Not again! Oh dear (the equivalence issue)

zlatko-photo

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F-stops are not used as a constant measure for depth of field across formats. Shoot the same subject at the same distance with a standard lens set to f/5.6 on various formats:
  • m43
  • 35mm / full-frame
  • 8x10" film
Those images will show substantial differences in depth of field. And yet there is no "cheating" even though all are shot at f5.6.
 

GFFPhoto

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Is it really that hard to understand the difference between field of view and focal length?
 

bikerhiker

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I suspect not many of the people who posted in this thread watched the whole video. I agree, is way too long. The first part is just some boring summary of the same old things.

Anyway I found the part about the aperture numbers, starting at 20:20 quite interesting. He just says that physically what is advertised as a 2.8 aperture is a 5.6 aperture. I get the same exposure because you need less light to lit a smaller sensor. But the aperture is just not that, and I think he's right.

I started a duplicate thread here: https://www.mu-43.com/showthread.php?t=64727
I watched the whole video. It was great entertainment; at least in value. :biggrin: Educational; maybe. Unfortunately, he's not the only one that's selling B.S, as in a Big B and and a Big S with a big freakin T. Sadly, there are instructors out there that are teaching this hogwash and they are taking money.

Aperture relates to DOF, but the effect of DOF relates closely to the circle of confusion. It's funny that I posted this on another thread and you kept insisting that this dude is right. He's not. Circle of confusion is a basic fundamental concept in photography. Circle of Confusion teaches us that photography IS a 2 dimensional art. Unfortunately again, some instructors out there teach people that photography is a 3 dimensional art. What a bunch of B.S again!
The point of sharpness in a photograph is only on 1 plane. That's right, just 1 plane since we are only dealing with a 2 dimensional art and everything else is based on perceptual sharpness. Which is why test charts are shot flat and at 1 fixed distance to determine the lens resolution and lens aberrations. This perceptual sharpness outside of this 1 plane of focus is dictated by the circle of confusion of the sensor or film size used. Only a instructor who teaches photography is a 3 dimensional art talks about aperture equivalency. This dude is teaching you that. A complete and utter lie. Sadly, there are people out there even in meetup groups milking away on people who don't know better.

Secondly, there is a standard in measuring focal length. And that is, the focal length number that's printed on the lens corresponds to the field of view of the subject matter that is focused at infinity. So a 12mm on MFT focused at infinity gives the same angle of view as a 24mm full frame lens focused the same, despite the fact that the measurement on the 12-35 is @ 12mm measured and the Nikkor 24-70 @ 24mm is truly 24mm! When we talk about angle of view equivalence, we are talking about the angle view of a given focal length with the subject matter focused less than infinity. Angle view changes when a lens is focus a subject matter at close distance. In fact, @ 200mm, three Nikkor lenses 70-300, 70-200 I and 70-200 II lenses give different angle of views. Is this a lie from Nikon, because my 70-200 VR II at close focus giving an equivalence of 180mm not 200mm focused at close distance? Canon does the same thing. It is not an error that some poeple like to make believe, but rather it is due to different optical designs which give them different angle of view shot not at infinity. Most people are more concerned about angle of view rather than focal length, because that is a more reliable gauge.
 

Klorenzo

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I checked this thread too and it is just talking about something else. He found "errors" that are instead the whole point of the video:

"when he did the math in the video to explain how aperture gets calculated he made the mistake to change the focal length variable"

No, it's not a mistake, it's the point of the video!

To me is just another thread that did not make the effort to follow the whole video trying to understand it and assumes that the guy is an idiot that does not know anything about photography. Easy.

You can read Northrup reply to this thread and others here:

http://petapixel.com/2014/05/18/are-camera-manufacturers-misleading-us-by-not-calculating-the-sensor-size-into-specs/
 

bikerhiker

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I wonder why he's not picking at Apple. Apple makes iPhones that has a built-in camera with a crop factor. I know why. Apple can sue the heck out of him for slander and misinformation. Just picking on the weaker guys like Olympus and Panasonic and Sony who's financials are weaker than Apple so they can't fight back..
 

