What is the Zone VI modified pentax spotmeter?

[walter23]

What's the modification here? These things go for a small fortune on ebay, and the only noticable thing is the little zone system paper strip that's always taped to the barrel. Anybody know what this modification is?

[David Karp]

Check the archives on this one. There have been a ton of postings on this, and different perspectives on whether the extras on the Zone VI version are worthwhile.

[Eric Woodbury]

The modification results in the meter 'seeing' the same as BW film, thus metering through filters for proper filter factors is possible and metering scenes with strong color accurately. Additional baffles were once included, too, to increase contrast in tough lighting situations. I believe the modifications have changed over the years, but if this changed the result, I do not know.

Photogs I know considered the extra cost worth it.

[Peter Lewin]

Here's a pretty good article by Paul Butzi on the Z6 Modified Meter. As an earlier poster mentioned, there are different opinions on whether the modifications are effective, so Mr. Butzi's view may be contradicted by others. For what its worth, I have and use the modified meter, but I've never tested it against an unmodified Pentax. http://www.butzi.net/articles/zone%20VI%20worth%20it.htm

[Kirk Gittings]

You will note in Butzi's update of his article http://www.butzi.net/articles/zone%20VI%20reprise.htm (http://www.butzi.net/articles/zone%20VI%20reprise.htm)
numerous references to my claims that the modifications are worth it. Understand, I am a working photographer and I have no time for equipment that doesn't perform, but because I am an actual working photographer I don't have the time (or the interest) to respond in kind to Paul's extensive testing. Mine work as per Alan Ross' claims and that is enough for me. I currently have two, one modified and one originally was regular when I got it. The modified out performed the regular so I had it modified too. It now works as well as the originally modified one. These are the 4th and fifth Pentax Spot meters I have owned and the only ones modified. They do the job. I can now meter accurately thru filters which I could not do as well on any of the unmodified meters. If these were stolen, I would replace them with ZVI modified meters.

Personally, in photography, when I am confronted with contradictory technical information, I look at the actual work of the claimants. Alan Ross and Richard Ritter are perfectionists and it shows in their work. They also have no time for crap that doesn't do the job.

[Brian Ellis]

The paper strip has nothing to do with the Zone VI modifications. The strip can be bought from Calumet (or used to be, I haven't checked to see if they still sell it or not) for about $5 and is just an easy way of applying the zone system with this meter. The modifications, on the other hand, involve physical changes to the meter. Here's what Zone VI Studios said they did in making the modifications: Installation of superior photo-electric cells; installation of a series of step-down baffles to eliminate flare; installation of a braod-spectrum (ultra-black) infrared absorbent coating to eliminate reflections; design and installation of four corrective filters, intended to match the meter's spectral response to the spectral response of the film.

I've owned used a modified Pentax digital spot meter for many years. I have no idea whether it performs better than an unmodified meter. I accepted Zone VI Studio's claims for it on faith.

[Helen Bach]

Is there anything preventing someone from offering a DIY version of the spectral response modifications? Would there be any demand for such a kit, perhaps for a different meter? You wouldn't have to reverse engineer a Zone VI meter, all you would have to do is to decide which B&W film to imitate, and you would only have to do it approximately.

Best,
Helen

[davidb]

I owned 3 meters at one point in time. All Pentax digital spot meters, one being modified. I believe it was modified about 10 years ago or so. The only difference I saw between them was the Z6 meter showed 2/3 stop difference between the others. I was given a very odd explanation for this including a line about the true speed of Tri-X (please don't ask). I've sold off two of the meters. Now I only use the unmodified meter that I bought new. My negs are as good as ever.

[walter23]

Is there anything preventing someone from offering a DIY version of the spectral response modifications? Would there be any demand for such a kit, perhaps for a different meter? You wouldn't have to reverse engineer a Zone VI meter, all you would have to do is to decide which B&W film to imitate, and you would only have to do it approximately.

Best,
Helen

There are probably scientific / optics companies that could build you a custom filter with the right spectral transmission characteristics. Might be fairly expensive though, and I bet there would also be an electronics correction (ie, a hard wired exposure correction) in the meter because there would probably be an overall loss of light from such a filter.

Anyway, now it makes sense. For awhile I honestly thought maybe the "Zone VI" modification was just taping a zone strip to the barrel for convenience and that people were being suckered or something ;)

[Ole Tjugen]

... design and installation of four corrective filters, intended to match the meter's spectral response to the spectral response of the film. ...

