Zone VI modified Pentax Meters

The recent thread on meters has got me thinking again about the Zone VI modification of Pentax spot meters. I understand the theory of the modification (I think), but have always wondered about the practical difference it makes. Has anyone ever taken a modified and unmodified meter and compared readings? Are they really different? If so, how much?

The best investment I ever made was getting my Soligor 1 degree

meter overhauled by Zone VI, if I remember right the difference

between my calibrated meter and before was a stop and 1/2. Well

work the money, oh, by the way, if you get one, get a pistol

lanyard for it, so you don't drop it like my friend did, cost him

almost 6 big ones to get it replaced. Pat

While the idea of the calibrated meter is nice, what film are you

going to use with this meter? Not all films have the same response to

light. Will they tell you what films spectral characteristics the

meter is calibrated to? And if they will recalibrate it if the film

maker re-formulates the film you use?

If someone sends in a meter and when it comes back it now reads 1 1/2

stops different than before there was something wrong with the meter

when it was sent in. Quality Light Metric most likely could have

repared it for less than a re-do to change the light reading

characteristics. But, if the meter, even if 1 1/2 stops off, was

linear in its readings and was repeatable in the 'error', it was

easily usable as you would change your ISO ratings for shooting &

processing film as you do a bit of simple testing to refine your

meter/camera/lens/ film combinations.

While the idea of these meters is nice, we have a lot of good

photography taken without them, both before and after they have come

on the market. If you want, get it, and if it helps your photography

in any way then it was probably worth it. I think spending the few

hundred dollars on film and going out to photograph while learning to

use the meter as is is probably of more benefit than getting another

meter or changing yours.

What Zone VI does is:

 

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1. Add a filter to prevent IR from hitting the photocell.

Phototransistors and photodiodes are sensitive to IR, and film

(except IR films) are not. To me this alone is worth the mod, and may

be the biggest factor in why the modified meters respond differently

than un-modified ones.

 

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2. They put a filter in that matches the response curve of Tri-X. As

far as I know, they do not offer other film matching curves. Tri-X

isn't a bad choice, since its spectral response is typical of most GP

(general purpose) b&w films. Just remember this if you're shooting a

film with extended red sensitivity (like Tech Pan), reduced Blue

sensitivity, or other unusual spectral response.

 

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3. They add additional flare control baffles & paint.

 

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4. They replace the photocell with one they like better (more

sensitive).

 

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5. They calibrate the meter with the new cell and modifications.

 

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Just calibrating and repairing the meter will not produce the same

results. The end result is a meter that give more consistent and

accurate readings.

 

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I know of no meter manufacturer that says they filter out the

unwanted IR light. It would be easy for them to do, but apparently

they just don't the practical issues.

I agree with Dan's comments about meters in general. Most meters will

help you to get a good exposure and learning to use it properly is

all that is really needed. After ten years with the same spot meter I

decided to buy a new one as a present to myself and I chose the Zone

VI. I did compare color response by metering threw different filters

and exposing threw those filters for a Zone V exposure. My old meter

made correct exposures with some of the filters but was as far off as

2 1/2 stops with some. The Zone VI on the other hand was right on the

money with most and as far off a 1/2 a stop on one. I did these tests

with T-Max and Tri-X. If I were making the decision again, I would

still choose the Zone VI but it will not make you a better

photographer and that is really what it is all about.

Interesting post found on the rec.photo.equipment.large-format news

group

 

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SNIP Richard Henry conducted and published a test on spot

meter flare. A white surface was illuminated to read EV15. A large

black

card board mask was placed over this surface exposing a 2.5" diameter

hole....SNIP

 

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After reading your thorough and scientific approach to this problem I

will not

try to challenge anything you've done, but to add my limited

experience I'll

mention this: I just returned from a workshop and was working next to

someone

else who had a zone vi modified meter, while I had the un-modified

one. We

each measured the same elements in the scene, to see if we got

readings that

agreed. Red metal roof, green leaves in the sun and in the shade,

dry yellow

grasses in the sun, a blue sky, the beige side of a cement building,

the sky

again pointing the meter towards the sun. In every case we got the

same

readings. This is how we would be using our meters in the real world

and they

agreed. Perhaps in strict laboratory conditions they might not, but

in the

field they did. If modifying your meter gives you peace of mind so

that you

are not distracted from picture making then mofdify. I've always had

this

nagging thought that the my photos would be so much better if my

meter was

modified. It seems that that suspicion has been laid to rest and I

need to

look elsewhere to improve my photos. Probably it has nothing to do

with

technique, but rather personal vision.

Just another opinion.

I recently purchased the Zone VI modified meter after using a Pentax

Spot Meter V (analog) for a couple of years. I gave the Spot Meter V to

my son. We shot side-by-side the last three weeks while on vacation. In

all situations our meters agreed on the EV. Maybe I should have asked

Dan's advice first and saved some money, but I do like using that

little modified meter and plan to keep it a long, long time.

I never quite got the need for IR filtration when most films are not

sensitive to that part of the spectrum. And Fred never said anything

about the more energetic end of the spectrum. The Ultraviolet or blue

wavelengths. Wouldn't they create flare the same way as Fred said IR

does? I have never seen the major differences between his meters and

the ones the rest of us use. And I've seen a lot of meters in the

bush. Negative materials should be exposed to a calibrated system and

if that system is calibrated to one of Freds meters or a different

kind, the negs will respond by giving a good rendition of the scene.

It's all relative. James

Here's an example of IR having a serious effect; a few years ago I was metering the obligatory sunset shot with a Minolta Spotmeter F, and where the sun was hidden behind dense clouds caused an increase in the reading of about four stops.

 

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The exact location of the sun's disc was completely hidden by cloud.

 

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The solution of course was simply to not meter that spot. <g>