Equivalence

[bad_doggie]

this is a philosphical statement, not a statement of fact.

No, it is a statement of fact for the definition of equivalence I
gave in the essay.

okay. you POSIT an equivalence. from this you derive this statement. you
accep this statement as true, because it is a consequence of your assumptions

on what "equivalent" means. i contend that it is not true in any sense that is meaningful to me as a photographer. HENCE, you have shown that your assumption leads to a contridiction, and i reject your assumption as false.

(P implies Q) and (not Q) implies (not P).

P = your assumption
Q = your conclusion

and one that i'm sure most would disagree with, if not plunked down in the
middle of intimidating language.

They may disagree all they want. Disagreement does not change what is.

if it does not invalidate the argument that leads to this conclusion, then it invalidates the original assumption.

i read it kind of like a master chef teaching other chefs: "its not
the taste of the food that matters, but how it is prepared and
presented."

More like a master chef teaching the other chefs: "it is the
temperture in the oven, not the heat of the flame, that matters."

which is false, since you might be frying, sauteeing, boiling or BBQ'ing.

in photography, as most photographers understand it, exposure is an
important measure for an image.

The definition of exposure is outdated. The reason is that in the
past, with film, photographers did not try to match the noise
characteristics between systems.

show me one reviewer of cameras who studies noise characteristics of cameras and uses this info to draw conclusions about lenses.

But I'm not discussing the artisitic merits between the systems. I'm
talking about the technical capabilities between the systems. And,
as the essay states, in terms of IQ (but not necessarily operation),
anything 1.6x can do, FF can do at least as well, and FF can do
things that 1.6x cannot even do.

but its not science or math: its an empirical study of cameras that exist out there right now. you have no way to know what the situation will be like in 5 or 10 years.

So, for people deciding between systems, they give up nothing in
terms of IQ if they go FF.

except money and the cost of greater magnification.

However, for those that shoot long, or
need to maximize DOF in low light, they may find that the advantages
of FF are wholly insignificant, and the operation of FF to be
expensive and cumbersome.

indeed. which covers just about all typical photographers.

 

[Gorim]

Joe, before this thread fills up, just want to say, congratulations on pulling another thread stuffer! I know no one keeps statistics, but if they kept them for people who regularly start threads that go all the way to 150, you will surely be #1.

 

[bad_doggie]

wow, big statement coming from you guys, whose whole thesis is comes
down to an equivalence relation on exif data.

You really need to pass 5th grade this time (third time's a charm,
don't you know). As usual, the entire point of this equivalence has
gone right over your head.

nope, not at all. i have before, and continue to say, that what you guys are passing off as a great revelantion is nothing of the sort, and of no practical value.

what is the point of the equivalence? i mean, really: say i'm a wildlife photographer and i'm really happy with my 300/2.8 on a 30d. argue to me why i should switch to a 5d+400/4.

the arguments you're making are of no practical benefit to most folks. and the proof of the pudding is in the tasting: FF cameras are rare..

 

[joe mama]

what is the point of the equivalence? i mean, really: say i'm a
wildlife photographer and i'm really happy with my 300/2.8 on a 30d.
argue to me why i should switch to a 5d+400/4.

Actually, 500 / 4L IS. And yes, you'll get better images for sure. But if you're satisfied with the 30D + 300 / 2.8L IS (and, quite honestly, how many need better than that?), then why bother?

the arguments you're making are of no practical benefit to most
folks. and the proof of the pudding is in the tasting: FF cameras are
rare..

DSLRs are of no practical benefit to most folks, either. What's your point?

--
--joe

http://www.josephjamesphotography.com
http://www.pbase.com/joemama/

Please feel free to criticize, make suggestions, and edit my photos. If you wish to use any of my photos for any purpose other than editing in these forums, please ask.

 

[bad_doggie]

The guy wants an 18-50 / 1.8 for his 1.6x DSLR. No such thing
exists. But he could get the same results with a 5D and 28-75 / 2.8,
but he doesn't understand that.

the guy wants to know why they don't make f/1.8 zooms. c'mon joe, you've asked the same question before yourself, about 17 f/1.8 prime or some such thing.

This guy, due to all the myths spouted by people who don't understand
equivalence, is scared away from a system that will suit his needs.

he has no needs, he was asking a pointless question. if you haven't noticed, these fora are now stuffed full of pointless questions. i think amazon has hired a gaggle of interns to seed these boards with "show me your X!" and "what would you do if Y?" and "I want a Z that has A and not B but maybe C or D, what would you do?"

That's why people need to understand. That's the reason for all the
technical talk. If croppers didn't spout all the misinformation in
the first place, I'd not have to be setting the record straight.

misinformation! lol.

dood, your many many many many many many "equivalence posts" always have a single bias: FF is superior.

for most folks, it is not. for most folks, your argument says: hey! you know, for most of the stuff you would normally do with a 5d, you can get equivalent, indistinguishable results from a 30d, so why even bother looking at FF when the alternative is equivalent and cheaper in all ways?

that's the take home message, because its a rare bird indeed that needs ultra shallow DOF that you can't achieve with a 30d and f/2.8 lens.

