Focal length 35mm equivalent, but not F-stop?

Started Jul 24, 2014 | Discussions
Lee Jay Forum Pro • Posts: 55,144
Re: Focal length 35mm equivalent, but not F-stop?

Lee Jay wrote:

Lee Jay wrote:

I also use equivalence to make purchase decisions, and decisions about what equipment to carry into certain situations. Sometimes I use it for determining what settings I want to use in some situations.
--
Lee Jay

"I also use equivalence to make purchase decisions,..." I like to challenge this sentiment.

I say that you have not chosen m43 because m43 f/2 is equivalent to f/4 on FF. You know FF can do f/2 as well as f/4.

Also, I will say that you have not chosen FF because f/4 is equivalent to f/2 on m43.

And so without the actual comparison of the real images that you're after, this equivalence is meaningless to make the purchase decision.

Nope...wrong. I use equivalence to plot lens (and format) performance envelopes, just like DPReview has started doing in their compact camera reviews (except mine are better). In fact they started doing that because of my repeated suggestions over several years.
--
Lee Jay

Now I'm being passive aggressive - so you don't look at the images from potential equipment you want to buy? You buy FF because f/4 is equivalent to f/2 on m43?

That is one consideration of many.
--
Lee Jay

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mostlyboringphotog Veteran Member • Posts: 9,007
Re: Focal length 35mm equivalent, but not F-stop?

pavi1 wrote:

Chikoo wrote:

All camera manufacturer when they publish technical specification of their camera lens publish the focal length and it's equivalent in 35mm. But the same is not done for F-stop. Why?

Because it is Babel.

May be for the fixed lens cams but the lens manufacturer would not list FL in equivalent unless they want to lose their prestige.

The reason the equivalent f-stop is problematic is because let's say f/2 4/3 lens is equivalent to f/4 on FF but if you attach f/2 4/3 lens on FF body, is it a f/2 lens or f/4 lens?

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Great Bustard Forum Pro • Posts: 43,683
Re: Focal length 35mm equivalent, but not F-stop?

Beachcomber Joe wrote:

bobn2 wrote:

So, how does 'total light' relate to 'highest image quality? Simply because it tells you, so far as your operation of the camera controls are concerned, how much noise or grain (depending on digital or film) will be in the image. And in the end, all else being equal, noise or grain is the major metric of image quality.

Oh wow, I see I haven't kept up with the times. Last year in the fantasy world where all else is equal resolution was the metric du jour of the technobabblers, a couple of months ago it was dynamic range, now you tell us it is noise. Any chance that you guys will ever consider subject matter, other than test charts and brick walls, and composition as being of some importance?

If little things like resolution, noise, DR, DOF, etc., don't matter to your photography, then you are free to instead participate in discussions that do not involve discussions about these matters. Indeed, DPR has several forums dedicated to the art of photography, as well as challenges, where, I dare say, differences in IQ and/or DOF range between systems seems to play little to no role in the "success" of the photo.

For some photographers, IQ may be the most important aspect of photography. For others, it may play no role at all or simply be an added plus. But it is time well spent to reflect on just how important IQ is to our own photography, given that IQ is, at best, merely a means to achieving a quality image, and, at worst, completely irrelevant to the photo.

bobn2
bobn2 Forum Pro • Posts: 63,503
Re: Focal length 35mm equivalent, but not F-stop?

mostlyboringphotog wrote:

pavi1 wrote:

Chikoo wrote:

All camera manufacturer when they publish technical specification of their camera lens publish the focal length and it's equivalent in 35mm. But the same is not done for F-stop. Why?

Because it is Babel.

May be for the fixed lens cams but the lens manufacturer would not list FL in equivalent unless they want to lose their prestige.

The reason the equivalent f-stop is problematic is because let's say f/2 4/3 lens is equivalent to f/4 on FF but if you attach f/2 4/3 lens on FF body, is it a f/2 lens or f/4 lens

It's always an f/2 lens. It will behave just like an f/2 lens on an FF camera, which is like an f/1.0 lens would behave on a mFT camera. It's image circle probably won't cover the whole frame. Users of system which have more than one sensor size tend to be aware of this.

