We need a "light quotient" to replace meaningless megapixels and confusing 1/x.xx sensor sizes.

[circa2000]

What other important variables do you allege are missing? By “important”, I mean not just that you would get significantly different results if you varied them (e.g. if you were to halve or double QE), but that in practice, they actually do vary to the point that the models proposed in this thread wouldn’t even be a decent approximation.

In a word, a lot. For instance yellow in RYYB sensors delivers 2x light over green in RGB.

 

[Edgar_in_Indy]

And here's how the proposed light-gathering score would work out for each of the new iPhones, using the specifications provided in the DPR article:

iPhone 17/Air main camera
Sensor: 1/1.56 (48mm²)
Lens: f/1.6
Score: 4.23

iPhone 17/17 Pro main camera
Sensor: 1/1.28 (71.5mm²)
Lens: f/1.78
Score: 4.50

iPhone 17/17 Pro ultrawide camera
Sensor: 1/2.55 (23.5mm²)
Lens: f/2.2
Score: 2.28

iPhone 17 Pro telephoto camera
Sensor: 1/2.55 (23.5mm²)
Lens: f/2.8
Score: 1.58

The main cameras are respectable, but the ultrawide and telephoto both fall short of my own OnePlus 12, which I chose specifically because those two cameras have larger sensors and/or apertures than average.

OnePlus 12 main camera
Sensor: 1/1.43 (?? mm²)
Lens: f/1.6
Score: ??

OnePlus 12 ultrawide camera
Sensor: 1/2.0 (30.7mm²)
Lens: f/2.2
Score: 2.67

OnePlus 12 telephoto camera
Sensor: 1/2.0 (30.7mm²)
Lens: f/2.6
Score: 2.18

So my ultrawide scores 2.67 vs the 17 Pro's 2.28, and my telephoto scores 2.18 vs the 17 Pro's 1.58. See how a number like that makes it so much easier to quickly compare basic hardware?

Unfortunately I haven't been able to find the exact dimensions of the OnePlus 12's 1/1.43" main sensor, which is Sony's LYT-808, so I can't score the main camera.

 

[spider-mario]

What other important variables do you allege are missing? By “important”, I mean not just that you would get significantly different results if you varied them (e.g. if you were to halve or double QE), but that in practice, they actually do vary to the point that the models proposed in this thread wouldn’t even be a decent approximation.

In a word, a lot. For instance yellow in RYYB sensors delivers 2x light over green in RGB.

Right, so an overall difference of about 40%, or roughly half a stop, so close to 0.5 on the scale we have been discussing.

 

[Edgar_in_Indy]

What other important variables do you allege are missing? By “important”,

In a word, a lot. For instance yellow in RYYB sensors delivers 2x light over green in RGB.

Nothing you've said makes the least difference in my original post, which already acknowledges variations in technologies. What you are saying is so obvious and so unnecessary.

By your logic, we may as well just stop talking about sensor sizes altogether, since performance varies from sensor generation to generation, and from company to company. I guess it'll be nice to finally stop worrying about whether a camera has an m43, APS-C, FF, or medium format sensor. There will be so many less arguments on here!

And when a lens is available for multiple formats, such as m43 and APS-C, or APS-C and FF, we should not even mention its focal length or aperture since so much of the lens's performance and rendering will depend on what format you're using it with, and even beyond that, which particular body you are using it with.

 

[Edgar_in_Indy]

In a word, a lot. For instance yellow in RYYB sensors delivers 2x light over green in RGB.

Right, so an overall difference of about 40%, or roughly half a stop, so close to 0.5 on the scale we have been discussing.

He's acting like the wheel has suddenly been reinvented. As I said earlier, I started out with an Olympus e-510 DSLR, so I was around when sensors were making massive gains from generation to generation. Nothing unusual here.

 

[spider-mario]

And here's how the proposed light-gathering score would work out for each of the new iPhones, using the specifications provided in the DPR article:

iPhone 17/Air main camera
Sensor: 1/1.56 (48mm²)
Lens: f/1.6
Score: 4.23

iPhone 17/17 Pro main camera
Sensor: 1/1.28 (71.5mm²)
Lens: f/1.78
Score: 4.50

iPhone 17/17 Pro ultrawide camera
Sensor: 1/2.55 (23.5mm²)
Lens: f/2.2
Score: 2.28

iPhone 17 Pro telephoto camera
Sensor: 1/2.55 (23.5mm²)
Lens: f/2.8
Score: 1.58

The main cameras are respectable, but the ultrawide and telephoto both fall short of my own OnePlus 12, which I chose specifically because those two cameras have larger sensors and/or apertures than average.

