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05-14-2022, 10:47 AM - 2 Likes   #46
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QuoteOriginally posted by BigMackCam Quote
I'm not sure how that would work technically, but it's a cool idea in theory...
Conceptually at least it is possible to have a CMOS image sensor work like a film negative, like for example pre-charging all sense cells to maximum level at sensor reset and have the capacitance discharge when exposed to light. There are probably some reasons why camera sensors aren't "non-linear negative sensors" like film negatives, could be poor quantum efficiency / base ISO value and leakage issues for long exposures.

05-15-2022, 12:19 AM - 2 Likes   #47
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QuoteOriginally posted by Dartmoor Dave Quote
…So what I'd like is a camera that I could set with a ten second timer delay, before handing it to the bozo in question for him to have a closer sneer at such inferior gear. Then, when the countdown hits zero, it would deliver an incapacitating electric shock. Nothing fatal; just nice and painful.

I suppose the camera would need a built in airbag or somesuch too. To cushion the fall.
An airbag for the camera, yes. Don’t need one for the bozo.
05-15-2022, 12:56 AM - 3 Likes   #48
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QuoteOriginally posted by Dartmoor Dave Quote
I'd like to have a digital camera equipped with something to help me out in those annoying moments when a total stranger starts giving me unwanted technical advice. I seem to keep getting that sort of hassle, because I'm someone who finds the most pleasure in getting good results out of basic, even primitive gear. Which means that, annoyingly often, some bozo festooned with all the latest hi-tech photo gubbinses will sidle up to me and offer some nugget of wisdom from his position of assumed superiority.

So what I'd like is a camera that I could set with a ten second timer delay, before handing it to the bozo in question for him to have a closer sneer at such inferior gear. Then, when the countdown hits zero, it would deliver an incapacitating electric shock. Nothing fatal; just nice and painful.

I suppose the camera would need a built in airbag or somesuch too. To cushion the fall.
Sorry to be so "PC", but... thinking more on this, whilst initially it seemed like an amusing idea - and I'll admit it did make me chuckle - there are serious implications here that really aren't at all funny ...
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... for example, reduction in battery life. It could seriously affect the CIPA rating...

Last edited by BigMackCam; 05-15-2022 at 01:07 AM.
05-15-2022, 10:11 PM - 4 Likes   #49
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QuoteOriginally posted by Dartmoor Dave Quote
some bozo festooned with all the latest hi-tech photo gubbinses will sidle up to me and offer some nugget of wisdom from his position of assumed superiority.
People talk of others having the ability to talk in a cutting way, It should be possible to develop a way of hearing things in a cutting way - to make something sound stupid just because someone vocalized it. To this end: when someone tells me something that any reasonably skilled photographer would deem to be stupid, I hold their gaze with a raised eyebrow, say nothing* and thus endow their words with the buoyancy of depleted uranium, and continue working.


* arguing with an entitled idiot only encourages them, producing good results in silence is the only way to stop adding fuel to their misguided zealotry.


Last edited by Digitalis; 03-28-2023 at 02:34 AM.
05-16-2022, 01:34 AM - 3 Likes   #50
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QuoteOriginally posted by Digitalis Quote
People talk of others having the ability to talk in a cutting way, It should be possible to develop a way of hearing things in a cutting way - to make something sound stupid just because someone vocalized it. To this end: when someone tells me something that any reasonably skilled photographer would deem to be stupid, I hold their gaze with a raised eyebrow, say noting* and thus endow their words with the buoyancy of depleted uranium, and continue working.

I wish I could do that single raised eyebrow thing, but I've never managed to get those particular nerves under control. So that's one of the world's most versatile facial expressions unavailable to me. Although I've got a great line in lowering my reading specs and delivering a stern look over the rim.

My usual real world response is to listen politely to the whoever-it-is who's trying to tell me how to use my clunky old gear, while at the same time getting out my incident meter and taking a reading. It generally does the trick.
05-16-2022, 06:41 AM - 3 Likes   #51
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QuoteOriginally posted by Digitalis Quote
...I hold their gaze with a raised eyebrow, say noting* and thus endow their words with the buoyancy of depleted uranium, and continue working.


* arguing with an entitled idiot only encourages them, producing good results in silence is the only way to stop adding fuel to their misguided zealotry.
QuoteOriginally posted by Dartmoor Dave Quote
I wish I could do that single raised eyebrow thing, but I've never managed to get those particular nerves under control. So that's one of the world's most versatile facial expressions unavailable to me. Although I've got a great line in lowering my reading specs and delivering a stern look over the rim.
I find a tilt of the head sideways also works wonders, while narrowing the eyes
QuoteQuote:

My usual real world response is to listen politely to the whoever-it-is who's trying to tell me how to use my clunky old gear, while at the same time getting out my incident meter and taking a reading. It generally does the trick.
Works a charm, that, since these sorts mostly have no idea what one is.
05-16-2022, 11:40 AM - 1 Like   #52
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QuoteOriginally posted by biz-engineer Quote
Conceptually at least it is possible to have a CMOS image sensor work like a film negative, like for example pre-charging all sense cells to maximum level at sensor reset and have the capacitance discharge when exposed to light. There are probably some reasons why camera sensors aren't "non-linear negative sensors" like film negatives, could be poor quantum efficiency / base ISO value and leakage issues for long exposures.
You might want to check out this article on how image sensors actually work:
Imaging Electronics 101: Understanding Camera Sensors for Machine Vision Applications


Your idea of pre-charge isn't in line with how the devices work - but something similar to your idea helps fight Residual Bulk Image (RBI).

