Juan, I love you. j/k j/k :P

But you are a good man for doing this all by yourself and all in your free time. *Pat on the back*

Can't wait to see the site!!!!

Zone system?
 

Hi,

Yes, there are lots of ways to taint the result, particularly if you start confusing yourself with unnecessary stuff like Mr. Adams' system. The system designed with very controllable printing in mind, for use with still photography, so its relevance to even motion picture film work is at best limited - and I fail to see that it has anything to do with determining the absolute dynamic range of an imaging device.

Phil

re: zone system?
 

actually the zone system is a three-fold process: controlling exposure, controlling negative density in processing (for b/w negs), and printing (which actually requires the least amount of precaution of the three steps). and like i said, it's totally possible that even someone inexperienced with a light meter could properly perform the tests, but it's simply my advice to get an experienced professional photographer who's fluent with the zone system. though the zone system wouldn't be used at all during the test, i feel it's safe to say that a fluent practitioner of the zone system will generally have a broader understanding of the way light ratios and spot meters work. basically, it's a safe indicator of in-depth knowledge.

if you were setting up a post facility and needed to setup a router, you could probably have an intern do it-- it's pretty simple and is more or less plugging cables into slots and making a record of it. but if it's something that you want to do once and never worry about it again, wouldn't you prefer to have an engineer with years of experience to do it?

also, based on years of reading ac, it seems like a large percentage, if not most, of "hollywood" dps use the zone system. its advantages in shooting motion picture (in terms of controlling exposure) are more so than still photography, in my opinion. especially when you have subjects moving in and out / to and from light sources, and have blocking changes that are being decided by someone other than the photographer/dp, in addition to the fact that it just plain gives you more control over how your images will look. i'm not trying to sound like a snob -- unfortunately, snobbery seems to often be associated with the zone system, which doesn't make sense because it's pretty easy to learn.

and with shooting video, it's completely irrelevant. all you need is a good monitor.

Hi,

> i feel it's safe to say that a fluent practitioner of the zone
> system will generally have a broader understanding of the way
> light ratios and spot meters work

That's exactly my point, it's got nothing whatever to do with ratios - we're looking at absolute range.

Then:

> basically, it's a safe indicator of in-depth knowledge.

But then:

> it's pretty easy to learn.

Um, er?

My problem with this is that it isn't a safe indicator of anything. It can be learned out of a book in about half an hour. And anyway:

> and with shooting video, it's completely irrelevant. all you need > is a good monitor.

Whaaaat? We're talking about video here! And anyway of course it's relevant! Differently-implemented, but still relevant. The system isn't tied to any way of metering light, it's a way of thinking about pleasing compositions in tonal value as well as space, which is relevant to anything that records an image.

Phil

> The system isn't tied to any way of metering light, it's a way of thinking
> about pleasing compositions in tonal value as well as space, which is
> relevant to anything that records an image."

sorry dude, but you must have the zone system confused with something else (like maybe EVERYTHING ansel adams ever wrote), because it's about the science of light's mechanical effect on emulsion, and fundamentally not about aesthetics.

and again, the zone system is indeed irrelevant for video (at least today's video) because the response curve and latitude are different from film emulsion. in fact, the zone system was developed as a way to have a mental equivalent of what video users have nowadays... a way to see the exact dynamic tonal range of the image we're acquiring (a full-res monitor).

and though the zone system is easy to learn, it requires more effort than thirty minutes of reading. and based on your inaccurate analysis and interpretation of the zone system, that's apparently how you learned it.

but again, i'd suggest juan get a pro who knows the zone system to help him out. at the very least, he'll save on not having to buy a spot meter.

for the sake of everyone else on this thread, i'll formally withdraw from this argument. sorry to juan and everyone else for wasting space.

Jaan, I appreciate your comments because I know what you are talking about. You aren't wasting space.

I think your suggestion of getting the help of a photographer/cinematographer who knows how to use a light meter could help Juan measure the range between the first visible details in a dark part of the image and the last visible details in the whitest part of the image.

A simpler way, not requiring a light meter, would be to shoot a white towel under constant, soft lighting. Stop down until you can just barely descern details in the shadows using a well calibrated monitor. Note the f-stop. Then open up until you can just barely descern details in the highlights. Note the f-stop. The difference is your usable lattitude.

image grading
 

Juan,

if you like, I could give you a hand by professionally grading some sample images for your website. As we all know, the main idea of 12-bit uncompressed footage is less about the appearance of the original capture and more about the expanded grading/scaling/sharpening possibilities in post. Side by side comparisons of dv footage and 4-4-4 footage (both graded for objectivity) could really make an impression on your potential customers.

