[HN Gopher] Photography for geeks
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Photography for geeks
Author : excite1997
Score : 245 points
Date : 2022-11-27 23:01 UTC (5 hours ago)
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| system2 wrote:
| Adding examples makes it better than other sites I've seen. I
| will share this with friends. Thanks!
| throw0101c wrote:
| If anyone wants to move beyond using the "auto" setting on their
| camera (or phone), I would recommend the book _Understanding
| Exposure_ by Bryan Peterson, the first edition of which was
| published in 1990:
|
| * https://www.goodreads.com/book/show/142239.Understanding_Exp...
|
| The principles involved haven't changed much in the intervening
| decades; the current fourth edition was publish in 2016.
|
| If all you have is a phone you don't have to get new equipment:
| just perhaps a third-party 'camera app' that allows you manual
| control of aperture, shutter speed, ISO/sensitivity.
|
| Once you know how each of these settings alter the resulting
| photo you can use them to alter the composition of photos, which
| is a whole other craft.
|
| Edit: seems recent smartphones have little-to-no adjustable
| camera settings.
| _HMCB_ wrote:
| I bought that book months back. Have yet to read it but thanks
| for the reminder.
| geokon wrote:
| I think when you break down all the variables there is really
| very little to play with bc no phones have variable apertures.
|
| ISO is basically a linear gain that's done on the sensor. As
| long as you aren't blowing out your photo and loosing
| information, it basically makes not difference if you do it in
| sensor or later while editing
|
| So the only variable left is the shutter speed - which is
| basically directly dictated by the amount of light you have.
| You try to get as much light as you can without blowing
| anything out. This is how you get the most information. You can
| decrease it to get faster shots with less blur, at the cost of
| more noise
|
| So it all boils down to basically one "slider"/variable between
| blur and noise
| CWuestefeld wrote:
| _ISO is basically a linear gain that 's done on the sensor.
| As long as you aren't blowing out your photo and loosing
| information, it basically makes not difference if you do it
| in sensor or later while editing_
|
| This is true for _some_ cameras, but certainly not all. Many
| cameras, especially pro or pro-sumer grade, have non-linear
| ISO. That is, there are ranges for which it behaves linearly,
| but typically there will be some range - say the minimum up
| to 1600 or something - where it behaves as a linear range,
| and then the next setting up from that (where the settings
| are typically 1 /3 stop) will reset to a lower snr. (And yes,
| that does imply that in such cases it often yields better
| results to go up by one or even two clicks in ISO)
|
| I'm not sure if there any camera-phones that behave this way,
| though.
| geokon wrote:
| "then the next setting up from that will reset to a lower
| snr"
|
| How does it magically make more photons fit the sensor..?
|
| And why wouldn't you use that same magic at lower iso gain
| factors?
| timbeccue wrote:
| The base stops are ISO 100, 200, 400, etc.
|
| Many cameras let you set the ISO in 1/3 stop increments,
| but if I recall correctly, many camera manufacturers just
| keep the sensitivity at the base stops and adjust the
| brightness via software.
|
| So shooting at ISO 250 really means ISO 200
| (underexposing what you requested) but then adding a
| third stop equivalent of brightening to the digital file.
| Conversely, using ISO 160 actually means the camera is
| using ISO 200 (overexposing) and lowering the brightness
| in software.
|
| What this means, at least 10 years ago when I was more in
| tune with the photography world, is that people would
| prefer to shoot at the [base ISO stop - 1/3] levels to
| because those were the levels with the least noise near
| that exposure setting. The cost is you risk saturating
| more pixels in the highlights.
|
| And for the same reasoning, the ISO setting s 1/3 over
| the base stops were typically avoided as they were
| noisier, albeit with slightly more dynamic range.
| spindle wrote:
| This is a great resource for finding out which ISO ranges
| various cameras are linear over:
|
| https://photonstophotos.net/Charts/RN_e.htm
| lucb1e wrote:
| Taking one of the few recent-ish mainstream phones on
| this list since the subthread is about smartphone
| sensors: Samsung Galaxy S7 has an ISO range of 50-800 and
| basically all the noise values (measured in
| log2(electrons)) are between 2 and 3. There is a downward
| trend from 50 to ~300, above that it's all around 2.
| Other phones have similarly shaped graphs with different
| absolute values.
|
| That sounds like the opposite of what GP (CWuestefeld)
| described. Am I misinterpreting the graph?
|
| Lower sounds better to me, so the downward trend on a
| scale called "Input-referred read noise" sounds like it
| is tuning the Signal to Noise Ratio (SNR) on the sensor
| rather than just multiplying the sensor's output value,
| and it stops doing that above ~300 ISO. GP described that
| it would be a linear multiplier up until (for many
| cameras, not specifically smartphones) ~1600 ISO and
| _after_ that it would be tuning the SNR. Do smartphones
| behave differently for some reason or am I
| misunderstanding something?