HappyFish

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same idiot who could not figure out a fuji camera strap ? has no clue what ISO really is and had to read a wiki page ?
as I say to those idiots show me on my light meter where the settings are for various film or sensor sizes are please :) cause when I know what the exposure is works on any size camera ;)
and again sad guy who lacks a basic brain other than what he has read on a few forums seems to think 35mm size sensor is the center of the universe and what all settings are based off of ?

again I can figure out my shot based on a light meter hitting subject and it won't be effected as he says by focal length ? I can figure out and set my FF gear and my M4/3 gear and Med format gear all the same and get the same look on the subject with the same Fstop values and shutter speeds and iso settings and I might get a dif look do to dof


hahahahahahahah OH what a tool he is
 

OzRay

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I checked this thread too and it is just talking about something else. He found "errors" that are instead the whole point of the video:

"when he did the math in the video to explain how aperture gets calculated he made the mistake to change the focal length variable"

No, it's not a mistake, it's the point of the video!

To me is just another thread that did not make the effort to follow the whole video trying to understand it and assumes that the guy is an idiot that does not know anything about photography. Easy.

You can read Northrup reply to this thread and others here:

http://petapixel.com/2014/05/18/are-camera-manufacturers-misleading-us-by-not-calculating-the-sensor-size-into-specs/
I read that as well and at the end of the day Northrup is really comparing apples with oranges with avocados. The manufacturers aren't lying about anything, they are presenting technical features as they physically exist. It's like car manufacturers, they advertise various specifications such as engine power, fuel economy etc, but in the real world these are not quite what the consumer gets. For example, engine power is universally measured on an engine dynamometer, the power output is affected by many factors and when the engine is installed in a vehicle, the power as measured on a chassis dynamometer is far less, due to driveline losses, manufacturing variations, environmental factors etc. The same applies for fuel economy, which is measured in on a chassis dynamometer, in an environmentally controlled lab and driven according to set procedures, it in no way reflects real world results. The manufacturers aren't lying, they are presenting measurable facts according to accepted principles.

The same applies to a cameras/lenses. For example, f2 is f2 if you are comparing any lens, as it's a mathematical calculation as already mentioned. Sensor ISO is what it is when measured using accepted testing procedures (or provided by the sensor supplier) under ideal conditions. Focal length (field of view) is focal length, usually defined by accepted equivalence figures. I'm not going to watch the video, but from what has been posted, I don't see his point and especially the need to call manufacturers liars. If it is indeed true, let him take it up with the relevant consumer organisation (which always appear to love taking these things up on the consumer's behalf) and give the manufacturers a fight.
 

Cruzan80

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I checked this thread too and it is just talking about something else. He found "errors" that are instead the whole point of the video:

"when he did the math in the video to explain how aperture gets calculated he made the mistake to change the focal length variable"

No, it's not a mistake, it's the point of the video!

To me is just another thread that did not make the effort to follow the whole video trying to understand it and assumes that the guy is an idiot that does not know anything about photography. Easy.

You can read Northrup reply to this thread and others here:

http://petapixel.com/2014/05/18/are-camera-manufacturers-misleading-us-by-not-calculating-the-sensor-size-into-specs/
Yes, it is a mistake. Nobody is saying it is the same. It is the same FIELD OF VIEW (only). The lens doesnt magically change focal length, so the aperture does change either. People get a lens that does have f2.8. That relates to exposure ONLY. Any comparison made about how much blur (bokeh/=/amt. Of blur) is independant of aperture. They get a lens that has a field of view from x to y, and a 2.8 aperture. The equivalent part is only so people can visualize how much different it will be to COMPOSITION.

Sent from my LG-P769 using Mu-43 mobile app
 

dnightingale

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Who's being cheated or lied to here? Smaller formats give greater DOF at the same aperture. Always have, always will. It's the laws of physics and all that. Once you know that, the facts are plain.

The term "full frame" is the problem here. It implies that this is the ultimate size for camera sensors. Once upon a time 24x36mm was called "miniature format" and was looked down on by "serious" photographers. The BPS voted in the late 30s to include 6x6cm in the miniature category too and that laughs at your puny "full frame" sensor :big grin:

IMO this whole equivalence business hinges on some pretty dodgy semantics and the old "blind with science" trick.
Exactly. I wish I had the skills, humor and time to make a 'pun' video explaining in the same condescending manner (Albeit disguised with such politeness and forced patience for those less enlightened by mathematics), how FF aperture equivalence is incorrectly reported by Nikon / Canon / Sony etc.. when compared to 6x7 or 6x6 format.

In the mean time, the end result is, pretty humorous if you don't take too much from it.

