The Recent F/stop Controversy

Started 4 months ago | Discussions
riveredger Veteran Member • Posts: 3,468
Re: No it's not
2

camerosity wrote:

riveredger wrote:

camerosity wrote:

Kung Fu wrote:

camerosity wrote:

And that I was able to do it during the film era makes it even more meaningful for me as film still represents the purest form of photography there is.

Film trolling on digital photography review, nice touch.

Dude. Chill. This forum is called "Open Talk". I don't need to apologize to you or anyone else for who I am. If you have a problem with it, that's entirely your problem. Sheesh.

I hear there is now a degree in Forum Etiquette at NYU.

You are now Blocked. See ya!

I think that feature is covered in the advanced curriculum.

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mamallama
mamallama Forum Pro • Posts: 56,308
Re: "Photography is more about being creative"
2

tony field wrote:

mamallama wrote:

Great Bustard wrote:

bolt2014 wrote:

The post about getting rid of the "F/stop" definition turned into such a technical subject that most photographers become lost in the jargon. I think that too many photographers become so embroiled in the technical aspects that they forget that photography is more about being creative .

I imagine most would not disagree that "photography is more about being creative", but understanding the technical side doesn't get in the way of that end. Well, maybe for some it does, like this guy who said:

Further proof that the equivalence people have done permanent damage to the art of photography.

By the way, the guy who said that is the same guy who started the thread you're referencing and didn't return to post in it.

Anyway, I must confess that I'm not quite sure how the "equivalence people" managed to do that. Maybe we need some people to come forward and tell us their stories of how good their photos were until they read all the discussions on Equivalence, and how their photography suffered as a result.

The Equivalence Controversy is like the Taiping Rebellion.

I really seem to have missed this part of the discussion. What is the "Equivalence Controversy" ?

If you don't know, don't bother finding out. You will just be caught into some gobbledygook gibberish. It's better to just let well enough alone.

You would be better off finding out about the Taiping Rebellion.

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Great Bustard Forum Pro • Posts: 43,252
"love"
4

kiwi2 wrote:

Great Bustard wrote:

mamallama wrote:

The Equivalence Controversy is like the Taiping Rebellion.

More like the Copernican Revolution. Amazingly similar, actually.

Man you love yourself.

I'll admit that I'm more a fan of what I say than what you say, and it might not just be me.  And it might not just be him, either.  I will say that I think your photography is very good, and would not say that you need to understand and use Equivalence to be a good photographer (of course, it doesn't hurt, either).  But when it comes to technical discussions, I really don't think you're in a position to throw stones.

LoneTree1 Senior Member • Posts: 1,567
Re: Controversy?

Instead of f-stops, controversy would be to overhaul ALL typical prime and zoom lens focal lengths and make new ones that were more in-line with what people shoot.  What is the biggest refrain of people with kit lenses?  "Darn, I could do with a few fewer mm's at the wide end."  What is the biggest concern of people with tele-zooms?  "Why do I need 70mm when I shoot mostly 300mm and why is the long end always the "worst" optically?

Great Bustard Forum Pro • Posts: 43,252
"Clarity"
7

riveredger wrote:

Great Bustard wrote:

Indeed. However, an important lesson that Equivalence explains is that, for a given DOF and exposure time, the same total amount of light is projected on the sensor for *all* systems. So, for a larger format to have a light gathering advantage over a smaller format, the larger format *must* use a more narrow DOF or a longer exposure time. That's worth knowing, methinks, even if one is otherwise uninterested in other Equivalence related topics.

While correct, I do not think it adds clarity to the discussion. The short version is that a larger sensor will always capture more total light than a smaller sensor, given the same exposure. The other consequences of exposure decisions remain the same, irrespective of format.

Well, I guess we disagree. I think the following three statements below add significant clarity:

  • For a given exposure, more light is projected on a larger sensor.
  • For a given scene, DOF, and exposure time, the same amount of light is projected on all sensors, regardless of size.
  • Thus, the only way for a larger sensor to collect more light is to use a more shallow DOF or longer exposure time.

