New Tutorial: Cameras vs. The Human Eye

[McQ]

This isn't yet public on the main site, but as usual, it's being posted here first...

Tutorial: Cameras vs. The Human Eye

This is one of those areas where there are a lot of myths circulating, but not many hard answers. I had a lot of fun putting this one together and learned a lot. Hopefully it will prove interesting and helpful to you all as well.

VS.

It focuses on three main differences: angle of view, resolution & detail, and sensitivity & dynamic range.

As usual, please let me know if you feel anything is unclear, if you notice any typos, or just want to add something from your own experience. This is a really broad ranging topic, so there is a lot that could potentially go into this tutorial...

Many thanks!

PS: some of this was motivated by a question a long time ago in this thread:
"Normal" focal length - how to mimic the human eye

[Peter Ryan]

Hi Sean,

I have had trouble participating lately - mostly too busy building the photography business but this is a great tutorial.

One area I am not getting though is the last paragraph under Resolution & Detail - Low-Contrast Detail. Can you please expand on what you are trying to get at here?

Please let me take this time to thank you, the mods and all members for helping me build my knowledge to be able to take it to a commercial level.

[rpcrowe]

Hi Sean... Thank you for taking the time and effort to produce and share this well thought out tutorial.

[McQ]

One area I am not getting though is the last paragraph under Resolution & Detail - Low-Contrast Detail. Can you please expand on what you are trying to get at here?

Hi Peter, thanks for sharing your thoughts. I think an illustration there would really help. I'll try and put one together later. In the meantime, the image below might help.

UPDATE: I've now included two visual examples and changed the wording accordingly...

[arith]

It is very nice.

I was entertained by the optical illusions, inparticular the clock with the missing dot. The comparisons with the camera were insightful.

It is a great introduction to an instruction book on photography.

[Peter Ryan]

Hi Peter, thanks for sharing your thoughts. I think an illustration there would really help. I'll try and put one together later. In the meantime, the image below might help.

UPDATE: I've now included two visual examples and changed the wording accordingly...

Thanks Sean - I can see where you are going with this now. This is a tutorial I need to re-read but I can understand it and relate to the content. For me this is something I would urge my students to read and understand. In fact I tell them all to become members but I am not sure I have seen any here yet.

Well done. Keep them coming.

[maloufn]

Sean,

Thanks for your enlightening tutorial. Being a biologist I would replace the word "mind" throughout the
tutorial with "brain" as it is a structural biological phenomenon- a brains interpretation of impulses from the
optical nerves. If we as photographers could only mimic the eye in all its functions we would have perfect
pictuires all the time and there lies the challenge!!

Keep the good work up. You guys are amazing.

Regards

Nasseem

[maloufn]

Hi Sean,

I have had trouble participating lately - mostly too busy building the photography business but this is a great tutorial.

One area I am not getting though is the last paragraph under Resolution & Detail - Low-Contrast Detail. Can you please expand on what you are trying to get at here?

Please let me take this time to thank you, the mods and all members for helping me build my knowledge to be able to take it to a commercial level.

Hi Peter,

Hope you are well. I take it you have been working on your business as a photographer- something I
would like to do in due course. I got a book from Amazon.com the other day which is the bible re the
business side of photography. Its a must for anyone contemplating going into business with photography.
Its called Best Business Practices for Photographers by John Harrington. Do yourself a favour. Buy it.

regards

Nasseem

[Peter Ryan]

Thanks Nasseem I will try and get a copy.

I have been preparing for a couple of weeks and today hung my exhibition in the Ballarat International Foto Biennale - some 18 pieces.

The markets are going well and I am starting to get calls outside of market times from people who have seen my work but now need a present. A friend and I have started a business (4wdexposure.com.au) offering weekend and extended tours taking people to remote locations and teaching them photography as we go. We are about to embark on a trial run across the Simpson Desert (might as well start big) in two weeks.

I did my first one day workshop on post production the other day and that went well and I have trouble finding enough time for the photography workshops.

It all seems to be happening at the moment.

[Colin Southern]

Its called Best Business Practices for Photographers by John Harrington. Do yourself a favour. Buy it.

One might be forgiven for thinking that Best Business Practices for Authors would be to make their work available in Kindle format on Amazon, but sadly, no

[ilovelucydog]

One might be forgiven for thinking that Best Business Practices for Authors would be to make their work available in Kindle format on Amazon, but sadly, no

Maybe they will... eventually? There's always hope, right?

