The Ultimate Exposure Computer

Monday317 · May 14, 2016

I hate to be a noob and come up with stuff that is Ancient History to the rest of you, but at the risk of doing so, I thought this would be of interest to the discriminating worker:

The Ultimate Exposure Computer

I have a very wonderful, simple, Zeiss Ercona I that makes beautiful 6 x 9 negs. Almost a metal Holga in its simplicity, it has a very basic viewfinder, Tessar lens, etc. NO METER.

For any daylight situation, I get by starting with the f/16 Rule, and estimate my exposures, which has always worked well. But for night and indoors images, I had to bracket extensively--an expensive proposition with only 8 shots on a roll of film! So I thought about creating a "Massive Exposure Chart" to relate exposure to lighting situation, subject and film speed.

As is always the case, someone else came up with the idea years before and did a better job. I wanted to let others know about it; the web page above covers everything any photographer needs to know about film exposure. Thank you, Mr. Parker wherever you are!

Michael Guzzi · May 14, 2016

Don't forget there are other "noobs" around! Info as this is IMHO always welcome, one can't know too much, right.

RE your Ercona, I too bought one, from the german Ebay "kleinanzeigen" (little ads). They say it's local but many people are willing to send abroad, and the prices are usually better than paid EBay. I paid all of EUR 45,00 for mine, exactly the same as yours, Tessar et al. Waiting for it to arrive atm.

bernard_L · May 14, 2016

Some truth, but many over-ambitious claims that might confuse beginners. Sure, between sunrise+2hrs and sunset-2hrs, one can guess exposure for open-space scenes. But...

covers everything

THROW AWAY YOUR LIGHT METER! Well..... maybe not. But you could if you wanted to.

Can you guess the esposure under heavy tree cover (to make a pic of that nice tree stump and ferns)? Write it down, then bring out your light meter (if you did not follow the previous advice). How far was your guess? When on an outdoors walk, I carry a tripod, even on sunny days, for just that kind of pictures.
Experiment #2. Try to guess the exposure 10 min after sunset... wait... a building facing the sunset? or facing the opposite side? or a street? You can use the wonderful Ultimate Computer. Then chheck with your meter.

On a bright, sunny day, the correct exposure for any subject is f/16 at the shutter speed nearest to the reciprocal of the film speed.

Experiment #3 Greenery, trees, especially but not only conifers... call for f/11. Again, check with your meter if you still have it.

removed account4 · May 14, 2016

hi monday317

that article is right on the money !

ic-racer · May 14, 2016

This exposure calculator from 1942 was pretty complete, perhaps the ultimate. It took into account latitude, longitude, atmospheric conditions, and other variables.

tedr1 · May 14, 2016

Forget calculators, get a spot meter and learn the Zone system (the Pentax Spotmeter V is suitable and inexpensive and a pleasure to use, it accepts a paper zone calibration attachment on the standard dial) you will soon stop bracketing

Monday317 · May 14, 2016

Michael Guzzi said:
Don't forget there are other "noobs" around! Info as this is IMHO always welcome, one can't know too much, right.

RE your Ercona, I too bought one, from the german Ebay "kleinanzeigen" (little ads). They say it's local but many people are willing to send abroad, and the prices are usually better than paid EBay. I paid all of EUR 45,00 for mine, exactly the same as yours, Tessar et al. Waiting for it to arrive atm.

You are going to LOVE the camera!! Hope it has been cleaned, lubricated & adjusted (CLA'd) as the lens motion and shutter may be difficult to use. If they are, you can do the work yourself on this camera without too much trouble. Be careful with the little focal range marker blade by the lens--easy to break off (mine did, but it's not critical). The Tessar is a wonderful lens, you won't miss having wide or tele's. If you get a 37 (sometimes listed as 36.5 on eBay)mm Series VI filter adaptor, you can get a wide range of hoods and filters to use. The adaptor's clips are too long to hold the filter at the lens and require trimming. Here's someone who has done it: Dave Thomas Ercona II

He has an Ercona II, same camera, little fancier top plate and viewfinder, all the rest same as Ercona I--which we both know is cooler, right..?

