David Stump's RED files are up

[david farland]

http://www.cinematography.net/red-exposure.html (http://www.cinematography.net/red-exposure.html)

Geoff says they're previews without full notes for those who can't wait

Dave Farland

[mikkowilson]

Edit: NOTE: Please refer to this thread for updates on David's testing & file downloads: http://www.dvxuser.com/V6/showthread.php?t=78235 (http://www.dvxuser.com/V6/showthread.php?t=78235)

Those thumbnails look really good. I don't seem to be able to access the actual image files though. Is he still uploading them?

- Mikko

[Andreas Fern]

Same problem. No linked files yet...

[donatello]

on front page click on comparitive test .. the click on RED exposure

[Jarred Land]

they are getting uploaded slowly one by one.. David has given permission to quote his notes verbatim, so this should be fantastic.

[mikkowilson]

Yay! Downloading the first one now ... 1.3MB/sec .. school has a nice connection. :) EDIT (20 sec later): Done!

Did I understand that as permission to host mirrors Jarred?

- Mikko

[Brook Willard]

They're nice and fast as of now, I have all 8 downloaded.

[mikkowilson]

I have them all too, and they look very good... Still waiting for permission before re-hosting.

- Mikko

[visceralpsyche]

Well I figured I'd try to colour correct the F11 one to see how close I could eyeball it (on a Dell 2407WFP so don't be TOO critical!):

http://www.users.on.net/%7Egrypen/Downloads/RGB_f11_cc_sRGB_8bit_small.jpg

I added in my own RGB chart (http://www.users.on.net/%7Egrypen/Downloads/GretagMacbeth_sRGB_Nov2006.tif) bottom right corner (sRGB profile) to match with and I'm pretty happy with the results for a quickie.

I did notice a few artefacts on the original image which no doubt everyone will spot as well:

- dust on the sensor or lens in a few spots
- on the CamAlign chart the right hand line resolver seems to have one vertical line where it "jumps" a line of pixels
- on the in camera GretagMacbeth chart the right hand black level appears to have some sort of yellowish horizontal distortion on it?

Anyway, great to see a professionally shot image (I know it's a test with stops etc) and great to see what can be done with it!

If anyone wants a full size version of my CC'd image you can download it here (http://www.users.on.net/%7Egrypen/Downloads/RGB_f11_cc_sRGB_8bit.jpg) (1.7MB 8bit JPG).

[mikkowilson]

I love how even without the chart filling the screen, you can see every single line to the ends of the resolution trumpets! :shocked:

They need to invent a sharper printer for charts next!

- Mikko

[jbeale]

My starting point was the f11 TIFF image at
http://www.cinematography.net/Red/ColorChartsExposureSeries/RGB_f11.tif

The image looks so nice with no visible flaws, I had to push really hard to find anything unusual. After sharpening to a completely ridiculous degree in Photoshop and blowing up to 200% using nearest-neighbors, you can see an interesting effect in the PNG crop below. There is relatively more single-pixel-level noise where the original image has high spatial frequencies, at the center of the starburst. I don't know if it is the debayer algorithm or a denoise or hot-pixel-removal process. I can't think what else would give you that kind of selective response (very smooth everywhere except in the sharpest-detail regions). Note, this effect is completely invisible to me at 100% with no sharpening.

http://www.bealecorner.com/D30/misc/Red-f11-RGB-sharpened-2x-detail-star.png

I should add that I have seen very similar things to this on DSLR images of resolution charts, near the point where the lines converge to the resolution limit. You can go to dpreview.com and see examples, for example from the EOS 1Ds Mark II (16 Mpixel)
http://www.imaging-resource.com/PRODS/EOS1DS2/1DS2DBWBD.HTM ...and of course if you did a 4k scan of any normal cine film stock and did similar sharpening and enlargement, it would be pretty noisy everywhere.

[Graeme_Nattress]

Even when the chart fills the screen, the camera out-resolves the chart. I think we need a new chart :-)

The pixel alignment and funnies in the black are a problem with Frankie, and why we don't move her. David says ". I must also state that in the course of dollying "Frankie" from one setup to another I ran over a cable which caused a sync issue in the signal for part of the exercise. We restarted the camera and the issue went away, but I am using some frames from the series of grayscale and color chart brackets we did before the reboot."

Obviously, those kind of problems won't exist in the RED camera, and remember Frankie is a sensor test rig.

