First of all, Equivalence is only relevant when comparing different formats or comparing using a longer lens or TC vs cropping. Secondly, there are a lot of factors that Equivalence does not cover (e.g. AF speed/accuracy, frame rate, weather resistance, distortion, flare, etc., etc., etc.) that may well matter more to a person than the factors that Equivalence does cover.
But, for example, if you care a lot about DOF, noise, and/or resolution (I know I sure do), then Equivalence can give you a good ballpark estimate of how different systems can compare. Of course, finding actual comparisons is more useful, but actual comparisons don't always exist. Think of it this way: imagine you're an mFT shooter and you'd like a 35-100 / 2. Well, there isn't one. But FF has a 70-200 / 4, which will do the same thing, so you could get that. Alternatively, let's say you shoot FF, like your 70-200 / 4, but wish it were smaller and lighter and were willing to give up a stop to get that. Well, there's a 35-100 / 2.8 on mFT which is a lot smaller and lighter than a 70-200 / 4 on FF. Understanding Equivalence makes it easier if the format you're using doesn't offer what you need.
Is it a big deal? Not in my opinion. More like "duh", really. But there are so, so, so many people that not only don't understand the "duh" of Equivalence, they actually argue against it. But that's par for the course in a world where the head of the FDA is an anti-vaxxer, amongst any number of other more important "duh" things that people just don't seem to get and even argue against.
The thing is, for sensors of the same generation, the differences in sensor performance aren't all that drastic except, on occasion, at the extremes. I mean, the difference between a QE of 45% and 55% is pretty trivial, really (1/3 of a stop difference in how much light is projected on the sensor for a given scene, f-number, and exposure time).
Same goes for electronic noise, where the differences are typically relevant only when heavily pushing shadows or when shooting in extremely low light situations (e.g. pushing shadows more than 4 stops and/or shooting in light so low that you'd be using, say, ISO 12800 or higher). Another form of noise that can matter a lot for people who shoot long exposures (several seconds or longer) is thermal noise, which is a result of the sensor heating up during the exposure.
In short, the more extreme the shooting conditions, the more the differences can matter, but, in my opinion, the differences are beyond trivial for the vast majority of shooting scenarios. Then again, the vast majority of shooting scenarios doesn't matter when your photography is outside that envelope, right? : ) In fairness, though, I honestly think that the differences in IQ and/or DOF options is moot for the vast majority with mFT and larger formats. Are there differences? Of course. I just don't feel that they matter with regards to the "success" of the photo for the vast majority of situations for the vast majority of people.
Absolutely. In the words of Dan Dreiberg (Nite-Owl):
"Is it possible, I wonder, to study a bird so closely and catalogue it's peculiarities in such minute detail, that it becomes invisible?Is it possible that while fastidiously calibrating the span of it's wings or the length of it's tarsus, we somehow lose sight of it's poetry?"
But in that statement there is the assumption that it is the "higher" IQ that should be achieved.
Why?
Didn't the need to get something in less than ideal light lead to push processing B&W film, and the subsequent over-development lead to the increased grain and blocked shadows that created the "look" synonymous with gritty realism? This is how the "photographic language" evolves, how a "look" is achieved and gains meaning.
If, on the other hand, we just invented better film so the IQ was "equivalent" then the photos would look the same (as equivalent photos should) and the grainy ones would just look like bad photos??
It is puzzling to see a sub-discussion about IQ in this "Equivalence" thread. For equivalence, it seems to be generally accepted that equivalent images can look different.
There is a relationship between aperture, shutter, focal length, etc. there is more than one answer depending on whether you hold exposure per unit area or total light constant. With total light you effectively cancel out the photo. You're not looking at how a photographer can capture a moment that resonates emotively with an audience, you are only looking at the performance of the camera, or as I call it IQ.
I don't find equivalence to be that technical. It's a fairly simple relationship. If you have a set of parameters that are related then by holding some constant other will cancel out. But you are still only looking at the numbers behind aperture/shutter/AOV and not the actual photos, so your understanding is the numbers and not the actual photos. It provides approximately zero insight into what actually constitutes an emotive image. Equivalent photos "may" be different, they "may" also be the same. But what does it matter as you have effectively canceled the photo from the equation in your very definition of "photos are equivalent when..."? Equivalency doesn't look at the photos, it only looks at the kit. Yes, thinking in terms of "total light" rather than "light per unit area" is certainly a helpful mindset when changing from film to digital, but the base assumption that all cameras are capable of taking the same photo ignores the basic truth that as humans we're illogical and don't take the same photos with different cameras, we don't use them in the same way or respond to them the same. Except on photo forums where equivalency buffs prove themselves correct. But then, again, the same forums make the bold statement that it's the photographer not the camera and launch into numerous discussions of how the difference in the kit matters and what new technical advance will change photography (I thought it was the photographer?)...
