Pondering sensors (again)

akptc

akptc

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This is probably a dumb question but.. why isn’t it possible (or is it?) for DSLRs or DSLR look-alike cameras with “live view” LCDs to allow the user to “dial-in” the sensitivity of the portion of the sensor showing (possibly blown) highlights independently of the rest of the sensor surface and / or to “dial-in” the sensitivity of the sensor areas showing dark shadows, so that the resulting image has just the “right” (as judged by the photog) zone coverage, within the limitations of the sensor, of course? Just wondering 🙂
 
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Wow, what deafening silence!

So is the question above:

a) too silly to answer
b) irrelevant
c) difficult to understand
d) other __________

Just curious 🙂
 
Andy,
I think the answer is that it would be possible. Heck, electronics...computers...most anything is possible.
If it has been thought of by the manufacturers, they've deciced that it's too complicated, not enough in demand, too expensive or all of the above. I know this because it hasn't been offered.
 
Thanks Steve. It kind of occurred to me that such a sensor function would end once and for all the too-dark-shadows/blown highlights problem. Here is crossing my fingers that someone starts manufacturing it soon 🙂
 
Andy, an interesting question, but I think it requires the sensor to actually be changed physically. Think about it with film, the physical property of the emulsion actually got changed during the exposure, and depending on the formulation of the emulsion, different tonal range can be recorded.

What I think you're going after is replacable sensor. I imagine in the future (maybe not so distant), you're going to be able to purchase different sensors with different tonal range recording ability.

Unfortunately, we're currently in the "middle ages" of digital, where the sensor is still too expesive/too complicated to be swappable.

Woah, enough thinking about digital for a day, let me get my Kodakchrome 200 and shoot some pictures 😀
 
Probably because bracketing and HDR would take care of that right now.

I cannot imagine a simple interface to map exposure settings. It's certainly much easier to do masking in PS after the fact.
 
I just read up on the Sony A700 and it's range expansion thingy. Would it be the same thing?

The way I imagine this working is more or less like this: the live view LCD grabs all the highlights and splits them into 3-5 ranges of values. the user cycles to the highlight he wants dialed down or up and adjusts the sensitivity for the key highlights. Similarly for shadows. If each pixes sensor can be communicated with individually, this does not seem like a difficult thing to do, does it? (I know nearly nothing of sensor electronics).

Wasn't there a digital P&S that had the zone system implemented on its LCD (I might have dreamt it, sorry )
 
Sony has "range expansion", Canon has something similar in the latest dslrs. Fuji has a second set of sensors for the highlights.

The Sony & Canon solutions have been know to cause a bit more noise in the shadows and it's primarily for the highlights.
 
Not sure if this is what you mean but my Panasonic L1 actually has something of this sort, at least as I interpret what you are asking for. You can select half a dozen or more different "film" types plus a couple you can define for yourself. For color and black and white, each has three "film" type options you can choose from; standard, dynamic and smooth. Colour also has a nature option which boosts greens and blues but not other colours.

The smooth option is the one which is relevant here as it renders shots with significantly lower contrast than the dynamic option. This kind of gives you what you are asking about as the camera tones down the contrast ressulting in less over-light and over-dark areas.

I am not sure if this changes the display when in live-view however. But thats fine by me, I never use it much anyway. I prefer to use the eye piece. Its easy to see the result on screen after taking the shot. The in-camera black and white option is exceptional by the way and even renders the sky / clouds with good contrast - something flim cameras struggle with unless you use a yellow orange filter to increase contrast. In smooth mode I would expect the sky to have less contrast but have not checked so cannot confirm this but I cna confirm that smooth otherwise seems to provide a lower contrast outcome. I find this is more noticeable in black and white than in colour, I guess because changes in greyscale are more obvious than changes in colour saturation.
 
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I very much doubt it's possible because what you're asking is essetially selective control over photo-diode output of specific regions on the chip, which i think is simply difficult, it would take quite a bit more programming into the image processor to enable that, and i imagine the actual circuitry would have to allow for selective/individual channeling of data instead of just transfering the whole chunk like it is now.
 
