Slide is totally black if image intensity reduced for creating SBS 3D

clement5 wrote on 9/6/2018, 1:53 PM

I am creating an anamorphic side by side 3D video in PAL 4k format using 20s slides. I wanted to overlay text on a reduced intensity slide, but when the intensity is reduced the entire 20s segment is black. Various other changes such as hardware encoding, creating MP4 or AVI... have no effect on this problem. Creating a 2D video works OK. Turning off the intensity change fixes the problem, but not what I wanted. There is no easy workaround for this problem. A nasty workaround is to create a second darker copy of the slide and use that. I have not tried all possible combinations of output, because it looks like it is an output independent bug.

Comments

johnebaker wrote on 9/6/2018, 3:25 PM

@clement5

. . . . anamorphic side by side 3D video in PAL 4k format using 20s slides . . .

Are these from a 3D camera as 1 SBS image or 2 separate images on 2 tracks - if not how are you creating the 3D effect?

. . . . I wanted to overlay text on a reduced intensity slide, but when the intensity is reduced the entire 20s segment is black . . . . There is no easy workaround for this problem . . .

I assume you mean you want the title on a darkened background to display for example for 6 secs - if so try making cuts at the start and end of where you want the darkened portion of the slide to be and then reduced the intensity of that portion.

HTH

John EB

clement5 wrote on 9/6/2018, 11:19 PM

For the video in question the stereoscopic pictures were taken by a Fuji W3 and then unpacked to a side by side full resolution image using Stereo Photo Maker. I set the slide length to be 20s. Yes, I wanted some text against the darkened slide and then wanted to create a 4k video SBS anamorphic. The 4k is really to preserve the resolution of the original slide after the 2x horizontal compression. The darkening of the slide causes that segment to be blank black. I can also create 3D digital images by scanning my 3D Realist slides, old stereographic cards, or View-Master reels. The Fuji W3 is the only decent available (used) digital camera. There are many good 35mm cameras from the 1950s (used) that could be used with a scanner. There are also inexpensive cameras such as the Loreo which use 35mm film. The Fuji can also create 3D videos. The other digital 3D cameras either produce anaglyph output (red/blue) or have lenses too close together.

RogerGunkel wrote on 9/7/2018, 4:43 AM

For the video in question the stereoscopic pictures were taken by a Fuji W3 and then unpacked to a side by side full resolution image using Stereo Photo Maker. I set the slide length to be 20s. Yes, I wanted some text against the darkened slide and then wanted to create a 4k video SBS anamorphic. The 4k is really to preserve the resolution of the original slide after the 2x horizontal compression. The darkening of the slide causes that segment to be blank black. I can also create 3D digital images by scanning my 3D Realist slides, old stereographic cards, or View-Master reels. The Fuji W3 is the only decent available (used) digital camera. There are many good 35mm cameras from the 1950s (used) that could be used with a scanner. There are also inexpensive cameras such as the Loreo which use 35mm film. The Fuji can also create 3D videos. The other digital 3D cameras either produce anaglyph output (red/blue) or have lenses too close together.

I'm in agreement with John's suggestion over cutting a section and darkening it, but slightly puzzled over why it is going black on the whole clip if you are just reducing the brightness for example with the gamma settings. You could also try a black overlay and reducing the opacity.

As an aside,I have a Fuji W1 and a W3 and they are great little cameras, although the 3d video is pretty low resolution. For my occasional 3D photography now, I use my Canon 5d full frame and take 'cha cha' images which gives a much higher resolution image than you can get from the tiny W3 sensors. Of course if there is moving content the 'cha cha' two shot method wouldn't work but for still subjects, any modern camera or even phone with a reasonable sized imaging chip would take better quality pics than the W3. The two images can still easily be aligned in SPM. Using a single camera for a 3D pic also means that you can set the stereo base for any pic to whatever you want.

Roger

johnebaker wrote on 9/7/2018, 4:47 AM

@clement5

. . . . . the stereoscopic pictures were taken by a Fuji W3 and then unpacked to a side by side full resolution image using Stereo Photo Maker . . . . .

This is not necessary, MEP can import the originals as can be seen below.

I used the original video and MPO images from the Fuji camera and keyframed the Brightness as you can see in the image above.

The same method should work for the scanned images as well.

HTH

John EB