Yes but equivalence never sets out to determine anything along the lines of "emotive image".
Perhaps it is better to think about why the concept of equivalence was created / defined in the first place, then stick to the definition and leave other aspects of the images to separate conversations.
For sure, failing to see the forest for the trees is definitely a thing. Also, maximizing the IQ of a photo via judicious choice and use of equipment is also a thing. Then there are those for whom the photo is merely a rough sketch for the art they wish to make, so eeking every last bit of IQ out of a photo is silly. For others, still, it's not the equipment, per se, that matters, but how simple it is take the photo and have the in-camera jpg engine process it in a way that they like. And, of course, there are a million other ways of viewing photography.
Indeed, it is my opinion that the last group mentioned above represents, by far, the majority of people taking photos and that is the reason that the smartphone is the camera of choice. This is especially true when the target audience primarily views your photos on a smartphone and sharing your photos quickly is important.
Apologies -- I didn't mean to imply the "should". I meant that it "could". Big difference.
Sure, "low IQ" can, and often does, take on an artistic value in and of itself. Noise, motion blur, blown highlights, strong vignetting, flare, etc., etc., etc. can all add to the artistic effect of a photo. Doesn't mean I want a "low IQ" camera/lens. On the other hand, for some photographers, it means they can accomplish what they need with a "low IQ" camera/lens system that is smaller, lighter, and less expensive than my kit. For example, a smartphone is so, so, so much better than my R5 for most people, if only due to its size/weight, "speed of publication", and incredible processing.
I can't imagine anyone using Equivalence as a means to an end for photography as opposed to a framework that relates the visual properties of different formats (and/or cropping/TCs) to the camera settings.
Were that everyone else had the same understanding!
Equivalence is all about how the photos look based on the camera settings on different formats, using a TC, and/or cropping. However, Equivalence only talks about certain visual aspects (perspective, framing, DOF, and motion blur) but other aspects can be added to the mix by adding in additional considerations (e.g. noise, DR, resolution, etc.).
Nothing to do with film vs digital -- that's all about the effect of the f-number on noise.
Equivalence does not make this claim, or anything even close to this claim. For a really simple example, you might be able to get a photo of a scene with your smartphone but can't with your camera because cameras are not permitted.
A huge element not covered by Equivalence is operation where differences in operation can, and often do, matter considerably more than differences in IQ and DOF options. So, for sure, one doesn't use a smartphone the same way one uses a FF camera, in the same way one doesn't use a bicycle the same way one uses a car. There is overlap, of course, and the more similar the operation is between two systems, the more the overlap is likely to be.
No more or less weird than scientists proving themselves correct about the Earth being a sphere. Sure, 99.9%+ of the population has no need, whatsoever, to know the shape of the Earth. But let's say that there's a discussion about why a plane's route from LAX to Narita passes close to Kamchatka, then it's good to know what the shape of the Earth is. Even for someone that still doesn't care ("Whatever -- all I need to know is that it takes me 10 hours to get from LAX to Narita"), which is fine, why argue against the facts? Just say you don't care and be done with it.
It certainly is the photographer, but part of the "it's the photographer" is based on the photographer knowing how to use their equipment. Equivalence, of course, plays no role in that, though. The role of Equivalence is when the photographer is debating between a smartphone, compact, mFT, APS-C, FF, or [digital] MF as the best tool to accomplish their goals, or if they're debating between cropping, using a TC, or getting a longer lens. In other words, Equivalence is about choices the photographer makes in choosing equipment, not using the equipment in hand.
So it's inherent in the statement that it doesn't really matter what camera you use, and as GB pointed out:
So it makes little visual difference what modern digital camera you use most of the time. Other than that...
Personally I find it distracting and counter productive. That we use a framework which specifies at it's core "equivalent photos", or in plain terms "copy machine" is strange in a creative medium as it's obvious that the creative side is left out, it's just the technical. Also it places an unwritten weight that the choices we make regarding the settings we have on cameras are what defines the photos. Yet it only looks at the absolute and measurable differences between the settings and so completely misses a core understanding in photography. Cameras always lie.
