"Equivalence" demonstrated: Canon 5D and Panasonic GX1

Started Apr 27, 2013 | Discussions
John King
John King Forum Pro • Posts: 14,941
Re: Not to crush your spirit....

ljfinger wrote:

But I'm going to crush your spirit.  Here are two images you would claim are equivalent (same exposure settings).  Do they look equivalent to you?

Now, here are two images taken with the same cameras with "equivalence" applied (same total light captured).  Do these look equivalent to you?

Neither of them do ... on my phone ...

Perhaps that highlights just one more problem for this "theory"?

-- hide signature --

Regards, john from Melbourne, Australia.
(see profile for current gear)
Please do not embed images from my web site without prior permission
I consider this to be a breach of my copyright.
-- -- --
.
The Camera doth not make the Man (nor Woman) ...
Perhaps being kind to cats, dogs & children does ...
.
I am a Photography Aficionado ... and ...
"I don't have any problems with John. He is a crotchety old Aussie. He will smack you if you behave like a {deleted}. Goes with the territory." boggis the cat
.
Gallery: http://canopuscomputing.com.au/gallery2/v/main-page/
http://canopuscomputing.com.au/gallery2/d/14844-3/C120644_small.jpg
Bird Control Officers on active service.

 John King's gear list:John King's gear list
Olympus E-30 Olympus E-510 Olympus E-1 Olympus E-M1 Olympus Zuiko Digital 14-54mm 1:2.8-3.5 II +17 more
Lee Jay Forum Pro • Posts: 53,073
Re: Not to crush your spirit....
1

John King wrote:

Neither of them do ... on my phone ...

Perhaps that highlights just one more problem for this "theory"?

That people don't know how to properly view images?  That cell phones stink for viewing images?  I'm sorry but that's not part of equivalence theory.

Let me see if you are honest enough to answer this.  Which of the two sets are closer to looking "equivalent" even on your phone?

-- hide signature --

Lee Jay
(see profile for equipment)

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon Extender EF 2x III +23 more
pidera Contributing Member • Posts: 912
No problem :-)

Yes I had to read that paragrph twice and decided it was best to ignore it

Note (as I am still typing) : in the lost post I wrote something like this : Equivalency is at it's best when used in it's most simple form, ignoring things like read noise, bellows factors, t-stops and stuff like that. If all all connexions in the brain are right, one should experience some kind of insight, not yet mudded by other details. By trying to 'prove' too much hower (like the superiority of one system over another), one often ends up 'proving' nothing at all.

Cheers, P.

 pidera's gear list:pidera's gear list
Nikon D800E Fujifilm X-E1 Fujifilm X-Pro2
moving_comfort
moving_comfort Veteran Member • Posts: 8,228
A half-hearted Coup

Detail Man wrote: .... long, long snip....

I recently proposed referring to such rough corollaries as "metametric" as opposed to "equivalent":

http://www.dpreview.com/forums/post/51322339

... but the participants involved in that particular discussion seemed too embroiled to pay attention.

.

Sounds like you really would like to replace "King James" with "King Detail Man," but no-one else is getting on board the boat to your new kingdom

I think the concept of 'equivalency' as described by Bustard is succinct, easy to understand and 100% accurate - for what it is and tries to describe.

.

-- hide signature --

Here are a few of my favorite things...
---> http://www.flickr.com/photos/95095968@N00/sets/72157626171532197/

 moving_comfort's gear list:moving_comfort's gear list
Nikon D800 Pentax K20D Nikon AF Nikkor 180mm f/2.8D ED-IF Nikon AF Nikkor 20mm f/2.8D Nikon AF Nikkor 50mm f/1.8D +10 more
echelon2004 Veteran Member • Posts: 8,128
Re: There is no accepted definition of "equivalent images"

echelon2004 wrote:

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

Since camera to subject distance ("perspective") is held constant in the comparisons that King James makes, the entire premise of your technical point seems to evaporate into misty dewdrops ...

You can't keep all things unchanged.

Your SIGINT is coming through heavily encrypted, soldier. Please do expound on your hypothesis.

It is not possible to create the same image with the same perspective, depth of field, field of view and carachterestics from the lens with different size sensors/film. That's the whole point having them...
And it would be terribly daft to spend time and money trying to emulate what is readily available

-- hide signature --

Anders

'It is nice to be important but it is more important to be nice'

Andy Crowe Senior Member • Posts: 1,587
FF advantage mainly applies to high iso

There's no point arguing that m4/3 sensors are as good as FF sensors, because other than comparing old FF cameras like the original 5D they aren't. That's what you're paying extra for an FF camera for.

