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?

-- Chris Patti (cmpatti@aol.com), July 01, 2000

Answers

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

-- pat krentz (patwandakrentz@aol.com), July 01, 2000.

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.

-- Dan Smith (shooter@brigham.net), July 02, 2000.

What Zone VI does is:

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.

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.

3. They add additional flare control baffles & paint.

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

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

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.

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.

-- Charlie Strack (charlie_strack@sti.com), July 03, 2000.

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.

-- Jeff White (zonie@computer-concepts.com), July 03, 2000.

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

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

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.

-- Sean yates (yatescats@yahoo.com), July 04, 2000.

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.

-- Darron Spohn (dspohn@photobitstream.com), July 10, 2000.

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

-- james (james_mickelson@hotmail.com), July 11, 2000.

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.

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

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

-- John Hicks (jbh@magicnet.net), July 11, 2000.