A camera will always show a scene in a way that differs from how we see it through human eyes, it always abstracts the viewpoint. If that is a simple as a static representation of movement or limited DOF or even how cameras capture the correct linear perspective which looks distorted to us, cameras will always show the scene in a way that's different to how our human eyes see the real world. And yet we understand photos as being the real world. In that is the process of how we attach real world meaning to a view we don't see in the real world and so how we interpret photos and give real world meaning to views that are abstracted from the real world.
In this viewpoint (from actual human eyes and human understanding rather than actual measurable differences in photos) it quickly becomes apparent that actual choice of aperture/shutter/ISO is not that critical. That to actual human eyes rather than the precision of science things like aperture and AOV don't define what we see as equivalent photos. In short the "machine view" of equivalent photos fails to match the "human perception" of what we actually see as equivalent. But instead of having the discussion that there is no relationship between the shutter speed/amount of blur and measured speed of the object photographed because it goes through the human process of translation of an abstracted view to one that's consistent with experience and memory, we keep trying to force it to fit the maths. The argument goes back to, "but those aren't true equivalent photos, the maths says... and the maths is the only way to communicate because it's the only way to arrive at the precise and absolute understanding we are looking for."
Like analysing the frequencies of the sound to determine which is the best violin whist ignoring human preference is based on memory and experience, and that what defines the best instruments is also dependent on how a practiced human hand can bridge that abstract connection and create emotive response.
Absolutely! High resolution photos have a look and feel, but doesn't the concept of equivalency tend to contradict this?
But I think the main driver for smart phones is that the processing is deliberately slanted towards mass market preference, or the WOW factor. Again it's not the "machine measured" difference that is the driver between the smart phone and the R5 but the human perception and preference for the level of processing and the likes gained on social media.
As above, "the "machine view" of equivalent photos fails to match the "human perception" of what we actually see as equivalent."
I don't argue with the relationships expressed in equivalent photos. But as you are saying:
Then I ask why the conversation hasn't progressed beyond being just an precise definition of equivalency? As above, I'm trying to say that if we look beyond the absolute comparison or real measured differences between photos (machine view) and include the vagaries of how human eyes actually see and translate the abstracted view the camera produces and attaches meaing to that we find that a lot of equivalency, especially the precision of the maths, fails to have any real relevance.
But we still don't seem to be having the conversation beyond how equivalency is correctly defined.
It also provides the logical framework we desire that allows us to categorise, compartmentalise and "get a handle on" photography and thus label it "understood". But it is a "logical" framework and as such still fails to bridge the gap to abstract understanding of visual principals. No, they're not separate subjects. Like our violinist who has learned the muscle memory necessary to play the music with a pleasant and consistent sound, somewhere along the line they still need to make that abstract connection between that muscle memory and how they feel. Equivalency still seems to be stuck on defining the correct muscle memory and every time we say, "look at sometime you need to just go with your gut and see how you feel to develop that emotive understanding," we get back to, "that isn't the correct definition of..." and reinforce the logic. Which is the opposite of emotive. 😁
I think you will find that one of the reasons for the creation of equivalence was to create a level playing field to enable discussion of the creative side to occur with equal footing, when comparing images from different formats...
Interesting to note that the only post showing example images is Bill Ferris' original post in this thread. All the rest add up to yards and yards of rebuttal verbiage - often written in SPV (Standard Photographic Vague) with no supporting links or formulae.
I think it's important to add that the "little visual difference" is for most people, for most of the scenes they photograph, based on how most people view the photos. Now, if you are not in the "most people" category (I know I certainly am not, and not just with regards to photography!), then it can not only make a huge difference -- it can make all the difference.
This is not merely limited to the equipment, mind you. It's true for lenses and camera settings. I mean, how often would a photo of a scene taken at 50mm with an f/4 zoom fail but be successful had it been taken at 50mm f/1.4 with a top prime? But for some reason, people are happy to discuss the merits of this lens vs that lens, the role of the photographer choosing the Canon settings, when any lens shot in auto mode would have gotten the job done most of the time.
Well, yeah! That's 'cause Equivalence is about, for example, converting Fahrenheit to Celsius, not about whether you feel hot or cold!
Again, Equivalence does no such thing. It just tells you the effect the settings have on different formats, or when using a TC, or when cropping.
