Sharpness control for transferring tapes??

[cjacek]

Hi,
I'm using the SONY EV-S900 to transfer some well preserved 8mm tapes to an external DVD recorder. The SONY 8mm player has a manual "sharpness" control wheel. Do I use that or leave it centered?
Thanks.

[jagabo]

The sharpness control varies on different devices. On some it may range from blur to sharpen with neutral in the middle. With others it may range from no sharpening to full sharpening with neutral at the former. Analog sharpeners are very crude and create over-sharpening halos -- so they should be left at neutral when capturing.

Find a shot clip with a sharp, high contrast vertical line or edge and capture it at several different sharpness settings. Use the setting that delivers the sharpest picture without a halo.



On the left the image is too blurry. In the middle the image is sharp but without halos. On the right the video is oversharp and has severe halos to the left and right of all high contrast vertical edges. Be sure to view the image full size by clicking on it a few times.

[johnmeyer]

When doing any transfer from analog video tapes, you want to defeat ALL sharpening circuits. On VHS decks there is often a control or menu item labeled "edit." When it is OFF (which is usually the default), the image is sharpened, but when it is ON (meaning you want to transfer the video to another deck or to the computer), the sharpening is turned off. So, you want Edit ON and Sharpening OFF.

The problem with any sharpening done in the camera or in the video deck is that it is totally primitive and is usually nothing more than a peaking capacitor that adds overshoot when there is a really sharp transition from light to dark. This has the effect of adding a little halo which, even in the small version of the sample you provided is quite evident on the right-hand picture. That halo obscures actual detail but, to some eyes, make the picture more pleasing to watch. The problem is, once that detail has been obscured by the halo, you never get it back again ... ever.

So, turn off all sharpening and then, if you want to add some later on, use one of the dozens of infinitely more sophisticated (and better) tools in AVISynth.

[JVRaines]

VCRs are different. Use blanket advice as a guide, but try different settings and judge for yourself. There is a tendency to assume that all analog circuitry is primitive and everything can be done better in the digital realm. That is not always true.

[johnmeyer]

My training is all on analog electronics, so I too have great admiration of clever design that can be done in circuitry, rather than using digital algorithms.

However, this is most definitely not one of those cases where the old analog circuit is better. More to the point, even if I am wrong, and it IS better, you still want to turn it off because, as I said in my last post, any enhancement of this sort will lose detail. Once lost, you don't get it back. And, since you have almost no detail in consumer analog 1980s and 1990s video, you need every last detail you can get.

If there are images or videos where people have compared sharpening on a high-end VCR to LimitedSharpenFaster or some other reasonably advanced AVISynth sharpening tool (I realize LSF is old, but it is the only one I can think of at the moment), and those show better results from the analog circuitry, I will be amazed, but after the amazement wears off, I'll be the first to admit that I am wrong.

[cjacek]

Thanks to everyone who replied. Much appreciated.