> I'm trying to get good, consistent, photographs of a VFD display > (single tube) and have having trouble with getting the colours right & > decent detail - this is when the tube is lit (all segments). > > Anyone done this with good success and care to share settings/ > technique etc.?
I've had reasonable success with two approaches. One approach is for when you want to show the actual device and its structure, so you want it well lit. For that, I use an off-camera flash, and adjust power and distance for a nice balance between the external light and the light of the VFD itself. I also juggle angles so highlights aren't in unfortunate places, covering up details I want to capture. One trick here is to put a polarizer on your flash and another on your lense, so you can filter out flash bounce more easily. With the external light giving your camera white balance cues, the colors tend to come out nicely. A more tricky situation is when the majority of the light is coming from the VFD itself. Then, you have to avoid having the camera guess the white balance, as the light is not white. One thing that works with some cameras is to turn on external light of appropriate brightness, let your camera choose focus, exposure, white balance, etc. (often done by half-pressing the shutter button), then turn off the lights and take the picture. It might come out a little dark, but that can be addressed by adjusting your exposure choices. Since you may not be working with fast lenses or bright devices, a tripod or some method of supporting the camera can be helpful (I often set it on something and use the timer to take the picture, so the vibration of me pushing the button will have dissipated by the time the shutter opens). Adding a color filter in front of the lense can help too, and also increase contrast. Finally, you'll often get the best results if you tweak the photo afterward and adjust the hue and saturation to get a more realistic depiction of what you're looking at. Odd-spectrum light sources (such as VFDs) can confuse your camera, which has to work backwards from a Bayer array of colour sensors to deduce the actual colour. As the filters in the camera have different sensitivity curves from the ones in your eye, the math used makes some assumptions that the spectrum is more or less smooth and continuous - which is not true in these cases, causing the camera to assign the wrong colours. Since this is a basic problem of physics, it's tough to avoid in any automatic way. Which is why tweaking things after the fact is often the best approach. I had a time trying to take a picture of an old, faded VFD, which showed the darker areas of the phosphor under the filament wires. Catching the filament wires brightly enough to see, without making the glowing phosphor too bright, was tricky! Verbosely yours, John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