-- hide signature --

Bob

Tim Tucker Senior Member • Posts: 1,337
Re: Let's correct it, then.

bobn2 wrote:

Tim Tucker wrote:

bobn2 wrote:

Lee Jay wrote:

Tim Tucker wrote:

Erik Magnuson wrote:

Tim Tucker wrote:

Erik Magnuson wrote:

Tim Tucker wrote: -

Is this the same as saying all f2 lenses transmit the same amount of light, but different sensor sizes collect different total amounts for the same exposure?

Amount is not a precise term. A 55gal drum and a 20oz red solo cup left out in the rain might both collect 1" of water. Is the same "amount" of water collected in each?

Eh? Total amount IS a precise term. Measure your volume in litres and you have a precise answer. But that is not what I asked.

It was the answer to your first question and use of "amount." All f/2 lenses do not transmit the same amount of light or my f/2 cell phone lens would transmit as much light as a 200mm f/2 lens. Even if I managed to put a 24x36mm sensor behind the call phone cam lens, it would not help much. What the lens transmits and what the sensor collects may be related, but they are not the same thing.

Sematics, as corrected by Lee Jay (my original statement above). Lenses for different formats do not have the same coverage therefore the total amount of light will not be the same but the light/square metre of sensor size (transmitted?) is the same at f2. A Super Angulon 90mm at f8 will produce the correct exposure regardless of whether I put 4"x5" film or 35mm film behind it.

More semantics...

"A Super Angulon 90mm at f8 will produce the same exposure regardless of whether I put 4"x5" film or 35mm film behind it."

It may or may not be "correct", whatever that means.

Here's a thought on this 'correct' exposure nonsense. Let's go back to film, since it is film based methodology which has confused people. Suppose we added to the equivalence requirements the condition 'equal granularity', and were looking at equivalence between 110 (roughly Four Thirds) and 135 (what we'd now call 'full frame'). If we wanted equal granularity in the image enlarged to the same output size, we'd want the same number of grains in each shot, which means that the 135 grains would need to be four times the area. Since each grain requires two photons to reduce it, both shots would need the same number of photons to expose. Thus the exposure of the 135 would need to be one quarter of that for the 110, or in other words, the ISO of the 135 film would need to be four times higher (which it would be in any case, since the grains were four times larger in area, so it would produce the same density for one quarter the number of photons).

Ah, but grain is a function of the film emulsion and development

Film emulsion, yes. A film works because an incoming photon liberates a photoelectron which reduces a molecule of silver chloride to an atom of silver. At least two silver atoms are required to catalyse the chemical reduction process which will turn the whole halide crystal to silver. These need to be at the same locality in the grain, so the grain needs an 'electron trap' so that the silver atoms are likely to occur at the same place. The process of increasing the quantum efficiency of emulsions involved (chemically) engineering better electron traps and also manipulating the shape of the crystal so that it presented a bigger surface area (compared with its overall size). So, that's much the same as digital, films improved in QE as emulsion formulations improved, but for a given formulation the basic change in speed depended on grain size, basically how much silver got produced per photon. So in the end 'film speed' was a function of QE and grain size, it could be increased either by increasing QE or grain size. So, my comment was assuming film of similar QE, where the speed would be controlled by grain size. So far as development goes, the silver atoms catalyse reduction in the sense that they speed it up. Leave the halide in a reducing agent, its all going to become silver in the end. In the end, development has to be controlled so that the proportion of exposed halide to the proportion of halide that gets reduced anyway favours the development of a good quality image. So more development (by means of a more aggressive developer, longer development time or higher temperature) increases the cahnces of all exposed grains being developed out (thus increasing 'speed') but also increases the chance of non-exposed grains being developed, this providing 'fog' in unexposed parts of the image, and reducing the overall DR.

(development produces the grain not exposure),

No, manufacture produces the grain. It is in the film. Exposure and development only determines which grains are turned into silver. Development can also effect the shape of the final developed grain.

but is also affected by focus

No

and over/underexposure.