[STKPhotoLA]

Nice Sean! Just wondering how Lytro would fall in this comparison?

[McQ]

Nice Sean! Just wondering how Lytro would fall in this comparison?

The Lytro camera is an interesting and useful concept, but at least based on their published articles, my understanding is that it unfortunately doesn't push any fundamental physics limits. It has to make substantial trade-offs with light-gathering area and/or resolution in order to achieve more flexibility with depth of field. Conceptually though, yes, one could definitely argue that the ability to change DoF after the fact can make cameras function similar to (or better than?) our own visual perception.

[nickjohnson]

Sean, many thanks for putting so much work into yet another tutorial. I must say that I find your work here on CiC particularly good in taking very technical subject matter and explaining it to just the right level of detail – not too long or short – just right.
Suggestion. I wonder if you might like to extend this new piece to show that post processing is to a large extent (but not exclusively) the act of making a camera image look more like a human perceived image, and thus a means of bridging the differences that you point out?

Regards,

Nick.

[FrankMi]

Hi Sean, I really enjoyed studying the tutorial and following the links for more enlightement on various aspects of the comparison. One thing I was looking for and did find in some cases, was the "what can we do about the differences". I try to get my images as close as I can to what I saw when I took the image. Because of these differences I'm often left with the feeling that I often can't show someone else what I actually saw, only an approximation. After all, you'd have had to been there to really see what I saw. <sigh>

When I do my post processing, I to try to get the image as close to what I saw as I can. Ironically, I can't be certain I can remember all the subtleties of color temperature and tones, lighting, depth of shadow, etc. and because I like bright colorful images, the result is, I'm sure, not as subtle as what I actually saw! Ideally I would have a photo to compare to as I make my adjustments but that is what I'm trying to achieve so I have to rely instead on an imperfect memory.

The link to the HDR tutorial in particular helps, but I was hoping to find a "here's the differences, and here is how you can overcome or minimize those differences" more clearly spelled out for each of the differences in question.

All in all it is an excellent tutorial and helps us to realize why the picture isn't simply an exact 2D rendering of the 3D image that we saw when we clicked the shutter.

[McQ]

Suggestion. I wonder if you might like to extend this new piece to show that post processing is to a large extent (but not exclusively) the act of making a camera image look more like a human perceived image, and thus a means of bridging the differences that you point out?

Hi Nick -- It's funny you mention that because I started a draft for one just this past evening, and it will primarily be about "why photo editing is necessary" (either manually or by the camera) or "photo editing: how much is too much" or some combination of these . No promises that it will be the next, but at least it's in the pipeline. I agree with your point that too often people presume that not touching an image will somehow make it more realistic, when often the oppose is the case.

[maloufn]

Thanks Nasseem I will try and get a copy.

I have been preparing for a couple of weeks and today hung my exhibition in the Ballarat International Foto Biennale - some 18 pieces.

The markets are going well and I am starting to get calls outside of market times from people who have seen my work but now need a present. A friend and I have started a business (4wdexposure.com.au) offering weekend and extended tours taking people to remote locations and teaching them photography as we go. We are about to embark on a trial run across the Simpson Desert (might as well start big) in two weeks.

I did my first one day workshop on post production the other day and that went well and I have trouble finding enough time for the photography workshops.

It all seems to be happening at the moment.

Congratulations Peter. I wish you all the luck. I would love to spend my later years doing just that. I might
draw on your expertise in due course. Meanwhile I will just keep on learning. I have just spent a few
months learning about "Lighting". Afterall its all about understanding light and how to manipulate/use it.
I have got into flash strobist photography using remore triggers (pocketwizards) and enjoying it thoroughly
doing portraits. Its just endless. There is so much to learn and I thank you guys at CIC for such a great
site and source of info. Let me know how your exhibition goes. Id love to part of the Simpson desert
workshop.

regards

Nasseem

[Peter Ryan]

Congratulations Peter. I wish you all the luck. I would love to spend my later years doing just that. I might
draw on your expertise in due course. Meanwhile I will just keep on learning. I have just spent a few
months learning about "Lighting". Afterall its all about understanding light and how to manipulate/use it.
I have got into flash strobist photography using remore triggers (pocketwizards) and enjoying it thoroughly
doing portraits. Its just endless. There is so much to learn and I thank you guys at CIC for such a great
site and source of info. Let me know how your exhibition goes. Id love to part of the Simpson desert
workshop.

regards

Nasseem

I am happy to help in any way I can when you are ready. I have learned a lot in the last 2 years not the least being it is hard to find exactly what clients want. I have always regarded myself as a landscape and wildlife photographer but my best selling images over the last 12 months are ones of iconic Melbourne buildings processed with a slight difference (check out my website below). I took them for a DVD of Victoria I was putting together and thought I should have some images of Melbourne and they have taken over.