See this high iso comparison of the 5DII and the GX1

Of course comparing the original 5D does show you can't assume that a larger sensor is always better, it depends on the sensor tech too.

Also for lenses m4/3 lenses tend to have their sharpness sweetspot at larger apertures, so for maximum sharpness you may be able to shoot at f/2 on an m4/3 lens where you'd have to use f/4 for the same sharpness on a FF camera.

pidera Contributing Member • Posts: 912
Not convinced...

The images on the left are better, yes, but to me this advantage is not more apparent in the iso 6400 - iso 1600 comparison than in the iso 1600 - iso 400 comparison.

Regards, Pieter

 pidera's gear list:pidera's gear list
Nikon D800E Fujifilm X-E1 Fujifilm X-Pro2
Olymore
Olymore Senior Member • Posts: 1,751
Re: An answer:

Then, when the pixel density is the same, (so number of MP smaller) and the  sensors have the same QE, the smaller sensored camera would have a DR advantage but a resolution disadvantage assuming the same total light

Basically I'm hoping that some point in the future when sensors have reached a ceiling for QE  I can carry a 2/3 inch or 1 inch sensored camera up a mountain and get the same DR as a much larger sensor for photos that predominantly require large DOF.

Current resolution and noise is sufficient for me.

I'll read Gollywop's explanation when I get home tonight.

Thanks for the help

 Olymore's gear list:Olymore's gear list
Olympus E-M1
OP walkaround Senior Member • Posts: 2,551
Re: Not to crush your spirit....
2

ljfinger wrote:

But I'm going to crush your spirit.

Rrrright...

Anyway, since Mr 15000 gets to define "equivalence" his own way, leaving out things I take for granted, like exposure for example, then I will define my own definition of "equivalence":

Equivalent images all have identical:

- ISO

- Shutter Speed

- Aperture

- Framing

Anyone who says "equivalence" means something other than the above is an idiot.

Anyone who disagrees with my definition of "equivalence" is an idiot.

I'm working on a 38 page dissertation describing the above in more detail, and anyone who doesn't read it is an idiot. My 12 sock puppet usernames will do a beat-down on you. They will also call me "King James" because it sounds cool, but actually it's like I'm calling myself King James because they are all me, er... yeah.

OP walkaround Senior Member • Posts: 2,551
Re: FF advantage mainly applies to high iso

Andy Crowe wrote:

There's no point arguing that m4/3 sensors are as good as FF sensors.

Agreed, which is why my post has nothing whatsoever to do with comparing 5D and GX1 image quality.

Lee Jay Forum Pro • Posts: 53,073
Re: Not to crush your spirit....
3

walkaround wrote:

ljfinger wrote:

But I'm going to crush your spirit.

Equivalent images all have identical:

- ISO

- Shutter Speed

- Aperture

- Framing

Anyone who says "equivalence" means something other than the above is an idiot.

As shown in my samples, those don't result in equivalent images.

Anyone who disagrees with my definition of "equivalence" is an idiot.

So, to you, the EXIF data is more important than the images.  To most of us, the images are more important than the settings used to take the images.

-- hide signature --

Lee Jay
(see profile for equipment)

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon Extender EF 2x III +23 more
OP walkaround Senior Member • Posts: 2,551
You are crushing my patience.

ljfinger wrote:

walkaround wrote:

ljfinger wrote:

But I'm going to crush your spirit.

Equivalent images all have identical:

- ISO

- Shutter Speed

- Aperture

- Framing

Anyone who says "equivalence" means something other than the above is an idiot.

As shown in my samples, those don't result in equivalent images.

Anyone who disagrees with my definition of "equivalence" is an idiot.

So, to you, the EXIF data is more important than the images.  To most of us, the images are more important than the settings used to take the images.

I see you're not understanding my sarcasm. Ok, so in all seriousness yes I see the noise in your example. I don't, and most people don't, shoot compact cameras at ISO 800.

