Does print size depend on sensor size, or just pixel count?

[Satyaa]

Hi. I may not be explaining this correctly in technical terms, but I hope I can make my intent clear. It is also a two-part question.

Let's say there is a FF camera (36x24mm) that produces 50MP, and a mobile phone (9x6mm) that also produces 50MP. Just assume that the images were shot in good daylight and look similar on screen without noise, grain, etc. I am assuming for simplicity that the 50MP image from phone is its native resolution and not using computational features. At the end, I am implying the sensor size is the only difference.

I used this random page from search results and in a table, it says that @300 dpi 50MP can make a 30" x 20" print. Megapixels vs. Print Size - How Big Can You Print? - Digital Photography Live

Let's accept this for the camera output. At certain ideal distance it looks perfect. Any closer viewing makes the image look bad (whatever that may be).

Now, can the 50MP file from the phone be printed at the same size and show the same quality at the same viewing distance? Or does it look worse because the pixels came from a smaller sensor?

Where I am going is, along with saying you need 'n' MP for certain print size, should we also say certain sensor size to get that quality? Do the prints from a 20MP MFT and 20MP FF camera have the same quality when viewed at the same distance? Let's assume appropriate lenses were used for similar DOF, etc.

Second question is an extrapolation.

Most phones use computational features. So, if the phone camera actually used 8 or 16 12.5 MP images to produce the 50MP images, would that change the answer in my earlier question?

Thanks.

--
See my profile (About me) for gear and my posting policy. My profile picture is of the first film camera I used in the early 80s, photo credit the internet.

 

[Rich42]

Two differently-sized 50 MP sensors are capable of producing equal-sized prints.

The camera with the larger sensor will have larger pixels, theoretically (and practically) providing higher quality images in terms of noise, dynamic range and other attributes of the digital information.

A lower number of megapixels (increased “computationally” to 50 MP) would produce lower image quality.

--
Rich

 

[BobKnDP]

Two differently-sized 50 MP sensors are capable of producing equal-sized prints.

The camera with the larger sensor will have larger pixels, theoretically (and practically) providing higher quality images in terms of noise, dynamic range and other attributes of the digital information.

A lower number of megapixels (increased “computationally” to 50 MP) would produce lower image quality.

It's not clear to me that a smartphone image would have the same quality as a DSLR/Mirrorless digital camera with the same number of real pixels.

However, the quality of current smartphone images is very good. I wonder that it's still possible to buy point and shoot cameras.

 

[bastibe]

It depends on resolution, not pixel counts. On a good camera, resolution will be close to the pixel level. On a bad camera, or with a lot of noise, or on a hazy day, resolution will be far, far lower.

But if you have a good camera that resolves up to the pixel level, print size is limited by pixel count, not sensor size.

 

[Macro guy]

A smaller sensor has smaller pixels, which means a lower signal to noise ratio. So a 50mp photo taken with an APS-C camera at ISO 100 would look the same as a photo taken with 50mp FF camera at ISO 200

 

[Rich42]

Two differently-sized 50 MP sensors are capable of producing equal-sized prints.

The camera with the larger sensor will have larger pixels, theoretically (and practically) providing higher quality images in terms of noise, dynamic range and other attributes of the digital information.

A lower number of megapixels (increased “computationally” to 50 MP) would produce lower image quality.

It's not clear to me that a smartphone image would have the same quality as a DSLR/Mirrorless digital camera with the same number of real pixels.

I already said that the larger sensor would (theoretically) provide a higher quality image (for criteria other than resolution).

However, 50 MP is 50 MP. Each sensor (regardless of size) could fulfill whatever final resolution is expected either for screen viewing or print (300 ppi, 250 ppi, 100 ppi - whatever).

However, the quality of current smartphone images is very good. I wonder that it's still possible to buy point and shoot cameras.

 

[Satyaa]

The four replies so far are on similar lines. Here's what I understand, in non-technical language.

Both images can be printed at full size because both have 50MP. Meaning the pixels are not stretched or the image is not pixelated in look.

However, the quality of the prints (in terms of noise, dynamic range, color accuracy, etc.) will be different. The print from larger sensor image will look better because of its better pixel quality.

Is that a good understanding?

Thanks.

 

[BobKnDP]

Two differently-sized 50 MP sensors are capable of producing equal-sized prints.

