Best practices with the Video WorkPrinter

[digvid]

Matt -

Any idea where to get an image processing algorithm for this exposure blending?

- Jeff Dodson

[S8 Booster]

may i suggest a technique used in dye transfer printing of stills all the time, and sometimes also when shooting static high contrast scenes, both stills and motion pictures. the idea is that if you do multiple passes, you can concentrate on getting one part of the range correct each time, and then its just a matter of combining the results in some way.

the easiest way to try this with the workprinter would be to transfer twice, the first time with a one stop underexposure, to get good highlight detail, and once one stop over, to bring up the shadows, and then just superimposing or "overlaying" these in the computer. i've used this technique for a lot of things, and it's really powerful. don't know what results it would give with the workprinter, but i'm curious and it seems like it could work, as long as there's detail in the film of course. you won't be able to create information already lost...

/matt

Have never tried any of this before but just wondering if it is possible to simulate it by using "any" WP (short) clip and make 2 duplicates and export them to Adobe Photoshop as filmstrip files and "tweak" one sample of each to make them analog to your suggetion. Then next export it back to Premiere or FCP to make the rest of the process you suggest?

Some of the filters required are possibly available in Premier so ther emay be no need to export it but there are some useful "Photo" filters in PS that are not available in AP.

Example: It is easy to set the white balance for one clip and "black" balance for another and "merge" them into one film strip.

Just wondering.

R

[mattias]

Any idea where to get an image processing algorithm for this exposure blending?

a simple superimpose works just fine, and maybe the overlay or screen compositing modes even better in some cases...

all of you who own a video camera can test this. shoot a bracketed exposure of something static and high in contrast, too high for the camera to handle under normal circumstances, then super all the versions together in your computer. you will get a completely noise free image with great color and excellent latitude. it will be low in contrast, but it's always easier to boost contrast later than to try and decrease it.

/matt

[mattias]

Have never tried any of this before but just wondering if it is possible to simulate it by using "any" WP (short) clip and make 2 duplicates and export them to Adobe Photoshop as filmstrip files and "tweak" one sample of each to make them analog to your suggetion. Then next export it back to Premiere or FCP to make the rest of the process you suggest?

yes, you can do that, and i often do in severe color correction situations where different ranges need different treatment, but you won't really see the true benefits and it would be easier to just shoot tests on video, as described above...

/matt

[jessh]

Now, what WILL work is if you flash your Kodachrome stock when you shoot the original footage in the field. That will definately compress the contrast quite a bit and allow for a nicer video transfer but will create an original that is pretty flat when projected for normal viewing on a screen. It is impossible at this point to have it both ways; nice for projection and nice for telecine.

would it be possible to lower the contrast through processing in order to get better telecine results? I can't remember if it is push or pull processing that is suposed to lower contrast.... of course you might end up with more grain. I believe Dwaynes offers push and pull processing, but of course they charge extra for it.

~Jess

[Bazz]

My camcorder has a still photo option, and I understand this is the only option that uses the full megapixel capability of the camcorder. Video uses about 800 pixels or so. Would it not be a benefit to set the camcorder to still photo (memory) option and use the firewire output to capture the workprinter frames into dodcap? I've testing the output from the camera in this mode and it does send the image through the firewire into dodcap. Would this give a better resolution or am I missing something?

[Andreas Wideroe]

That's very interesting. I too have this function on my camera though I haven't tested it with Dodcap yet.

Anyone?

[digvid]

That is interesting. Just from "eye-balling" the frames, how do they look compared to normal DV frames?

Also, exactly how do you trigger your camera to take a frame in still photo mode?

- Jeff Dodson

[mattias]

my guess would be that the firewire output as seen by dodcap is still normal dv. the video capture drivers aren't the same as the still transfer drivers, and i don't think the capture nor transfer of megapixel stills is real time. there could be a small gain though since capturing large and scaling down improves the image slightly, so if that's what it does for the preview you should go ahead and shoot a test chart for us...

/matt

[digvid]

I agree...Dodcap will always capture DV resolution over the firewire port. That is, 720x480 for NTSC, 720x576 for PAL. However, it is the case (as Matt mentions) that you might sometimes gain from capturing at a higher res and downsampling. Maybe you could post some test samples using both the still and motion methods and we can compare?

[Bazz]

My cam's main power switch has a setting for camera or memory . If you switch it to memory, you can set the menu settings to super fine and picture size to 1152x864. BUT the steadyshot function seems to be on (I think) and cannot be deactivated when in memory mode. When you zoom in, you cannot go in as far as you can with camera mode. I thought this was due to steadyshot but when I switch steadyshot back on in camera mode, it zooms in as far as it does without it on. I hope that makes sense. Maybe it doesn't zoom in so far when you use more pixels on the CCD, I don't know the technicalities. I do know that the cheaper version of my cam that has a smaller CCD has a larger zoom range.

It's difficult to see any difference between the two settings just by switching the switch from camera to memory, as the zoom depth changes between each setting. When it gets dark later, I'll do a capture of the same frame using both settings and post them as full size bmp so you can see what you think. Would that be the best way to do it? I've just cleaned a B/W commercial disney film that I want to capture anyway as a test for my focusing (I can't seem to get a sharp image). I'll post a link once it's done.

[Bazz]

I've uploaded 2 bmp images if anyone would like to see. The first is with my camcorder set to normal camera mode. The second is with it set to memory mode (still pictures). I couldn't get the zoom set quite the same but near enough. There is a definate difference! I don't know whether one is better than the other though, I'd like to hear what you think. Also, this is the best focusing I am able to get. This is a pre-recorded film, would you expect the focus to be better? Again, I'd love to know.

Capture with camcorder set to video:
http://www.royalbox.plus.com/camera.bmp

Capture with camcorder set to memory:
http://www.royalbox.plus.com/memory.bmp

[tenkanen]

Capture with camcorder set to video:
http://www.royalbox.plus.com/camera.bmp

Capture with camcorder set to memory:
http://www.royalbox.plus.com/memory.bmp

In my eyes, "camera.bmp" looks clearly sharper than "memory.bmp".

[digvid]

Actually, I would agree. In this example at least, I see more detail in the camera version.

[avortex]

Why I always see some lens distortion in all these transfer images? Is it a constant using this machine? 8O