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05-27-2014, 11:37 AM   #136
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QuoteOriginally posted by jsherman999 Quote
Please, please, please read the JJ link and Falk Lumo's paper. If you want, I can supply some dpreview threads where those authors engaged in some explanations as well.
I'll only say it once, as I don't believe you are listening anyway: I read Falk Lumo's paper quite some time ago. I read most of JJ's article, and I understand his point.
You know what' s funny? I see you have no issue with the video contradicting JJ's article; and you're not insisting that Tony should read it.

QuoteOriginally posted by jsherman999 Quote
And so it is with equivalence. You have no choice in the matter - it's the way it is.
You are gravely mistaken. The "equivalence" in its most acceptable form is nothing more than a convention that 5 parameters can decide if an image can be called "equivalent" or not. JJ is actually saying:
"We can compare systems in many different ways. The five parameters of Equivalence (same perspective, framing, DOF, shutter speed, and display size) are simply guidelines to comparing systems on the basis of the most similar visual properties of the final photo, and are certainly not a mandate that systems must be compared in such a fashion. Therefore, it is important to specify the purpose of the comparison, and then not artificially handicap one or the other system with the conditions of the comparison."

05-27-2014, 11:47 AM   #137
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QuoteOriginally posted by ElJamoquio Quote
I don't think one-format-only shooters should ignore it. Or at least, people new to any format shouldn't ignore equivalence. People who are buying a camera should know what capabilities they're getting and why.
I was thinking more of folks who know what they have already (aps-c,) know how to make the most of it and just don't ever plan to buy FF or m43. And by 'ignore' I don't mean 'actively deny it exists' , I mean 'ignore' - bypass discussions, don't worry about it.

That's what I did the first few years I shot aps-c DSLR, I was aware of 'equivalence' but barely cared. It was only when I started thinking about an upgrade from a K20D/D90 to a D300 when I started looking into lens capabilities so I could get the most for my money - knowing about equivalence probably actually saved me some money and got me a better system (for me) than what I would have been able to put together around a D300. To have had a FF Pentax available during that time would have been nirvana and would have saved me even more, as I already had the FA Limiteds then

(Had I personally known about equivalence before I bought aps-c it wouldn't have mattered anyway - to me - I was on a specific budget in 2006-2007 that didn't cover the lowest-end FF body. That's not to say everyone's in the same boat as the 2006-me, many people might have cared and made the budget stretch for the body to save on the lenses.)

.

QuoteQuote:
Knowing equivalence will kill the 'you should get a smaller format because it combines large DOF with low noise' myth.... that otherwise will never die.
That's a particularly bad and potentially expensive one that folks get suckered into.


QuoteQuote:
Alternatively it should also kill the 'you should get a larger format because it'll produce a picture with less noise than a smaller format camera'... that always ignores that the picture isn't the same, too.
Yep.


.
05-27-2014, 11:48 AM   #138
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QuoteOriginally posted by Winder Quote
And as I pointed out we are talking about camera lenses not telescopes. They don't get adapted to camera lenses until 1839. Photographers have not been having this discussion for centuries.


His first lenses that he produced for photography were uncorrected single element lenses. If you can find a link to a pre-1839 "corrected" lens I would love to see it.
Boy, I already gave you the link above but I'll happily regurgitate and spell it out for you:

Charles Chevalier's Paris optical firm produced lenses for both Niépce and Daguerre for their experiments in photography. In 1829[citation needed], Chevalier created an achromatic lens (a two element lens made from crown glass and flint glass) to cut down on chromatic aberration for Daguerre's experiments. Chevalier reversed the lens (originally designed as a telescope objective) to produce a much flatter image plane and modified the achromat to bring the blue end of the spectrum to a sharper focus. Reversing the lens caused severe spherical aberration so it needed a narrow aperture stop in front of the lens to control this. On 22 June 1839, Daguerre contracted Alphonse Giroux (France) to manufacture his official daguerreotype apparatus, including the world’s first production photographic camera. The Giroux Le Daguerreotype camera used an almost 16 inch (40 cm) focal length reversed achromatic lens with a f/16 stop in front of it made by Chevalier to take 6½×8½ inch (about 16.5×21.5 cm) images.[3][4]
05-27-2014, 12:13 PM   #139
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QuoteOriginally posted by eyeswideshut Quote
Boy, I already gave you the link above but I'll happily regurgitate and spell it out for you:

Charles Chevalier's Paris optical firm produced lenses for both Niépce and Daguerre for their experiments in photography. In 1829[citation needed], Chevalier created an achromatic lens (a two element lens made from crown glass and flint glass) to cut down on chromatic aberration for Daguerre's experiments. Chevalier reversed the lens (originally designed as a telescope objective) to produce a much flatter image plane and modified the achromat to bring the blue end of the spectrum to a sharper focus. Reversing the lens caused severe spherical aberration so it needed a narrow aperture stop in front of the lens to control this. On 22 June 1839, Daguerre contracted Alphonse Giroux (France) to manufacture his official daguerreotype apparatus, including the world’s first production photographic camera. The Giroux Le Daguerreotype camera used an almost 16 inch (40 cm) focal length reversed achromatic lens with a f/16 stop in front of it made by Chevalier to take 6½×8½ inch (about 16.5×21.5 cm) images.[3][4]
I'm talking to brick wall. That lens was created in 1829, my history is off 10 years. We are still not talking about centuries. Photographers were not discussing equivalency in the 1700's. Photographers have not been having this discussion for centuries.