|
| (It doesn't seem as though the absolute value says
| anything about the quality by the way, as a 10th gen
| Apple phone has a much lower value on this "noise" scale
| than a 12th gen one. The page does remark "raw values are
| not appropriate for comparing camera models because they
| are not adjusted for area", so this is probably that.)
| throw0101c wrote:
| > [...] _bc no phones have variable apertures._
|
| :(
| rsch wrote:
| If you underexpose too severely, the JPEG compression will
| eat up all the detail in the shadows.
| TreeRingCounter wrote:
| > ISO is basically a linear gain that's done on the sensor.
|
| It's usually not done on the sensor - it's usually done by
| the ADC that performs sensor readout.
|
| Some cameras use a technology like Aptina-DRPix to
| dynamically change the capacitance of the sensor FETs, but
| (as far as I'm aware) this only exists in a simple binary
| form right now. E.g. one of my cameras reduces sensor gate
| capacitance when the ISO exceeds 800, but otherwise any ISO
| changes only affect off-sensor hardware.
| geokon wrote:
| Right, sorry. Not on the sensor, but the hardware that's
| reads it off the .. which I guess is not technically the
| sensor.. haha
|
| You're still multiplying what is the photo-count or
| shotnoise
|
| Didn't know there is technology built on top of that...
| Does changing the capacitance increase the sensitivity
| somehow? I guess then the question is.. why isn't that
| always enabled. There must be some downside to it
| mgraczyk wrote:
| This is only true if you take just one capture. On Pixel,
| iPhone, and others we take many small captures and merge them
| together. There's lots of cleverness there and it allows you
| to have less noise without motion blur or blowing out
| highlights.
| sva_ wrote:
| > no phones have variable apertures.
|
| Even my almost 5 years old Galaxy S9+ has aperture. Surely
| something better came out since.
| wtallis wrote:
| Wikipedia says the S9/S9+ was the first phone since 2009 to
| have a variable aperture. The S10 series also had it, but
| it was gone again in the S20. So it's definitely not
| common, and even in the handful of phones that had it, it
| was only one stop of adjustment.
| gofreddygo wrote:
| Aperture Size, Shutter Speed and ISO. Just understand what they
| are. And their units.
|
| Actually see pictures varying one and keeping others constant
| to get a hang of things.
|
| Then go backwards, check professional pictures and guess the
| values. Professional photography forums all photos have these
| values published .
|
| Night/Day photography, moving/still and background focus are
| the only 3 skills you need as an amateur photographer. They
| rely on the 3 settings above.
|
| Beyond that lies the rabbit hole that, if you venture, speak
| not to any people whom you wish to keep friends. They hate when
| you try to tell them.
|
| Don't spend over 2k on lenses.
|
| Have printed photos on glossy, matte paper. Touch and feel
| them. Worth the time.
| Terretta wrote:
| This is very well done for a new-to-photography audience. Will be
| sharing around to people who say all their things look like
| snapshots, what's up with that.
|
| Great use of examples, except for one: kid on bridge.
|
| > _At the same time, it must be said that color and tone can be
| what separates a mediocre photograph from a memorable one. To
| illustrate, let 's look at the potential evolution of this
| vacation shot deliberately chosen for its mediocrity..._
|
| Then the dynamism is removed by 'correcting' the dutch angle to
| horizon, the surprisingly good color balance is skewed off, and
| the whole thing gets that circa mid-2000s HDR look from Flickr
| and Shutterfly and the like where every photo got tone-mapped.
|
| Underwhelming of an end result, especially compared to the later
| color and tone examples (e.g. kitchen superhero).
| SamBam wrote:
| I had the exact same thought on that sequence.
|
| The angle is a personal choice, though I think I agree that the
| mirroring angles of the two bridges was more interesting than
| having the horizon straightened. But the final "Tone Curve
| Corrected" turned a fairly nice image into a typical HDR-ruined
| photo, where the eye can't focus anywhere because all the
| colors have the same value.
|
| To add some praise with the criticism, I thought the
| explorations of light white the photos of the wife were well
| done. Pointing the rear light at the subject's back to create
| that subtle halo is nice and I had not considered it.
| excite1997 wrote:
| In the mid-2000s, HDR was all about jacking up local contrast,
| giving you that unique look of gritty skin and halos cropping
| up all over the place. I'm talking stuff like this:
|
| https://digital-photography-school.com/wp-content/uploads/20...
|
| Less obnoxious tone mapping that compresses shadows and
| highlights is a more modern trend, I'd say post-2012. It's
| basically done by every cell phone today when shooting a high-
| contrast scene.
| lxe wrote:
| This is helpful for my stable diffusion prompts.