The camera with the larger sensor will have larger pixels, theoretically (and practically) providing higher quality images in terms of noise, dynamic range and other attributes of the digital information.

A lower number of megapixels (increased “computationally” to 50 MP) would produce lower image quality.

It's not clear to me that a smartphone image would have the same quality as a DSLR/Mirrorless digital camera with the same number of real pixels.

I already said that the larger sensor would (theoretically) provide a higher quality image (for criteria other than resolution).

However, 50 MP is 50 MP. Each sensor (regardless of size) could fulfill whatever final resolution is expected either for screen viewing or print (300 ppi, 250 ppi, 100 ppi - whatever).

However, the quality of current smartphone images is very good. I wonder that it's still possible to buy point and shoot cameras.

"higher quality images in terms of noise, dynamic range and other attributes of the digital information"

I was thinking in terms of the somewhat vague aspect of sharpness. Maybe you intended to cover that under "other attributes".

 

[BobKnDP]

As usual, it may be more complicated than that.

I have a Canon Pro 200 printer. I haven't experimented with low pixel counts, but it may process print jobs so that pixelization isn't visible when pixel frequencies below the traditional 300 ppi are printed. (Processing via drivers and/or printer hardware.)

Experts may be able to confirm or deny that.

The result would lose sharpness, but it would still look like a traditional photograph.

I recall my late father had an image from mutual friend professionally printed at poster size. (The source was probably 20Mp.) It wasn't sharp at that scale, but the software eliminated any pixelization without harming the resolution further.

Smartphones are likely to trade resolution for sensitivity in low light imagery, so those pictures may look best on a tiny screen.

 

[Rich42]

Two differently-sized 50 MP sensors are capable of producing equal-sized prints.

The camera with the larger sensor will have larger pixels, theoretically (and practically) providing higher quality images in terms of noise, dynamic range and other attributes of the digital information.

A lower number of megapixels (increased “computationally” to 50 MP) would produce lower image quality.

It's not clear to me that a smartphone image would have the same quality as a DSLR/Mirrorless digital camera with the same number of real pixels.

I already said that the larger sensor would (theoretically) provide a higher quality image (for criteria other than resolution).

However, 50 MP is 50 MP. Each sensor (regardless of size) could fulfill whatever final resolution is expected either for screen viewing or print (300 ppi, 250 ppi, 100 ppi - whatever).

However, the quality of current smartphone images is very good. I wonder that it's still possible to buy point and shoot cameras.

"higher quality images in terms of noise, dynamic range and other attributes of the digital information"

I was thinking in terms of the somewhat vague aspect of sharpness. Maybe you intended to cover that under "other attributes".

Sharpness is influenced by several factors. Many think it’s only about resolution. But local contrast is just as important. It’s possible to show two images of the same subject in which the one with substantially lower resolution, but higher local contrast looks much sharper.

But with current practices in lens designs for digital sensors, in almost all cases, a steady image from a high-pixel smart phone camera (tiny sensor) will hold its own against a large sensor image of equal MP count in terms of “sharpness.”

However, there is no denying that it will always be possible to get better absolute “image quality” from the larger sensor.

--
Rich
"That's like, just your opinion, man." ;-)

 

[Macro guy]

The four replies so far are on similar lines. Here's what I understand, in non-technical language.

Both images can be printed at full size because both have 50MP. Meaning the pixels are not stretched or the image is not pixelated in look.

However, the quality of the prints (in terms of noise, dynamic range, color accuracy, etc.) will be different. The print from larger sensor image will look better because of its better pixel quality.

Is that a good understanding?

Thanks.

It all depends on the difference in sensor sizes. If we look at noise, the difference between APS-C and FF is one f/stop. So, if you shoot APS-C at ISO 100, the images will look identical to the FF shot at ISO 200. The noise and dynamic range differences may not be noticeable depending at which ISO you shoot. Color accuracy doesn't depend on sensor size.

Theoretically, the print from a larger sensor will look better. In practical terms, you may not be able to see a difference.

 

[Satyaa]

The four replies so far are on similar lines. Here's what I understand, in non-technical language.

Both images can be printed at full size because both have 50MP. Meaning the pixels are not stretched or the image is not pixelated in look.

However, the quality of the prints (in terms of noise, dynamic range, color accuracy, etc.) will be different. The print from larger sensor image will look better because of its better pixel quality.

Is that a good understanding?

Thanks.