Enjoy!

Monday317 · May 14, 2016

bernard_L said:
Some truth, but many over-ambitious claims that might confuse beginners. Sure, between sunrise+2hrs and sunset-2hrs, one can guess exposure for open-space scenes. But...

Can you guess the esposure under heavy tree cover (to make a pic of that nice tree stump and ferns)? Write it down, then bring out your light meter (if you did not follow the previous advice). How far was your guess? When on an outdoors walk, I carry a tripod, even on sunny days, for just that kind of pictures.
Experiment #2. Try to guess the exposure 10 min after sunset... wait... a building facing the sunset? or facing the opposite side? or a street? You can use the wonderful Ultimate Computer. Then chheck with your meter.

Experiment #3 Greenery, trees, especially but not only conifers... call for f/11. Again, check with your meter if you still have it.

Well in daylight, I have been about 90% successful in getting shots right under most conditions without bracketing. I confess, I most often shoot Acros at box speed, which is very forgiving. My worries have been indoors and nights, with which this article was very helpful. I'm working on making a spreadsheet to compress, laminate and stick in the old nylon lunch bag that holds my stuff (very conveniently, I might add for all you Hasselblad/Mamiya snobs... ) so I'm hoping to lust after an old Pentax Digital no more.

Monday317 · May 14, 2016

tedr1 said:
Forget calculators, get a spot meter and learn the Zone system (the Pentax Spotmeter V is suitable and inexpensive and a pleasure to use, it accepts a paper zone calibration attachment on the standard dial) you will soon stop bracketing

Did you actually go to the website? The point was to not have to rely on a meter.

As Mr. Parker wrote, all a meter does is give you an EV for the film speed you tell it, when pointed at something, to render a Zone IV on the negative. The purpose of TUEC is to tell us how to do that--and more--without a meter. Parker suggests, as I have long believed, that a meter is something of a crutch that isn't needed in most cases if the photographer truly understands how light, film and camera relate.

As for professional illustration and portraiture, I couldn't say. The little bit I have done myself was all by eye with some bracketing and went fine. Since the bulk of such work is digital now, the question thereupon is IMHO, moot.

I am well up on the Zone System, and the intricacies of exposure. It simply occurred to me from a purely technical standpoint, that for any given film speed, any Zone placement will require some quantifiable EV that could be used to determine aperture and shutter speed for a given circumstance. Once that was known, you could chart out EVs for anything, then just sweat reciprocity for long exposures. Fred Parker did the work I was going to undertake three years ago.

The Internet is a wonderful thing...

Monday317 · May 14, 2016

ic-racer said:
This exposure calculator from 1942 was pretty complete, perhaps the ultimate. It took into account latitude, longitude, atmospheric conditions, and other variables.

I've seen that before, thank you. A good technical tool, I grant you, but I feel TUEC is a more practical tool.

If you are familiar with the work of Ansel Adams, you may recall his image titled Moonrise Over Hernandez, New Mexico. He related that he had only a brief few moments to set up for the shot as the sun lighting the crosses was setting rapidly. He didn't have time to meter, but recalled the correct EV for the rising moon and made the exposure based on that--with a #25 Red filter to boot. The sun set before he could make a backup exposure.

That's a classic illustration of what is so great about this tool: you could shoot a child blowing out a birthday candle in the dark, or get the fur on a polar bear in the snow on a cloudless day, both exposed correctly, color or monochrome--using nothing more than your brain.

Photography at its simplest, if not best!

Michael Guzzi · May 14, 2016

Monday317 said:
You are going to LOVE the camera!! Hope it has been cleaned, lubricated & adjusted (CLA'd) as the lens motion and shutter may be difficult to use. If they are, you can do the work yourself on this camera without too much trouble. Be careful with the little focal range marker blade by the lens--easy to break off (mine did, but it's not critical). The Tessar is a wonderful lens, you won't miss having wide or tele's. If you get a 37 (sometimes listed as 36.5 on eBay)mm Series VI filter adaptor, you can get a wide range of hoods and filters to use. The adaptor's clips are too long to hold the filter at the lens and require trimming. Here's someone who has done it: Dave Thomas Ercona II

He has an Ercona II, same camera, little fancier top plate and viewfinder, all the rest same as Ercona I--which we both know is cooler, right..?

