How many megapixels is enough?

ian-83

ian-83

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Ian
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Looking at a possible new camera and was wondering how many megapixels would be enough for say printing upto A2 size? Is 16mp enough or would 24mp be better?
Camera is likely to be APSC sensor size.
 
I would say 24 mp is better but I was and many others printing a2 back in the day with no problems with 8mp .
 
I found 16mp to be about right on a crop sensor, good balance between printable size, detail and noise.
Think its more to do with the quality of the original that determines the print output, crappy photo at whatever mp is still a crappy photo
 
tijuana taxi said:
Think its more to do with the quality of the original that determines the print output, crappy photo at whatever mp is still a crappy photo
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This!
Unless you print so large, and view so close, that the square shape of the individual pixels becomes apparent, the on-sensor pixel count doesn't really matter... that would be either a huge print/short viewing distance, or a really low resolution sensor (< 2MP).
 
A2 is certainly doable from 10MP (40D) if you are careful. 16 is going to be plenty, if you are careful

24mp on apsc will require some wonderful glass and tripod to make the fullest use of it.
 
One 16Mpix camera will be different to another 16Mpix in the same conditions, good technique always helps so Using the full image to fit A3 we get approx 280ppi from 16Mpix and 340ppi for 24Mpix and once that is printed it will be difficult to spot the difference because you will not print at 280/340 dpi

Mike
 
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Thanks for the replies, looks like 16mp is more than enough for my needs.
 
MP will become interesting again in 3-4 years when 8k TVs become mainstream. Something like ~33MP displays. Fun :)
 
frod said:
MP will become interesting again in 3-4 years when 8k TVs become mainstream. Something like ~33MP displays. Fun :)
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3-4 years for mainstream 8k TV's? 4k is still not mainstream yet. Anyway back to the topic. 5 mp would be fine .Anything more is good for cropping and fixing.
 
Photopaque said:
3-4 years for mainstream 8k TV's? 4k is still not mainstream yet. Anyway back to the topic. 5 mp would be fine .Anything more is good for cropping and fixing.
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odd, when I can buy a 4k TV for less than 300 quid I consider that mainstream.
 
GreenNinja67 said:
If you're Ken Rockwell then 6MP is enough for anything ,but then again he's a bit of a t***.
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He might be a bit of a t***, but in this case he's correct.

You can make prints any size you like from an image which has only 6 megapixels.

The key issue is the viewing distance. As you print bigger and bigger, the optimal viewing distance increases, so the resolution you need (measured in PPI) decreases, and these effects exactly cancel one another out. I can show you the maths if you're interested. But the bottom line is that with 6 megapixels you wont see any pixellation, when viewing the image from the normal / optimal distance.
 
StewartR said:
He might be a bit of a t***, but in this case he's correct.

You can make prints any size you like from an image which has only 6 megapixels.

The key issue is the viewing distance. As you print bigger and bigger, the optimal viewing distance increases, so the resolution you need (measured in PPI) decreases, and these effects exactly cancel one another out. I can show you the maths if you're interested. But the bottom line is that with 6 megapixels you wont see any pixellation, when viewing the image from the normal / optimal distance.
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Years ago I produced stuff for plays and of course you needed to be able to see the detail you were meant to see from the back of the theatre. That experience helped me to understand the resolution, size and distance relationships.
 
I might be wrong here.....
if a camera manufacturer made a low megapixel body version of their high resolution version, wouldnt the low megapixel version have the better ISO / DR abilities due to the bigger sensor lens photosites? :)
 
somewhere in a glass cabinet like the terminators arm is a 200 megapixel camera with lightning fast AF that can take a perfect picture in near darkness with no noise , every 6 months they take a step towards it , spend the money on longer lenses and what's been available for the last 5 years will be more than enough in good light, noise control improves with every generation , megapixels are a sales gimic IMO
 
Riz_Guru said:
I might be wrong here.....
if a camera manufacturer made a low megapixel body version of their high resolution version, wouldnt the low megapixel version have the better ISO / DR abilities due to the bigger sensor lens photosites? :)
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Yup! This is why Panasonic brought out a GH5s, with only 10mp, specifically for videographers who need better low light performance - it also has no IBIS like the standard GH5 but costs more!
 