In practical terms, which must rely also on the same science he uses to explain noisy images, E-M5 holds it's own very well to a Canon 1DS II in regards to ISO performance at least.
 

MAubrey

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Has Panasonic ever claimed the 12-35mm f/2.8 to be a 24-70mm f/2.8??? I don't remember seeing such an idea. This guy point to a popular Amazon review, but...that's not Panasonic.
 

HappyFish

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the fact a guy has to try to raise a storm to get folks to look at his videos shows how pathetic he is IMHO at least ;)

just present solid great content to drive folks to your site ;) to say LOOK AT ME I AM A IDIOT I can't put on a camera strap and I want to argue f/2.8 is not unless its on a FF camera

crazy for sure just flat out crazy and kinda sad anyone would now listen to him
 

hankbaskett

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I didn't both to watch it (who has 38 minutes of their life to waste watching something like this), but I can imagine how it goes. It's likely somebody who owns a FF camera making themselves feel better about their purchase by belittling smaller sensor cameras (DoF, noise, etc.)

It doesn't matter the size of the sensor, exposure should be the same regardless of sensor size (f/2.8 on FF is the same as f/2.8 on m43 when looking at ISO, Aperture, and Shutter Speed values. The only way this would differ, is due to light loss within the lens, which is why cinema lenses are rated with T-stops, which measure actual light transmittance, compared to F-stops, which are calculated for theoretical light transmittance). Where it differs is DoF, where typically m43 is 2 stops behind FF, or 1 stop behind APS-C (so a 25mm lens on m43 at f/2.0 would render the same DoF as a 50mm lens on a FF camera at f/5.6).

I honestly don't understand what is so difficult about this. The fact that people can't wrap their heads around this is baffling. I honestly feel sorry for them, and wonder how they make it through life, since there are FAR more complicated issues to deal with in real life compared to this sort of thing.
Haha, thank you for this. I was watching this video and the guy is talking like he just figured out how to split an atom or something and going on about how antiquated and unnecessarily difficult it is to work with ISO, aperture and shutter speed. Surely you could teach a group of grade 4 or 5 children this concept? Not necessarily the "why's" behind it, but just how to relate different lenses on different sensors?

I can't decide if the guy who created the video is a moron for thinking that anyone needs this explained and acting like he's blown the roof off some grand camera conspiracy, or whether he's a genius for noticing that there are people who really don't understand this stuff and putting together a video that caters to their poor understanding.
 

Fri13

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Haha, thank you for this. I was watching this video and the guy is talking like he just figured out how to split an atom or something and going on about how antiquated and unnecessarily difficult it is to work with ISO, aperture and shutter speed. Surely you could teach a group of grade 4 or 5 children this concept? Not necessarily the "why's" behind it, but just how to relate different lenses on different sensors?

I can't decide if the guy who created the video is a moron for thinking that anyone needs this explained and acting like he's blown the roof off some grand camera conspiracy, or whether he's a genius for noticing that there are people who really don't understand this stuff and putting together a video that caters to their poor understanding.
I really wanted to understand the logical reasoning behind the claims he does, and all what I find out is he wants to generate clicks and protect the decision why 35mm small format sensor size is superior to APS-C and m4/3 sensors.

Functioning science isn't supporting him at all, real life results what anyone can test are not supporting either. He only use math to proof own calculations.
And people believe because he use math, he is correct because "math doesn't lie".

Well, isn't it just marvelous how no one ever has managed to do wrong math calculations getting as results something totally different than actually wanted simply using wrong formula? Why in math we check and recheck formulas and results by recalculating and using inversing operation? Because using math isn't a proof itself, results are and there is no wrong or right results as even results being untrue with algorithm, can proof something correct.

If hes point was to suggest we should abandon the ISO as value and replace it with the other like previous linear ASA or logarithmic DIN values so we could more easily calculate in our heads (and camera display etc) large sensitivies like 102400 vs 153600 in stops, then I failed to see it. Or if he wanted to standarize the ISO value to dynamic range and the look of the noise, I failed to see that as well.

Or does he just want to cut compatibility to all other cameras (including film cameras) for next generation digital cameras by how light sensitivity is calculated?

After all, exposure triangle doesn't make any sense to him and he say so!
Meaning it is like others would need to proof him wrong (what others have done) or promo he from finding the ultimate camera conspiracy to fool people selling anything else than 35mm sensor cameras. Damn…
 
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