 

[bad_doggie]

Actually, 500 / 4L IS. And yes, you'll get better images for sure.
But if you're satisfied with the 30D + 300 / 2.8L IS (and, quite
honestly, how many need better than that?), then why bother?

better? better? i thought equivalent? wtf??

the arguments you're making are of no practical benefit to most
folks. and the proof of the pudding is in the tasting: FF cameras are
rare..

DSLRs are of no practical benefit to most folks, either. What's your
point?

as a noo yawka, i have to disagree. i see lots of dslr's every single day. not as common as P&S for sure, but i see at least 25 in action every day.

 

[joe mama]

this is a philosphical statement, not a statement of fact.

No, it is a statement of fact for the definition of equivalence I
gave in the essay.

okay. you POSIT an equivalence. from this you derive this statement. you
accep this statement as true, because it is a consequence of your
assumptions on what "equivalent" means. i contend that it is not true in any
sense that is meaningful to me as a photographer.

Tell me what other definition of equivalence leads to two images from two different systems producing images that look more alike.

Not interested in producing the same types of images on two different systems? For the most part, me neither. I'm more into what FF can do that 1.6x cannot. However, this essay is to debunk all those that say that FF cannot do what 1.6x does.

shown that your assumption leads to a contridiction, and i reject
your assumption as false.

(P implies Q) and (not Q) implies (not P).

P = your assumption
Q = your conclusion

Dude, you're using logical symbols. That's so cool. : )

i read it kind of like a master chef teaching other chefs: "its not
the taste of the food that matters, but how it is prepared and
presented."

More like a master chef teaching the other chefs: "it is the
temperture in the oven, not the heat of the flame, that matters."

which is false, since you might be frying, sauteeing, boiling or
BBQ'ing.

"Equivalence" in that we are preparing the same meal.

in photography, as most photographers understand it, exposure is an
important measure for an image.

The definition of exposure is outdated. The reason is that in the
past, with film, photographers did not try to match the noise
characteristics between systems.

show me one reviewer of cameras who studies noise characteristics of
cameras and uses this info to draw conclusions about lenses.

None that I know of. Your point?

But I'm not discussing the artisitic merits between the systems. I'm
talking about the technical capabilities between the systems. And,
as the essay states, in terms of IQ (but not necessarily operation),
anything 1.6x can do, FF can do at least as well, and FF can do
things that 1.6x cannot even do.

but its not science or math: its an empirical study of cameras that
exist out there right now. you have no way to know what the situation
will be like in 5 or 10 years.

We'll come back to this in 5 or 10 years, then, and see what's changed. Hint: nothing. : )

So, for people deciding between systems, they give up nothing in
terms of IQ if they go FF.

except money and the cost of greater magnification.

Note: I said "in terms of IQ". And, no, they don't give up greater magnification, they just have to buy a 1.4x TC. Or do you mean that for lenses that don't accept TCs, you get more magnification with cropped sensors? True. I concede that point.

However, for those that shoot long, or
need to maximize DOF in low light, they may find that the advantages
of FF are wholly insignificant, and the operation of FF to be
expensive and cumbersome.

indeed. which covers just about all typical photographers.

You know, you sure presume a lot about what other people need and/or want. Let's say this information I'm providing is valuable to only 5% of the people out there. Why fight me? Have I lied? Have I said something untrue? Why not just let the 5% learn something that matters to them?

--
--joe

http://www.josephjamesphotography.com
http://www.pbase.com/joemama/

Please feel free to criticize, make suggestions, and edit my photos. If you wish to use any of my photos for any purpose other than editing in these forums, please ask.

 

[joe mama]

Actually, 500 / 4L IS. And yes, you'll get better images for sure.
But if you're satisfied with the 30D + 300 / 2.8L IS (and, quite
honestly, how many need better than that?), then why bother?

better? better? i thought equivalent? wtf??

You didn't read the essay, did you? Go back and read the chapter called, "SITUATIONS WHERE VIOLATION OF EQUIVALENCE IS VALID". Here's the link:

http://www.josephjamesphotography.com/equivalence/

the arguments you're making are of no practical benefit to most
folks. and the proof of the pudding is in the tasting: FF cameras are
rare..

DSLRs are of no practical benefit to most folks, either. What's your
point?

as a noo yawka, i have to disagree. i see lots of dslr's every single
day. not as common as P&S for sure, but i see at least 25 in action
every day.

That's all I'm sayin' -- way more compact users than DSLR users, just like there are way more 1.6x users than FF users.

