How Many Megapixels = Resolution of
Fuji Velvia ISO 50 35mm Slide Film?

Answer : 15.5 Megapixels
Go to Page1
Go to Views of Kodachrome and Velvia Through a Microscope
Go to Page Showing Upsampled Sticker Area from the Digicam, Velvia, and Portra 160NC Negative
Go to Page Comparing 200% and 400% Upsampling

Crop from the
Nikon Coolpix 5000
5 Megapixel Image 		View of the Velvia Slide Through a Microscope 4000 dpi Scan of the Velvia Slide 4000 dpi Scan of the Velvia Slide Upsampled 400%
(4 Times Horizontally & Vertically = 16 Times as Many Pixels)
Although there might be very slightly more information in the slide image than in the 4000 dpi scan of it, for all practical purposes, the 4000 dpi scan captured all the important detail on the slide. This becomes apparent after upsampling the 4000 dpi scan.

If we agree on this point, then my digital camera's sensor would unquestionably match the resolution of Velvia 35mm slide film if it could match the resolution of the 4000 dpi slide scanner.

The 4000 dpi slide scanner placed 16 pixels across the cropped area shown above.

My Nikon Coolpix 5000 placed 9 pixels across the same area.

Coolscan : 16 x 16 = 256 pixels per unit area

Coolpix : 9 x 9 = 81 pixels per unit area

Therefore, the scanner effectively has 256/81 = 3.16 times as many pixels as the digital sensor in my Coolpix.

The Coolpix sensor has 4,915,200 effective pixels.

Therefore, 4,915,200 x 3.16 =
15,532,032 pixels would be required to match the resolution of Velvia ISO 50 35mm slide film.
15.5 Megapixels = Resolution of Fuji Velvia ISO 50 35mm Slide Film
Notes :

• Fuji Velvia is among the best films you could use for comparison with digital sensors.

• Fewer megapixels would be needed to match a grainier film like Kodak Gold 200.

• This test only addresses the question of resolution. I don't deny that other qualities of digital sensors might mean that they can produce better prints than Velvia with fewer than 15.5 megapixels.

• The resolution being discussed here - down at the microscopic level - would only be noticeable in very big enlargements. This resolution is certainly overkill for 8"x10" prints, and probably unnecessary for prints up to 16"x20" (maybe bigger).