Cheers,
Chris

Alright guys, here's an example of latitude for ya.


http://www.hot.ee/chrisrubin/leaves_comp_sd.psd

This is a frame Juan posted here several months ago, before he had figured out the exposure / white balance bit. It is in Photoshop format, with two layers - the original (as posted by juan) and the graded one. This image represents possibilites far beyond the scope of dv. Notice also the noise, which, although clearly visible, looks much more like film grain than digital distortion. It's pleasant to look at. I've seen lots of weakly lit 16mm material blown up to 35mm and projected on a large screen - this sample here is very similar to that.

La vita è bella,
Chris

Chris,

I can't seem to open your file in Photoshop 7. I keep coming up with an error that reads:

"could not open: .... an unexpected end-of-file was encountered"

Was this image created with Photoshop CS?

Yes, it's done with Photoshop CS. But I was able to open it in PS 7.0 as well, albeit as a flat image. I think you may have an incomplete download. Try downloading again...

Chris

PS:

here are the same layers as jpg's:

www.hot.ee/chrisrubin/leaves_before.jpg

www.hot.ee/chrisrubin/leaves_after.jpg

Thanks Chris :)

So any ideas how much this mod is going to cost. Plus what about repairs since I'm sure there will be a few bugs until everything is worked out.

Wow... I've never had the pleasure of working with a 16-bit "DV" image before. Amazing out of that "darkened" base image what you can get with a little adjustment of the levels and gamma curve. I took the darker (original CCD) image and applied to very easy tweaks to it and it came out great.

If anyone wants to see, I put it up at:
http://www.madmojo.com/leaves-edit.jpg

I am curious to see what the dynamic range of this ends up being. Seems to me that it would end up being similar or the same to what the camera normally offers, because I would guess that the camera just has a set curve/gamma adjustment it makes on the image before it gets compressed and saved to the tape. If that was the case, it would seem like if you used a similar setting, that you could expose properly for the tape and the firewire out, which would be very nice for "backup" and post processing reasons.

Of course, I may be way off base here.

"Seems to me that it would end up being similar or the same to what the camera normally offers, because I would guess that the camera just has a set curve/gamma adjustment it makes on the image before it gets compressed and saved to the tape. If that was the case, it would seem like if you used a similar setting, that you could expose properly for the tape and the firewire out..."

Eric,

This is what I figure as well. It makes sense. There might be a little gain in dynamic range, but what's important is to test and determine how much gain there is if any.

That's why I suggest the dynamic range test as I posted in my previous post. Others might have suggestions too that could be better.

Yes, that's a great idea. I'd love to get my hands on the same image taken with DV and with the mod, in the same lighting conditions, etc. to see what kind of gamma/level adjustments could be made to make them look as close as possible in terms of hue, luminance, etc.

Theoretically there should be a huge gain in dynamic range, at least 2 stops more. The reason?

With the current DVX100, you are dealing in post with a gamma-corrected, 8-bit, 5:1, 4:1:1 compressed DV Signal. If you ever try to underexpose your DVX and then "bring up the shadows", forget it, unless you like the look of those square pixelated compression arifacts lurking in the shadows. With 12-bits and the number of levels it gives you (4096), there is a lot more room for underexposure to bring the highlights down and under control, but with enough information in the shadows to then bring them back up without compression artifacts or banding.

Yes, that will be the case, but the nice thing is, you don't HAVE TO expose like you did with DV. You now have the freedom to underexpose the picture to keep the highlights under control, but still have plenty of information in the shadows to increase the color saturation down there, and also normalize them/apply gamma, etc. without banding or other compression artifacts poking their heads up. That's why I'm saying at least 2 if not 3 more stops, depending on the amount of noise in the shadows. Now your only limiting factor in playing/color-correcting the picture is noise, not extreme compression and it's nasty side effects out of the current DV stream from the DVX.

So, how about some proper tests, Juan? It's not anything that any of us can do, even from images you post, unless you post a whole slew of DV and uncompressed images side by side. You can use a single set up either outdoors or indoors, and just run the gamut of full stops the camera has, from next to fully closed to fully open, while noting all the fstop settings of each frame you capture.

We will be able to see on what frames you just start to see shadow detail and on what frames you lose all your highlight detail. The lighting has to be constant and should be within a range that is useful for the test. Some experimentation should help figure out what that is.

hey everyone, i did some quick tests to see roughly what the potential latitude might be. the info and images are at
http://www.jaanshen.com/juanmod

though unscientific, they're very exciting (at least for me).

BTW, with anything more than 1000:1 (10 f-stops) and 12-bit linear, you're going to get visible banding in the shadows. With 1000:1 you're essentially exposing a 90% white card at 10%-that's very, very dark, and you're only giving 400 levels to that top 90% range, excluding the noise that is present that far down in the luminance range. So your 11 f-stops might be a bit optimistic, I'd say we're probably at 10-10 1/2 f-stops depending on noise. Most likely 10 f-stops is the limit with tolerable noise levels.