OnePlus 12 main camera
Sensor: 1/1.43 (?? mm²)
Lens: f/1.6
Score: ??

OnePlus 12 ultrawide camera
Sensor: 1/2.0 (30.7mm²)
Lens: f/2.2
Score: 2.67

OnePlus 12 telephoto camera
Sensor: 1/2.0 (30.7mm²)
Lens: f/2.6
Score: 2.18

So my ultrawide scores 2.67 vs the 17 Pro's 2.28, and my telephoto scores 2.18 vs the 17 Pro's 1.58. See how a number like that makes it so much easier to quickly compare basic hardware?

Unfortunately I haven't been able to find the exact dimensions of the OnePlus 12's 1/1.43" main sensor, which is Sony's LYT-808, so I can't score the main camera.

The pixel pitch is 1.12μm according to Sony, and it has 50MP. If the aspect ratio is 4:3, that translates into 8165×6124 pixels, so the sensor would have a width of 8165·1.12μm ≈ 9.14mm and a height of 6124·1.12μm ≈ 6.86mm, so an area of 62.7mm², and a score of 4.61.

(Although, actually, since we are using the area and not the diagonal, the aspect ratio doesn’t affect the calculation: either way, it’s 50MP×(1.12μm)².)

 

[Edgar_in_Indy]

Unfortunately I haven't been able to find the exact dimensions of the OnePlus 12's 1/1.43" main sensor, which is Sony's LYT-808, so I can't score the main camera.

The pixel pitch is 1.12μm according to Sony, and it has 50MP. If the aspect ratio is 4:3, that translates into 8165×6124 pixels, so the sensor would have a width of 8165·1.12μm ≈ 9.14mm and a height of 6124·1.12μm ≈ 6.86mm, so an area of 62.7mm², and a score of 4.61.

Perfect, thank you.

So it looks like my main camera light gathering score edges out the 17 Pro's main camera despite my sensor being slightly smaller, thanks to my larger f/1.6 aperture vs f/1.8.

 

[Bill Ferris]

And here's how the proposed light-gathering score would work out for each of the new iPhones, using the specifications provided in the DPR article:

iPhone 17/Air main camera
Sensor: 1/1.56 (48mm²)
Lens: f/1.6
Score: 4.23

iPhone 17/17 Pro main camera
Sensor: 1/1.28 (71.5mm²)
Lens: f/1.78
Score: 4.50

iPhone 17/17 Pro ultrawide camera
Sensor: 1/2.55 (23.5mm²)
Lens: f/2.2
Score: 2.28

iPhone 17 Pro telephoto camera
Sensor: 1/2.55 (23.5mm²)
Lens: f/2.8
Score: 1.58

The main cameras are respectable, but the ultrawide and telephoto both fall short of my own OnePlus 12, which I chose specifically because those two cameras have larger sensors and/or apertures than average.

Which begs the question, if you want a tight framing on a distant subject, which camera would produce the better quality image: a cropped photo from the main camera or an uncropped photo from the telephoto camera?

If both cameras were used to photograph the same subject from the same distance and the subject filled the frame of the telephoto camera, how deep a crop would be needed to create an image from the main camera having the same framing? How many of its pixels and how much of the light-gathering advantage would be lost?

 

[Edgar_in_Indy]

Which begs the question, if you want a tight framing on a distant subject, which camera would produce the better quality image: a cropped photo from the main camera or an uncropped photo from the telephoto camera?

Excellent point, which makes me wonder about the utility of even including a telephoto when the sensor and aperture is so much smaller than what the main camera offers, like what we are seeing on the iPhone 17 Pro.

At what point are you actually gaining anything by switching over to the tiny sensor with the dimmer lens? Is the telephoto, as implemented, actually useful, or is it just more of a way marking a checkbox for marketing purposes?