Also no. What can happen is that printing to compensate for a thin or thick negative makes the grain in the final image more apparent.

If you scan you have artefacts of noise, nyquist considerations, sharpening artefacts, if you print then you have development and over developed/under exposed/temperature etc. considerations. Noise in film is not translated into the final image in the same way that digital noise is.

The starting process is exactly the same, a photon releases a photoelectron. The difference is because film is more digital than digital is. While a pixel will continue to accumulate charge so long as its FWC is not exceeded, and can thus count tens of thousands of photons, a silver halide grain can only ever count a few photons (that's why film is non linear, as exposure increases the chance of any photon finding an unreduced grain reduces). So, in the end, what I said is true. Keep the same film technology and development, and to produce the same granularity with 135 as 110 you need a film with four times the grain area, which will have four times the ISO. And I can be allowed 'same film technology and development' if the f2=f2=f2 brigade can be allowed to insist on the same film.

The point being that it as a pointless argument because it doesn't apply to grain size.

It certainly does, you need to brush up on your film chemistry.

I know this is supposed to be an analogy but this is getting out of hand. Stick to the facts.

I am, not my fault if you've got the wrong impression of the facts.

Good grief! I'm sorry, and no disrespect because I'm sure your theory is right... But in the real world? Equivalence in film grain? Just what is the point? With 30 years of experience developing I stand by what I say. It is a completely pointless exercise. Development affects grain size, try push processing, out of focus areas look a lot grainier, - no this is pointless...

Great Bustard Forum Pro • Posts: 43,683
Why I chose FF.

mostlyboringphotog wrote:

Now I'm being passive aggressive - so you don't look at the images from potential equipment you want to buy? You buy FF because f/4 is equivalent to f/2 on m43?

I chose FF because:

  • I love shallow DOF (but that does not mean I have to always use shallow DOF with FF).
  • The more detail the better.
  • The less noise the better.
  • I could afford to do so and the size and weight were not a limiting factor.

As I always like to say, if it were not for differences in size, weight, and price, we'd all be shooting FF, even if we did not need a more shallow DOF than what FF offers, did not need more resolution than we currently have, and did not need less noise than we currently have.

Many ask me why I don't shoot MF. Well, there's that whole size, weight, and price thing, right?

Lee Jay Forum Pro • Posts: 55,144
Re: Let's correct it, then.

bobn2 wrote:

Tim Tucker wrote:

bobn2 wrote:

Lee Jay wrote:

Tim Tucker wrote:

Erik Magnuson wrote:

Tim Tucker wrote:

Erik Magnuson wrote:

Tim Tucker wrote: -

Is this the same as saying all f2 lenses transmit the same amount of light, but different sensor sizes collect different total amounts for the same exposure?

Amount is not a precise term. A 55gal drum and a 20oz red solo cup left out in the rain might both collect 1" of water. Is the same "amount" of water collected in each?

Eh? Total amount IS a precise term. Measure your volume in litres and you have a precise answer. But that is not what I asked.

It was the answer to your first question and use of "amount." All f/2 lenses do not transmit the same amount of light or my f/2 cell phone lens would transmit as much light as a 200mm f/2 lens. Even if I managed to put a 24x36mm sensor behind the call phone cam lens, it would not help much. What the lens transmits and what the sensor collects may be related, but they are not the same thing.

Sematics, as corrected by Lee Jay (my original statement above). Lenses for different formats do not have the same coverage therefore the total amount of light will not be the same but the light/square metre of sensor size (transmitted?) is the same at f2. A Super Angulon 90mm at f8 will produce the correct exposure regardless of whether I put 4"x5" film or 35mm film behind it.

More semantics...

"A Super Angulon 90mm at f8 will produce the same exposure regardless of whether I put 4"x5" film or 35mm film behind it."

It may or may not be "correct", whatever that means.

