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Alternative Imaging Methods
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Old June 28th, 2004, 06:27 PM   #871
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Anders,

I was actually recommending to Juan that he test the exposure range on his modified DVX. We can probably trust Michael Phillips' assertion in American Cinematographer that the DVX normally has an exposure range of 8 stops, but thanks for the offer anyway.
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Old June 28th, 2004, 06:29 PM   #872
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If the 8-stop figure is to be trusted, then i think that just by comparing the DV output and the RAW output in the latitude test we can get the 2-fstop number. It's actually a bit over 2-fstops, but if we round it down to 2, we get 10-fstops of latitude.

This actually sounds very close to what can be observed from the 35mm comparison. Everything looks similar except for an area in the green box which is washed out, but that is partly due to the fact that the two cameras were in different positions.

10-fstops...nice.

Juan
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Old June 28th, 2004, 06:35 PM   #873
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Actually Juan, you bring up a good point about the cameras shooting from different locations.

At the time you said that, since the camera was open, it was hard to move. Now that it is closed up, would it be possible to re-do the shoot with the DVX right in the same spot as the film camera? That would be the ultimate comparison.

My ultimate wish list in this shot would have some shadow areas that go almost black, and some areas of white that have detail right up to the point where they go pure white, and most of the rest of the scene somewhere in the middle. That would allow us to not only see how they compare, but also how much they can be pushed in relation to each other. And, of course, it should be a perfectly static scene, much like the previous one (for repeatability).

Thanks for everything, Juan. I'm 'bout to jump out of my skin this is so exciting.
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Old June 28th, 2004, 06:40 PM   #874
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I was just thinking about that. I'm going to do it tonight or tomorrow, then get the film developed and post the results.

One question though...the lens on the DVX and on my film SLR camera have different angle of view...should i still put them in the exact same location or should I have the film camera closer if it's wider, etc?

Although now that I have the anamorphic adapter, they might be similar....

Juan
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Old June 28th, 2004, 07:15 PM   #875
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Oh, yeah.

I would recommend trying to get the exact same framing, and similar perspective. Of course, this will require a different distance/focal length combination from the 35mm camera to the DVX, and it will never match exactly.

The main thing I was interested in was seeing the shots from the same angle. That way the angles on the lighting are as close as possible.
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Old June 28th, 2004, 07:19 PM   #876
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Also Juan, when you get the film "developed", you are just taking it in and having it put on disk, right?

When you do that, do you get an option as to what quality the pictures are, things like resolution, compression and such? Seems like it could make a difference. I would hate to find out that the 1-hour photo place compresses the pictures after they scan the negative, and said compression cuts down on the lattitude of the picture, giving us misleading results. Might be worth checking into.
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Old June 28th, 2004, 10:26 PM   #877
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Two things:

First of all, i looked into the DVI solution to replace the SDI and it seems like it is the way to go. Even though I already have the SDI FPGA configuration, I could really use the free gates, and DVI takes almost no gates to implement. This would allow the device to be connected to any flat screen and monitor the RAW video in 4:4:4 8-bit RGB.

About the film developing: Afaik, it is a 2K scan of the negative, this means that it is scanned with a CCD which reacts linearly to color. However the film reacts logarithmically, so we should still get the latitude of film. The images are JPG compressed but my best guess is that this has no effect on latitude.

It's a good comparison.

Juan
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Old June 29th, 2004, 12:43 AM   #878
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Regarding the XL1 as being a bad candidate.

Not to sound foolishly brand-loyal, but i really do love the XL1. The results are typically a bit soft, and they do have a low pixel count, but the colors are very vibrant, the artifacting is extremely minimal (because the picture isn't over sharpened like the DVX), and all of our stuff gets converted the 24p in post and color corrected heavily anyway.. so i would love the ability to color correct natively in 16bit space, rather than convert to 16bit from DV. I know for some (many?), the DVX is a better camera.. but I already get good results following the formula of 30i --> 24p --> color correction --> edit.. so if i can skip a step and already be working in the right color space, that would be nice. it would help increase canon's limited resolution, and be great for chromakey etc. not to menion mini35..

If the XL2 comes out anytime soon, and the pricerange is right, we'll buy one or two of those and maybe seen if juan's mod would be better suited to that. but for now, the XL1 is my winner.

i guess we'll wait and see when juan finished the DVX version and how well it works.
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Old July 5th, 2004, 05:20 PM   #879
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Update:

It works! The first stage of the prototype is working, capturing directly to my mac via Firewire 800. It is caseless for now, but in a week or so i will be able to post pictures of the prototype case on the camera. The final device will probably be machined out of aluminum, but I did this one in polycarbonate plastic to save time.

This week we will be testing the DVI interface as well.

Does anyone know if any of the 35mm 'adapters' (Aldus35, etc) discussed in these forums work with the anamorphic adapter? i.e. can i get 35mm DOF and 16:9 on the 4:3 chips?

Juan
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Old July 5th, 2004, 05:36 PM   #880
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Juan,

Congratulations!
Glad to hear the prototype is together!

I think the solution would be to get an anamorphic lens to put on the adapter, not adding the Panasonic anamorphic adapter to a standard 35mm lens.

You could put the DVX anamorphic adapter on a standard 35mm lens, but it would probably not be worth it due to the quality of the glass, and the adapter steps needed to attach it.

Just my 2 cents.

-Luis
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Old July 5th, 2004, 06:00 PM   #881
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Very cool - can't wait to see clips. I can host large clips if you need space.
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Old July 5th, 2004, 07:24 PM   #882
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This is how the DVX looks once the probing cabling has been installed.

http://expert.cc.purdue.edu/~pertierr/DSC00417.jpg
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Old July 6th, 2004, 08:10 AM   #883
 
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WOW!!!!

Congratulations Juan!!!!!!!!

That's awesome. And the the camera looks great. Only difference seems to be the cable out the bottom. Fantastic. Good Job. Can't wait to see some footage.
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Old July 7th, 2004, 07:20 AM   #884
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camera body

juan,

sorry for my lack of knowledge, but does this means that this cabling is the only thing which is outside of the camera itself. everything else will be in that aluminium/plastic box?

does this means if someone wants to upgrade dvx to juanHDvx solution - must send the camera to you? or it can be done in diy manner?

thanks

filip
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Old July 7th, 2004, 11:00 AM   #885
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That's right.

Like i said before, if you had to solder to install the probes, it would be really difficult because it is all 0.5mm pitch surface mount. But since I am not soldering at all, it is even more difficult. It takes special tools and careful alignment to install it, but it is extremely reliable andf very simple to remove. To illustrate, the first time i did it it took me several days(weeks?) just to figure out how to align it properly(documented in this thread). Now, it only takes me 30 minutes to install including dissasembly/assembly.

I've had unexpected tests of how well the probing method works, i've had the DVX fall to the floor from 4ft up dissasembled, and all the probing cabling is still perfectly in-place and working...while the camera's stock DV connector was ruined in the fall.

Juan
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