The question you bring up helps highlight the importance of providing transparency about the camera hardware.

 

[spider-mario]

Which begs the question,

(raises the question)

if you want a tight framing on a distant subject, which camera would produce the better quality image: a cropped photo from the main camera or an uncropped photo from the telephoto camera?

If both cameras were used to photograph the same subject from the same distance and the subject filled the frame of the telephoto camera, how deep a crop would be needed to create an image from the main camera having the same framing? How many of its pixels and how much of the light-gathering advantage would be lost?

If the telephoto camera is advertised as being “4×” in relation to the main, “1×” camera, as is the case on the iPhone 17, then that’s how much one would have to crop the output of the main camera to get the same framing as the telephoto.

Per my previous analysis, that would penalise the score by 2·log₂(4) = 4. For the iPhone 17 Pro, that would make the final score 0.50, which compares unfavourably to the 1.58 of its telephoto by about a stop.

 

[circa2000]

Right, so an overall difference of about 40%, or roughly half a stop, so close to 0.5 on the scale we have been discussing.

The 40% is debatable but even if you believe in that, it means that comparing rgb sensors with ryyb we should assume 40% area difference for the same light sensitivity.

 

[Eric Fossum]

Perhaps the number of pixels is meaningless to you, but for the rest of us, resolution is an important metric, give or take what is actually resolvable. Maybe what you really want are the active pixel area dimensions?

If the lens is not interchangeable then sure, lens F# would be a useful metric for a particular configuration.

Speaking for the image sensor technology community!

Of course this is mostly a photographers' forum so feel free to make as many additional FOMs as you need.

EF

 

[spider-mario]

Right, so an overall difference of about 40%, or roughly half a stop, so close to 0.5 on the scale we have been discussing.

The 40% is debatable but even if you believe in that, it means that comparing rgb sensors with ryyb we should assume 40% area difference for the same light sensitivity.

Yes, similar to a 1.18× crop.

 

[Edgar_in_Indy]

Perhaps the number of pixels is meaningless to you, but for the rest of us, resolution is an important metric, give or take what is actually resolvable. Maybe what you really want are the active pixel area dimensions?

It's your "what is actually resolvable" statement that is key, so I expect we're already on the same page.

Yes, resolution, as expressed by the number of pixels, is certainly not meaningless, but the way the phone manufacturers have been using and abusing the term lately has made it, at best, an ambiguous indicator of image quality, and, at worst, completely misleading.

There's a couple things going on that have made it problematic to use "megapixels" as an image quality benchmark.

1) They advertise the camera as, say, 48 megapixels, but meanwhile the resultant photos are only 12 megapixels. (And yes, I am fully aware of pixel binning, so hopefully nobody here feels the need to go into that, but I'm not optimistic, lol.)

and/or

2) They actually give us the advertised number of pixels, or at least the option to get the full count, but there are very few situations, if any, where that many pixels are actually useful, and most of the time you are just pushing the sensor far beyond its useful SNR limits and generating ridiculously huge image files.

 

[circa2000]

Right, so an overall difference of about 40%, or roughly half a stop, so close to 0.5 on the scale we have been discussing.

The 40% is debatable but even if you believe in that, it means that comparing rgb sensors with ryyb we should assume 40% area difference for the same light sensitivity.

Yes, similar to a 1.18× crop.

Or a difference between 1” sensor and 0.8” one

 

[Edgar_in_Indy]

In light of this discussion/debate, with some people claiming that "nobody cares" about camera hardware, or that it doesn't even matter, I was encouraged by a cell phone ad that I just happened to get on Instagram this morning.

Here it is:



In the ad, we have a cell phone manufacturer (outside of China) actually bragging about the new larger sensor in their phone, and leading with the line "Let the light in".

What they're bragging about is how the ultrawide 1/2.5" f/2.2 camera from the Xperia 1 VI has been replaced with a larger and brighter 1/1.56" f2.0 ultrawide camera on the Xperia 1 VII.

(I wonder how this new camera scores compared to the old one?)

Yeah, this is from Sony, not Apple, Samsung, or Google, and this model isn't even available in the US as of now, but I see this advertising strategy as a hopeful sign that people are starting to actually pay attention to phone camera hardware.