It all depends on the difference in sensor sizes. If we look at noise, the difference between APS-C and FF is one f/stop. So, if you shoot APS-C at ISO 100, the images will look identical to the FF shot at ISO 200. The noise and dynamic range differences may not be noticeable depending at which ISO you shoot. Color accuracy doesn't depend on sensor size.

Theoretically, the print from a larger sensor will look better. In practical terms, you may not be able to see a difference.

OK, thank you.

 

[JohnSil]

The four replies so far are on similar lines. Here's what I understand, in non-technical language.

Both images can be printed at full size because both have 50MP. Meaning the pixels are not stretched or the image is not pixelated in look.

However, the quality of the prints (in terms of noise, dynamic range, color accuracy, etc.) will be different. The print from larger sensor image will look better because of its better pixel quality.

Is that a good understanding?

Thanks.

It all depends on the difference in sensor sizes. If we look at noise, the difference between APS-C and FF is one f/stop. So, if you shoot APS-C at ISO 100, the images will look identical to the FF shot at ISO 200. The noise and dynamic range differences may not be noticeable depending at which ISO you shoot. Color accuracy doesn't depend on sensor size.

Theoretically, the print from a larger sensor will look better. In practical terms, you may not be able to see a difference.

OK, thank you.

I'm having a little trouble wrapping my head around this question. I think it goes so much deeper than what has been said. Sure noise etc are but the obvious factors.

Let's consider the quality of the cameras. We spend 1000's of dollars on cameras and lenses to get the BEST glass and sensors.

Phone cameras have mostly optical cast plastic lenses though some do add some glass. Next let's consider those cheap plastic components and sensors. To print a 16x20 a FF sensor has to be magnified maybe 100 times. A phone image has to be magnified maybe 10,000 times. ANY defects such as noise, scratches, dirt or CA's get magnified 10,000 times making them very obvious. A phone's best attribute is its extreme DOF giving the impression of sharpness. BUT the actual sharpness is only as good as the quality of the plastic in it's lens and the quality of the pixels in the sensor.

A 16x20 from a FF is magnified 100 times. A photo on the back of a phone is also 100 times but to print it bigger and bigger the defects will start to be magnified. Like softness in the plastic lens and low quality pixels that may not be reproducing true colors which would all come into play in a large print.

So personally it's not possible that 50mp phones could be equal to a 50mp MF camera except in pixel count!!!

John

 

[BobKnDP]

In the usual sense of magnification, 36 mm on a FF sensor going to 20" (508mm) is a magnification of 14X.

The long axis of an iPhone 16 Pro's main sensor is about 9.76mm, so the magnification would be 52X.

Area ratios would be meaningful, but not the normal usage of magnification.

 

[MarkB56]

One of my favourite images at the gallery that does my speciality printing and framing has a roughly 36"x60" print from an iPhone 5. Looks as good as any 25mp print in the gallery.

Remember that billboards have ben printed from <10mp sensors and few if anybody was bothered...

 

[SethG]

One of my favourite images at the gallery that does my speciality printing and framing has a roughly 36"x60" print from an iPhone 5. Looks as good as any 25mp print in the gallery.

Remember that billboards have ben printed from <10mp sensors and few if anybody was bothered...

yeah, but the viewing distance from the billboard is dozens or hundreds of feet.

I have a large printer. Out of curiosity, I printed a 6mp image from my D70 that i shot years ago. It’s tack sharp on my 5k screen as a background. At 24x36 I expected it to be pixelated (about 83 dpi) but it wasn’t. It was EXTREMELY soft though.

 

[Macro guy]

One of my favourite images at the gallery that does my speciality printing and framing has a roughly 36"x60" print from an iPhone 5. Looks as good as any 25mp print in the gallery.

Remember that billboards have ben printed from <10mp sensors and few if anybody was bothered...

yeah, but the viewing distance from the billboard is dozens or hundreds of feet.

I have a large printer. Out of curiosity, I printed a 6mp image from my D70 that i shot years ago. It’s tack sharp on my 5k screen as a background. At 24x36 I expected it to be pixelated (about 83 dpi) but it wasn’t. It was EXTREMELY soft though.

Run it through Gigapixel AI and it will look great!

 

[JohnSil]

One of my favourite images at the gallery that does my speciality printing and framing has a roughly 36"x60" print from an iPhone 5. Looks as good as any 25mp print in the gallery.