Here's a thought on this 'correct' exposure nonsense. Let's go back to film, since it is film based methodology which has confused people. Suppose we added to the equivalence requirements the condition 'equal granularity', and were looking at equivalence between 110 (roughly Four Thirds) and 135 (what we'd now call 'full frame'). If we wanted equal granularity in the image enlarged to the same output size, we'd want the same number of grains in each shot, which means that the 135 grains would need to be four times the area. Since each grain requires two photons to reduce it, both shots would need the same number of photons to expose. Thus the exposure of the 135 would need to be one quarter of that for the 110, or in other words, the ISO of the 135 film would need to be four times higher (which it would be in any case, since the grains were four times larger in area, so it would produce the same density for one quarter the number of photons).

Ah, but grain is a function of the film emulsion and development

Film emulsion, yes. A film works because an incoming photon liberates a photoelectron which reduces a molecule of silver chloride to an atom of silver. At least two silver atoms are required to catalyse the chemical reduction process which will turn the whole halide crystal to silver. These need to be at the same locality in the grain, so the grain needs an 'electron trap' so that the silver atoms are likely to occur at the same place. The process of increasing the quantum efficiency of emulsions involved (chemically) engineering better electron traps and also manipulating the shape of the crystal so that it presented a bigger surface area (compared with its overall size). So, that's much the same as digital, films improved in QE as emulsion formulations improved, but for a given formulation the basic change in speed depended on grain size, basically how much silver got produced per photon. So in the end 'film speed' was a function of QE and grain size, it could be increased either by increasing QE or grain size. So, my comment was assuming film of similar QE, where the speed would be controlled by grain size. So far as development goes, the silver atoms catalyse reduction in the sense that they speed it up. Leave the halide in a reducing agent, its all going to become silver in the end. In the end, development has to be controlled so that the proportion of exposed halide to the proportion of halide that gets reduced anyway favours the development of a good quality image. So more development (by means of a more aggressive developer, longer development time or higher temperature) increases the cahnces of all exposed grains being developed out (thus increasing 'speed') but also increases the chance of non-exposed grains being developed, this providing 'fog' in unexposed parts of the image, and reducing the overall DR.

(development produces the grain not exposure),

No, manufacture produces the grain. It is in the film. Exposure and development only determines which grains are turned into silver. Development can also effect the shape of the final developed grain.

but is also affected by focus

No

and over/underexposure.

Also no. What can happen is that printing to compensate for a thin or thick negative makes the grain in the final image more apparent.

If you scan you have artefacts of noise, nyquist considerations, sharpening artefacts, if you print then you have development and over developed/under exposed/temperature etc. considerations. Noise in film is not translated into the final image in the same way that digital noise is.

The starting process is exactly the same, a photon releases a photoelectron. The difference is because film is more digital than digital is. While a pixel will continue to accumulate charge so long as its FWC is not exceeded, and can thus count tens of thousands of photons, a silver halide grain can only ever count a few photons (that's why film is non linear, as exposure increases the chance of any photon finding an unreduced grain reduces). So, in the end, what I said is true. Keep the same film technology and development, and to produce the same granularity with 135 as 110 you need a film with four times the grain area, which will have four times the ISO. And I can be allowed 'same film technology and development' if the f2=f2=f2 brigade can be allowed to insist on the same film.

The point being that it as a pointless argument because it doesn't apply to grain size.

It certainly does, you need to brush up on your film chemistry.

I know this is supposed to be an analogy but this is getting out of hand. Stick to the facts.

I am, not my fault if you've got the wrong impression of the facts.

Good grief! I'm sorry, and no disrespect because I'm sure your theory is right... But in the real world? Equivalence in film grain? Just what is the point? With 30 years of experience developing I stand by what I say. It is a completely pointless exercise. Development affects grain size, try push processing, out of focus areas look a lot grainier, - no this is pointless...

Pushing is like increasing ISO, in film and in digital. Bob explained why that increases the visibility of the grain.

Did you ever wonder why grain is so much less visible in a print from 35mm film than 110 film of the same type, or from 645 versus 35mm of the same type? Yep...equivalence would make them equal.
--
Lee Jay

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bobn2
bobn2 Forum Pro • Posts: 63,503
Re: Let's correct it, then.