Joel,

I already did a test such as the one you are describing. I took a set of images at of the exact same scene with the same settings, while varying just the aperture. I took DV and RAW counterparts of each frame.

expert.cc.purdue.edu/~pertierr/LatitudeTest.jpg

You can also clearly see the artifacts in the redhat box. The only problem with that test was that I didn't adjust white balance, so the dynamic range is actually more than what you see there. White Balance works by limiting what the maximum value that comes out of each A/D is. So even though you can represent 0-4096 (12-bit) levels on each channel, you might only get an image with, say, 3980 as the maximum, washed out white on the RED channel for example.

Yes, and that makes me wonder....what color do I have to put in front of the camera such that a white balance adjustment will yield the absolute maximum range from all three A/D's? THe image color would look terrible, but it would allow the maximum resolution for working in post! It's only a little extra color resolution, but it sounds simple enough to find out.

Here's a PSD capture, uncorrected but with WB adjusted on the camera. Only thing I did was align the frames as much as I could.

http://expert.cc.purdue.edu/~pertierr/cap12_RAW.psd

Oh yeah, and that is with the anamorphic, but it also has the overscan area since it is the full CCD, so you will actually get something like 1.80-1.85 aspect ratio.

Juan

Ah yes, Juan I forgot about that test you did. It's been a while. Thanks for reminding me of it. It looks really good aside from the white balance issue, which makes it difficult to compare dynamic range.

Interesting about the optimal white balance. I hope you figure it out. Sounds promising.

Hi,

Something odd is going on there. Is it just that the blue channel is running into clip much faster than the others, or is there something odd we've all overlooked?

Phil

Ive been away for about 6 months. Can anyone post a quick report on the progress? Last I heard was that Juan had captured a single frame from test jumpers on a chip. Any working models yet?

74 pages...sheesh!

John, I believe Juan is working on a web page that should answer all of your questions, now I'm not sure exactly when he will post it (he's trying to get the info accurate before he releases the website to the public) but hopefully it will be in the next couple days, I think september 1st would be a good goal...

In case that doesn't happen, the results are that juan has now captured a sequence of frames and almost completely elliminated the noise in them. He has re activated his white balance and the main thing we're all waiting and discussing right now is how much lattitude one can get with the camera. (is it plus 4 stops or plus 5, and how much did it have to begin with, 6?)

Hopefully that brings you up to speed enough until www.444yourdvx.com (or whatever it will be called) is up until then we just have to stick with www.waitforyourdvxtobe444d.com

Okay Juan, now WAY WAY way back on like the first few pages, people thought the DVX could make a high def image. I remember you saying it can't, except maybe with some pixel shift. The DVX and the XL2 have horizontal pixel shift. How would I be able to use there pixel shift to make a higher res image using your mod?

The DVX already uses the pixel shift so you cannot use it again. Juan has shown us some images captured however that were blown up to 2k images and they look damn good. A program such as s-spline pro can make it even better. I however have used just Photoshop and even went up to a 4k image size with it still looking pretty damn good although a hair soft. Just having raw RGB pixels alone make the blowups look very good. It is sort of like if you have a 2 megapixel digital camera and it says you can get 8x10 photos from it. Well those 8x10 photos would be less than 150 dpi which isn't as good as getting a 4 x 6 at 300 dpi. However because digital cameras use RGB pixels the blowup looks much better that if you were to try and do it with a video frame. Juan's mod is basically allowing us to turn the DVX into a 1 megapixel digital camera that shoots 24 frames per second at perfect raw RGB.

So to answer your question you can blow up the footage to be 1920 x 1080 HD rez and it will look great except for a slight softness compared to actual HD footage. Some may actually like this softness because it makes the footage seem a little more film like instead of HD like.

I second Thomas' statement.

Up-rezzing the full quality output of my device will simply give you the BEST possible enhancement without actually upgrading the sensors or other hardware. The only limitation is how good the up-rez algorithm is, and S-Spline is pretty darn good.

The full color sampling and high color precision transposes to the HD up-rezzed image. Remember that most of the HD footage we see is decimated, just like any footage that originates on a compressed format. Even the tape outputs on the high-end HD cinema cameras is decimated.

By starting with an undecimated SD image, you can obtain color comparable to a HD image that originates on HD chip(s). The downside, of course, is detail. S-Spline does a great job at enhancing detail but detail is simply limited by the resolution of the sensor.

My experience so far, however, is that S-Spline generates some awesome HD images when based on RAW images from my device, and it even introduces some subtle grain-like noise in the up-rezzed image which looks remarkably like film grain.

I've been looking without success for a location with a film printer, such that I can print a couple of frames to projection film and see what that looks like.