Enjoy!

Yep! I chose it because it looks classier(IMO) than the II. And I went Ercona because they shoot 6X6 AND 6X9.
I noticed yours has a Tempor Shutter, mine has a Compur Rapid. It has not been CLA'd but that doesn't worry me. And I have an original Zeiss yellow filter to go with it. That lens shade looks good! Thanks for the link! With that and the link on the original post I'm all set!

I'll still take my spotmeter along though, just in case!

LJH · May 14, 2016

I can also ride a horse to my location and listen to a wax gramophone in the darkroom. Yet I don't as there are much better options available.

At $20 per sheet of 8x10 E6, I'll stick to a spot meter and not flagilate with this antiquated process.

DWThomas · May 14, 2016

Monday317 said:
[ . . . ] If you get a 37 (sometimes listed as 36.5 on eBay)mm Series VI filter adaptor, you can get a wide range of hoods and filters to use. The adaptor's clips are too long to hold the filter at the lens and require trimming. Here's someone who has done it: Dave Thomas Ercona II

He has an Ercona II, same camera, little fancier top plate and viewfinder, all the rest same as Ercona I--which we both know is cooler, right..?

Enjoy!

Thanks for the mention (I think ... ). The adapter fingers aren't too long, but rather too thick, so I thinned them a bit in a hobby lathe AKA an ancient "Unimat." On my Ercona at least, there is one setscrew that protrudes into that groove where the 37mm filters go, so I filed the rounded notch seen in those pictures to clear it. No idea if all were like that or maybe mine had a substitute screw put in. It came CLA'd from certo6 and gives a decent account of itself -- I'm thinking the II has double exposure prevention but that's hardly a major deal maker/breaker either way. Both models were post WW-eye-eye, as "Ercona" was in response to lawsuits over the East German remnants of Zeiss using the Ikonta name (if I understand it all). And I think the I and the II are only a few years apart.

I also obtained a step-down adapter with a 40.5mm female thread which I tried as a coupling to fit a 52mm adapter on to the outside of the lens barrel. It's not all that obvious, but in what looks like knurling on the lens barrel there is actually a thread. I probably won't go with that approach, as there is so little thread engaged I fear it might not stay attached reliably. The ultimate cool thang might be to have a shade that screws on to the outer thread, and be able to plug push-on filters in independently. I do have a couple of push-on filters, as well as two "closeup" lenses, but in general 37mm push-ons are rare as hen's teeth and $$$$. Of course, the camera won't close with much of anything on the front either.

I don't have the 6x6 mask, so mine is strictly for when I have 6x9 urges (the Perkeo II, Yashica 124G or the Bronica SQ-A handle 6x6 nicely, choice dependent on circumstances).

MattKing · May 14, 2016

ic-racer said:
This exposure calculator from 1942 was pretty complete, perhaps the ultimate. It took into account latitude, longitude, atmospheric conditions, and other variables.

My god, ic-racer has turned into Stephen Benskin!

Doremus Scudder · May 15, 2016

IIRC, Ansel Adams missed the exposure on "Moonrise" by quite a bit and considered the negative very difficult to print because of the severe underexposure. And, it wasn't as if he didn't use a meter; he used one religiously, it's just that he couldn't find the meter fast enough (he had misplaced it) for "Moonrise" and had to wing it. He would have preferred to have metered and got a better-exposed negative.

I'll stick with my spot meter as well. Although the general idea of finding an EV for every situation is intriguing, I find myself often enough in situations with strange lighting that I wouldn't feel confident without checking with the meter.

Best,

Doremus

Monday317 · May 15, 2016

Michael Guzzi said:
Yep! I chose it because it looks classier(IMO) than the II. And I went Ercona because they shoot 6X6 AND 6X9.
I noticed yours has a Tempor Shutter, mine has a Compur Rapid. It has not been CLA'd but that doesn't worry me. And I have an original Zeiss yellow filter to go with it. That lens shade looks good! Thanks for the link! With that and the link on the original post I'm all set!