Because Equivalence is not about how to take a photo -- it's about how the visual properties compare between formats (or when using a TC or cropping) based on the camera settings.
[/quote]Cameras always lie.[/quote]
A lie is when you present something as true that you know (or believe) to be untrue. Cameras record a limited version of reality in the same way that our eyes do. Would you say that our eyes lie because they do not see radio waves?
Our eyes and brain do the same with regards to reality.
We understand photos to be representations of the real world, not the real world itself.
Again, no. Thinking the purpose of Equivalence is to take Equivalent photos is like saying the purpose of converting Fahrenheit to Celcius is to make everything the same temperature.
I vehemently disagree. Put the same jpg engine in a smartphone that my R5 uses and it would have zero effect on how many choose a smartphone over an R5.
As above, "the "machine view" of equivalent photos fails to match the "human perception" of what we actually see as equivalent."[/quote]
Take a photo of a scene at 25mm f/2.8 1/500 ISO 800 on an OM1. What settings on an R5 would produce a photo that is most similar? That's the entirety of what Equivalence is about. It's like you're arguing against the science behind vaccines because people don't trust the medical establishment.
So, for example, you want to have a conversation on the differences between the photos someone took with their smartphone vs the photos they took with their FF camera? Sure. Nothing to do with Equivalence, however, unless technical subjects such as DOF, DR, noise, resolution, etc., came up in the discussion.
Again, you completely misunderstand the purpose of Equivalence. Equivalence says nothing about how to take a "good" photo. Equivalence says nothing about how to use the camera in your hand. Equivalence merely says that these settings on this camera give a similar result to these settings on this camera, or that cropping a photo or using a TC will have these effects compared to using a longer focal length. That's it. That's all it says.
For whatever reason, you're conflating Equivalence with using the camera in hand to take photos and the emotional impact the photos may or may not have. Equivalence says nothing about that at all.
I think the main issue at this point is resolving the misinterpretation of the purpose of Equivalence. If someone understands Equivalence, the "proper" response would be, "OK" or "I don't care -- it doesn't have anything to do with how I use my camera".
By the way, Bob just sent me an email with a classic example of people misrepresenting Equivalence out of gross ignorance of what it says:
Now imagine that same kind of ignorance being used with regards to vaccines, global warming, tariffs, etc., etc., etc., and you can see more than a little clearly why the world is in the state it is currently in.
This is kinda the core of the disagreement here. GB, you're so invested in this that you will not accept that the visual properties when measured scientifically differ from the visual properties when viewed with human perception. Every time I try to get past this and discuss how human perception translates or makes sense of these visual cues you keep dragging it back to the absolute measured properties of the image and the way the camera creates them.
For instance your eyes have a very limited range of foveal vision so your vision is a composite of scanning the scene, you move the camera position so it is a composite of "looking directly at". Not only that but we also move through the landscape so your composite image is also layered over time and movement. Not only that but the concept of time is far more abstract as it includes the mostly inaccurate human memory, up to 80% sometimes if you just glance and assume. We also actively resolve the inconsistencies in the "adaptive pano" as we move and assimilate information and relate it to different memories in line with confirmation bais and not fact. And not only that but we actively believe that each revised "adaptive pano" is the absolute truth and always has been so we can act on visual info with absolute confidence, we actively ignore that it changes and adapts.
So how do you interpret the correct linear perspective of a wide angle FOV as rendered correctly on a sensor when we have no visual reference in our memory of viewing the real world that is "equivalent" to it except by how we learnt to interpret photos and other 2D renderings of correct linear perspective. Your statement:
Is so far off base here.
There is a very real difference between how the camera renders a scene and how eye/brain present the same scene. And also how in how we measure differences in images and what we actually see when we view the photos that can't be dismissed with the blanket statement above. They do not cancel out and to suggest such does a disservice to your scientific curiosity. Sorry GB but from here you seem a little dogmatic in that you will not let the conversion progress beyond how you wish to quantify.
Seriously, if you view photos with human eyes then you MUST consider the limitations of the equipment used to measure and the effects that has on the results, if you don't then your assumptions will introduce an error in your conclusions. And if there is a real difference in your measured differences in images and the differences we actually perceive when we examine the images, the effects of human perception don't conveniently cancel out, then you have to revisit your statement that we are discussing the visual differences when in fact you are only discussing the measured differences.
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 all take the same photo!
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.