Can you please understand that the point of my original post was merely to show that f/2 is f/2 regardless of the format. To prove that I used identical ISO and shutter speed. Is that so difficult to get? Stop trying to make it about noise, image quality, dof. The EXPOSURES are the same in my post. The light areas are equal lightness and the dark areas are equal darkness. I shoot at base ISO, I don't give a sh*t about sensor noise. I never said "the noise" is the same, or the image quality. And I explicitly stated that the dof is different.

Lee Jay Forum Pro • Posts: 53,073
Re: You are crushing my patience.
1

walkaround wrote:

Can you please understand that the point of my original post was merely to show that f/2 is f/2 regardless of the format.

Do you understand that that is like proving 1=1?  It's trivial and useless result.

To prove that I used identical ISO and shutter speed. Is that so difficult to get? Stop trying to make it about noise, image quality, dof. The EXPOSURES are the same in my post.

So what?  Again, that's a trivial and useless result.

The light areas are equal lightness and the dark areas are equal darkness. I shoot at base ISO, I don't give a sh*t about sensor noise. I never said "the noise" is the same, or the image quality. And I explicitly stated that the dof is different.

You also said,""Total light on the sensor" is a meaningless concept."

That is flat-out wrong, and something you don't understand or you wouldn't have said what you said above.

-- hide signature --

Lee Jay
(see profile for equipment)

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon Extender EF 2x III +23 more
Andkar Regular Member • Posts: 402
Re: You are crushing my patience.
1

walkaround wrote:

Can you please understand that the point of my original post was merely to show that f/2 is f/2 regardless of the format. To prove that I used identical ISO and shutter speed. Is that so difficult to get? Stop trying to make it about noise, image quality, dof. The EXPOSURES are the same in my post. The light areas are equal lightness and the dark areas are equal darkness. I shoot at base ISO, I don't give a sh*t about sensor noise. I never said "the noise" is the same, or the image quality. And I explicitly stated that the dof is different.

But the images are not equivalent. The box in the lower right corner, for instance, is clearly sharper in the GX1 shot, because the DOF is greater.

Not equivalent pictures. They are not "the same".

OP walkaround Senior Member • Posts: 2,551
Re: You are crushing my patience.

ljfinger wrote:

walkaround wrote:

Can you please understand that the point of my original post was merely to show that f/2 is f/2 regardless of the format.

Do you understand that that is like proving 1=1?  It's trivial and useless result.

To prove that I used identical ISO and shutter speed. Is that so difficult to get? Stop trying to make it about noise, image quality, dof. The EXPOSURES are the same in my post.

So what?  Again, that's a trivial and useless result.

If my whole post is "trivial and useless", why are you commenting on it over and over again? Why not just ignore me and move on?

Lee Jay Forum Pro • Posts: 53,073
Re: You are crushing my patience.

walkaround wrote:

ljfinger wrote:

walkaround wrote:

Can you please understand that the point of my original post was merely to show that f/2 is f/2 regardless of the format.

Do you understand that that is like proving 1=1?  It's trivial and useless result.

To prove that I used identical ISO and shutter speed. Is that so difficult to get? Stop trying to make it about noise, image quality, dof. The EXPOSURES are the same in my post.

So what?  Again, that's a trivial and useless result.

If my whole post is "trivial and useless", why are you commenting on it over and over again? Why not just ignore me and move on?

Because you said, ""Total light on the sensor" is a meaningless concept."

That's wrong, and indicates you have a lack of understanding.  It further indicates that demonstrating that exposure works (duh?) wasn't the whole point of your post.

-- hide signature --

Lee Jay
(see profile for equipment)

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon Extender EF 2x III +23 more
olypan Regular Member • Posts: 183
Re: "Equivalence" is not "Equivalence" - try a new terminology.
1

Great Bustard wrote:

pavinder wrote:

Great Bustard wrote:

pavinder wrote:

Great Bustard wrote:

Similarly to say "these 2 photos are visually equivalent but not technically equivalent" is far more helpful than to just argue about whether they are "equivalent" under some all-encompassing definition.

So, what are your parameters for "visually equivalent" and what are your parameters for "technically equivalent"?  I mean, next thing we know we're going to be talking all sorts of "equivalences" for size, weight, price, AF speed/accuracy, build, etc., etc., etc.

Visually equivalent - very simple.  And exactly what it says. They look the same.

Framing, perspective, what's in focus and what's not, what's light, what's dark, etc.

In other words if you showed someone the 2 photos, they would look and think "yes, it's the same photo".

Well, that's basically Equivalence as I've defined it, then:  same perspective, framing, DOF, shutter speed (motion blur), and display size.