Tim Tucker wrote:

bobn2 wrote:

Tim Tucker wrote:

bobn2 wrote:

Lee Jay wrote:

Tim Tucker wrote:

Erik Magnuson wrote:

Tim Tucker wrote:

Erik Magnuson wrote:

Tim Tucker wrote: -

Is this the same as saying all f2 lenses transmit the same amount of light, but different sensor sizes collect different total amounts for the same exposure?

Amount is not a precise term. A 55gal drum and a 20oz red solo cup left out in the rain might both collect 1" of water. Is the same "amount" of water collected in each?

Eh? Total amount IS a precise term. Measure your volume in litres and you have a precise answer. But that is not what I asked.

It was the answer to your first question and use of "amount." All f/2 lenses do not transmit the same amount of light or my f/2 cell phone lens would transmit as much light as a 200mm f/2 lens. Even if I managed to put a 24x36mm sensor behind the call phone cam lens, it would not help much. What the lens transmits and what the sensor collects may be related, but they are not the same thing.

Sematics, as corrected by Lee Jay (my original statement above). Lenses for different formats do not have the same coverage therefore the total amount of light will not be the same but the light/square metre of sensor size (transmitted?) is the same at f2. A Super Angulon 90mm at f8 will produce the correct exposure regardless of whether I put 4"x5" film or 35mm film behind it.

More semantics...

"A Super Angulon 90mm at f8 will produce the same exposure regardless of whether I put 4"x5" film or 35mm film behind it."

It may or may not be "correct", whatever that means.

Here's a thought on this 'correct' exposure nonsense. Let's go back to film, since it is film based methodology which has confused people. Suppose we added to the equivalence requirements the condition 'equal granularity', and were looking at equivalence between 110 (roughly Four Thirds) and 135 (what we'd now call 'full frame'). If we wanted equal granularity in the image enlarged to the same output size, we'd want the same number of grains in each shot, which means that the 135 grains would need to be four times the area. Since each grain requires two photons to reduce it, both shots would need the same number of photons to expose. Thus the exposure of the 135 would need to be one quarter of that for the 110, or in other words, the ISO of the 135 film would need to be four times higher (which it would be in any case, since the grains were four times larger in area, so it would produce the same density for one quarter the number of photons).

Ah, but grain is a function of the film emulsion and development

Film emulsion, yes. A film works because an incoming photon liberates a photoelectron which reduces a molecule of silver chloride to an atom of silver. At least two silver atoms are required to catalyse the chemical reduction process which will turn the whole halide crystal to silver. These need to be at the same locality in the grain, so the grain needs an 'electron trap' so that the silver atoms are likely to occur at the same place. The process of increasing the quantum efficiency of emulsions involved (chemically) engineering better electron traps and also manipulating the shape of the crystal so that it presented a bigger surface area (compared with its overall size). So, that's much the same as digital, films improved in QE as emulsion formulations improved, but for a given formulation the basic change in speed depended on grain size, basically how much silver got produced per photon. So in the end 'film speed' was a function of QE and grain size, it could be increased either by increasing QE or grain size. So, my comment was assuming film of similar QE, where the speed would be controlled by grain size. So far as development goes, the silver atoms catalyse reduction in the sense that they speed it up. Leave the halide in a reducing agent, its all going to become silver in the end. In the end, development has to be controlled so that the proportion of exposed halide to the proportion of halide that gets reduced anyway favours the development of a good quality image. So more development (by means of a more aggressive developer, longer development time or higher temperature) increases the cahnces of all exposed grains being developed out (thus increasing 'speed') but also increases the chance of non-exposed grains being developed, this providing 'fog' in unexposed parts of the image, and reducing the overall DR.

(development produces the grain not exposure),

No, manufacture produces the grain. It is in the film. Exposure and development only determines which grains are turned into silver. Development can also effect the shape of the final developed grain.

but is also affected by focus

No

and over/underexposure.

