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-   -   relationship between film and digital (https://forums.steves-digicams.com/general-discussion-11/relationship-between-film-digital-226283/)

Shinnen Jul 9, 2018 3:52 PM

relationship between film and digital
 
Hi all,
When I took my film in for processing today, I asked the technician what resolution the prints will be, (they will be on CD), and he told me 300dpi. That got me wondering about how digital sensors and film compare wrt to resolution. I'm sure it varies form sensor to sensor, but how does one measure the resolution of film?
Anyone care to enlighten me?
Thanks,
..... john

Ozzie_Traveller Jul 9, 2018 5:57 PM

Quote:

Originally Posted by Shinnen (Post 1415203)
Hi all,
When I took my film in for processing today, I asked the technician what resolution the prints will be, (they will be on CD), and he told me 300dpi. That got me wondering about how digital sensors and film compare wrt to resolution. I'm sure it varies form sensor to sensor, but how does one measure the resolution of film?
Anyone care to enlighten me? Thanks,..... john

G'day mate

12-15 years ago I first read something along these lines and there's been heaps of stuff since then - as film is 'organic' in its grain structure and digital is 'mechanical' wrt image construction, there can be no exact comparison ... however I have read other 'experts' claiming that 35mm Kodachrome-25 film was variously equal to 20mpx to 50mpx ... but no-one has ever proved it

Certainly these days when I pull out a 12"x16" print and compare both optical [lens] sharpness and inherent grain structure ... today's lenses are sharper and the pixel fineness is better than film ~ however I do like seeing grain and I am more than happy to see today's 'noise' as part of the image makeup ... so ther's no accounting for taste!

Hope this helps
Phil

Shinnen Jul 9, 2018 6:11 PM

Yes, it does help.
Thanks again Phil.
.... john

TCav Jul 9, 2018 8:08 PM

Film is analog, while digital is ... well ... digital. Even the 300 dpi images you got from the lab were digital conversions of the analog original. That's a limitation of the analog to digital conversion, not the analog original.

Transparencies (negative or slide) can be scanned on a drum scanner at resolutions of up to 24,000 dpi, and with greater dynamic range as well.

As for the resolution of the film itself, that varies with the size of the grains, and the size of the grains varies with the film speed. Faster films generally use larger grains, and so have a lower resolution.

But remember that film with larger grains can still be scanned at the maximum resolution of a drum scanner, so there's no way to directly compare the resolution of film to digital.

Shinnen Jul 9, 2018 10:01 PM

Thanks TCav,
That's good to know.
When he told me 300dpi, I must admit, I wasn't impressed; but he said that that's quite a high resolution??? I don't have the pictures back yes, so .....
I don't know if there's any co-relation, but even an old scanner like my LIDE70 will do 600dpi, so 300 doesn't sound like anything to write home about.
.... john

VTphotog Jul 10, 2018 9:08 AM

300 DPI for prints is good quality for most photos. It's about the limit most people can resolve with the naked eye, and it's probably what his printer's resolution is. Your negatives will have more resolution than that, though and can be printed considerably larger. (guessing at 4"x6" prints)
brian

TCav Jul 10, 2018 9:41 AM

Yes, that 300dpi is the resolution of the prints, which has nothing to do with the resolution of the negative or the analog to digital conversion.

Shinnen Jul 10, 2018 11:54 AM

Hi Brian/TCav,
Yes, alright. He said that the resolution of the 'prints', albeit on CD, is 300dpi; and that that is the maximum resolution he can get. For the hell of it, I'll probably see if I can improve on that by photographing the film using my analogue slide viewer and the FZ150; but that won't be for a couple of weeks. What do you think my chances of succeeding are?
..... john

TCav Jul 10, 2018 3:29 PM

Quote:

Originally Posted by Shinnen (Post 1415233)
Hi Brian/TCav,
Yes, alright. He said that the resolution of the 'prints', albeit on CD, is 300dpi; and that that is the maximum resolution he can get. For the hell of it, I'll probably see if I can improve on that by photographing the film using my analogue slide viewer and the FZ150; but that won't be for a couple of weeks. What do you think my chances of succeeding are?
..... john

The limitation with the system you're using is the resolution of the prints, so bigger prints gives you higher resolution images. If you had ordered 8x10s, you'd probably have gotten the same 300dpi resolution, but the result would have been a much higher resolution image that you could put on a flatbed scanner and gotten great digital images from.

VTphotog Jul 10, 2018 4:40 PM

If you open the CD and look at the properties of the images, it should give you the size of the image in pixels. Pixels correspond with dots in printing, so if your prints are 4"x6", at 300 DPI, that would give you 1200x1800 pixel images, around 2 megapixels.

brian


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