I've always said 16-20mp is enough for most peoples needs.
 
Icee said:
I've always said 16-20mp is enough for most peoples needs.
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It is hard to argue with that. I only rarely really need double or so. But it would be so nice to have it!
 
Riz_Guru said:
I might be wrong here.....
if a camera manufacturer made a low megapixel body version of their high resolution version, wouldnt the low megapixel version have the better ISO / DR abilities due to the bigger sensor lens photosites? :)
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That is what the Sony a7S body is, a low Mp camera that is good at higher ISO's.
a7SII - 12Mp = max ISO of 102400
a7III - 24Mp = max ISO of 51200
a7RIII - 42 Mp = max ISO of 32000

Dynamic range should be in theory better on a lower Mp camera, but may depend on how old the camera is in comparison to those it is being compared to, and the choices the designers make, to bias towards high ISO ability, rather than maximum image quality. The a7SII does not seem to have a better dynamic range at base ISO than the a7III and a7RIII, but it is now a generation behind.

If they bring out a version 3, it may see a big improvement. Time will tell, whether they bring out a new version, and if they do, if it is indeed a big improvement on the previous version, and significantly better than the a7III and a7RIII. :)
 
I printed up to that size with a 12mp 5d (Mk1), although the file was resampled using Genuine Fractals. Don't forget however, quality of the image is not purely based on the sensor, but also the quality of the lens. With a 21mp sensor I often have to de-sample (downsize the image) as the file sizes are too large for the clients.
 
Riz_Guru said:
I might be wrong here.....
if a camera manufacturer made a low megapixel body version of their high resolution version, wouldnt the low megapixel version have the better ISO / DR abilities due to the bigger sensor lens photosites? :)
Click to expand...
No, not for any equivalent print/display size.
The ISO/DR capabilities primarily come from light/area and NOT light/pixel. In fact, if there is an advantage it will go to the higher MP sensor due to "oversampling" (more sample points/greater accuracy).

The reality is that ~12-14MP is the limit of what a human can discern in an image when it occupies an ~ 45* FOV ("normal viewing"). And anything even close to that is going to seem amazingly detailed/sharp (~8MP). But that is actual recorded resolution, which is almost always something less than the sensor resolution... often significantly less.
 
Riz_Guru said:
I might be wrong here.....
if a camera manufacturer made a low megapixel body version of their high resolution version, wouldnt the low megapixel version have the better ISO / DR abilities due to the bigger sensor lens photosites? :)
Click to expand...

Maybe, maybe not. The key factors are:

a) How much light is falling on the sensor?
Obviously larger physical sensor area wins here.

b) How much light is actually captured?
Sensor design makes a big difference and earlier versions were not so good, leading to the belief that more pixels always led to more noise. But modern sensors have all the 'furniture' moved to the back so it can't block any light, plus gapless microlenses collect more light right to the edges of the pixel well, and off-set microlenses are better at collecting off-axis light around the edges of the sensor. These days, more pixels certainly doesn't automatically mean more noise.

c) How efficient is the image processing chain ?
Basically, newer cameras have better signal amplifiers - the processing engine.

More pixels does mean sharper images (from the same sensor format and lens) but the difference is slight and you'll need to look close at big enlargements. At normal viewing distances, as explained above, it's very hard to see once you get above quite a modest threshold of 12mp or so. If it's sharper images that are needed, then a physically larger sensor and better lenses are the ways to go.*

*NB Actually the best place to start is usually with basic technique - critically accurate focusing, stable hand-holding and fast shutter speeds, low ISO. And the light - overcast days reduce contrast and images will look pretty flat regardless. Bright sun enhances contrast and sharpness.
 
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HoppyUK said:
b) How much light is actually captured?
Sensor design makes a big difference and earlier versions were not so good, leading to the belief that more pixels always led to more noise. But modern sensors have all the 'furniture' moved to the back so it can't block any light, plus gapless microlenses collect more light right to the edges of the pixel well, and off-set microlenses are better at collecting off-axis light around the edges of the sensor. These days, more pixels certainly doesn't automatically mean more noise.
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I believe the current technology has a fill factor of around 98% w/o BSI... there was no significant gain in SNR with the D850's switch to BSI.
 
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