Also no. What can happen is that printing to compensate for a thin or thick negative makes the grain in the final image more apparent.

If you scan you have artefacts of noise, nyquist considerations, sharpening artefacts, if you print then you have development and over developed/under exposed/temperature etc. considerations. Noise in film is not translated into the final image in the same way that digital noise is.

The starting process is exactly the same, a photon releases a photoelectron. The difference is because film is more digital than digital is. While a pixel will continue to accumulate charge so long as its FWC is not exceeded, and can thus count tens of thousands of photons, a silver halide grain can only ever count a few photons (that's why film is non linear, as exposure increases the chance of any photon finding an unreduced grain reduces). So, in the end, what I said is true. Keep the same film technology and development, and to produce the same granularity with 135 as 110 you need a film with four times the grain area, which will have four times the ISO. And I can be allowed 'same film technology and development' if the f2=f2=f2 brigade can be allowed to insist on the same film.

The point being that it as a pointless argument because it doesn't apply to grain size.

It certainly does, you need to brush up on your film chemistry.

I know this is supposed to be an analogy but this is getting out of hand. Stick to the facts.

I am, not my fault if you've got the wrong impression of the facts.

Good grief! I'm sorry, and no disrespect because I'm sure your theory is right... But in the real world? Equivalence in film grain? Just what is the point? With 30 years of experience developing I stand by what I say. It is a completely pointless exercise. Development affects grain size, try push processing, out of focus areas look a lot grainier, - no this is pointless...

There is indeed 'equivalence in film grain' as most film users who used multiple formats knew, and as the film manufacturers knew, reserving the slow, fine grain emulsions for smaller formats. On what development does and doesn't do, of course you observe what you observe, but then its worthwhile understanding what you are observing. A film has a spread of grain sizes, they aren't all the same size or the same shape. Both exposure and development affect which grains get developed and the size distribution of the developed grains. After printing, that can be observed as an apparent increase in grain size, but in reality the size of grain was fixed when the film was manufactured. So, my assertion about grain size holds true,

-- hide signature --

Bob

mostlyboringphotog Veteran Member • Posts: 9,007
Re: Focal length 35mm equivalent, but not F-stop?

bobn2 wrote:

mostlyboringphotog wrote:

Lee Jay wrote:

Lee Jay wrote:

I also use equivalence to make purchase decisions, and decisions about what equipment to carry into certain situations. Sometimes I use it for determining what settings I want to use in some situations.
--
Lee Jay

"I also use equivalence to make purchase decisions,..." I like to challenge this sentiment.

I say that you have not chosen m43 because m43 f/2 is equivalent to f/4 on FF. You know FF can do f/2 as well as f/4.

Also, I will say that you have not chosen FF because f/4 is equivalent to f/2 on m43.

And so without the actual comparison of the real images that you're after, this equivalence is meaningless to make the purchase decision.

Nope...wrong. I use equivalence to plot lens (and format) performance envelopes, just like DPReview has started doing in their compact camera reviews (except mine are better). In fact they started doing that because of my repeated suggestions over several years.
--
Lee Jay

Now I'm being passive aggressive - so you don't look at the images from potential equipment you want to buy? You buy FF because f/4 is equivalent to f/2 on m43?

You buy FF because when you see that f/4 is equivalent to f/2 on mFT, you realise that you have two extra stops in hand, if you need them. If you're never going to need them, then FF is a waste.

I think that's what I was trying to say; now I'm not sure of anything

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Tim Tucker Senior Member • Posts: 1,337
Re: Focal length 35mm equivalent, but not F-stop?

Great Bustard wrote:

Tim Tucker wrote:

bobn2 wrote:

Beachcomber Joe wrote:

bobn2 wrote:

Beachcomber Joe wrote:

The total light will decrease but not the light per square mm of area. Since the amount of light falling on a specific area of the sensor remains the same the exposure remains the same. A lot of the technobabble you read hear is about total light. Total light can be ignored. What matters from a photographic standpoint is the amount of light per square mm hitting the sensor.