You can already take a RAW file and 'develop' it giving it different tonal ranges, then dodge/burn and adjust the tone curve and contrast after the fact.

If the purpose of doing this is to equalize the contrast in the scene, then bracketing the exposure and combining them later is probably the quickest way.

I'm sure it's possible to do it in the camera, but the hard part would be telling the sensor which exact parts to lighten or darken. If you give it a fixed range of brightness values, then that range will be adjusted but the rest of the image won't, and the tones will look very screwed up. Your darkest shadows might end up being the same shade as your mid grays, kind of like poorly scanned B&W film.
 
I am all for in-camera processing as I already spend too much time in front of the PC. Ideally, I would have two on-camera dials or sliders whose job would be to (dial #1) lighten the shadows and (dial #2) to darken the highlights. Even if the functionality of the dials was identical to the same two functions in Photoshop, i.e. no on-LCD selection of the shadow/highlight areas, I think I would use it all the time.
 
Andy,

It does exist to some extent. Go do a google on Nikon's D-Lighting system. I'm just starting to experiment with it on the D300.

Best,

Ray
 
harmsr said:
Andy,

It does exist to some extent. Go do a google on Nikon's D-Lighting system. I'm just starting to experiment with it on the D300.

Best,

Ray
Click to expand...
Ray, I found the following description here: "Setting Active D-Lighting before shooting produces results that are automatically corrected to faithfully reproduce the contrast of the scene as the photographer viewed it. Rather than correcting the entire image, localized tone control technology adjusts highlights, shadow areas, and midtones to achieve natural looking contrast across the entire image. This function is particularly helpful with high contrast scenes, such as shooting a brightly lit outdoor scene from inside a relatively dark room, or shooting at the beach on a sunny day. Active D-Lighting offers three application strength levels - Moderate, Normal and Enhanced."

This sounds VERY interesting!

Cheers,
 
If I understand the OP's question correctly, the gamma of an electronic sensor can be adjusted within limits, but nothing like what might be required to adjust for a scene with an extreme brightness range; we know that silver gelatin film has a wider lattitude than electronic sensors, but even with film it requires special processing to get the most out of a scene with high contrast (contracted development, for instance.)

It should also be mentioned that professional video cameras often have a 'zebra stripe' mode that shows the portion of the image in the electronic viewfinder in dark/white zebra stripes if it is over-exposed above 100 IRE. This would perhaps be a handy mode to have in a still camera - maybe it's already available; I'm not current on the upper end of DSLR features.

What I believe might work for high contrast scenes is a digital camera designed to take two exposures in rapid succession, where one exposure is biased to show good shadow detail and the other biased to show good highlight detail; then the internal software would merge these two exposures into one image file with full detail at both extremes. The camera's multi-spot metering could even detect when such high contrast scenes occur and automatically trigger the 'double-tap' mode when needed, without the operator having to manually intervene to change settings.

Of course, this 'double-tap' mode would be limited by shutter speed settings, since at too low of a shutter speed the scene would change slightly between the two exposures, resulting in image blurr.

~Joe
 
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NEVER GOING TO HAPPEN!! (said smiling ;>) )

NEVER GOING TO HAPPEN!! (said smiling ;>) )

In the sense that I think you are posing the question... It's not a question of possibility. It's a question of Why. Or more succinctly, it's a marketing question. Just as the computer industry (where I make my living) has structured the marketplace so that the upgrade/replacement decision is weighted toward replacement, so to will the imaging industry go.

I think I can reasonably assure you that no manufacturer, ie Leica, Nikon, Canon, etc, have set aside one or more engineers/designers set to the task of designing a camera where the end user can simply change out sensors to achieve better photography.

Right now, I am imagining the response in the Board Room of Nikon, where a newby upstart has just proffered the idea that perhaps the company should design a camera that will not need to be replaced, but rather drop in some updated parts, like say, a bigger improved sensor??? (Can you hear in this fantasy, the loud gales of laughter... followed by the pregnant pause as the other directors realize this young fellow is serious and a shudder ripples through the room at the thought of the Annual Reports that would follow such an event.)
 
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