To me, that's all good-to-know stuff, and only one bullet point outside what I once saw written here on DPR: "If it takes more than a sentence or two to explain, it's probably not worth knowing." 

Great Bustard Forum Pro • Posts: 43,252
Re: "Photography is more about being creative"
3

Carol T wrote:

Great Bustard wrote:

bolt2014 wrote:

The post about getting rid of the "F/stop" definition turned into such a technical subject that most photographers become lost in the jargon. I think that too many photographers become so embroiled in the technical aspects that they forget that photography is more about being creative .

I imagine most would not disagree that "photography is more about being creative", but understanding the technical side doesn't get in the way of that end. Well, maybe for some it does, like this guy who said:

Further proof that the equivalence people have done permanent damage to the art of photography.

By the way, the guy who said that is the same guy who started the thread you're referencing and didn't return to post in it.

Anyway, I must confess that I'm not quite sure how the "equivalence people" managed to do that. Maybe we need some people to come forward and tell us their stories of how good their photos were until they read all the discussions on Equivalence, and how their photography suffered as a result -- like before and after photos:

Before I learned about Equivalence:

After I learned about Equivalence:

You know -- something like that.

No, she would need to be jumping up and down with her fingers in her eyes screaming "nanananana, I can't hear you."

To be honest, of all the facts that people don't want to know about, Equivalence is pretty near the bottom of the list with regards to importance.  Then again, so is everything on DPR, so I don't know why Equivalence gets singled out. 

riveredger Veteran Member • Posts: 3,468
Re: The Recent F/stop Controversy
1

Great Bustard wrote:

riveredger wrote:

Great Bustard wrote:

riveredger wrote:

Great Bustard wrote:

riveredger wrote:

Michael Fryd wrote:

bolt2014 wrote:

The post about getting rid of the "F/stop" definition turned into such a technical subject that most photographers become lost in the jargon. I think that too many photographers become so embroiled in the technical aspects that they forget that photography is more about being creative .

I don't think the issue was about being technical.

With photography, as with many other subjects, there are multiple frames of reference that one can use. A big part of the "f/stop" discussion was which frame of reference to use.

Traditionally, Photographers use the light per unit area ("exposure") as their frame of reference. The primary reason we use relative apertures (f/stops) is that it makes it easier to relate the aperture to the light per unit area. Light per unit area is key when shooting film.

The question is that when one is shooting digital, is it still a good idea to place such importance on light per unit area. In terms of the resulting image, the correlation is much stronger with total light captured.

That's a reasonable question to ask, and a reasonable discussion to have. There are certainly pros-and-cons to either frame of reference.

it's not so much a technical question as a philosophical one. Is the frame of reference designed for the limitations of film the best frame of reference to use for digital?

Well, sir, I think light per unit area is easier to maximize than is total light gathered.

One in the same, for a given camera and scene. That is, if I maximize the exposure of a photo, I've also maximized the total light gathered.

One does not need a larger sensor for the former (which, incidentally will also maximize the total light captured for a given sensor), but will need a larger sensor to significantly impact the latter.

Of course, maximizing the exposure on a smaller format will result in less total light gathered than if one maximized the exposure on a larger format. However, neither is easier than the other.

Your first comment was exactly what I stated (parenthetically) in my next sentence

As to your second comment, I would say that it depends entirely on the equipment you have on hand at a given moment. The fact that I could gather more light with a FF camera when I only happen to have my 1" sensor compact with me is not going to change the outcome of ny photo. It will, though, encourage me to bring my DSLR out next time

Indeed. However, an important lesson that Equivalence explains is that, for a given DOF and exposure time, the same total amount of light is projected on the sensor for *all* systems. So, for a larger format to have a light gathering advantage over a smaller format, the larger format *must* use a more narrow DOF or a longer exposure time. That's worth knowing, methinks, even if one is otherwise uninterested in other Equivalence related topics.

