Spotmeter used as densitometer?

[markus.heinisch]

Hello,
can I use a spotmeter (Minolta Spotmeter F) as a densitometer to determine the densities of my negative. I want to calibrate my film/developer/camera combination (Fuji Neopan 400/Rodinal/Pentax67) according to the zone system.
I messured the following F-stops deltas:
Zone 0: 0.0 (I accually messured a value, but Zone 0 is the fog base and set to 0)
Zone 5: 2.1
Zone 8: 4.1
Is there a calculator to convert F-stops or Ev into densities?

Cheers, Markus

 

[ic-racer]

Yes.
Convert F-stops to log density by multiplying by 0.3.

So one F-stop is 0.3 log density.

So, your Zone I should be 0.1 log which is one-third of an F-stop.
Your Zone 8 is 1.23 log d. You could plot out the whole curve and check the gamma or slope of the straight part.

 

[Chan Tran]

I have tried but without much success. May be because I am a 35mm shooter and my neg is too small. 1 stop is about 0.30 density. It's the log(2). So simply D=EV*0.30.
Your reading seems right.

 

[Shaggysk8]

Could you not run a roll of film at each different zone and check that with the meter? then it should work, then you could print each flat zone to get the prints right? just a thought, I might be wrong

 

[michaelbsc]

can I use a spotmeter (Minolta Spotmeter F) as a densitometer to determine the densities of my negative.

Check out "Beyond the Zone System" for this. There's a pretty good discussion of exactly how to do it, but you can mod it to meet your needs.

 

[markus.heinisch]

Thanks for your tips!
Is it really that simple??
Great!!

Cheers, Markus

 

[Mike Wilde]

Could you not set an enlarger to fixed head height, same bulb, same lens on enlarger and aperture, same condenser height/set, same dichroic settings - ie standardized light source, and then read light vaules off a baseboard to get this to work with 35mm?

 

[Denis K]

Check out this thread on APUG:

(there was a url link here which no longer exists)

Consider also getting a step wedge and doing a simple visual comparison on a light table.

Denis K