05-27-2014, 12:17 PM   #140
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QuoteOriginally posted by Kunzite Quote
I'll only say it once, as I don't believe you are listening anyway: I read Falk Lumo's paper quite some time ago. I read most of JJ's article, and I understand his point.
If you don't see why it's usually important to convert aperture as well as focal length - if you consider equivalence an "abomination" (your words,) then you didn't really understand his point, or you're cherry-picking.

.
QuoteQuote:

QuoteOriginally posted by jsherman999:
And so it is with equivalence. You have no choice in the matter - it's the way it is.

You are gravely mistaken. The "equivalence" in its most acceptable form is nothing more than a convention that 5 parameters can decide if an image can be called "equivalent" or not.
Yes, and the math behind how those parameters interact isn't something you can argue away. Just like you can't argue away F=MA.

QuoteQuote:
JJ is actually saying:
"We can compare systems in many different ways. The five parameters of Equivalence (same perspective, framing, DOF, shutter speed, and display size) are simply guidelines to comparing systems on the basis of the most similar visual properties of the final photo, and are certainly not a mandate that systems must be compared in such a fashion. Therefore, it is important to specify the purpose of the comparison, and then not artificially handicap one or the other system with the conditions of the comparison."
OF COURSE, and this is exactly what I've said in this thread and have been relaying for three years. He's saying there that there is no mandate for getting equivalent images, that equivalence is a guideline for comparing systems. Are you simply skimming the article picking parts that you somehow think contradicts something I've said? Do I need to quote myself now to keep you on track?

Here, I'll do that - here's the most recent from me, relaying what JJ said in the part you quoted - did you not see this the first time? :

QuoteOriginally posted by jsherman999 Quote
No, no, no, no, no. And I'm not picking on you, I think 50% of the people who encounter equivalence get this wrong. They think it's somehow mandating that everyone needs to or wants to create equivalent images when they move between formats. Not what it's saying, not what it's there for.

It's not "you must want to create equivalent images, so here's how."

Its: "here's how the two formats in question relate to each other, using the method of creating equivalent images to describe the relationship."
By the way, the 'handicap one or the other system' came about in part when people started thinking that they had to match the DOF of the smaller-sensor system, and that if you didn't you were somehow taking a less-good photo. That was an artificial handicap that didn't apply in many or most cases.

.

Last edited by jsherman999; 05-27-2014 at 01:00 PM.
05-27-2014, 12:34 PM   #141
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Twisting my words again? I said clearly which kind of "equivalence" is an abomination; JJ's isn't (it's just irrelevant in most cases). JJ and Tony are making several very different claims; whom are you supporting?

Yes, please - quote yourself where you said people "have no choice in the matter". Apparently, not using equivalence is similar to claiming that F=m/a.
05-27-2014, 12:47 PM   #142
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QuoteOriginally posted by Kunzite Quote
Yes, please - quote yourself where you said people "have no choice in the matter".
You have no choice but to accept the math, the physics behind it. In other words, you can pretend it's not real in your mind, but you can't wish it away out here in the physical universe.

You can certainly ignore it if you only want to stay with one format, you can even ignore it if you want to shoot more than one format if you want, no-one is forcing you to see what's there - but you can't deny it exists unless you're also open to, for example, spending potentially a lot of money thinking that you're getting something you're not. And that goes for buying m43, aps-c or FF. Arm yourself with information, not denial.

I'd imagine the Catholic Church came up with a lot of reasons why Heliocentricity couldn't be real and didn't matter if it was, anyway.
05-27-2014, 01:07 PM   #143
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In other words, you cannot or are unwilling to make the distinction between math, physics and the idea of choosing a set of 5 parameters and claiming that images are "equivalent" if those parameters matches.

"Equivalence" has much less practical use than its advocates are believing; and in its complete form I'd guess it's only used to prove a point.

Oh, the Catholic Church again... yep, it's just like playing chess with pigeons...

