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PME90 Question

P

Pavel

New Member
I bought a second hand, in like new condition, PMe 90. My problem is that I can't make sense of the readings. It seems like in reflective mode I get correct readings but all the incident readings are about 2.5 stops off ... too bright.

Is there some kind of issue or setting that I may be unaware of or do I just simply have a bad meter? Is there any kind of reset or re-calibration that can be performed on a meter like this?

I like incident reading better, and am used to that, and may just give it back to the dealer, but I wanted to check here to see if there is something unexpected about these meters ... this is not typical ... is it?

Thanks. :)

.. so far ... loving this hasselblad ... and film as well. :)
 
Incident and reflective readings will not be the same. Reflected is influenced by the color of the subject. Can you check your prism reading against a hand held meter?
 
thanks ... I should have mentioned that I have many years experience in a studio that I used to have and am familiar with how all types of meters give you a readout and how to "fineness" them, but in this case the readings don't jive with my readings off a grey card nor with my old minolta IV meter - they are 2.5 stops off and would completely burn out the shots.

The reflective and the incident of my minolta are about half a stop off from each other ... which is kind of typical and fine ... the MPe90 is 2.5 stops off consistently from the decisions of the incident readings of the PMe90 and two to two and a third off of the minolta incident readings. To me, it means the unit is either out of calibration and I don't know if this is something common which has to be sent out to fix or simply a meter out of whack ... and in that case possibly about to slowly (or quickly) die?
 
Hello Pavel,

I am glad my initial answer got lost because it contained words like grey cards etc.
It just ocurred to me, did you check the condition of the battery in the PME 90?
Some meters tend to give higher readings when batteries are about to die.

Writng this I still wonder, 2.5 stops off.
In your original post you mention too bright.
Do you mean the readings are too high?

In the second post you say the shots will be burned out.
That means the reading is too low.

The PME 90 is a processor controlled instrument.
Calibration is not done by changing the settings of variable resistors but by changing the processor programming.
Any repairs are best left to a Hasselblad service center.

I copied part of the owners manual that concerns incident light measurements.


Paul

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Polypal, I did not think of that! I will buy and try a new battery tomorrow. Just to clarify, the meter is great and accurate in reflective mode but only the incident meter is out of sync with what it should be. It reads lower values so following it makes the resultant photo extremely bright.

I've not heard of case where a dying battery would affect once circuit differently than another but I think it is perfectly logical and possible.

I had gone through all the settings and they are all fine, and there is no way to set a bias for incident only (but there is a global setting in the custom functions).

Thanks everyone ... I will post tomorrow whether a new battery was the needed trick. :)
 
There is a self test for the PME 90 by depressing three buttons simultaneously: ISO, Fmax and method.
The display should light all characters and symbols.
Press any button after those three and the display is turned off temporarily and a short beep is heard.
Going back to operating mode is done by depressing the three buttons once again.

Both the PME 90 and the PME 45 were quite expensive when new, they still are as used accessories, but they are very sophisticated instruments.
 
I got a used PM 45 one week ago. It works great, I compared to my 202FA.
Particulary sophisticate instrument. Reading the manual is realy needed.
 
Gentlemen, thanks! I don't quite know what happened but it started to work fine this morning. The only thing I can think of that could be the difference is that after reading the advice here I took the battery out of the chamber to see what kind it was. I didn't have another like it so I simply put it back ... but even with the old battery in, all of a sudden it is working just the way it should be.

I think the thought of a drained battery could be valid and perhaps it was not seated perfectly? I don't know ... but I'm happy to be back in business. THis is quite a sophisticated meter full of unique features.

Thanks everyone. :)
 
Pavel said:
Gentlemen, thanks! I don't quite know what happened but it started to work fine this morning. The only thing I can think of that could be the difference is that after reading the advice here I took the battery out of the chamber to see what kind it was. I didn't have another like it so I simply put it back ... but even with the old battery in, all of a sudden it is working just the way it should be.

I think the thought of a drained battery could be valid and perhaps it was not seated perfectly? I don't know ... but I'm happy to be back in business. THis is quite a sophisticated meter full of unique features.

Thanks everyone. :)
Click to expand...

Besides the battery, we must be careful with the focusing screen we are using. There are two stops difference in metering with old type focusing screen and the new Accumat focusing screen. The Accurmat screen has two small notch at the frame of the focusing screen.

The old PME45 is calibrated with old focusing screen while the new PME45 (with incident metering) is calibrated with Accumat focusing screen. Therefore, with wrongly matched screen there will be two stops difference in meter reading.

Regards

Patrick
 
amoebahydra said:
The old PME45 is calibrated with old focusing screen while the new PME45 (with incident metering) is calibrated with Accumat focusing screen. Therefore, with wrongly matched screen there will be two stops difference in meter reading.

Regards

Patrick
Click to expand...

No doubt with old PME45 Patrick refers to prisms from the PME range.
Starting with the PME 3 and later PME 5 and 51 these prisms were calibrated for use with Acute Matte screens.


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polypal said:
No doubt with old PME45 Patrick refers to prisms from the PME range.
Starting with the PME 3 and later PME 5 and 51 these prisms were calibrated for use with Acute Matte screens.
Click to expand...


Thankyou Paul for the elaboration.

The other point that I want to emphasize is even you use a new PME45 or PME90, but using the old focusing focusing screen, you still got two stops metering error. However, the inicident reading should give the right reading disregard of what type of focusing screen used.

Actually, I think you are using old screen with the PME90 and thus get 2 stops overexposure, while in later test you use a new screen instead. I don't believe battery drain has anything on processor controlled PME90, with stable voltage requirement of the PME90, it should has either go or no go with battery deterioration.

Regards

Patrick
 
Do not forget to change the "F" value when you change lenses.
With the old PM45 it's easy to see this value. With the new one you need to push right buton
 
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