This post was initiated by a number of other threads related to the quality and nature of digital images.

I have to state first that digital is more nearly akin to a reversal film with a variable ISO or like an eye with a truncated tone scale. Negative film is a linear film with a long tone scale, nearly 5x longer than any reversal or digital image and is therefore very flexible. You do see the toe and shoulder of a print from such a negative though, but it retains more detail than a pos-pos print.

A digital image, like a reversal slide image, has a toe and shoulder in each and every frame shot. However, with a slide film an error in exposure smacks us in the face with either the toe or shoulder, whereas digital can compensate electronically. Well, actually this is the point here. Digital always compensates and always manipulates by introducing changes (enhancements) into the image via software.

Here is an analysis:

1. Two pictures were taken, one with a Nikon 2020 on Portra film and the other with a Nikon D70. Both used the same lighting and the same subject as far as was possible.

2. The analog negative was scanned to yield about the same resolution (as far as possible) as the digital image, that is they were the same size on-screen.

3. They were both manipulated digitally to look into the depth and quality of blacks, whites and edges. By this, I mean that contrast and brightness were exaggerated to enable a closer look, as if you were stressing the system by enlarging for example at different sizes and contrast grades. They were also inverted to look into the blacks. You will see the high contrast inverted images here.

The first picture shows all 4 results. The top two show the analog picture; on the right top is the original and the stressed example is the top left. The bottom two pictures have the digital original on the left and the stressed example on the right.

Please note that the originals of both show a non-uniform gray black background. The stressed inverted analog image shows that the black is made up of a non-uniform white in reverse as we expect, but the digital inversion is made up of digital noise. Since there was no image, there is nothing to look at and you get noise. This is not untypical of an under exposed digital object. It becomes noisy. Also note that in all cases the digital images appear quite sharp.

If you magnify these images, you will clearly see the pixels that make up the edge of the digital image, and the manipulation enhances an edge effect trying to increase sharpness to compensate for the jagged edges introduced by pixels (mainly in curved objects). This is seen in the second picture, which is a closeup of the manipulated digital image.

Now, this is all quite subjective, but my intent was to show that even by scanning a negative, the information content is huge and is there. The scanner sees it and the editing software (PS) sees it as well and retains it faithfully. OTOH, a digital original is flawed due to tone scale and excessive noise. By manipulation you can reveal the noise and reveal the attempts made by software in the camera and in PS trying to cover it over. This is the only purpose of this exercise.

Current digital is quite good, but flawed, and software attempts to plaster over the flaws. Analog is very mature and of high quality. You have a hard time "breaking" a good analog image.

This experiment is somewhat equivalent to taking a pos-pos analog system and running through several generations of prints. You see the dupey look as the image degrades. If you use a neg-pos analog system for the same set of prints, you retain high quality.

Try it yourself. Play with a digital image and try to break it. Play with an analog image and try to break it. It is a lesson waiting to happen.

PE

Interesting. Since I don't know enough about digigraphy to even ask intelligent questions please allow these two to be asked without prejudice. :(

Does shooting 'raw' make a difference, or does it just delay the software manipulation.

Does a higher pixel count make a difference in the likelihood of noise, or is that going to be present in any case.


I'm not sure if this potential discussion should even be broached here rather than on Hybrid, but it does involve film so perhaps it can remain (even though my questions aren't about film.)

I don't think that the mode would make any difference, as the image has in it the manipulations done by the camera before it is stored. And the sensor causes the proble. Stacked sensors with smaller size is the only answer to these problems. Even a higher pixel count would not help unless stacked.

PE

So another conclusion from this test would be that scanners can achieve much better image quality than in-camera sensors?

AFAIK, most scanners use CCD technology, as do most digital cameras. The quality of scanners' CCD sensors compared to that of digicam is thus one reason why the scanned film looks better under stress than the digi shot?

so basically, you are discussing film exposure and digital capture. What about digital prints from film? do you think digital prints are getting close to a silver print in quality or are they and always will be different animals?

drew

I don't think it is fair to compare cropped digital and full-frame film...

To address some of these issues....

No image in the picture on the left was cropped. The righthand image is cropped and stands alone to illustrate the noise in a digital black, and to show the manipulation done for the sake of sharpness.

Second, scanning film gives a result superior to a digital original if the scanning is done carefully. Therefore, a good digital print from a good analog negative can now approach an all analog print except for image smear with time and image stability.

And, since the scanning process works the way it does, a scanner does produce better quality than a static digital sensor. Evidence for this is the fact that scanning backs are extremely high in quality and produce the equivalent of a very high pixel count.

So, in order of quality 1: Analog-Analog, 2:Analog-Scan-Digital Print, and 3:All digital. Scanner and printer will influence 2 and 3, but then skill of the photographer goes into all of it as does darkroom skill, printing skill and artistic ability.

PE

I can confirm these results in my dayjob as a 1-hour lab operator. It's MUCH easier for me to rescue an image originating on scanned film from a "super-happy-fun-snap" brand disposable camera than a poorly shot image from even a high-end digicam.