| lelandfe wrote:
| A lot from the article will not work, because the terms are too
| overloaded ("three point"). SD photography and lighting keyword
| dump I've tested for 1.5:
|
| _f1.8, dof, bokeh, soft focus, chiaroscuro, backlit, golden
| hour, soft lighting, natural lighting, warm colors [but not
| "cool"], Polaroid, lens flare_
|
| "85mm", "50mm" etc all make the image realistic, but don't do
| anything specific.
|
| Pro-tip: use "windows" to get many of the outdoor lighting
| keywords available indoors.
| kyleyeats wrote:
| Thanks for these. Can vouch for _golden hour_. I can see why
| directors are obsessed with it.
| [deleted]
| yieldcrv wrote:
| I've been using photography and focal length prompts on stable
| diffusion since I first installed it, would recommend
| muglug wrote:
| The main thing about photography is your first 10,000 photos will
| likely be bad. Modern technology makes it possible to get through
| 10,000 snaps much faster and much cheaper than when using film.
|
| But taking those photos is not enough -- it's in the editing of
| those first 10,000 photos that you will find the hidden
| photographer in you.
|
| Photography is a lot like writing code: you can create something
| that does the job, but does not do it beautifully. You can keep
| on creating until creating beauty becomes easier.
| bradknowles wrote:
| I wouldn't say it's your first 10k photos. Because anyone can
| just hold down the button and take hundreds of photos. And
| those hundreds of photos don't really count as separate
| pictures in this regard.
|
| I would say that it's more like your first 10k different
| photographic compositions/subjects.
|
| From there, I agree that you really learn in the editing.
| oogali wrote:
| For me, it truly was after my first 10K photos -- speed
| shutter and all.
|
| Once you sit down and go searching through that burst for the
| perfect or otherwise usable photo of that burst, you start to
| notice the small things: the slight detail changes at the
| edges, what may have transpired between captures, how a light
| source that changes in milliseconds can affect the overall
| feeling.
|
| It took me about 2.5 years to reach that point. Shooting at
| different times of the day, different seasons. Countless
| hours tweaking levels and cropping in Photoshop, Capture One,
| etc. Lots of changes in gear: UV/haze filters, circular
| polarizers, tripods, zoom lenses, prime lenses. Flashes,
| reflectors, gray cards. Exploring the different modes on my
| camera, Magic Lantern firmware, etc.
|
| It all counts. But the post processing is the crucial part of
| the feedback loop.
| spoils19 wrote:
| What a great resource!
| vanillax wrote:
| Love it!
| qntty wrote:
| See also, Marc Levey (CS professor at Stanford specializing in
| computational photography) gave some good lectures at Google a
| few years ago on digital photography:
|
| https://sites.google.com/site/marclevoylectures/home
| mgraczyk wrote:
| Levoy!
| qntty wrote:
| Oops, sorry!
| lucb1e wrote:
| The word "Levoy" does not occur on the page. Perhaps the
| site's author should have put their name in the page title
| instead of, appropriately, in a header picture!
| yieldcrv wrote:
| This is good, I would add that "made up composition rules" are
| instead "made up composition _guidelines_ ", that people should
| learn how to deviate from after constricting themselves with
| false constraints
| semireg wrote:
| The things I'm drawn to in life is where art meets science. In
| hindsight, so much of the secret is knowing how to avoid failure.
| Baking bread? Build the intuition over time and you'll realize
| baking is forgiving so long as you don't do these "5 bad things."
| Gardening/farming? Yeah, there's a big list of bad things.
| Brewing beer? Another list of things to avoid. The basic rules
| (rooted in science) are like guardrails and everything else is
| the art. I love this so much.
|
| In my early 20s I had a week long mind meld knowledge transfer
| from a self taught photographer. It made me fall in love with
| photography. I'm still using it to this day to photograph new
| label printers (black plastic is terrible to photograph) and
| labels (oh god they are 2D!).
|
| I'm doing an OK job. Room for improvement but fine for the
| initial launch. You can see them here:
| https://mydpi.com/products/professional-synthetic-direct-the...
|
| In case you're like "why is this guy selling label printers?!"
|
| I'm a solo software dev that wrote Label LIVE (electron) to
| design and print labels. Now I'm vertically integrating with a
| printer I've imported from China and labels made in the USA.
|
| Business and entrepreneurship: just avoid these 9999 things and
| you'll be fine! Science and art...
| photochemsyn wrote:
| An interesting site with lots of information about 35mm
| photography and film vs digital techniques is 35mmc.com. Here for
| example is a very clear and concise discussion of depth of field
| and the factors that control it (such as aperture, focal length):
|
| https://www.35mmc.com/25/07/2016/basic-optics-photographers/
| skhr0680 wrote:
| Pretty awesome overall, one improvement would be to shoot the
| model in the focal length shot face on to better illustrate the
| big nose, no ears (too wide) and pancake face (too tele) effects
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