Intentionally mis-calibrating auto exposure?

[dmr]

Ok, gang, tell me if you think this wild idea is workable, or if you think I'm on drugs! 🙂 🙂 🙂

I want to be able to shoot 1600 film in the GIII, but the ASA/ISO setting only goes up to 800, as some of you have noted.

I was thinking about trying a calibration of the meter against one I know was good (I still don't know how accurate this one is -- it does have the "wrong" battery, but the readings I get on it seem sane) when a thought came to me ... What would be stopping me from intentionally mis-calibrating it by one stop, such that when the ASA/ISO dial says 800 it would really be set to expose for 1600, and a setting of 200 would really be exposing for 400, etc.?

Has anybody ever tried something like this? (If so, any luck?)

Can anybody think of any reason this wouldn't work, or have nasty side-effects?

TIA, gang! 🙂

 

[Gabriel M.A.]

Why do you feel you need to do this? I would not tinker with it unless you want to make it a permanent change or a more-than-frequent setting. I don't know how to operate the GIII, so I'll ask: can't you just manually compensate for the extra stop? That would be two standard shutter speeds. I hope somebody with direct experience with the same camera chimes in, but my gut feeling would be not to fool around with the meter.

 

[BrianPhotog]

Why noy set the ISO at 800, then either:

1) If your cam has an exposure adjustment dial, set it to -1
2) Underexpose a stop from your camera meters reading when you take a picture?

 

[dmr]

I'm kinda responding to both responses here ...

Let me also clarify that I'm making this my "low light" camera, and I want to squeeze yet another f-stop out of it if I possibly can.

Why do you feel you need to do this?

Because I want to shoot Fuji 1600 in it and expose it more or less properly.

I would not tinker with it unless you want to make it a permanent change or a more-than-frequent setting.

Actually this would be semi-permanent.

I don't see myself *EVER* shooting ISO 25 film, which is the other extreme of the ASA/ISO dial. The effect I want to get is to move the range of ISO from 25-800 to 50-1600.

can't you just manually compensate for the extra stop?

Not that easy on the GIII. The one thing I *REALLY* miss from the old Mamiya is that match-needle mode, as antiquated as some may think it is.

but my gut feeling would be not to fool around with the meter.

I don't want to play around with the mechanical part of the meter at all. I'm just talking about the calibration adjustments, which look like they are all electronic and adjustable with a jewlers screwdriver.

One thing I want to do whether or not I do this little trick is to check and recalibrate the meter. It appears to give sane exposures even with the "wrong" battery in it. My guess is that it currently is within +/- 1 stop of being correct. I do want to be sure, however.

Why noy set the ISO at 800, then either:

1) If your cam has an exposure adjustment dial, set it to -1
2) Underexpose a stop from your camera meters reading when you take a picture?

It doesn't have an exposure adjustment like that. It has 2 modes, one is auto, which I'm growing to like, actually, but when the exposure is out of range either low or high it has a hard lock-out.

The other mode is dumb-as-a-rock manual. I guess I could use an external meter, but I don't want to. If this thing had match-needle operation on manual it would be perfect, well, sorta. 🙂

I know the range of the meter is good enough in low light to do this. Using 800 film, if I brace and go down to 1/15 or 1/8, the meter handles it fine. I just want to be able to have a bit more cushion on the low-light end. 🙂

 

[Kin Lau]

Funny, but all the answers are from people who don`t have a GIII, and have never shot with one, so they don`t understand the issues.

The GIII only meters in automatic mode, like many of the 70`s compact RF`s. So if you want to shoot Neopan 1600 or Delta 3200, you`re stuck having to meter manually.

While what dmr436 wants to do is possible (how likely are you to use the iso 25 setting anyhow ), it`s hard to know whether the meter is sensitive enough. I just carry a pocket meter with me if I`m shooting iso 1600 or 3200 in low light, because even most of my older SLR`s with match needle meters aren`t accurate at low light anyhow.