[sibyrnes]

I have seen it stated and accepted by most here that the resolution of digital photography has surpassed that of film. It seems to be a very confusing issue with me. The comparisons I have seen are of scanned film images compared to digital camera images. Would not such comparisons be dependent on the resolution of the scanner used? How does the resolution of a 35mm slide(the actual slide - not a scan) compare to a digital image and how does one go about making such comparisons? I have read articles where the stated resolution of 35mm film varies from 20 mp to as high as 80 mp. What's the real story?

[photoptimist]

This long report has all the gory details:

http://cool.conservation-us.org/coolaic/sg/emg/library/pdf/vitale/2007-04-vi...resolution.pdf

The statistical nature of film grain does make estimating resolution a bit harder because film's resolution does not stop abruptly at the pixel pitch the way digital does. Fortunately, statistical analysis of granularity does enable estimating an equivalent resolution.

In the case of color, digital is better even at low ISO. In the case of B&W, low ISO film is still better. For any shooting situation over about ISO 400, digital is better. And for really high ISO, digital crushes film.

[ShawnH]

A good 35mm negative can yield an image as sharp as a 4mpx digital camera. There is just no comparison in sharpness. An 11X14 inch print was the best you could hope for from a 35mm format and it would be soft by todays standard. A 24X36 inch print from a digital APS format is routine.

[tuco]

The story is small format film has never had high resolution images even in the film glory days. The negative/positive is just too small.

[stevebrot]

A good 35mm negative can yield an image as sharp as a 4mpx digital camera. There is just no comparison in sharpness. An 11X14 inch print was the best you could hope for from a 35mm format and it would be soft by todays standard. A 24X36 inch print from a digital APS format is routine.

I have printed 16x20 from a 35mm negative with no loss to the print quality. As for information in a digitized image, the conventional number is 22 Mpx maximum for 35mm film. As for 24x36 from APS-C...I guess it depends on pixel count and fussiness about quality. 300 dpi is 300 dpi. My K-3 provides 6016 pixels on the long axis. The math does not lie (hint: 20"), though at larger sizes, one may fudge and let the printer apply a little upsampling to fill in the "blanks" and allow a larger print.


Steve

(...remembering a sales clerk in 2007 claiming that one could print poster size from a D80's 10 Mpx output...right...)

[tuco]

I have printed 16x20 from a 35mm negative with no loss to the print quality.

No way, Steve. You are pulling the grain apart so much at that enlargement the tonal scale suffers.

[stevebrot]

I have read articles where the stated resolution of 35mm film varies from 20 mp to as high as 80 mp. What's the real story?

It depends on the size of the negative and the resolution of the scanner. Here are a few talking points:

• A film image does not have pixels. Acceptable print size for display is the appropriate point of comparison.
• Film resolution is determined by direct examination of contact exposures from a reference resolution target. From that lp/mm or MTF data may be generated.
• Manufacturers generally publish the product MTF and values for the better emulsions can be quite impressive
• Conventional wisdom is that negative size determines the quality limits for print size and, as noted above, rare is the 35mm negative that will pass muster above 16x20" for a darkroom print and even then, technique must be near perfect
• One can print impressively large from 6x6, 6x7, and larger 120 medium format and less impressively from 645
• Large format negatives (4x5" and larger) contain a scary amount of information

One more point...the comparison of digital to film is natural and to be expected. After all, the tools are very similar in usage and appearance. However, while painters may discuss the virtues of oils vs. tempera vs. acrylic, most will concede that different media have different uses and some resonate more strongly with a particularly artist.*


Steve

* I was privileged to view the Andrew Wyeth retrospective in Seattle earlier this month. While proficient in multiple media, his choice was generally dry brush tempera on hard board. The results are spectacular. Oils would not have sufficed.

[sibyrnes]

Thanks Steve for you informed opinions. As for some of the other responses, gee, I wish someone would have told me back in the 90's that "An 11X14 inch print was the best you could hope for from a 35mm format". That would have saved me a lot of money! I have a 16 X 20 print from Velvia hanging on my wall and I routinely projected images on a 6 foot screen that looked pretty good. Many of those images where shot with the same lens I now use with my K-1! Anyone remember slide projectors? I wonder how a projected image from a digital photo compares to one from a Kodachrome or Velvia slide. Has anyone made such a comparison?

Of course your comments about the media used are true - I just find the comparisons to be interesting.

