Checking the calibration of an old Capital spot meter

hoffy · Feb 18, 2022

Howdy all,

I have an old Capital digital SP-II Spot meter in my kit, that I've hardly ever used.

It does work, but I want to check that its accurate before I start using it (or at least account for any issues).

What would be the best way to calibrate it? I would like to compare it against my Minolta IVF meter

Cheers

shutterfinger · Feb 18, 2022

Gray card in several lighting conditions such as direct sun, open shade, deep shade, indoor low and medium light and others that you can think of until your satisfied using both meters in each lighting situation.

hoffy · Feb 18, 2022

shutterfinger said:
Gray card in several lighting conditions such as direct sun, open shade, deep shade, indoor low and medium light and others that you can think of until your satisfied using both meters in each lighting situation.

So, basically, point the spot meter at the gray card and meter the light conditions that are being projected onto the gray card?

RalphLambrecht · Feb 18, 2022

hoffy said:
Howdy all,

I have an old Capital digital SP-II Spot meter in my kit, that I've hardly ever used.

It does work, but I want to check that its accurate before I start using it (or at least account for any issues).

What would be the best way to calibrate it? I would like to compare it against my Minolta IVF meter

Cheers

checking and comparing it iseasy with agray card and 'sunny 16' but calibrating it (other than noting and accounting for any deviation) requires hardware surgery; meaning not so easy.

shutterfinger · Feb 19, 2022

Set the gray card in a lighting condition, meter with both meters, reading should be within 1/2 stop each other. A 30° or 15° averaging meter may need to be closer to the gray card than a 1° spot to eliminate extraneous scene light without casting a shadow on the card.

ic-racer · Feb 19, 2022

Do a zone I test.
Unless you are calibrating it to an incident meter, a gray card is not needed.

Chan Tran · Feb 19, 2022

ic-racer said:
Do a zone I test.
Unless you are calibrating it to an incident meter, a gray card is not needed.

But you do need a large evenly lit surface because the 2 meters have different angle of acceptance. 1 degree vs 40 degrees for the autometer IVF. Preferably a neutral color surface not red or blue etc..

BrianShaw · Feb 19, 2022

RalphLambrecht said:
checking and comparing it iseasy with agray card and 'sunny 16' but calibrating it (other than noting and accounting for any deviation) requires hardware surgery; meaning not so easy.

The uncomfortable truth in every thread on this topic.

tokam · Feb 19, 2022

Periodically I put all of my cameras and meters up against the wall, so to speak. Actually facing an evenly lit wall. They nearly all agree within a 2/3 stop range and that's good enough for me. If I had one meter calibrated to the nth degree I suppose I could note the differences and apply an offset for the errant meters. Would it materially improve my results when I mainly shoot black and white negatives? I really don't think so.

hoffy · Feb 19, 2022

BrianShaw said:
The uncomfortable truth in every thread on this topic.

Touché
Yes, I probably should have said "check". Hopefully any discrepancies are consistent.

ic-racer · Feb 21, 2022

Chan Tran said:
But you do need a large evenly lit surface because the 2 meters have different angle of acceptance. 1 degree vs 40 degrees for the autometer IVF. Preferably a neutral color surface not red or blue etc..

Good point.

gone · Feb 21, 2022

I'd take it outside on a sunny day and see if it reads right w/ sunny 16, then take it inside and see if it's right compared to the other meter.

Checking the calibration of an old Capital spot meter

Privacy & Transparency

Privacy & Transparency