Tuesday, March 26, 2013

Vignette Illusion?

Maybe that frame vignette not being as prominent on further shots is just an illusion. So I set the camera at one setting and moved it around. One close and one far. Setting the exposure manually to its highest setting seemed to help the vignette a bit in just eyeballing it, but here is some real results.

Here is the frame closer up. Note obvious vignette.

Here is the same frame further away. the vignette doesn't seem as noticeable. I didn't change any of the settings on the webcam but you can tell that there was some brightness changes.

Thanks to the magic of image manipulation software I'm able to compare the two images side by side for comparison. Just so one doesn't appear "more correct" I rotated them sideways.

Can you tell which image is which? The one on the left is "further away shot" you can tell because the facial coloring is slightly brighter and looks a little better.

Stare at the corners real hard and you can tell that the right side does have a slightly more cropped corner. At that level does losing a little bit of corner make up for the loss of resolution? Is the slightly more cropped corner because the image is darker and a little out of focus?

It is probably in my best interest to attempt to find a halfway point that isn't too far out, but close enough to get a perfectly locked focus. It does appear like the further from the screen you are the more accurate the ability to focus and more accurate color representation.

Adventures in Telecine Vignettes

So I blogged about how I picked my camera for my telecine previously. So I've been tinkering with settings and trying to figure out just how to get the best image quality. Increase exposure, decrease gain, adjust white temperature, etc. Then I came across an interesting artifact I didn't think I'd see.

Here is what my blank canvas looks like. Nothing special. I compared the colors from the far left with the colors from the far right and the center and they match perfectly.

A typical frame capture from the box and you'll note a pretty strong vignette happening. That upper right corner is almost completely black, but it isn't on the source. I had to investigate.

I moved the camera to the right side of the frame and a lot of that vignette disappears.

Who would have thunk it. Same on the left.

Shoving the camera in real real close and letting it stay out of focus shows a slightly different vignette effect.

Pulling the camera further out shows almost no vignette of the original source. You can still tell that the blue of the sky in the middle is a lighter tone than that of the surrounding sky but it doesn't drastically drop off. Of course I'm going to lose some of my resolution, but the colors are truer which is more important to me.

*The last shot shows a slight obstruction from a piece of wood in the bottom left corner. This was just experimentation after all.

I'm going back to the camera and see if fiddling with some of the settings might increase or decrease the vignette effect. If I can't find something worthwhile at least I made some progress today.

Here is a follow up with just to make sure the vignette wasn't a complete optical illusion.