Why do you presume to speak for everyone as to what they need to know and what they don't need to know? Am I trying to convice compact users to get a DSLR? Am I trying to convince croppers to go FF?

No.

I'm just saying that, for those that do not understand, they can get the same images on a FF DSLR as they get with a 1.6x DSLR with no IQ sacrifices that some croppers always harp about: soft corners, vignetting, diffraction, distortion, etc.

--
--joe

http://www.josephjamesphotography.com
http://www.pbase.com/joemama/

Please feel free to criticize, make suggestions, and edit my photos. If you wish to use any of my photos for any purpose other than editing in these forums, please ask.

 

[joe mama]

The guy wants an 18-50 / 1.8 for his 1.6x DSLR. No such thing
exists. But he could get the same results with a 5D and 28-75 / 2.8,
but he doesn't understand that.

the guy wants to know why they don't make f/1.8 zooms. c'mon joe,
you've asked the same question before yourself, about 17 f/1.8 prime
or some such thing.

Sure, sure. I'll most certainly concede that I misinterpreted. However, are you saying that the info I gave is not something interesting that's worth considering?

This guy, due to all the myths spouted by people who don't understand
equivalence, is scared away from a system that will suit his needs.

he has no needs, he was asking a pointless question.

I'll pass that along to him. : )

if you haven't noticed, these fora are now stuffed full of pointless questions. i
think amazon has hired a gaggle of interns to seed these boards with
"show me your X!" and "what would you do if Y?" and "I want a Z that
has A and not B but maybe C or D, what would you do?"

I have to ask, then, why you have posted so many replies in a thread about a pointless concept?

That's why people need to understand. That's the reason for all the
technical talk. If croppers didn't spout all the misinformation in
the first place, I'd not have to be setting the record straight.

misinformation! lol.

Yes, misinformation. FF does not have soft corners. FF does not vignette more. FF does not have more distortion. FF does not force a more shallow DOF. FF does not suffer diffraction softening at a more shallow DOF (that's one that you, yourself, even spouted -- want the link?).

dood, your many many many many many many "equivalence posts" always
have a single bias: FF is superior.

If it's true, it's not a bias. I make it clear in the essay that I am talking about IQ, not operation. Are you saying that 1.6x has the same IQ as FF?!

for most folks, it is not.

For everyone, it is. Whether they have the knowledge and ability to use it to that end, is another story.

for most folks, your argument says: hey!
you know, for most of the stuff you would normally do with a 5d, you
can get equivalent, indistinguishable results from a 30d, so why even
bother looking at FF when the alternative is equivalent and cheaper
in all ways?

Because my message is really:

"Hey! You know all that BS people have said about FF? You know, soft corners, more vignetting, DOF too shallow, etc., etc. Well, it's all bunk. FF actually has higher IQ across the board, except in a light limited, deep DOF situation, but even then, it still matches smaller formats in terms of IQ."

that's the take home message, because its a rare bird indeed that
needs ultra shallow DOF that you can't achieve with a 30d and f/2.8
lens.

I'm glad you're here to make the right choices for everyone. Mao is dead, long live bad doggie! : )

--
--joe

http://www.josephjamesphotography.com
http://www.pbase.com/joemama/

Please feel free to criticize, make suggestions, and edit my photos. If you wish to use any of my photos for any purpose other than editing in these forums, please ask.

 

[Al_10D]

FF is corner softener and darkener. How about that?

 

[joe mama]

Joe, before this thread fills up, just want to say, congratulations
on pulling another thread stuffer! I know no one keeps statistics,
but if they kept them for people who regularly start threads that go
all the way to 150, you will surely be #1.

Unfortunately, I think all my "thread stuffers" are all on this same topic. I don't know why it's so controversial. It's why I finally decided to create the essay, so I can simply link to it, without rehashing all the same things repeatedly throughout the same thread.

Alas, it appears as though that may not work, since, by many of the responses, some have not bothered to read and understand the essay, but I think it's important work. Check out Al_10D's post above:

http://forums.dpreview.com/forums/read.asp?forum=1029&message=24412696

It's to combat BS like that that I go to all this effort.

Lee Jay warned me that it was too long, but I don't know how to make it shorter, yet still be complete. Even if I cut it down to just the essentials, and had links for more in depth explanations, most wouldn't go deeper than the front page -- just like the newspaper.

We (Americans) live in a society of instant gratification. We elect politicians on catch-phrases, start wars on emotion without reviewing the facts, and make false statements like "My version is shorter: FF is corner softener and darkener. How about that? " : )

In any event, I consider this "the good fight" and I receive justification with all the kind emails I get from people telling me how much they appreciate my efforts. No need to save the world, as it were, just do what you can do help those who appreciate it.

--
--joe

http://www.josephjamesphotography.com
http://www.pbase.com/joemama/

Please feel free to criticize, make suggestions, and edit my photos. If you wish to use any of my photos for any purpose other than editing in these forums, please ask.