I'll still take my spotmeter along though, just in case!

Lucky hound!

The Compur Rapids were what they had been using before the division. The Tempors were what they designed after they ran out of Compurs. What's your speed range? The Tempors go from B to 1/250. Good for general work, but I find them a bit slow over 1/60 and must use a tripod and cable release to keep details clear. The plus side is they are sturdy and relatively easy to maintain.

Great for you!

Monday317 · May 15, 2016

LJH said:
I can also ride a horse to my location and listen to a wax gramophone in the darkroom. Yet I don't as there are much better options available.

At $20 per sheet of 8x10 E6, I'll stick to a spot meter and not flagilate with this antiquated process.

Well, yeah. E-6 can be a little tricky, though I have shot a couple rolls of Rollei 200 with no trouble--in daylight. I believe TUEC could get you a start for nighttime work BUT, you'd want to practice with the same film in 35mm to get the reciprocity correct. I agree with your economic concerns; have to watch my budget as well!

Poop on the wax cylinders though: a cassette player will give great analog audio!

Monday317 · May 15, 2016

DWThomas said:
Thanks for the mention (I think ... ). The adapter fingers aren't too long, but rather too thick, so I thinned them a bit in a hobby lathe AKA an ancient "Unimat." On my Ercona at least, there is one setscrew that protrudes into that groove where the 37mm filters go, so I filed the rounded notch seen in those pictures to clear it. No idea if all were like that or maybe mine had a substitute screw put in. It came CLA'd from certo6 and gives a decent account of itself -- I'm thinking the II has double exposure prevention but that's hardly a major deal maker/breaker either way. Both models were post WW-eye-eye, as "Ercona" was in response to lawsuits over the East German remnants of Zeiss using the Ikonta name (if I understand it all). And I think the I and the II are only a few years apart.

I also obtained a step-down adapter with a 40.5mm female thread which I tried as a coupling to fit a 52mm adapter on to the outside of the lens barrel. It's not all that obvious, but in what looks like knurling on the lens barrel there is actually a thread. I probably won't go with that approach, as there is so little thread engaged I fear it might not stay attached reliably. The ultimate cool thang might be to have a shade that screws on to the outer thread, and be able to plug push-on filters in independently. I do have a couple of push-on filters, as well as two "closeup" lenses, but in general 37mm push-ons are rare as hen's teeth and $$$$. Of course, the camera won't close with much of anything on the front either.

I don't have the 6x6 mask, so mine is strictly for when I have 6x9 urges (the Perkeo II, Yashica 124G or the Bronica SQ-A handle 6x6 nicely, choice dependent on circumstances).

Hey Davidus Magnus,

First, thank for sharing all that good dope on all things Ercona! You de man!! You wouldn't think there that many aficíons Erconais out here, but there you go.

Second, yessir, the blades are quite thick; I butchered mine with a Dremel tool--but they work fine. I can use Series VI filters, hold down ring and aluminum lens hood without fear of everything falling off, unless I were sprinting down Mt. St. Helens trying to keep ahead of a pyroclastic flow...

Third, I have the 6 x 6 mask for the Ercona, and never use it. For the price of a new Porsche, it can be yours...

Monday317 · May 15, 2016

Doremus Scudder said:
IIRC, Ansel Adams missed the exposure on "Moonrise" by quite a bit and considered the negative very difficult to print because of the severe underexposure. And, it wasn't as if he didn't use a meter; he used one religiously, it's just that he couldn't find the meter fast enough (he had misplaced it) for "Moonrise" and had to wing it. He would have preferred to have metered and got a better-exposed negative.

I'll stick with my spot meter as well. Although the general idea of finding an EV for every situation is intriguing, I find myself often enough in situations with strange lighting that I wouldn't feel confident without checking with the meter.

