robertdfeinman
Robert Feinman
The new Canon has 5616 pixels on the long side. If you divide this by 300 (for high quality prints) you get 18.72. This means that one could make an 18 inch print without any interpolation.
My Minolta film scanner will do 5400 dpi which using the same calculation gives 18x which is a 24 inch print. With great care I have been able to make 18x enlargements from 35mm color negative film. Now, in actuality, it is seldom the film that is the limiting factor in getting sharp enlargements.
The one limiting physical factor is lens resolution. But in the field it is usually mis-focusing and/or camera shake. Most people consider 50-80 lpmm as the practical limits of resolution on film. If you want to get about 7 lpmm on the print (which most people will consider "sharp" ) you see that this should limit enlargements to about 7-10x. I usually tell people the magic number is eight. The discrepancy comes about because, for many subjects, there isn't enough fine detail to matter and/or the film grain obscures the finest detail anyway.
Whichever way you chose to measure it, it seems that the new sensor has reached the same limits as happen with film. That is one would need a "better" lens to get more resolution. This leads to a discussion of diffraction which limits resolution no matter how good the lens. So "better" lens would only have higher resolution at large openings which is exactly where the aberrations are the most noticeable.
It is interesting that in the early days of digital Kodak and others used to say that film was about equal to 20 Mpix, but stopped talking about it when most consumers were happy at much lower resolution limits. I'm not sure how this affects the market for larger sensors, such as those used in medium format cameras. These typically have about 20+ Mpix as well, but they are spread over a bigger sensor. This makes the individual pixels larger which makes them less noisy or more light sensitive, but might make the resolution lower.
There are still some arguments of the dynamic range of film compared to digital. I've seen the scientific results, but since most of the difference is in the darkest parts of the image it's not clear how visible the differences are.
Here's one of my tips which shows the potential of film:
Scanning to Get More from 35mm Film
In theory the lenses are better than the sensors (film or digital) but the combined resolution isn't affected much by the further improvements in the lens.
The formula for computing total resolution of a system is 1/(res of lens) + 1/(res of sensor) = 1/(combined res)
So for,say, a sensor with 50 lpmm resolution and 100 lpmm lens the result would be 33 lpmm.
Now raise the lens to 200 lpmm (far beyond the possible) the result would be 40 lpmm - not that much of an improvement.
I think I need to modify my rule of thumb about the degree of enlargement possible. It was formulated in the days of making prints in the darkroom. The final resolution on the print was influenced the lens, the film, the enlarging lens and the photopaper. This worked out to about 8-10x. Which is why most people felt that an 8x10 was about the largest one could go with 35mm film with average care.
Now with a high quality scanner the degradation caused by the darkroom steps has been eliminated. A scanner that can do 3000 dpi or better is essentially a lossless step. In one of my tips I show how proper image sharpening can compensate for the small losses in the scanning process as well. (This is not cheating.) The inkjet prints also have better detail capture than photopapers.
I'm not sure what the new rule of thumb should be, but it is better than the prior 8-10x. I have produced 16x from scanned film and others do this frequently from digital capture. I think this may be stretching things for highly detailed subjects.
This leads into another area - perception.
Back in the 1960's when Kodak wanted to introduce the Instamatic they did a bunch of perception studies to see how bad an image could get before the average snap shooter would notice. They then designed a system which was slightly better than this - the Instamatic. What people find acceptable varies greatly. Most snapshots are of familiar people and the emphasis in on recognition and memory of the event. People don't study the technical aspects of the shot. The same is true of much vacation photography. If it looks like the Grand Canyon then you were there.
There are some very discriminating viewers and they have a different set of internal standards. This is why we see disagreements over things like large and medium format photography compared to digital and 35mm. The two groups are using different acceptability criteria. The same thing happens in the music area. Many people are happy with MP3 compressed playback, which sets the hi-fi "golden ears" crowd in a frenzy.
Many people seem to become defensive when they think their personal choices are being challenged. No one likes to feel that they are being treated as a fool because of their choices. This is why I try to present data and leave the acceptability to the user. I'm not trying to convince anyone to use one technology over another, but I will say that scanning gives new life to film that most of us probably never expected to see.
I'm still sticking with film, mostly because the cameras I use have properties that I don't find comparable in digital so far. Specifically my rangefinder camera and its ultrawide 12mm lens are not available in this combination. In addition my swinglens panoramic camera is still only film-based.