Well 3 out of 5 is not quite the same.

Shutter speed and display size are quantitative, not qualitative.

They're all quantative.  We can quantify perspective (subject-camera distance).  We can quantify framing (width and height of the scene on the focal plane).  We can quantify DOF (total distance front and back of the focal plane that is within critical focus).  In other words, they are all quantative just like shutter speed and display size.

Here, let me ask you a question:  would anyone disagree that 25mm f/2.8 1/100 ISO 400 with the 14=54 / 2.8 on an Olympus E1 is equivalent to the same settings with the 12-35 / 2.8 on an Olympus EM5?  I'm thinking no one would say they are not "equivalent", despite the fact that the noise, detail, dynamic range, etc., would all be quite different.

Thus, I see no reason not to use the word "equivalent" to describe photos that have the same perspective, framing, DOF, shutter speed, and display size even when other elements of IQ are not necessarily the same.

Keep digging. You should reach Australia soon. Pop in and see John King. He could maybe give you some wisdom, or at least the "entertainment" you so enjoy.

OP walkaround Senior Member • Posts: 2,551
Re: You are crushing my patience.

ljfinger wrote:

Because you said, ""Total light on the sensor" is a meaningless concept."

It is, unless you're having a theoretical discussion of sensor noise, which I'm not. There is no concept of "total light on the film" either. Go out and shoot with your "total light" settings if you like. I could care less.

Lee Jay Forum Pro • Posts: 53,073
Re: You are crushing my patience.
1

walkaround wrote:

ljfinger wrote:

Because you said, ""Total light on the sensor" is a meaningless concept."

It is, unless you're having a theoretical discussion of sensor noise, which I'm not.

It's useful for much more than that.  I use it all the time in actual shooting conditions because I often shoot with two or three different formats at the same time.

There is no concept of "total light on the film" either.

Yes, there is.  More film = more light captured.  Why do you suppose MF cameras do better in low light than 35mm cameras, or 35mm cameras do better in low light than 110 cameras even when using the same type of film?

Go out and shoot with your "total light" settings if you like. I could care less.

Then why are you here lamely attempting to "diss" that which you don't understand and don't care about?

-- hide signature --

Lee Jay
(see profile for equipment)

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon Extender EF 2x III +23 more
Great Bustard Forum Pro • Posts: 41,758
The "conversation" and "failure to communicate"
1

boggis the cat wrote:

Ulric wrote:

boggis the cat wrote:

Great Bustard wrote:

Thus, I see no reason not to use the word "equivalent" to describe photos that have the same perspective, framing, DOF, shutter speed, and display size even when other elements of IQ are not necessarily the same.

'Equivalent' does not have the narrow meaning that you may prefer it to have.

I had this very conversation only yesterday.
GB: "Addition goes like this: you add two numbers and the result is 5."
U: "What? It depends on the numbers, the result can be anything."
GB: "The numbers are 2 and 3. It says so on my blog."
U: "What if the numbers are 2 and 4?"
GB: "Why am I constantly being misrepresented? The result is 5 because the numbers are 2 and 3!"
U: "Have you considered making up a name for the process of adding these particular numbers, to distinguish from addition in general?"
GB: [googles addition and cuts and pastes definition from online dictionary] "Is there something else you want me to explain?"
U: [goes to bed]

Actually, the "conversation" went like this:

http://www.dpreview.com/forums/post/51293032

which, of course, is quite different than what you say (ask me if I'm surprised).

Yes, there does seem to be a disconnect somewhere.  But not like a cultural gap or misunderstanding -- more like trying to communicate with an alien species.

I concur:

http://www.dpreview.com/forums/post/51375058

For the record, you are saying that a photo of a scene taken at 25mm f/2.8 1/100 ISO 400 on an Olympus E1 is *not* equivalent to a photo of the same scene also taken at 25mm f/2.8 1/100 ISO 400 on an EM5.

Noted.

and

Well, first you say that 25mm f/2.8 1/100 ISO 400 on an E1 is not "equivalent to" 25mm f/2.8 1/100 ISO 400 on an EM5, then you say that 50mm f/2 on 4/3 is "equivalent to" 100mm f/2 on FF, so I'm thinking that if anyone is causing "unnecessary confusion"...

Nicely sums up the whole matter for me.

Keyboard shortcuts:
FForum MMy threads