While correct, I do not think it adds clarity to the discussion. The short version is that a larger sensor will always capture more total light than a smaller sensor, given the same exposure. The other consequences of exposure decisions remain the same, irrespective of format.

Well, I guess we disagree. I think the following three statements below add significant clarity:

  • For a given exposure, more light is projected on a larger sensor.
  • For a given scene, DOF, and exposure time, the same amount of light is projected on all sensors, regardless of size.
  • Thus, the only way for a larger sensor to collect more light is to use a more shallow DOF or longer exposure time.

To me, that's all good-to-know stuff.

It is good to know stuff, but not necessary in the explanation.

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Pixel Pooper Veteran Member • Posts: 3,177
Re: Really?
4
  • Michael Fryd wrote:

Actually, at the same angle of view the "equivalent aperture" is the one with the same diameter. In other words it really is the same aperture; no math needed.

You only need to do the math if you normalize everything to light per unit area (which is a great idea when shooting film).

Whether you are shooting film or digital makes no difference. The reason we use the f/stop is that it gives us the same exposure regardless of focal length or angle of view. If we used aperture diameter it would be more complicated because we would need to change the diameter every time we changed our focal length.

While shooting I am much more likely to change my field of view than my sensor size and if I do change my sensor size it is to take advantage of the differences between the two formats, not to take the same picture on both.

The fact that the same aperture diameter gives the same total light at the same field of view is good to know, but it's not as useful when taking pictures. Whatever format you use, the way to maximize total light is to maximize exposure and your total light is limited by the need to avoid overexposure.

Equivalence is a way of comparing formats, and it is a great framework to understand how things work, but it is not a replacement for f/stops and exposure.

Carol T Contributing Member • Posts: 810
Re: "Photography is more about being creative"

Great Bustard wrote:

Carol T wrote:

Great Bustard wrote:

bolt2014 wrote:

The post about getting rid of the "F/stop" definition turned into such a technical subject that most photographers become lost in the jargon. I think that too many photographers become so embroiled in the technical aspects that they forget that photography is more about being creative .

I imagine most would not disagree that "photography is more about being creative", but understanding the technical side doesn't get in the way of that end. Well, maybe for some it does, like this guy who said:

Further proof that the equivalence people have done permanent damage to the art of photography.

By the way, the guy who said that is the same guy who started the thread you're referencing and didn't return to post in it.

Anyway, I must confess that I'm not quite sure how the "equivalence people" managed to do that. Maybe we need some people to come forward and tell us their stories of how good their photos were until they read all the discussions on Equivalence, and how their photography suffered as a result -- like before and after photos:

Before I learned about Equivalence:

After I learned about Equivalence:

You know -- something like that.

No, she would need to be jumping up and down with her fingers in her eyes screaming "nanananana, I can't hear you."

To be honest, of all the facts that people don't want to know about, Equivalence is pretty near the bottom of the list with regards to importance.Then again, so is everything on DPR, so I don't know why Equivalence gets singled out.

True, I suppose, especially here in the US the last couple of years. Even simple facts and realities of nature are 'fake news' to the people who don't want to hear them.

I guess we should be happy that such precious children are present in the world, though, and that some of us are lucky enough to have them living with them and acting as their models.

Pixel Pooper Veteran Member • Posts: 3,177
Re: The Recent F/stop Controversy
2

There was no "f/sop controversy" in that thread. For the most part everyone understood that the OP was just a troll taking a clumsy swipe at equivalence.

mamallama
mamallama Forum Pro • Posts: 56,308
Re: The Recent F/stop Controversy
1

I love the clarity when just the mention of equivalence results in multiple threads that limit out at 150. A  concise one sentence definition of equivalence might help the clarity.

