielding you know, from bright light - which does affect the lightmeter - and that is known with the Mamiya 6. You have to measure towards the darker areas of an image, and cover the upper side of the light meter with your hands, so that the in falling light form the sky, isn't affecting your readings...

I do all that. I am not an amateur or a guy who is all blonde and dumb. (Which doesn't mean, one makes errors). But I got it covered so far.

So: the mystery denses.

I continue trying to observe the whole thing. Perhaps something unusual pops into my mind, figure things out. Sometimes the muse has a way of giving your hints... if you are the open kind.

 

My "fastest" medium camera

The Mamiya 6 is for me with my eyes, still the "fastest" model among my medium format cameras to handle. The other ones like Pentax 645 and Pentax 6x7 - there I need a special magnifier in order to really nail the focus exactly (because medium format cameras are more demanding on that you set the focus correctly) - but are not easy to do so, with only looking looking on the matte screen (though a finder).

Without finder, by using the chimney, you have a loupe - and that does nail the focus. But with the Pentax 6x7 you loose the internal lightmeter... And with the 645, you can't take the finder away. You have to use a magnifier to really nail the sharpness exactly. That however is a fiddly extra step, i have noticed. It slows you down enormously. And the magnifier is dim, shows a tiny part of the screen.

The only advantage is, that you do get the focus at exactly the right spot - which makes it more fun when you develop and see that wow, finally the images are in focus. For example in portraits - it is critical. You do not wish the sharpness to be back on the ears. You want them exactly on the front most eye of the person. Otherwise it looks... well weird. And sloppy, in my opinion.

 

After thought

Another thing I could and should test, is how the aperture responds. What if it got sticky in the lenses? Or doesn't open all the way? I have to pay attention to that and see, if something is going on there (maybe). But then again, it would mean all three lenses (and their central shutters or aperture blades) are affected by the same? That seems odd. But who knows...

I have to test it. Anything goes. To find the answer to the riddle of vast underexposure when using nominal ISO like a film's speed has.


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