My Minolta film scanner will do 5400 dpi which using the same calculation gives 18x which is a 24 inch print. With great care I have been able to make 18x enlargements from 35mm color negative film. Now, in actuality, it is seldom the film that is the limiting factor in getting sharp enlargements.
The one limiting physical factor is lens resolution. But in the field it is usually mis-focusing and/or camera shake. Most people consider 50-80 lpmm as the practical limits of resolution on film. If you want to get about 7 lpmm on the print (which most people will consider "sharp" ) you see that this should limit enlargements to about 7-10x. I usually tell people the magic number is eight. The discrepancy comes about because, for many subjects, there isn't enough fine detail to matter and/or the film grain obscures the finest detail anyway.
Whichever way you chose to measure it, it seems that the new sensor has reached the same limits as happen with film. That is one would need a "better" lens to get more resolution. This leads to a discussion of diffraction which limits resolution no matter how good the lens. So "better" lens would only have higher resolution at large openings which is exactly where the aberrations are the most noticeable.
It is interesting that in the early days of digital Kodak and others used to say that film was about equal to 20 Mpix, but stopped talking about it when most consumers were happy at much lower resolution limits. I'm not sure how this affects the market for larger sensors, such as those used in medium format cameras. These typically have about 20+ Mpix as well, but they are spread over a bigger sensor. This makes the individual pixels larger which makes them less noisy or more light sensitive, but might make the resolution lower.
There are still some arguments of the dynamic range of film compared to digital. I've seen the scientific results, but since most of the difference is in the darkest parts of the image it's not clear how visible the differences are.
Here's one of my tips which shows the potential of film:
Scanning to Get More from 35mm Film
In theory the lenses are better than the sensors (film or digital) but the combined resolution isn't affected much by the further improvements in the lens.
The formula for computing total resolution of a system is 1/(res of lens) + 1/(res of sensor) = 1/(combined res)
So for,say, a sensor with 50 lpmm resolution and 100 lpmm lens the result would be 33 lpmm.
Now raise the lens to 200 lpmm (far beyond the possible) the result would be 40 lpmm - not that much of an improvement.
I think I need to modify my rule of thumb about the degree of enlargement possible. It was formulated in the days of making prints in the darkroom. The final resolution on the print was influenced the lens, the film, the enlarging lens and the photopaper. This worked out to about 8-10x. Which is why most people felt that an 8x10 was about the largest one could go with 35mm film with average care.
Now with a high quality scanner the degradation caused by the darkroom steps has been eliminated. A scanner that can do 3000 dpi or better is essentially a lossless step. In one of my tips I show how proper image sharpening can compensate for the small losses in the scanning process as well. (This is not cheating.) The inkjet prints also have better detail capture than photopapers.
I'm not sure what the new rule of thumb should be, but it is better than the prior 8-10x. I have produced 16x from scanned film and others do this frequently from digital capture. I think this may be stretching things for highly detailed subjects.
This leads into another area - perception.
Back in the 1960's when Kodak wanted to introduce the Instamatic they did a bunch of perception studies to see how bad an image could get before the average snap shooter would notice. They then designed a system which was slightly better than this - the Instamatic. What people find acceptable varies greatly. Most snapshots are of familiar people and the emphasis in on recognition and memory of the event. People don't study the technical aspects of the shot. The same is true of much vacation photography. If it looks like the Grand Canyon then you were there.
There are some very discriminating viewers and they have a different set of internal standards. This is why we see disagreements over things like large and medium format photography compared to digital and 35mm. The two groups are using different acceptability criteria. The same thing happens in the music area. Many people are happy with MP3 compressed playback, which sets the hi-fi "golden ears" crowd in a frenzy.
Many people seem to become defensive when they think their personal choices are being challenged. No one likes to feel that they are being treated as a fool because of their choices. This is why I try to present data and leave the acceptability to the user. I'm not trying to convince anyone to use one technology over another, but I will say that scanning gives new life to film that most of us probably never expected to see.
I'm still sticking with film, mostly because the cameras I use have properties that I don't find comparable in digital so far. Specifically my rangefinder camera and its ultrawide 12mm lens are not available in this combination. In addition my swinglens panoramic camera is still only film-based.
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