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J A C S
J A C S Forum Pro • Posts: 15,076
Re: The Recent F/stop Controversy
2

bolt2014 wrote:

The post about getting rid of the "F/stop" definition turned into such a technical subject that most photographers become lost in the jargon. I think that too many photographers become so embroiled in the technical aspects that they forget that photography is more about being creative .

I do not think we have started yet with the technical aspects. How about this (Wikipedia):

As Rudolf Kingslake explains, "It is a common error to suppose that the ratio [D/2f] is actually equal to tan θ, and not sin θ ... The tangent would, of course, be correct if the principal planes were really plane. However, the complete theory of the Abbe sine condition shows that if a lens is corrected for coma and spherical aberration, as all good photographic objectives must be, the second principal plane becomes a portion of a sphere of radius f centered about the focal point".[4] In this sense, the traditional thin-lens definition and illustration of f-number is misleading, and defining it in terms of numerical aperture may be more meaningful.

Aaron801 Veteran Member • Posts: 6,174
Re: Really?

Pixel Pooper wrote:

  • Michael Fryd wrote:

Actually, at the same angle of view the "equivalent aperture" is the one with the same diameter. In other words it really is the same aperture; no math needed.

You only need to do the math if you normalize everything to light per unit area (which is a great idea when shooting film).

Whether you are shooting film or digital makes no difference. The reason we use the f/stop is that it gives us the same exposure regardless of focal length or angle of view. If we used aperture diameter it would be more complicated because we would need to change the diameter every time we changed our focal length.

While shooting I am much more likely to change my field of view than my sensor size and if I do change my sensor size it is to take advantage of the differences between the two formats, not to take the same picture on both.

The fact that the same aperture diameter gives the same total light at the same field of view is good to know, but it's not as useful when taking pictures. Whatever format you use, the way to maximize total light is to maximize exposure and your total light is limited by the need to avoid overexposure.

Equivalence is a way of comparing formats, and it is a great framework to understand how things work, but it is not a replacement for f/stops and exposure.

Yes!!! F-stop is useful for exactly as you say, to determine exposure. If you want to debate performance, one format vs another you can do a bunch of math and go far beyond the idea of f-stop values, but it isn't really going to help your photography to do so... You might have a bit of an upper hand though in an online argument so having this sort of knowledge can't be said to be entirely useless.

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mamallama
mamallama Forum Pro • Posts: 56,308
Re: The Recent F/stop Controversy

J A C S wrote:

bolt2014 wrote:

The post about getting rid of the "F/stop" definition turned into such a technical subject that most photographers become lost in the jargon. I think that too many photographers become so embroiled in the technical aspects that they forget that photography is more about being creative .

I do not think we have started yet with the technical aspects. How about this (Wikipedia):

As Rudolf Kingslake explains, "It is a common error to suppose that the ratio [D/2f] is actually equal to tan θ, and not sin θ ... The tangent would, of course, be correct if the principal planes were really plane. However, the complete theory of the Abbe sine condition shows that if a lens is corrected for coma and spherical aberration, as all good photographic objectives must be, the second principal plane becomes a portion of a sphere of radius f centered about the focal point".[4] In this sense, the traditional thin-lens definition and illustration of f-number is misleading, and defining it in terms of numerical aperture may be more meaningful.

Now you have opened Pandora's Box  for those who want to outdo the Equivalent genius. 

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Lee Jay Forum Pro • Posts: 54,894
Re: Really?
1

Pixel Pooper wrote:

The fact that the same aperture diameter gives the same total light at the same field of view is good to know, but it's not as useful when taking pictures.

It's useful if you're shooting with two formats at once or if you are planning to buy new equipment and want to compare on a fair basis.

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Lee Jay

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kiwi2
kiwi2 Veteran Member • Posts: 4,755
Re: Really?

Lee Jay wrote:

Pixel Pooper wrote:

The fact that the same aperture diameter gives the same total light at the same field of view is good to know, but it's not as useful when taking pictures.

