Good link assuming that when it says "aperture" it means aperture size, not f/number.
It says: Aperture is a measure of light transmission. The exposure of an f1.4 lens on medium format, full frame, M43 or a phone is exactly the same! Equivalence was created for the internet and by influences that want to ... sound smarter than you.
Let's put that to the test. Using the definition of Equivalence: Equivalent photos are photos of the same scene that are taken from the same position with the same focal point and [diagonal] framing using the same aperture diameter, same exposure time, processed in the same manner, displayed at the same size, and viewed from the same distance on the same medium.
Now, given that I have two of these photos from two different systems, are you saying that the "scientific visual properties" of perspective, DOF, and motion blur will differ from those same properties when "viewed with human perception"? That is, would someone looking at the two photos taken in the described manner say they are different based on those properties? I mean, some properties may differ, such as flare, distortion, resolution, noise, etc., of course, but if we put additional constraints on the equipment used, these, too, can be accounted for.
What Equivalence is absolutely not saying is that different photographers (one with, say, a smartphone, another with an EM5 + 12-100/4, and another with an R5 + 50 / 1.4) will take the same photo. Hell, even if all three photographers had the exact same equipment no one is saying they would, or even should, all take the same photo!
What Equivalence does say, however, is that if, for example, if 50mm f/5.6 1/400 ISO 1600 represents the "best" photo on FF, then 25mm f/2.8 1/400 ISO 800 will represent the "best" photo on mFT. Equivalence also says that if 50mm f/1.4 1/400 ISO 1600 represents the "best" photo on FF, then mFT cannot take an equivalent photo and thus must take a different photo. In addition, if 25mm f/1.4 1/400 ISO 1600 on mFT represents the "best" photo, then 50mm f/2.8 1/400 ISO 6400 on FF represents and equivalent photo, but FF might be able to take a "better" photo using settings that mFT has no equivalent for.
As a side, can mFT, for example, take a "better" photo than FF? Before answering, let me first note that this question is all together a different question than "Can mFT be the better choice than FF?" -- they are two very, very, very different questions. That said, the answer to the first question is "No" -- assuming relevant factors with regards to the photos taken are more or less equal (but that is not to say that any differences would necessarily have any effect of the "success" of the photo). The answer to the second question is not only "Yes!", but, in my opinion, usually true for the vast majority of people in the vast majority of situations.
That's it. That's the whole of it. And, as I noted, it presumes relevant factors are more or less equal (e.g., if one system has image stabilization and the other doesn't, then that throws a rather large wrench in many situations, and, yes, Equivalence does discuss these things -- that's one reason why the Equivalence Essay is so freakin' long!). But, again, Equivalence absolutely does not say that you would, or should, take Equivalent photos using different formats.
So, apologies for ignoring the rest of the post, but until we have a clear and unambiguous response to the above, it's meaningless to go further.
I'm afraid I have to disagree, even if that were true. For example, the following:
But also because a crop sensor lens of the same field of view length is wide for example my 25mm vs a 50mm on full. I get more depth of field. No still not aperture equivalence. It’s just that on the m43 I’m shooting at 25mm and get the DOF a 25mm affords. When I don’t want background blur, the M43 camera actually improves my hit rate and makes focusing easier.
is absolute bunk.
I missed that - you're right.
That is one hell of a weighted question. "Scientific visual properties"?? And defining the same photos are different??
But YES!!!
You make a statement above that is a long way from fact:
They don't, see my post above. This is very provable, and simple to prove. Plus let's look at another example. Take two photos and show them on a screen one after another, the difference being one f-stop. Flick between them and you will clearly see the difference. Proves your point? No, I say it misunderstands the nature of human vision. So we try again. Put one photo on the screen and once viewed send the viewer off to get a cup of coffee and whilst they're gone swap the photo. Now ask if they are different. You may say that's not a fair test, but I still say that you misunderstand the nature of human vision. And the fact remains that if you perform the test in different ways you get different answers. You can't just pick the result that agrees with your theory and ignore the other.