05-27-2014, 01:22 PM   #144
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QuoteOriginally posted by Kunzite Quote

"Equivalence" has much less practical use than its advocates are believing; and in its complete form I'd guess it's only used to prove a point.
I guess that would be true if 'aperture' was only used to prove a point - and knowledge of it wasn't useful at all in taking photos.
05-27-2014, 02:25 PM   #145
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QuoteOriginally posted by Winder Quote
I'm talking to brick wall. That lens was created in 1829, my history is off 10 years. We are still not talking about centuries. Photographers were not discussing equivalency in the 1700's. Photographers have not been having this discussion for centuries.
QuoteQuote:
And as I pointed out we are talking about camera lenses not telescopes. They don't get adapted to camera lenses until 1839. Photographers have not been having this discussion for centuries.


His first lenses that he produced for photography were uncorrected single element lenses. If you can find a link to a pre-1839 "corrected" lens I would love to see it.
QuoteQuote:
I'm talking to brick wall. That lens was created in 1829, my history is off 10 years. We are still not talking about centuries. Photographers were not discussing equivalency in the 1700's. Photographers have not been having this discussion for centuries.
That information I gave you - first as a link then as a quote. You asked for evidence of a pre-1839 corrected lens? Now you have it. Both 1730 and 1829 are before 1839. Will you concede that and consider that part answered?

You then say, cameras only came into being in 1839 (as though that is not centuries!) and assert photographers did not have equivalence discussions then. Had you actually read and understood what I said, you might have noticed that I did not say they had equivalence discussions but merely wondered when the custom of using focal length as short hand for angle of view arrived.

The more important question, however, still remains unanswered. What has an achromat got to do with equivalence? Why do you even bring up a type of lense?
05-27-2014, 03:15 PM   #146
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QuoteOriginally posted by Kunzite Quote
In other words, you cannot or are unwilling to make the distinction between math, physics and the idea of choosing a set of 5 parameters and claiming that images are "equivalent" if those parameters matches.
QuoteOriginally posted by jsherman999 Quote
I guess that would be true if 'aperture' was only used to prove a point - and knowledge of it wasn't useful at all in taking photos.
I give up.

eyeswideshut, I read photography books of different ages; I watched Internet discussions as soon as they were started - yet I never heard about this "equivalence" until after the digital. What one would see and seek was the differences, not "equivalence" between formats, and how these differences would serve him.
I'd say the "custom" also appeared after the digital: point&shoots having smaller sensors (with film, even disposables could use 135) and Canikon APS-C DSLR owners being told that "full frame is the standard". This, and "learning" from the Internet instead of books.
05-27-2014, 04:13 PM   #147
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QuoteOriginally posted by eyeswideshut Quote
That information I gave you - first as a link then as a quote. You asked for evidence of a pre-1839 corrected lens? Now you have it. Both 1730 and 1829 are before 1839. Will you concede that and consider that part answered?
We are talking about cameras and lenses. NOT telescopes. I admit I'm off by 10 year with the achromatic lens.

QuoteOriginally posted by eyeswideshut Quote
You then say, cameras only came into being in 1839 (as though that is not centuries!)
Centuries is PLURAL. We have not had cameras for over 200 years, so not its not centuries. Do you know how long a century is? You really are trolling aren't you? You can't really be this dense.

QuoteOriginally posted by eyeswideshut Quote
Had you actually read and understood what I said, you might have noticed that I did not say they had equivalence discussions but merely wondered when the custom of using focal length as short hand for angle of view arrived.
You do realize that there were no standard plate/paper/film sizes at this point in time. People made their own cameras and produced their own paper/plates with chemicals. The AoV changed then just as it does today when you changed the size of the plate. The photographer could have a holder that held multiple plate sizes all of which would capture a different AoV and have a different aspect ratios. Its next to impossible to have a conversation on equivalency without first having standard sizes and aspect ratios. Not only that, but both the aperture and the focal length varied from what was marked on the lens. In the 1800's a lenses aperture could be (and probably was) off by more than a stop. If you bought 2 lenses that were marked the same focal length they could easily be off by a significant amount and/or have significantly different areas of sharpness. In school we had lenses for our view cameras from the 1920's through 1980's that had been donated to the program. Even in the 1920's there was a noticeable difference between some of lenses of the same focal length.

Who would waste their time having a conversation about equivalence when you don't have standard plate sizes/aspect ratios and the focal length and aperture where what is marked on the lens could be off by 20-30mm and +/- a full stop. Maybe you can post a link to the "famous equivalence debate of 1830". I'm sure the media would have covered such an event.


QuoteOriginally posted by eyeswideshut Quote
What has an achromat got to do with equivalence?
I'm not going to keep saying the same thing over an over again. Figure it out or don't. I don't care.
05-27-2014, 07:07 PM   #148
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05-27-2014, 08:58 PM   #149
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QuoteOriginally posted by filoxophy Quote
Mods?
Yes?

05-27-2014, 09:29 PM   #150
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I could care less about this whole debate - I'm just reading it for entertainment.

However, I do want to point out that quoting from Wikipedia and referencing YouTube videos as gospel is rather sophomoric. If you're gonna get into such heated discussion, use credible sources!
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