[richard0170]

I don't think we will ever know the correct answer to this question. I have seen various answers from different sources. Some saying 14mp, some up to 40 mp and here 4mp! Historically, when my partner shot here Nikon D40 (6mp) and I was still exclusively on film (Velvia or Sensia, XP2), my film images were vastly superior in IQ terms. What I will say in this day and age is why should we bother or indeed care? I shoot film and digital, and the best results get blown up to around 16"X20". At this size I have various resolution digital prints from around 8mp to 24mp and some B&W prints from Ilford XP2 plus and PanF, and a colour print from Velvia. All, digital and film, are properly exposed and perfectly shake free, and all look great. And this is what matters. As a general subjective observation, I prefer the look of the digital colour prints over that of the one from Velvia. I prefer the look of the XP2 prints over the digital B&W. I also have a 11"X11" print taken 33 years ago handheld on Superia 100 with a Yashica, so not the best quality film or technique. In terms of tonal gradation the old print from medium format knocks 35mm and 24mp into a cocked hat! Due to the nature of how the picture was taken I would not make a final comment on the resolution of medium format as compared to a 24mp print, but I suspect it will also be far higher.
The reasons to shoot one format rather than another should really not be based on which gives one the highest resolution, but on what one enjoys using. If your technique is good enough 35mm high quality film is more than adequate for 16"X20" prints at normal viewing distances. For what its worth I took 2 pictures of the same subject using an old Canon FT with 58mm f1.2 lens at 1/125 sec f5.6 on Agfa Precisa 100, and K3 at ISO 200 with DA35mm f2.4 at 1/250 f5.6. The 24mp photo was printed up to 16"X20", as I assumed it would be a better quality print. I printed the low res, c3mp, scan direct from the disc provided by Peak Imaging to A4, and was immensely surprised by the comparison. Its is very hard. to see a significant improvement in resolution in the larger digital print. If one peers closely there is some increase but not enough to trouble me. The print from the old film camera and lens though appears to me to be more pleasing. I do not know what this is down to. It could be the particular qualities of the lens or the film or a combination thereof. Whatever, the conclusion I draw from this less than scientific experiment is not to worry too much about resolution.
As an aside, I shoot film for the following reasons:-
1. I like the gear more
2. For general walk around photos, usually with somebody else as company, film is more social as one is not continually looking at a screen
3. I like having to wait a period of time before I see the results. It helps to relive the memories
4. As stated above I find B&W film more appealing than digital B&W
I shoot digital for the following reasons
1. I do not always know whether I want to shoot B&W or colour, digital gives me a convenient choice in one camera.
2. Its a lot cheaper to shoot digital telephoto or close up photos due to the high failure rate in these subject areas, and due to things like high ISO performance, instant review and IBIS, a lot easier!
3. Despite what I say in my experiment above I generally prefer the digital colours over that of film. This may change as I now have some Ektar to play with!

[6BQ5]

DSLR-scanning my film gave me an idea of film resolution.

I started DSLR-scanning with my K-30 which is 16 MP. Then I moved to a K-3 which is 24 MP. I noticed that I didn't gain any resolution so to speak. All I got was a better view of the grain. I would say good consumer film processed properly seems to yield somewhere between 12 and 16 MP. If you want more resolution then you need to shoot with larger format film.

About three years ago I made a 16"x24" print from a DSLR-scanned E6 positive. I can't remember the film now ... I'm at work ... but I'm pretty sure it was a lower speed Fuji 135 sized film. The print turned out nice with a very "analogue" rendering. Plenty sharp and crisp but certainly not "digital".

That's an exception though. Normally something like 8"x10" is big enough for me and 135 negative film.

[gofour3]

Thanks Steve for you informed opinions. As for some of the other responses, gee, I wish someone would have told me back in the 90's that "An 11X14 inch print was the best you could hope for from a 35mm format". That would have saved me a lot of money! I have a 16 X 20 print from Velvia hanging on my wall and I routinely projected images on a 6 foot screen that looked pretty good. Many of those images where shot with the same lens I now use with my K-1! Anyone remember slide projectors? I wonder how a projected image from a digital photo compares to one from a Kodachrome or Velvia slide. Has anyone made such a comparison?

Of course your comments about the media used are true - I just find the comparisons to be interesting.

Yep I did many larger prints from my Kodachrome slides back in the 1970's up to 24x36 and they are beautiful!

