Multi-spot exposure meter on camera challenge

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KenS

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For a significant number of years I no longer "meter the scene" I carry a 'swatch' of clean white towel (in a plastic bag) and use that as a 'subject' in the scene with similar 'light' (I'm looking for a 'white with texture to 'place on ZoneVIII+1/3 and the film given "Normal' development (in the developer of choice... mine is Pyrocat HD)

This technique was provided by Kodak's Dr. Martin Scott a significant number of years at at a meeting of the BPA,
(now known as Biocom.org).

Ken
 
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superflash

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KenS:
Thanks for your contribution.
This method is very interesting, but how would Dr. Scott proceed with the slides? And to measure the contrasts, have you illustrated other alternative systems to the use of a spot or multispot light meter?
 

138S

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This method is very interesting, but how would Dr. Scott proceed with the slides? And to measure the contrasts, have you illustrated other alternative systems to the use of a spot or multispot light meter?

This is a kind of incident metering. A white towell do the job, a grey card (Kodak R-27) is a more standard tool to do the same, it converts an spot meter to an incident meter.

The question is when an incident meter is suitable and when not, we meter incident light reaching the place we are, but out subject can be far, perhaphs in the shadow...

The R-27 grey side reflects 18%, the white side reflects 90%, mostly like the towell

If we place the reading in the towell at Z-VIII+1/3 then we overexpose a bit, which may not harm negative film but it probably would not be good for slide film.
 

KenS

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KenS:
Thanks for your contribution.
This method is very interesting, but how would Dr. Scott proceed with the slides? And to measure the contrasts, have you illustrated other alternative systems to the use of a spot or multispot light meter?

Martin Scott (head of 'Scientfic Imageing)That Kodak's Kodachrome processing had the 'Tightest' of all processing 'anywhere'
I 'believed him then' (he was 'pesenting' at an International Annual meeting of the Biological Photographer's
Association (if my ageing memory is correct it was in Philadelphia with a LOT of 'medical photographers from the UK present.
I Used it from that time on when in the employ of Agriculture Canada's 'Research Branch' but continue using it as of today (even though i am now 'retired' but still exposing LOTS of B/W sheet film and posting my post-retirement
endeavours (which include earning my BFA at the nearby University) I have also been submitting my 'artistic endeavours at the 5x4.co.uk website (as KenS) for the past year (or so) I believe i am receiving significant
"positive feedback' fro the other members.
You will find that the 'white with texture' will be within 1/3 of an f-stop of an incident meter reading


Ken
 
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superflash

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138S:
I agree with you.
In my opinion, the spot measurement can be replaced by the incident one or by the towell if the film admits wide margins of tolerance and if the scene has uniform direct lighting. If the film is demanding and the lighting conditions are disparate, the spot seems essential to me.
 
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superflash

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KenS:
Thanks for sharing this method. I only take slides so I don't know how far it can be applied, but if I happen to work with negatives I will try it.
You who shoot with the large format, do not use the measurement on the focal plane with probe?
 

Chan Tran

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Actually modern camera do have multi spot with automatic averaging like that of the Olympus OM-4 but it doesn't work. When you set a modern Nikon in center weighted mode and make the center area cover the entire image (it's something you have to go into setup to do. The F5 would need the photo secretary software to set it that way) then it makes reading of all the spots in the image area. The fewest is the F5 with 1005 spots. Newer ones have a whole lot more but then after averaging it gives the average...
 
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superflash

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Chan Tran:

Multi-area systems that calculate the average after doing a myriad of calculations have a different purpose than the multi spot:
- the first analyze the scene by measuring the light in many points, then make an average with a ponedazione based on a flood of parameters, but in any case both always give a result that the photographer can use without reasoning independently
- in the seconds the average calculated between the various readings is only an indication that serves to place the readings on the scale, for example in the T90 the arithmetic average is the value that is updated and set to 0 on the scale so as to see at a glance eye the deviations of the other readings, but it is not the exposure to use, it should not be taken as a value to shoot, it is only an ideal value, while the definitive exposure is decided only by the photographer with his brain making personal considerations based on the film and the result he wants to achieve.
Definitely:
Matrix: a single exposure to shoot
Multi-spot: multiple readings for reasoning
 

wiltw

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we have had some various divergent discussions, but coming back to the point of the OP subject...

Has there been any clear outstanding capability identified in any camera, that can outdo the original OM-4 multispot 8-point averaging with biased readings for Shadow and Highlight?
 
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superflash

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wiltw:
There are no better systems but there are alternative systems.
In the OM4 the presets for the highlights and shadows are fixed, while for example in the T90 they are variable and can be fixed by the user within +/- 4EV.
In OM4 each reading with the same value is displayed only once, while in the Minolta Program Back 90 it is possible to view all the readings made (up to 8) even if several have the same value because there is not a scale of values but one graphical representation in 2 dimensions of the measurements visible on a large display and it is possible to fix the zero on the average or on one of the stored readings.
The only unique prerogative of the OM4 which represents an absolute and undefeated record in analog photography is the possibility of measuring in spot automation, with aperture priority, up to -6EV.
 

Chan Tran

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Chan Tran:

Multi-area systems that calculate the average after doing a myriad of calculations have a different purpose than the multi spot:
- the first analyze the scene by measuring the light in many points, then make an average with a ponedazione based on a flood of parameters, but in any case both always give a result that the photographer can use without reasoning independently
- in the seconds the average calculated between the various readings is only an indication that serves to place the readings on the scale, for example in the T90 the arithmetic average is the value that is updated and set to 0 on the scale so as to see at a glance eye the deviations of the other readings, but it is not the exposure to use, it should not be taken as a value to shoot, it is only an ideal value, while the definitive exposure is decided only by the photographer with his brain making personal considerations based on the film and the result he wants to achieve.
Definitely:
Matrix: a single exposure to shoot
Multi-spot: multiple readings for reasoning

I mean if you use a modern Nikon set it to Center Weighted and set the weighted area to full screen it still do a multi spot but average these spot using simple algorithm not a complex one like matrix. The same algorithm the Oly OM-4 would do in multispot.
 

138S

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i believe owner's of Leica R8/9 would beg to differ.

For sure :smile: :smile: :smile: A Leica is like Harley Davidson, regarding owners :smile:

Leica has impressive gear, no doubt. But regarding meter the F5/6 matricial mode plays in another league: 1005 RGB pixels covering all the format, and an exceptionally well trained Neural Network interpreting the scene, the Neural Network was trained with very well selected sample images made for great Pros. From R-G-B evaluation the Network "understands" the scene, it "sees" sky, snow, water, concrete and human skin.. In spot or ponderated mode the thing is quite simple, but such an intelligent system plays another game. Personally I use spot mode and M in the F5, but when there is no time to think then that matricial system does not fail. Other systems oscillate when changing the framing, perhaps you take more luminous sky in the average, the F5/6 do not doubt because it has interpreted the scene and it won't change much exposure because you take more or less sky... a marvel...

The R8 has a 6-segment matrix, may be comparable to the F100 10 segment, but the F5 checks 1005 RGB spots linked to a Neural Network...
 
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