[Graeme_Nattress]

Funky single pixels like that come from a number of things:

1) uncharacterized sensor

2) blowing up nearest neighbour and over-sharpening

3) above interacting with adaptive demosaic.

Yes, such things are normally invisible until you go silly with them! Try the same thing with any camera and you'll get serious nasties.

Graeme

[Jarred Land]

Yes.. thanks for making that clear Graeme.

When your looking at the frame, the far right slice, about 20% of the frame, is out of alignment and has a broken signal. At the time, it was decided that since it was a latitude test and that the slice did not affect the charts, that we would still be able to use the shots to judge latitude so it was ok to proceed instead of just calling it a day. The Greenscreen shots should be clean of that defect.

[Nick_Shaw]

Presumably when the line frequency of a pure black and white image approaches the pixel frequency of the Bayer pattern, no de-mosaic algorithm in the world is going to produce a perfect b/w image, and some off-colour pixels are inevitable. Over sharpening will obviously exagerate this.

With real-world images, in a real-world viewing situation I can't see this being a problem at all.

Nick

[Graeme_Nattress]

Yes, it's a pathalogical image to an extent, but even still, under every normal viewing condition I've not had any bother with rez charts yet. When I did over-sharpen and stuff on the image above, I couldn't make it break that way :-)

Graeme

[adaml]

So has it been determined how much latitute Frankie has? I realize all the images and notes aren't up yet so maybe those in the know are waiting for David Stump to reveal his results without giving anything away first.

[jbeale]

Is there a well-defined way to determine an exact latitude? Seems like it must include some subjective judgement about what image quality is "good enough". Particularly in the blacks where in theory you can push them up almost any amount, but at some point the resulting image is going to be too noisy. So you might end up with many different effective latitude numbers, depending on if your final output is 4k, 2k, HD or SDTV and they might be considerably different.

[gunleik]

I must admitI have never had that much fun examining something as dull as a chroma-chart before.

Gunleik

[polispol]

another thing... the things are not clean at all... or maybe it's dust in the sensor?
http://img230.imageshack.us/img230/4899/taquesenpetitph5.jpg

Click for bigger:
http://img473.imageshack.us/img473/7884/taquesqt8.jpg

[boothba]

So you might end up with many different effective latitude numbers, depending on if your final output is 4k, 2k, HD or SDTV and they might be considerably different.

Exceptionally good point. Couldn't agree more.

[ProLost]

I must admitI have never had that much fun examining something as dull as a chroma-chart before.

Not to veer the thread, but I'm hoping that some of this chart-tastic fastidiousness rubs off on the generous folks who take it upon themselves to perform side-by-side tests of the various 35mm lens adaptors.

-Stu

[jbeale]

@polispol: I'm pretty sure those blurry grey spots are bits of dust, either directly on the sensor or some surface close to it, eg. a cover glass or anti-alias filter. At least dust on the sensor on my DSLRs looks very similar, and is easily cleaned off with a small brush like the VisibleDust.com product.

[polispol]

I had the same feeling, jbeale, it seems a lot to pictures with dust on the sensor taken with my DSLR nikon. Even the fact of having a high F-stop (11 at that picture) doesn't help to that.


btw my english is getting worse everyday!

[Jarred Land]

rememver frankie is not sealed, and i can gurnatee that there is Dust on the sensor.. there was construction happening in the back of the warehouse as well that didn't help things much.

CML needs help with mirrors they are getting hit hard.. so if anyone wants to throw some up that would be very cool.

[mikkowilson]

So we are cool to mirror?

Ok, starting uploads...

- Mikko

[mikkowilson]

Ok, mirror copies of the files are going up to: http://red.mikkowilson.com (http://red.mikkowilson.com)

They are big files, and taking quite some time to upload.
Files in red are still uploading.

- Mikko

[dillont]

I love the fact that the director of the test is stated to be Jim Jannard. :)

[pablovi]

Ok, mirror copies of the files are going up to: http://red.mikkowilson.com (http://red.mikkowilson.com)

They are big files, and taking quite some time to upload.
Files in red are still uploading.

- Mikko
Thanks Mikko, but can someone post David's comments? I can't subscribe to that forum, I have requested it many times and never get susbscribed, I am subscribed to other CML disscusions, but not that one.

Thanks again.

[mikkowilson]

I'm not subscribed to CML either.