Best,

Doremus

You are correct: he failed to add a bit for the Red filter--shoulda checked that again. He under exposed nearly two stops, then burned a corner later on, during the lab fire. Didn't they learn after the Library of Alexandria..?

Being married to roll film, I feel confident in not sweating a meter any more. That said, each to their own, particularly you large format folks. Bracketing isn't really an option thereupon, unless you work with 35mm first to get the response down pat.

Been told by one bugshutter that B & W is a crutch for those not willing to learn C-41/E-6 at home, which I felt was complete male bovine excrement, so meter away with no sneer curling this lip.

tedr1 · May 15, 2016

Monday317 said:
Did you actually go to the website? The point was to not have to rely on a meter.

I did now, and I'm skeptical, someone who has to rely on phrases like "your light meter is lying to you" is working with emotions in an area where facts are needed.

Building an internal mental model of the light levels found in available light is something many photographers do, without it being a "EUREKA" moment, it happens over time with experience. Negative film is forgiving of exposure errors nevertheless I know how to use my "lying" exposure meter and will not be selling it anytime soon.

Stephen Benskin · May 15, 2016

The Ultimate Exposure Computer of Fred Parker looks to me to be derived from The ANSI standard Photographic Exposure Guide ANSI PH2.7 - 1986. Which is itself derived from Loyd Jones' work and subsequent paper Sunlight and Skylight as Determinants of Photographic Exposure. It has been said that if the guide is carefully followed and a meter disagrees with the guide, the meter is probably wrong. The exposure meter standard references Jones' paper, so the two are closely related.

BTW, if ic-racer is me, then who am I.

Monday317 · May 15, 2016

tedr1 said:
I did now, and I'm skeptical, someone who has to rely on phrases like "your light meter is lying to you" is working with emotions in an area where facts are needed.

Building an internal mental model of the light levels found in available light is something many photographers do, without it being a "EUREKA" moment, it happens over time with experience. Negative film is forgiving of exposure errors nevertheless I know how to use my "lying" exposure meter and will not be selling it anytime soon.

To be fair, building the mental model of which you speak is part in parcel what TUEC is for!

I agree with your point about negative film--particularly Acros which, in its own way is something of a crutch, being as advanced as it is.

As to Parker's hyperbole, I think it was written so as to give some shuttersbug paths to a Eureaka! moment, if they were open to it. As stated by others wiser than I, "You can lead a horse to water, but you can't teach him new tricks...", or words to that effect.

Monday317 · May 15, 2016

Stephen Benskin said:
The Ultimate Exposure Computer of Fred Parker looks to me to be derived from The ANSI standard Photographic Exposure Guide ANSI PH2.7 - 1986. Which is itself derived from Loyd Jones' work and subsequent paper Sunlight and Skylight as Determinants of Photographic Exposure. It has been said that if the guide is carefully followed and a meter disagrees with the guide, the meter is probably wrong. The exposure meter standard references Jones' paper, so the two are closely related.

BTW, if ic-racer is me, then who am I.

You know, I think you're correct, sir. Seems I ran across material of that sort in the late '70s-mid '80s when I was fooling around with sheet film meself, thinking at the time, "Who needs a f@#$%^g meter, if you know this stuff..?". Then went ahead and bought a Zone VI-modified Pentax Digital spot meter anyway; such meatheads we are before reaching 30...

BTW, I dunno who you are, but your name's been bantered about in a positive way. Got me beat; I think Paul Simon heard my story and wrote a song some years back, involving some goof named Julio...

Monday317 · May 15, 2016

Here's some light reading for the casual shutterbug:

APEX System-Wikipedia lots historical & technical exposure poop

Exposure Value-Wikipedia restatement of ANSI dope

Bill Burk · May 15, 2016

ic-racer said:
This exposure calculator from 1942 was pretty complete, perhaps the ultimate. It took into account latitude, longitude, atmospheric conditions, and other variables.

Haa, My dad's going to Washington D.C. this June. Maybe I'll take an old Pentax Spotmatic, set the shutter at 1/60, the f/stop at f/16 and load it with a roll of Panatomic-X for him...

The Ultimate Exposure Computer

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