Author Topic: [DONE] Gratuated Neutral Density Filter  (Read 7477 times)

Peter

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[DONE] Gratuated Neutral Density Filter
« on: June 10, 2013, 11:02:11 AM »
How about implementing an electronic version of gratuated ND filter?

Mei Lewis

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Re: Gratuated Neutral Density Filter
« Reply #1 on: June 10, 2013, 11:54:47 AM »
Unless it was possible to change the iso gain on a row-by-row basis this wouldn't do anything that couldn't be done easily and with more control in post right?

ItsMeLenny

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Re: Gratuated Neutral Density Filter
« Reply #2 on: June 10, 2013, 12:02:04 PM »
This actually may be possible to an extent, as they were able to hack into  the "peripheral illumin. correct." and control it manually. I would think it would be something similar.
But you do realize if it could be done it wouldn't be of any use in RAW, only in jpeg and mov.

a1ex

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Re: [WONTFIX] Gratuated Neutral Density Filter
« Reply #3 on: June 10, 2013, 07:14:48 PM »
Yep, it's possible to control digital ISO for each scan line (just look at the bugs from 1-2 years ago). I don't see the point though.

l_d_allan

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Re: Gratuated Neutral Density Filter
« Reply #4 on: June 13, 2013, 10:09:24 PM »
Unless it was possible to change the iso gain on a row-by-row basis this wouldn't do anything that couldn't be done easily and with more control in post right?

My impression is that quite of bit of HDR could be avoided if there was an electronic graduated neutral density filter. I used to think that a GND could be accomplished in p.p., but I had a chance to see a GND in action.

With many scenics with a bright sky, my realization was that you could reduce the exposure a stop or two to capture shadows in the foreground, with less risk of blowing highlights in the sky.

If it could be accomplished, it would only be advantageous for my "use cases" if it worked in RAW. Also, I usually shoot scenics at low ISO, so adjusting the ISO per scan line wouldn't seem to be an advantage either.

a1ex

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Re: [WONTFIX] Gratuated Neutral Density Filter
« Reply #5 on: June 13, 2013, 10:20:01 PM »
Note: you can't adjust analog ISO, only the digital one. It would help only a small amount with H.264 and no advantage at all with raw.

c2s07

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Re: [WONTFIX] Gratuated Neutral Density Filter
« Reply #6 on: June 14, 2013, 04:58:01 PM »
Yep, it's possible to control digital ISO for each scan line (just look at the bugs from 1-2 years ago). I don't see the point though.

It is? Even though you guys don't seem to find it of any practical use, this was amazing to hear, even if it can be accomplished only digitally.

If you don't mind, I have a couple of questions about the controllability, out of curiosity:

1) Would it really be controllable for each scan line, ie. one could apply the effect 0 - 100 (%, vertically, bottom - top), or 50 - 100, or 75-85, etc, as desired?
2) How finely could one control the exposure, for example +/- 1 digital ISO for each new scan line, or even fractions such as 0.1 ISO?
3a) Do you think it work without hiccups in video recording?
3b) If yes to above, I assume it would apply before the picture styles and the 8 bit conversion?

It would be interesting to try this out. Granted, using it would take a slight dynamic range penalty (ETTR with low analog ISO would help), but on the hand, it would be one less optical element in front of the lens potentially degrading image quality.

a1ex

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Re: [WONTFIX] Gratuated Neutral Density Filter
« Reply #7 on: June 14, 2013, 05:02:45 PM »
Timing is very difficult, lookup those bugs (I guess there are videos showing them). But once you figure out how to sync with LiveView at scanline level, it's possible.

I don't know if the CPU is even fast enough for that kind of sync.

The increments are very fine (4096 = 0EV). It's applied before picture styles, just like digital ISO from the menu.

Audionut

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Re: [WONTFIX] Gratuated Neutral Density Filter
« Reply #8 on: June 14, 2013, 05:12:33 PM »
I'm not exactly sure how the data is being captured in raw with liveview, but what about with silent pics? 

Expose for shadows and it automagically reduces ISO for the highlights to bring within saturated levels.  1 shot HDR.

a1ex

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Re: [WONTFIX] Gratuated Neutral Density Filter
« Reply #9 on: June 14, 2013, 05:17:14 PM »
Right, this will only benefit H.264.

Audionut

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joze

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Re: [DONE] Gratuated Neutral Density Filter
« Reply #11 on: June 01, 2015, 11:20:24 PM »
Hi,

Is it really done?

I'd find a digital gradient neutral density (GND) filter VERY useful too.
Many of my outdoor landscape shots suffer from the dynamic range of the sensor/image not beeing sufficient from sky (bright) to ground (dark).
This can only partly be recovered by post processing.

I wonder if the dynamic range between sky and ground could be improved by something which is similar to dual iso -- read out the sky with a low iso and the ground with higher iso.
From a users point of view, I'd like adjust at least the iso factor between sky and ground and the gradient width -- if the gradient should be harder or smoother.

I'd believe that the location of the GND edge could be determined in LiveView by some clever algorithm automatically.

  • is something like this possible?
  • would something like a smooth iso gradient be possible, or can the digital readout only be set in coarse iso steps?