Playing With A Spectra Combi II

[Rob-F]

So I have this Spectra Combi II meter, designed for cinematographers, and it's really neat. It takes incident light readings and reflected light readings. OK, that's not new, my Gossen Luna-Pro does that too. The really neat part is, it has two photocells. One reads the reflected light at the same button press with the other one taking the incident reading. It has a mode to average the two.

That's the good news.

Before I go any further, yes I know that each meter has its own angle of acceptance, and that various brands may differ in how they think the meter should be calibrated (etc.). So we don't expect them to agree.

Except that most of mine do agree. Just not The Spectra Combo II. It calls for about 2/3 stop to one stop more exposure than my digital Luna-Pro, Norwood Directors, the meters in my Leicas, Nikons . . .

Well, it could simply be wrong. But it seems to me there is no aging process in modern meters with silicon blue cells and such. So it has occurred to me, that since cinematographers usually shoot negative films, which tolerate some overexposure, maybe the Spectra is calibrated with this in mind? No, that's crazy. It's just wrong. Right? I should send it in.

But has anyone else played around with the Spectra Combi II? What has been your experience with it? Is it worth the trouble to get it calibrated and to use it?

 

[Chriscrawfordphoto]

I have two of them, both are out of calibration. They're nearly 40 years old, and Silicon cell meters CAN age and go out of spec. I had two Minolta Flash Meters whose cells lost sensitivity and caused overexposure.


Spectra told me they could still service them; I think they said $70 to overhaul and recalibrate it. I haven't had the money to send mine in. The concept is interesting. The best part is the Reflected/Incident averaging function. This technique is useful for metering backlit or strongly sidelit subjects, as seen in this tutorial I made:


Incident-Reflected Average Metering


With other meters, you must take two separate readings, one incident and one reflected, them average them. The Spectra does it for you with a single reading!


I don't like the cumbersome dial and range-setting system though. I wish Spectra had kept this feature on their current meter, the digital Spectra IV-A.

 

[Rob-F]

Then I think I might send mine in. It's the averaging mode that I wanted it for. I wonder if it would give reliable readings if I just set it 2/3 stop ISO number higher?

 

[Chriscrawfordphoto]

Then I think I might send mine in. It's the averaging mode that I wanted it for. I wonder if it would give reliable readings if I just set it 2/3 stop ISO number higher?

It might.


There are several possible problems, though.


1) The two sensors might not be equally inaccurate, so the averaging mode won't work well.


2) The meter might no longer be linear. This is a common problem with aged meters. What does that mean? A light meter should be accurate at every light level. A meter that is not linear may be accurate at some light levels and off at others. Or it might be overexposing at some level and underexposing at others.


3) Assuming it is linear and that both sensors are off by the same 2/3 stop, it means you will lose 2/3 of a stop at the bottom end of the range. The Combi II has very low light reading capability when it is working right. It is capable of reading down to EV -6, if I remember right.

 

[Rob-F]

So dialing up the ISO isn't likely to result in a very accurate meter, then. Best to send it in.

Got it!

 

[Rob-F]

I still haven't sent it in, but I did email Spectracine to verify that it's OK to send it. No response. I wonder if I should just send it to Quality Light Metrics instead?

 

[Rob-F]

I sent it to Spectra-Cine (Quality Light Metric is no longer in business). They received it on June 1, and had it all calibrated and back in the mail on June 2. It has a calibration sticker that indicates the calibration is good for six months, until December. I'm sure that's because most of these are probably used by cinematographers shooting 50 million dollar movies!

I compared it to my old original Spectra with selenium cell. Perfect agreement! Impressive on both counts! I'll use it in Colorado this summer.