I must admit that the workshops and lecture series are extremely popular and I do enjoy the teaching. So, yes, there is plenty to keep you active and interested in retirement.

My friend and I will be running trips next year into the Northern Flinders Ranges (including the Gamon Ranges) and Coongie Lakes so stay tuned. Let me know if you are ever in Melbourne and we can have a coffee.

[rhadorn]

This is certainly a fundamental piece of tutorial for understanding photography. Bravo and thanks!
I am waiting with interest for that other piece, which will show how editing somehow tries to bridge the eye's and the camera's views – or to exaggerate those differences to create a style. Focus bracketing bridges, whereas shooting the picture at f 1.4 exaggerates the difference...

To me, the reference to the mind (rather than to the brain) is the appropriate one, in as far as the brain is certainly the matrix for our mind but encompasses more than the brain – namely culture and subjectivity. We also use to speak of a «*mental image*» constructed by human vision, not of a «*brain image*». Mental obviously refers to the mind, not to the brain.

The tutorial mentions that the dynamic range of the human eye is about 10 to 14 EV wide. There is a lot of difference between 10 and 14. There is probably also a difference, whether one considers the limiting dynamic range or some kind of practical range. I tend to consider the practical range close to 10 EV's, a little more than the 8-9 EV's reproduced on a print or on screen. This gives also sense to high contrast, low key or high key pictures, which may be viewed as interpretations of the limited dynamic range capacity of the eye in a one glance - one picture kind of vision.

Who is right? I suppose such a big variation as from 10 to 14 largely depends on the experimental setting. I would really appreciate that you share some of your sources with us, so helping us going further into some of the issues. The forum is probably a more appropriate medium for that than the tutorial itself.


Reto

[McQ]

The tutorial mentions that the dynamic range of the human eye is about 10 to 14 EV wide. There is a lot of difference between 10 and 14. There is probably also a difference, whether one considers the limiting dynamic range or some kind of practical range. I tend to consider the practical range close to 10 EV's, a little more than the 8-9 EV's reproduced on a print or on screen. This gives also sense to high contrast, low key or high key pictures, which may be viewed as interpretations of the limited dynamic range capacity of the eye in a one glance - one picture kind of vision.

Who is right? I suppose such a big variation as from 10 to 14 largely depends on the experimental setting. I would really appreciate that you share some of your sources with us, so helping us going further into some of the issues. The forum is probably a more appropriate medium for that than the tutorial itself.

Hi Reto, these are good points. To clarify: I was very hesitant to put anything but ranges for many of the numbers in this tutorial because these are highly dependent on subject matter and viewing conditions. I want to avoid the scenario where someone says "oh, 14 is greater than 13, therefore the former is better than the latter" -- when in reality the difference is insignificant, and this advantage doesn't apply universally. Instead, I'd like readers to conclude from these ranges that one is generally better than the other, but not always.

For example, with the human eye, I used a range of 10 to 14 because this primarily depends on (i) ambient light levels and (ii) subject contrast. This reflects a contrast ratio range of 1,000:1 to 10,000:1. At night we're often closer to the upper end of that spectrum, but during daytime we might be closer to the lower end. Similarly, our visual system is really a contrast detection engine -- not a strict pixel capture device like a camera. Therefore, if the subject matter doesn't contain high contrast texture, we'll end up seeing a reduced dynamic range. Regardless, I tend to agree with you that a good rule of thumb for *most* human viewing conditions is around 10-ish f-stops of dynamic range. There's a little more on this in the tutorial on dynamic range in photography (in the human eye section near the end).

Plus, these ranges don't just apply to biological aspects; our cameras abilities vary substantially. For example, the dynamic range of an SLR depends on whether one is shooting in RAW mode (which increases the DR but may not preserve accurate color in extended DR regions), the ISO setting (generally higher ISO values decrease DR), optical effects such as flare, or even the outdoor temperature (which can impact noise levels).

Clearly there's a lot more to these topics than was summarized in this tutorial. I'd consider doing a part 2 later on if it weren't something that I thought would become too technical. This would also give me an excuse to continue delving into more research papers . It would likely focus a lot more on color vision and depth perception, amongst other topics.