Which film? And would it be equally well matched to other films?

All BW films have slightly different spectral response. IMO it makes more sense to learn the characteristics of the film you are using than to buy a meter perfectly matched to one specific film.

[Per Berntsen]

Which film? And would it be equally well matched to other films?

I believe it was designed to match Tri-X 4 x 5. (Fred Picker's favorite) I have been using it with T-Max 100 4 x 5 with great success for many years. When the T-Max films came out, I remember that they would render a blue sky darker (more natural-looking) than any other film I'd used. So that may be the biggest difference between these two films. In general, I would have thought that the differences in spectral response between films would be negligible when using this meter.

The best thing about the Zone VI Modified in my opinion, is that its response to green (at least in nature) is much more correct than an unmodified meter. Before I got this meter, I was using an umodified one, and grass and foliage would often come out about 1 zone darker than expected. The modified meter would provide a correct reading of these subjects, and I could adjust exposure and/or development to get what I wanted.
Another advantage is that this meter will give a correct reading through strongly colored filters.

[Bruce Barlow]

Fergeddabout modifying a meter yourself. It's not an easy job, nor can you acquire a filter pack (yes, it's multiple filters) from any source for a price less than the cost of a modification (if, in fact, you can still get meters modified).

Richard Ritter just investgated the cost of getting a supply of filter packs, in case Calumet would grant him permission to do modifications (looks like they're going to stop doing it). He couldn't afford them. Neither could I, based on what he said the optical company was asking.

Plus, after the modification, the meter has to be calibrated, requiring a known reference light source and the skill to know what to do.

By the way, any Pentax Digital will "drift" over time, needing recalibration. Richard Ritter does that. He keeps mine in trim, and I know Hollywood guys send him multiples to calibrate and align so thay all read the same.

Life would be much harder without my modified meter and my Compensating Developing Timer. I don't know if Butzi's position is accurate. I do know that I have total peace of mind in the field, and I never have to worry that it MIGHT be inaccurate.

[Helen Bach]

Which film? And would it be equally well matched to other films?

All BW films have slightly different spectral response. IMO it makes more sense to learn the characteristics of the film you are using than to buy a meter perfectly matched to one specific film.

Yes, it appears to be possible to get well exposed pictures with unmodified meters.

The differences in the spectral responses of B&W films are most marked at the red end of the spectrum, which is probably the most critical end for metering through filters. Making the blue end of the meter's response more like that of film, and removing the green peak could be worthwhile though. (Side note: when you look at the spectral sensitivity of B&W film you need to bear in mind that Kodak publish equal energy curves, and almost everyone else publishes wedge spectrograms made in tungsten light. This leads to a very different shape, and comparing the two can be very misleading.)

My musings on a DIY kit were just musings. Is there a demand? I wasn't asking from a commercial viewpoint, but because it would be an interesting side project. I have modified a Pentax Digital Spotmeter to mimick HIE. Even expensive filter material is cheap for the amount needed to modify a meter - you just need to share out bits of the 50 mm squares among your friends. Deciding on the filter pack isn't rocket science. I wrote some software a while ago for designing optimum filter packs for another purpose, but it could be adapted for mimicking film spectral response using commercially available filters. Finding time is a different matter, of course, and if nobody wanted it, not even me, I wouldn't take this any further. I don't wish to tread on anyone's toes either.

Best,
Helen

[naturephoto1]

I have used my Zone VI modified Soligor Digispot II since 1987? very successfully with transparency film.

Rich

[Alan Rabe]

"I believe it was designed to match Tri-X 4 x 5."
IN another thread by Richard Ritter he debunks this claim. It is true that Fred said to do it to Tri-x but they knew better and did an average of all the primary films available at that time.

[Mark Sampson]

As far as the "calibrated for which film" question goes, it's worth noting that the respsonse of the standard CdS cell is off by a mile compared with any film; so the "inches" difference between various (panchromatic) b&w films is functionally irrelevant. To quote Paul Caponigro; "if you're measuring to that level, you're living inside a test tube".

[Brian Ellis]

Which film? And would it be equally well matched to other films?

All BW films have slightly different spectral response. IMO it makes more sense to learn the characteristics of the film you are using than to buy a meter perfectly matched to one specific film.


