Comparing Digital Imaging Technology to the Human Eye

There’s an interesting discussion going on over at the DPReview forums regarding how the human eye compares to the technology we have in digital cameras.

Here are some of the findings that were compiled from various sources on the web:

Human Eye Specifications (typical):

  • Sensor (Retina): 22mm diameter x 0.5mm thick (section); 10 layers
  • Resolution: 576MP equiv.
  • Visual Acuity: ~ 74 MP (Megapixels) (printed) to show detail at the limits of human visual acuity
  • ISO: 1 – 800 equivalent
  • Data Rate: 500,000 bits per second without colour or around 600,000 bits per second including colour.
  • Lens: 2 lenses – 16mm & 24mm diameter
  • Dynamic Range – Static: contrast ratio of around 100:1 (about 6 1/2 f-stops) (4 seconds)
  • Dynamic Range – Dynamic: contrast ratio of about 1,000,000:1 (about 20 f-stops) (30 minutes)
  • Focal Length: ~ 3.2mm – (~ 22mm 35mm equiv)
  • Aperture: f2.1 – f8.3 (f3.5 dark-adapted is claimed by the astronomical community)
  • FOV Field of View: 95° Out, 75° Down, 60° In, 60° Up
  • Color Space – 3D (non-linear) RGB
  • Color Sensitivity: 10,000,000 (ten million)
  • Color Range: 380 to 740 nm
  • White Balance: Automatic (constant perceived color under different lighting)
  • Refresh Rate: foveal vision (high-quality telescopic) – 3-4fps; peripheral vision (very inaccurate) – up to 90fps

Obviously compiling this creates some very big assumptions – many of these are interrelated to the brain’s processing of the eye’s signals. I am sure that while the above statistics are factual, presenting them as a direct apples-for-apples correlation to common camera specifications is probably fraught with inconsistencies. So bear in mind that I did this just for fun!

Another interesting idea that came up was the possibility of using the human eye as the lens and sensor for future imaging devices:

Maybe future “cameras” will actually link to your eyes – since the eyeball is such a great lens, who knows? Getting signal from the eye is the trick – would require a surgical implant or a means of reading brainwaves. Maybe that’s 200 years out – similar time [frame] the Mayo clinic is talking about for correcting double/triple vision.

Perhaps in the future we’ll all be documenting our lives at 576 megapixels through our eyes and ears, and storing the photos and videos on petabyte external hard drives at home.

What do you think of this discussion? Is there anything that jumps out at you as being wrong, or do you agree with the comparison for the most part?

1. posterior chamber 2. ora serrata 3. ciliary muscle 4. ciliary zonules 5. canal of Schlemm 6. pupil 7. anterior chamber 8. cornea 9. iris 10. lens cortex 11. lens nucleus 12. ciliary process 13. conjunctiva 14. inferior oblique muscle 15. inferior rectus muscle 16. medial rectus muscle 17. retinal arteries and veins 18. optic disc 19. dura mater 20. central retinal artery 21. central retinal vein 22. optic nerve 23. vorticose vein 24. bulbar sheath 25. macula 26. fovea 27. sclera 28. choroid 29. superior rectus muscle 30. retina



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