It's useful if you're shooting with two formats at once or if you are planning to buy new equipment and want to compare on a fair basis.

I just took two photos off the back doorstep with two different format sizes. One with my APS-C X-T2 and another with a 1/2-inch sensor pocket camera...

Framing is roughly where I wanted it and DOF is ample for everything to be in focus with both.

Why exactly should I be worried about achieving equivalence between the two..??

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Michael Fryd
Michael Fryd Forum Pro • Posts: 11,807
Re: Really?
4

kiwi2 wrote:

Lee Jay wrote:

Pixel Pooper wrote:

The fact that the same aperture diameter gives the same total light at the same field of view is good to know, but it's not as useful when taking pictures.

It's useful if you're shooting with two formats at once or if you are planning to buy new equipment and want to compare on a fair basis.

I just took two photos off the back doorstep with two different format sizes. One with my APS-C X-T2 and another with a 1/2-inch sensor pocket camera...

Framing is roughly where I wanted it and DOF is ample for everything to be in focus with both.

Why exactly should I be worried about achieving equivalence between the two..??

You shouldn't be concerned about equivalence between these two. These are examples of images where a wide range of settings will give you a very similar image. A big factor in this is that you have a lot of light.

If you look at the minimum aperture diameter that gives you the depth of field you need, and the slowest shutter speed that stops motion blur, you still have more than enough total light reaching the sensor to keep noise below an acceptable level. This means that you have a lot of options for setting the camera that will give you a similar image.

In your case the particular settings aren't important, so there is no need to match them across formats.

====

But not everyone is shooting in such a bright environment.

There are many shots where the depth of field needs to fall into a particular range. You may want all of the model's face to be within the depth of field, but the background to be blurry.

Your model may be moving, and you may need a shutter speed fast enough to freeze motion.

In that case, there may be a very small range of acceptable settings. In such a situation equivalence would be quite helpful of you needed to switch cameras, but still wanted to capture the image you envisioned.

====

The bottom line is that different photographers are in different situations. We can absolutely imagine situations where equivalence is not important, and we can imagine situations where it is critical.

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Chaplain Mark
Chaplain Mark Senior Member • Posts: 5,588
Re: No it's not

camerosity wrote:

It just means some of us here have a more technical background than others here. (Some of us are working pros as well).

Anyone can buy a digital SLR these days and call themselves a Pro. That's why a lot of professional wedding photographers left the business, because prices went down through the floor.

I'm proud of the two years I spent in college studying Commercial Photography, it wasn't wasted time and it earned me 12 years of work in the professional photo industry after I graduated.

You can pooh-pooh it all you want, but for me, it was an amazing time of my life that I'd gladly repeat if I could. And that I was able to do it during the film era makes it even more meaningful for me as film still represents the purest form of photography there is (seeing those guys out there with the 8x10 view cameras on a tripod never ceases to blow me away).

Well said...!

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Great Bustard Forum Pro • Posts: 43,252
Yep, that's the modern world, all right.
2

mamallama wrote:

I love the clarity when just the mention of equivalence results in multiple threads that limit out at 150. A concise one sentence definition of equivalence might help the clarity.

If you can't say it all in a Twitter post, then it isn't worth saying -- that's the world we now live in. Maybe if I ask the POTUS, he can do it just for you.

Great Bustard Forum Pro • Posts: 43,252
It's weird, isn't it?
3

Michael Fryd wrote:

kiwi2 wrote:

Why exactly should I be worried about achieving equivalence between the two..??

You shouldn't be concerned about equivalence between these two.

It's weird that so many [intentionally] misrepresent Equivalence saying that they should be shooting Equivalent photos on different formats, even though Equivalence *explicitly* says quite the opposite.  It's as if someone said to multiply mi/hr by 1.6 to get km/hr, and they said, "Why should I drive the same speed in Europe as I do in the US?"

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