As for perspective it's assumed in the real world and certainly not an absolute quantity in an image. You are so wrong about the nature of perspective when it comes to human vision, it's nothing like that of the camera, see my post above. It is very possible to take two photos of the same scene that aren't equivalent by a long chalk and still have people seeing them as the same when they are viewed in isolation, try it with a car, same size in the photos but use different focal lengths, apertures, shutter speeds and view them in isolation (the coffee trip in between again) and I bet people don't notice the perspective difference. They'll notice if it's a different car though.
Here:
You start with assumptions that what you hold as measurably constants actually remain as visual constants, or at least become visual differences if they are changed. But this isn't necessarily true. For instance viewing distance isn't really important as the initial assumptions you make when you first view hold remarkably consistent at nearly all viewing distances. So two people can certainly look at the same photo and certainly form different opinions about what it actually shows. Forget the very narrow parameters that you continue to try and restrict the conversation to:
Or trying to restrict it to one person viewing the images, it still remains that human perception varies. If you use the same person glancing at the same photo a year apart I bet their description of what they see will be different when you compare the records...
Honestly GB, you really need to review your assumptions about the nature of human vision, the conclusions you make seem to be based upon your understanding of the actual real differences that can be measured, and that they remain constant through human perception is far enough off the mark for me to say that your switching between "measured" and "visual" as being the same is an assumption not supported by evidence that you need to re-visit.
That's a long way from being:
Equivalence, by definition, is weighted. It concerns itself with perspective, framing, DOF, and motions blur (but can be extended to include resolution, noise, DR, etc. with additional assumptions about the equipment).
No idea what you are saying here. Are you calling perspective, framing, DOF, and motion blur "scientific visual properties"? If so, then sure. If by "defining the same photos are different" you mean that two photos of the same scene can be different, even though the aforementioned "scientific visual properties" listed are the same, then obviously -- color, distortion, flare, etc., etc., etc.. If you mean anything other than what I spelled out here, then I have no idea what you mean.
No, that proves my point.
You're talking about memory here, which is a totally different discussion. If I flick back and forth between two photos and you see a difference, the difference is real. If I show you one photo, you leave the room, come back, show you another photo, and you don't notice a difference, that's not because the photos are not different, it's because you don't remember all the information that was in the photo.
Let's take a more interesting example. If I have someone look at two photos, one on a 4K monitor and the other on an 8K monitor, and they can't see the difference, it's not that the photos are not different, it's that their visual acuity is unable to discern the difference and/or the difference is so inconsequential that they pay no attention to it.
No one said, or implied, that perspective is an absolute quantity in a photo. What is being said is that if two photos are taken from the same position, displayed at the same size, and viewed in the same manner, the perspectives will be the same. This is relative, not absolute.
"Don't notice" is not the same as "isn't there". If I show two photos of the same scene, but change the face of someone in the background and people don't notice, that does not mean the photos are the same (or equivalent). It simply means they didn't notice the difference.
The "they didn't notice the difference" combined with "they noticed the difference but didn't care" is why I say that pretty much any camera cuts the mustard IQ-wise today, to include smartphones. Absolutely there are situations where the equipment makes a huge difference, but for the vast majority of people in the vast majority of circumstances, the only differences that matter are differences in operation, not differences in IQ and/or DOF options.
Let me give a nice example. The following photo was taken at 50mm f/1.4 on a 45 MP FF R5 (larger size here):
If it had been taken at 25mm f/5.6 on a 20 MP EM5, how many people do you think would care about the differences? Not many, I would think. Myself, I care. But I see myself as being in a small minority. What if I had taken it with my smartphone? I think more would notice the differences, but still not care. Maybe express a preference one way or another if pressed, but that's about it. For sure, I can post photos where the differences probably would make a difference, but, again, I'm talking about the vast majority of photos people take, not the minority.
the world is in the state it is because governments are taxing the wealthy countries and passing it on to the 3rd world countries via global warming claims without the general population having any clue as to what's going on.
Good to see an actual image posted in this verbacious thread along with some actual camera parameters. Slightly puzzled - would the EM5 f/number theoretically be f/0.7 (same aperture diameter, as you said earlier) ?
You'll have to be more specific (and cite credible sources) to support your claim. Prove to us all that you know better than ChatGPT:
chatgpt.com/share/689ac48c-8dac-8007-bd82-ee4952e63bfa
😁