Juan

Juan,

If you want a film-out, I would recommend putting the frames on a CD, taking the disc to a photo finishing place and asking them to make slides. I am pretty sure most places can do that.

Would that work for what you are trying to accomplish?

Hi,

I think everyone's overlooking the fact that the DVX-100 is a 4:3 camera and under most circumstances you'd want a 16:9 image, or thereabouts, for your filmout or HD presentation. Not to say that this won't look a lot better than a DVX would normally in any case, but it's still a 40% cutoff. Might be time to reach for the mni35 with anamorphic primes.

Phil

<<<-- Originally posted by Thomas Smet : The DVX already uses the pixel shift so you cannot use it again. Juan has shown us some images captured however that were blown up to 2k images and they look damn good. A program such as s-spline pro can make it even better. I however have used just Photoshop and even went up to a 4k image size with it still looking pretty damn good although a hair soft. Just having raw RGB pixels alone make the blowups look very good. It is sort of like if you have a 2 megapixel digital camera and it says you can get 8x10 photos from it. Well those 8x10 photos would be less than 150 dpi which isn't as good as getting a 4 x 6 at 300 dpi. However because digital cameras use RGB pixels the blowup looks much better that if you were to try and do it with a video frame. Juan's mod is basically allowing us to turn the DVX into a 1 megapixel digital camera that shoots 24 frames per second at perfect raw RGB.

So to answer your question you can blow up the footage to be 1920 x 1080 HD rez and it will look great except for a slight softness compared to actual HD footage. Some may actually like this softness because it makes the footage seem a little more film like instead of HD like. -->>>

So, your basicly saying that when a camcorder like, lets say, an XL1s uses pixel-shift it then uprezzes it to 720x480. that doesn't quite make sense to me. But then again I never quite understood how shifting the green CCd 1/2 a pixel to the right thus increasing its sampling points would allow a CCd with 270,000 pixels to provide a DV image. If anything I kind of assumed pixel shift would sort of work as and uprezzing thing.

Phil&Mark

Phil:
You can always use the anamorphic adapter, which is what I am using. Since you can get the full width of the CCD, you actually get a ~1.83 ratio out of it.

I am working hard on re-designing the box and choosing the production circuitry such that both the box and mini35 can be mounted at the same time.

Does anyone have a picture of the ~bottom~ of the DVX with the mini35 on it?

Mark:
The best way I can explain pixel shift, is by looking at how single CCD color cameras work. Each pixel sensor has a color filter on it, such that the raw image is not a black and white image with absolute brightness(Y) for each pixel, but rather a mosaic of colors, with the magnitude of a specific color content for each pixel. Adjacent pixels of different colors can then be used to approximate the color of that pixel.

To the best of my knowledge, pixel shift is this same idea but with 3 CCD's...by simply offsetting CCD's slightly from each other, you can have a pixel element of, say, the green channel capturing a detail which lies in a element division of the other CCD's. The data can be combined into a larger image, with better detail, although as you might expect the color rendition is slightly affected because technically each element of each sensor doesn't capture the exact same detail color.

Now that I lay it out like this, it would be interesting to somehow have an up-rez program like S-Spline take 3 RAW RGB layers and take CCD shift into consideration. What i've been doing so far is aligning the layers, but if there is indeed intentional CCD shift in the DVX, that info can be used to create ~even better~ HD images.

Juan

Hi,

Please excuse the repetition, but I'd like to ask again what you are doing about a filesystem on the hard disk recorder. Does your device comprise a microprocessor system running a full-blown operating system or have you implemented a common filesystem in firmware? I would be impressed if you had!

Phil

I'm using FAT32, in configurable logic.

Hi,

I am duly impressed.

- Phil

Hi Juan
Mini 35 compatibility really is a must I think.
It's well worth the hard work it's putting on you, and I am sure many
will bless you if you succeed.
Can't wait
Take care
Emmanuel

Well, i've done some significant changes, and the box should now fit snuggly behind the mini35 adapter. I haven't played with a mini35, but I'm assuming that using the tripod mount is out of the question, since any vertical offset may cause the mini35 to not align properly with the lens? Does this make sense?

I'm going to have to figure out some other way of attaching it to the bottom of the DVX.

Juan

Yes it does--did you get the picture of the Mini35 setup I sent you Juan? So, just curious--by "behind" the adaptor, what does this mean exactly?

Charles:

Yes, i received the picture and it was very helpful, sorry i didn't get back to you.

If you look at the original box in the picture i posted, and imagine splitting the box in half along the length of the camera, the new box occupies what would be the rear half, slightly behind the tripod mount.

Juan

Out of curiosity, I've started a discussion thread:

4:4:4 Uncompressed 1080i HDR-FX1?