Of course the printing process was different back then, as a MF sized inter-negative was created from the slide and the print done from that.

Phil.

[richard0170]

I've done some quick maths. If we assume a good 35mm neg is equivalent to a 12mp raw image something like Velvia 24mp, that would mean a good 6X4.5 neg is approximately equivalent to 40mp to 80mp raw image. I have some old 6X9 folders, they would generate a 75mp tp 150mp image!
However, if you want to print your digital image, you have to convert it to JPEG. Now a 24mp raw file is about 27mb. a 24mp JPEG less than 6mb. So the conversion to JPEG has lost around 50% of the linear detail. I do not know what detail we would lose with good printing or scanning technique of film, but I suspect it is a lot less than 50%.
Even so this to me is not a reason to shoot film over digital, as I mentioned in my post above the perceived IQ between 35mm and digital on printed images is negligible due to sensor resolution, but many other factors must be involved.
Its been a while since I dragged my slide projector out, but I can recall stunning resolution images thereon from tripod mounted shots on Velvia at very big enlargements. I also acquired a medium format projector last year, which is still waiting to be used, and when I get round to it I am expected to be amazed by the images it projects. Trouble is finding the time to do all this!
ON a slight tangent, back in the 80's the Fleet Street photographer Victor Blackman wrote a weekly column in Amatuer Photograher. He did an experiment on lens resolution on 35mm film. His conclusion was you could tell the difference between different lenses on film like Kodachrome 25 to 64, "which you might expect" for colour film, but also on film like TriX rated at 400ISO for B&W, which "you certainly would not!" Conclusion, 35mm film is more than capable of superb results, given good technique.

[Alex645]

In the case of color, digital is better even at low ISO. In the case of B&W, low ISO film is still better. For any shooting situation over about ISO 400, digital is better. And for really high ISO, digital crushes film.

+1 in simple terms, this nails it.

(...remembering a sales clerk in 2007 claiming that one could print poster size from a D80's 10 Mpx output...right...)

Well you could....if you just stood back far enough.....

I wonder how a projected image from a digital photo compares to one from a Kodachrome or Velvia slide. Has anyone made such a comparison?

Kodachrome 25 and even 64 was amazing. I printed many P-30 Ciba/Ilfochrome 16x20 from them and started filmmaking with tiny Super8mm Kodachrome that projected beautifully (in a standard size cinema screen at both UCLA's Melnitz Hall and in a theatre in Durango, Colorado). It looked less grainy and sharper than most 16mm films and even pushed 35mm color print positives. The key, however, was the optics used. If I shot with a Yashinon Super8 camera and then projected with a zoom lens, it looked mediocre at best. If I shot with a Nikon Super8mm and then projected with a prime lens, it was stunningly good.

The measured resolution for any film image is going to be the result of the camera lens, the format(!!!), the exposure index, the emulsion, the processing (chems, temps, times, etc), and then if we aren't scanning, the enlarger or projection optics. In the perfect scenario with 35mm Ektar 100 or Ilford Pan F50, the resolution was around 24MP. With 645 film, again with ideal conditions, it's closer to 80MP.

For slides, Velvia 50 is about as good as it gets, but I've still not seen an E-6 match the K-14 of yesteryear.

[CDW]

Anyone remember slide projectors? I wonder how a projected image from a digital photo compares to one from a Kodachrome or Velvia slide. Has anyone made such a comparison?

Of course your comments about the media used are true - I just find the comparisons to be interesting.

Unfortunately, affordable UHD projectors are still quite expensive, leaving you with the option of 1080P projectors. They look very good but not up to optical projection of color transparency film. That said, my images scaled to 4K on a 55" OLED display look better than any slide projector. That is mainly as a result of the contrast and ability to deliver pure blacks that projected images cannot deliver unless the environment is virtually a pitch black room with no light reflective surfaces.

FWIW, 6x7 projectors capable of displaying medium format transparencies are superb.

[IgorZ]

This is a question rather than an intelligent contribution to the discussion. I was reading an article comparing film and digital (PhaseOne vs 4x5 and 8x10 Velvia) and the article mentions a B&W film I've never heard of that has a resolution of 800 lines per mm. That is way higher than your usual lens, is it not? If I remember correctly, K and M lenses max out just below 100 lines per mm. So what do we compare? A digital image and a film image taken with the same lens?