Supposedly it's matched to Tri X. I've never done any testing with the meter so I don't know for sure whether it would be equally well matched to other films. However, I don't use Tri X, I use TMax 100 and HP5+, and it seems to work fine with both of them. The original question was "what's the modification" and nobody had actually answered that question. So I listed the things that Zone VI Studios said they did in making the modifications. I deliberately avoided commenting on the merits of the modifications since I don't really know, never having tested a modified vs an unmodified meter (I did skim Paul Butzi's article some time ago but wasn't sufficiently interested to really study it). But if it makes more sense to you to learn the characteristics of the film you're using rather than using a modified meter then that's certainly fine for you.

[Kirk Keyes]

I wrote some software a while ago for designing optimum filter packs for another purpose, but it could be adapted for mimicking film spectral response using commercially available filters.

Helen - can I get a copy of your software?

I would love a DIY kit for this. I've done some spectral scans of a few different meters and there as differences between different models especially response to IR. (my scans went from 320 to 900 nm.) I've yet to scan a modified Pentax meter though to compare.

I've looked into the Zone VI mods and they say there are 4 filters. I can't remember what 3 of them do, but one is an IR blocking filter. I suspect that a magenta filter is used to level out the high green response that many meters have.

Kirk

[Kirk Keyes]

Plus, after the modification, the meter has to be calibrated, requiring a known reference light source and the skill to know what to do.


It doesn't really have to be calibrated to a known light source.

As long as you don't care for "absolute" accuracy, you could just slap a correctoing filter pack on the meter, and then do a film test with that meter making the expsoure determination, and that would give you an EI that would work for that meter and film. Just don't expect it to be very close to box speeds depending on how much filtration you've added.

[Helen Bach]

Helen - can I get a copy of your software?

Kirk,

Yes. I'll have to remove some information that isn't mine to give away but otherwise there should be no problem.

Best,
Helen

[Bruce Barlow]

It doesn't really have to be calibrated to a known light source.

As long as you don't care for "absolute" accuracy, you could just slap a correctoing filter pack on the meter, and then do a film test with that meter making the expsoure determination, and that would give you an EI that would work for that meter and film. Just don't expect it to be very close to box speeds depending on how much filtration you've added.

My understanding, having watched Richard do it many times, is that he adjusts high, medium and low response to ensure linearity. The meter has different adjustments for each. For that, he uses a known, calibrated light source. After that, yes, you should do an EI test for your film.

I have now exceeded everything I know on the subject.

[Kirk Keyes]

Kirk,

Yes. I'll have to remove some information that isn't mine to give away but otherwise there should be no problem.

Best,
Helen

Thanks, Helen!

Kirk

[Kiron Kid]

What's the modification here? These things go for a small fortune on ebay, and the only noticable thing is the little zone system paper strip that's always taped to the barrel. Anybody know what this modification is?


My Soligor (Zone VI modified) is extremely accurate.

Kiron Kid

[Peter De Smidt]

Recently, I tested a Hoya RM72 infrared filter for use as a very strong neutral density/red filter with regular bw film. Metering through the filter with a ZVI modified PDM gave a result 5 stops lower than the regular PDM. So one thing the ZVI meter has is a strong IR blocking filter.

[Turner Reich]

My Soligor (Zone VI modified) is extremely accurate.

So is mine, purchased directly from Fred Picker, Putney Vermont, it has never failed to give the correct reading regardless of the color of the subject. Reads through filters also.

[ljsegil]

My meters, modified or not and I do use both types, don't fail me. I do. Ultimately I must use their provided information appropriately, and that ability is what separates a good photographer who works with the scene in front of him, and the information available to him, from a gearhead novice (like me). All the precision data in the world, modified or otherwise, won't help my images if I cannot learn to see. I find that much harder than examining a metered reading, and my learning curve does reflect that final truth. I don't believe there is a device made that will substitute for the growth that only experience provides, and for which I need to continue to strive (Zone X modified self, maybe? Don't think it will market well, and don't yet know all the necessary ingredients either).
Larry

[William McEwen]

Here is a page devoted to the meter, by someone who tested it:
http://www.butzi.net/articles/zone%20VI%20reprise.htm

(Since I'm relatively new to the forum, I haven't seen this discussed, although my guess is it has already been covered....)