Completely wrong. What matters is the total number of photons captured. Differences in exposure can always be compensated by simply changing the relationship between exposure and output grey scale. The total light locks in a noise pattern in the image, which can't be altered apart from noise reduction, which will usually lose you image detail. Those wishing to maximise image quality deal in total light. Of course, if you stick to one sensor size, there is no difference between total light and exposure.

Some people may not have known what I meant by the term technobabble. Thank you for providing such an excellent example.

Technobabble it might be, but it is true technobabble, and you have no way of refuting it. So, when you 'Total light can be ignored. What matters from a photographic standpoint is the amount of light per square mm hitting the sensor.' you're still 100% wrong. Choose to call what you're incapable of understanding 'technobabble' if you like, it doesn't make you any less wrong.

I'm following this with interest, and learning some useful bits and bobs...

...such as how sensors work.

But I am a bit perplexed as to how "total light" and "highest image quality" relate to good image. In the 20th century film produced fantastic images, even early digital cameras produced fantastic images. In fact some of the images produced are still fantastic, so if you used the same cameras could you not produce fantastic images today?

Sure. But do you not agree that higher exposures for a given camera, no matter what camera you are using, result in higher IQ, all else equal, so long as you don't blow the highlights?

This I am beginning to learn, another reason to ETTR.  

That's because more light fell on the sensor (film). The thing is, though, that the same exposure on different formats results in more light falling on the sensor (film) of the larger format, and thus the higher IQ (all else equal).

What matters from a photographic standpoint is the image you produce.

I don't think anyone disputes that. It's the IQ of the resulting photo as it relates to the amount of light that made up the photo that is being discussed.

This is giving me an insight into how sensors work, this is normally good for me.

And isn't there an argument that working within the limitations of your media produces the creativity and the strength of the image?

There is, indeed, such an argument. There are many who use cell phones as their cameras of choice, and I've seen excellent photos come from them. That said:

http://www.josephjamesphotography.com/equivalence/#iqvsqi

But what, exactly, is IQ, and what does it have to do with the "success" of a photo? The first step in defining "IQ" is to make the distinction between "image quality" and a "quality image". Many would take it as a given that if we have two photos of the same scene with the same composition then, all else equal as well, the photo with "higher IQ" would be "more successful". That is, the photo with "higher IQ", for example, would place better in a photo competition, would be more likely to sell, would sell for a higher price, etc. For sure, this may certainly be true for a large number of photos, such as a landscape photo displayed at a huge size. But it is important to acknowledge that there is a class of photography where image quality, as opposed to a quality image, is all but irrelevant (please see these outstanding photos, for example).

Furthermore, while one system may yield "higher IQ" than another, those differences may not be large enough to make any significant difference in the appeal of the photo, depending on the QT (quality threshold) of the viewer, the scene itself, the size at which the photo is displayed, and how closely it is scrutinized (see here for an interesting example of this point), and the processing applied to the photo. In other words, it is not merely whether System A has "higher IQ" than System B, but under what conditions it has higher IQ (and, indeed, which has "higher IQ" may flip-flop, depending on the conditions), and if the IQ is "enough higher" to make any significant difference.

For some photographers, IQ may be the most important aspect of photography. For others, it may play no role at all or simply be an added plus. But it is time well spent to reflect on just how important IQ is to our own photography, given that IQ is, at best, merely a means to achieving a quality image, and, at worst, completely irrelevant to the photo.

With all the disclaimers said about the relevance of IQ to the "success" of the photo, we can discuss what IQ is. The attributes of IQ include, but are not limited to:

Attributes of IQ do not include: subject, composition, focus accuracy, DOF, etc., which are attributes of system operation, available lenses, artistic design, and/or photographer skill. Of course, it's important to note that operational differences, such as focus accuracy, can have a substantial effect on the ability to capture a "high IQ" image. The "overall IQ" of a photo is a function of how the viewer subjectively weighs the individual objective components of IQ, which often depend greatly on the scene and how large the photo is displayed.

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