Unlike film negatives, CCD/CMOS APS devices are linear because some number of photons X converted to some number of electronics Y (resulting in a e- charge in a CCD, or voltage in CMOS APS) - that's the Quantum Efficiency Y/X. Once you hit the Full Well Depth of the pixel (how many total electrons it wll hold), it won't hold any more - and may bloom into neighbouring pixels, or just tosses them away like extra beer spilling over the sides of a glass. The FWD is the point where it becomes non-linear. Brighter stuff just can't make the charge (or voltage) go any higher.
At the bottom end, dim images are often overwhelmed by Dark Current - electrons that kick up a fuss through thermal heating effects, this leads to glow in the image, a background level that is not pure black.


Fighting RBI:in some low-light applications like astronomy, there are LEDS placed near the sensor to flood it with near infra-red light, completely topping up the sensor before it is cleared (emptied out of charge). This ensures any ghost images caused by charge that is remaining gets evened out, as all pixels eventually drain to near-zero (actually their bias/dark current level).

05-16-2022, 01:09 PM - 2 Likes   #53
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QuoteOriginally posted by ProfessorBuzz Quote
You might want to check out this article on how image sensors actually work:
Imaging Electronics 101: Understanding Camera Sensors for Machine Vision Applications


Your idea of pre-charge isn't in line with how the devices work - but something similar to your idea helps fight Residual Bulk Image (RBI).

Unlike film negatives, CCD/CMOS APS devices are linear because some number of photons X converted to some number of electronics Y (resulting in a e- charge in a CCD, or voltage in CMOS APS) - that's the Quantum Efficiency Y/X. Once you hit the Full Well Depth of the pixel (how many total electrons it wll hold), it won't hold any more - and may bloom into neighbouring pixels, or just tosses them away like extra beer spilling over the sides of a glass. The FWD is the point where it becomes non-linear. Brighter stuff just can't make the charge (or voltage) go any higher.
At the bottom end, dim images are often overwhelmed by Dark Current - electrons that kick up a fuss through thermal heating effects, this leads to glow in the image, a background level that is not pure black.


Fighting RBI:in some low-light applications like astronomy, there are LEDS placed near the sensor to flood it with near infra-red light, completely topping up the sensor before it is cleared (emptied out of charge). This ensures any ghost images caused by charge that is remaining gets evened out, as all pixels eventually drain to near-zero (actually their bias/dark current level).
Although it is true that the prevailing semiconductor sensors in cameras are intrinsically designed to create a positive image by collecting photons, it's not the only way to design a photosensitive semiconductor device for imaging.

In fact, Xerox machines from 1960 and their descendants are exactly like what @business-engineer proposed. They use a semiconductor-coated surface (amorphous selenium in the original Xerox and organic semiconductors or doped silicon diode layers in more recent copiers and laser printers), pre-charge it (to about 600V), and then expose it to light. Where ever light falls on the drum, the semiconductor bleeds the charge leaving a negative image. In copiers and printers, the residual charge (in the black parts of the image) attracts the toner particles which then get transferred to the paper.

Mind you, I've no idea how nice, linear, and precise the technology can be. The fact that copiers and laser printers tend to be high-contrast makes me think that accurate continuous tone would be hard to create.
05-17-2022, 05:45 AM   #54
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QuoteOriginally posted by photoptimist Quote
In fact, Xerox machines from 1960 and their descendants are exactly like what @business-engineer proposed. ...
Mind you, I've no idea how nice, linear, and precise the technology can be. The fact that copiers and laser printers tend to be high-contrast makes me think that accurate continuous tone would be hard to create.
Excepting of course the sheer non-portability of the thing and inability to read out the data digitally. Not linear at all - pretty binary - toner or no toner/charge or no charge.
I guess we could go back to arrays of photo-diodes, selenium or cadmium sulphide cells. Fairly linear within their ranges, although the resolution would be poor. e.g. Grandma represented by 1 pixel.
05-18-2022, 11:49 AM - 1 Like   #55
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QuoteOriginally posted by ProfessorBuzz Quote
the resolution would be poor. e.g. Grandma represented by 1 pixel.
... but - looking for the positives - no need for airbrushing of wrinkly skin. So... you know... there are potential benefits
05-20-2022, 03:48 AM   #56
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QuoteOriginally posted by ProfessorBuzz Quote
guess we could go back to arrays of photo-diodes, selenium or cadmium sulphide cells
And recreate the ecological disasters that went before? No thanks, we only have one planet.
05-20-2022, 10:55 PM   #57
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QuoteOriginally posted by BigMackCam Quote
... but - looking for the positives - no need for airbrushing of wrinkly skin. So... you know... there are potential benefits
Now, if , prior to exposure, the camera use its accelerometer to measure camera shake local statistic in the time domain, taking into account sensor stabilization bandwidth, lens focal length and pixel density to calculate the lowest acceptable shutter speed and lowest ISO for hand held exposure, is it still a bad idea?
05-21-2022, 02:48 AM - 2 Likes   #58
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One thing I think would be really handy is if every Pentax SLR did automatic focus calibration on every Pentax lens -- including at three or four focal lengths for zooms. It feels like with computer tech where it is this should be possible and would probably improve real world shooting performance for many photographers.
05-21-2022, 11:27 PM   #59
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QuoteOriginally posted by Rondec Quote
One thing I think would be really handy is if every Pentax SLR did automatic focus calibration on every Pentax lens -- including at three or four focal lengths for zooms.
I will add
At different distances
05-22-2022, 02:40 AM   #60
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QuoteOriginally posted by Ian Stuart Forsyth Quote
I will add
At different distances
Maybe so. It would have to be pretty easy to do, otherwise folks would mess it up at home.
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