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Photography for geeks

lcamtuf.coredump.cx

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Re: Photography for geeks

#11

Post by wtallis »

sva_ wrote: post #9
geokon wrote: post #7

Earlier quoted context omitted.

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 b…

> no phones have variable apertures. Even my almost 5 years old Galaxy S9+ has aperture. Surely something better came out since.

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.

Re: Photography for geeks

#12

Post by CWuestefeld »

geokon wrote: post #7
throw0101c wrote: post #5

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…

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 b…

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.

Re: Photography for geeks

#13

Post by TreeRingCounter »

geokon wrote: post #7
throw0101c wrote: post #5

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…

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 b…

> 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.

Re: Photography for geeks

#14

Post by mgraczyk »

geokon wrote: post #7
throw0101c wrote: post #5

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…

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 b…

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.

Re: Photography for geeks

#16

Post by mgraczyk »

qntty wrote: post #10

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

Levoy!

Re: Photography for geeks

#17

Post by excite1997 »

Terretta wrote: post #6

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 deliberatel…

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.

Re: Photography for geeks

#19

Post by yieldcrv »

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
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