Remember that billboards have ben printed from <10mp sensors and few if anybody was bothered...

yeah, but the viewing distance from the billboard is dozens or hundreds of feet.

I have a large printer. Out of curiosity, I printed a 6mp image from my D70 that i shot years ago. It’s tack sharp on my 5k screen as a background. At 24x36 I expected it to be pixelated (about 83 dpi) but it wasn’t. It was EXTREMELY soft though.

Yes softness is the problem. It won't pixelate because the printer is filling in the missing pieces. But the printers algorithm uses Nearest Neighbor which is not bad but if it has to fill more than one pixel it now has to invent that pixel. So if you're working with too few pixels it can only look soft.

Obviously today the solution is to PP it through an AI program to fill it better but even the AI will be guessing , hopefully it will guess better!!! My printer ids too old to have AI but I'm sure some of the newest and better printer are already in incorporating AI in the printer itself. Or we can of course PP it with an AI program to up rez.

Regardless what everybody says about viewing distance, the SHARPER your images are the more they BEG to be examined more closely if you can get closer!!!

SS

 

[SethG]

One of my favourite images at the gallery that does my speciality printing and framing has a roughly 36"x60" print from an iPhone 5. Looks as good as any 25mp print in the gallery.

Remember that billboards have ben printed from <10mp sensors and few if anybody was bothered...

yeah, but the viewing distance from the billboard is dozens or hundreds of feet.

I have a large printer. Out of curiosity, I printed a 6mp image from my D70 that i shot years ago. It’s tack sharp on my 5k screen as a background. At 24x36 I expected it to be pixelated (about 83 dpi) but it wasn’t. It was EXTREMELY soft though.

Yes softness is the problem. It won't pixelate because the printer is filling in the missing pieces. But the printers algorithm uses Nearest Neighbor which is not bad but if it has to fill more than one pixel it now has to invent that pixel. So if you're working with too few pixels it can only look soft.

Obviously today the solution is to PP it through an AI program to fill it better but even the AI will be guessing , hopefully it will guess better!!! My printer ids too old to have AI but I'm sure some of the newest and better printer are already in incorporating AI in the printer itself. Or we can of course PP it with an AI program to up rez.

Regardless what everybody says about viewing distance, the SHARPER your images are the more they BEG to be examined more closely if you can get closer!!!

SS

I’m actually planning on testing that. I have some shots of a lilac-breasted roller in flight that covers about 10% of the frame, so that’s 4-5mp. I upsized it with Gigapixel, but I’m also going to use PS and see how the two look

 

[JohnSil]

One of my favourite images at the gallery that does my speciality printing and framing has a roughly 36"x60" print from an iPhone 5. Looks as good as any 25mp print in the gallery.

Remember that billboards have ben printed from <10mp sensors and few if anybody was bothered...

yeah, but the viewing distance from the billboard is dozens or hundreds of feet.

I have a large printer. Out of curiosity, I printed a 6mp image from my D70 that i shot years ago. It’s tack sharp on my 5k screen as a background. At 24x36 I expected it to be pixelated (about 83 dpi) but it wasn’t. It was EXTREMELY soft though.

Yes softness is the problem. It won't pixelate because the printer is filling in the missing pieces. But the printers algorithm uses Nearest Neighbor which is not bad but if it has to fill more than one pixel it now has to invent that pixel. So if you're working with too few pixels it can only look soft.

Obviously today the solution is to PP it through an AI program to fill it better but even the AI will be guessing , hopefully it will guess better!!! My printer ids too old to have AI but I'm sure some of the newest and better printer are already in incorporating AI in the printer itself. Or we can of course PP it with an AI program to up rez.

Regardless what everybody says about viewing distance, the SHARPER your images are the more they BEG to be examined more closely if you can get closer!!!

SS

I’m actually planning on testing that. I have some shots of a lilac-breasted roller in flight that covers about 10% of the frame, so that’s 4-5mp. I upsized it with Gigapixel, but I’m also going to use PS and see how the two look

It will be interesting to see what you come up with. Though I haven't used it much, the newest versions of OPS have all the erase ability like to take out wires, or poles or people. I does a pretty good job. Foe me, bird feathers are biggie. ?????????Feathers are so soft and detailed and look sooo good when all that detail is there and very sharp, naturally. If you post the results, make sure you also post the bird SOOC!!! Good luck, looking forward with what you come up with!

John