My Mirror has all the image files up now.

- Mikko

[jbeale]

Thanks Mikko, but can someone post David's comments? I can't subscribe to that forum, I have requested it many times and never get susbscribed, I am subscribed to other CML disscusions, but not that one.

I managed to subscribe to the future-cameras forum right away first try; I don't know why it worked for me. There is much commentary by onlookers but David Stump hasn't posted much more real detail yet, he says that's coming soon and that he's a slow typist.

[adaml]

A new post from Mr. Stump today, including this:

"I think there may be more work coming in terms of characterizing the
sensor and tweaking the matrix. I'm currently studying the top end of
the exposure curve. I think there may be another half stop to a full
stop up there just lurking, waiting to be used by tweaking the top end
of the matrix. Which may also yield a little more sensitivity."

[Graeme_Nattress]

Yup, we still have a fair bit of characterizing to do, but we're on track, so no worries.

Graeme

[Jarred Land]

thanks for the mirror Mikko.

[adaml]

Yup, we still have a fair bit of characterizing to do, but we're on track, so no worries.

Graeme

No worries from me. I'm thrilled to hear that you may get even a little bit more from the sensor than what we've seen so far.

[pablovi]

I managed to subscribe to the future-cameras forum right away first try; I don't know why it worked for me. There is much commentary by onlookers but David Stump hasn't posted much more real detail yet, he says that's coming soon and that he's a slow typist.

Thanks, well it seems I never get the confirmation e-mail, everytime I try I never get it. Thanks again.

[Rob Lohman]

My normal email address didn't work either, had to sign up with another one

[pablovi]

My normal email address didn't work either, had to sign up with another one

Thanks, I tried another e-mail with no luck, I'm gonna try with eve yet another account.

[mikkowilson]

We have started a new thread for updates & mirrors: http://www.dvxuser.com/V6/showthread.php?t=78235

- Mikko

[sndrk]

I did a very strange thing. I opened the well exposed shot in Photoshop, made another layer, scaled that down 50% and then enlarged it 200%, trying to see what the visual difference is between 4k and 2k. Conclusion: it is very very hard to see. Only in the very fine details you see a difference when you look closely, everywhere else there is none. This was looking my screen that made the image 2 times wider than the distance of my eyes to the screen - well, if I had a screen like that :-)

What does this mean? Are we looking at the limit of what the lens can resolve? Or is 4k just not that much better than 2k? Would it be better visible with a moving image..?

Don't get me wrong, I don't care about the amount of pixels that much. I think at the image size we are talking about lattitude and color are much more important. I was just curious about what 4k actually meant.

[Graeme_Nattress]

You can make the 4k sharper if you want - change the demosaic to a different one, but I like the smoothness and continuousness of the current one. However, There's significant difference in your test between 2k and 4k it would seem. Also, the resolution trumpets are for HD, not 4k, so don't go detailed enough.

[mikkowilson]

Interesting.

Is that image you just posted 100% from the orginal?
At 100%4K the differences between 4K and re-scaled 2K are very small - one pixel only - and so they are hard to see. However if you blow that up for a closer look where the human eye can see a difference, or run it throguh some processing, like keying, then the differences will be clearer

Also, keep in mind when re-scaling that the upscaling algorythem will work best when it's bringing back something that was scaled down with the same algorythem. The difference in true 2K and 4K source may be more noticable.

- Mikko

[Jarred Land]

sndrk.. on a little screen the difference between 4k and 2k isnt that noticable... on a 40' screen it definately is.

[Graeme_Nattress]

Exactly Jarred!

[sndrk]

The images I posted are 100% crops from the original, no sharpening or scaling or anything else. I agree there is a difference but I would have expected it more to be since there are 4x more pixels in the 4k one.

As said, it is not something I am worried about. Just think it is interesting and I wonder what it is.

I doubt it would be more visible on a 40' screen unless you're uncomfortably close to it. I mean, like closer to it than the 1/2 the width of the screen.

[im.thatoneguy]

I'm noticing a strange artifact on the left flare. The red (no pun intended) flare has a sharp and dramatic cutoff. This is only in the red channel. Is this a lens characteristic or something strange happening on the chip?

It's most evident on f2-4.

[Graeme_Nattress]

Gavin, earlier footage I have doesn't flare like that, so I'm looking into what's up.

Graeme