Detail versus Aperture setting

[Eugene Kosarovich]

What exactly does the aperture setting on the detail page of the F3xx menus do?

I haven't found any docs that explain it. I understand what the detail setting does and how it does it, but not the aperture setting.

To restore detail in the knee area, we adjust the knee aperture, so obviously aperture must be similar to the detail setting.

And then I read the BBC research on the best menu settings, and they specifically mentioned they didn't like the results of using the detail setting and instead used the aperture setting to adjust the detail level.

So, what exactly does the aperture setting do?

Thanks.

[Simon Wyndham]

This is a tricky one because the lines between the two adjustments seem to have become blurred somewhat.

Aperture Correction to give it its full definition is mainly the enhancement of the higher frequency edges (for example the edge of a building roof against a plain sky).

The BBC documents that you refer to were devised by Alan Roberts. Alan really does know his stuff and he helped me a lot, although I think his XDCAM evaluation was a bit rushed.

His documents are largely devoted to achieving a film look with high definition cameras. In order to achieve this Alan usually reduces the overall detail level to an absolute minimum, but boosts the aperture correction in an attempt to mimic the detail behaviour of an average generic film stock after a telecine process.

Adam Wilt has done an excellent article explaining aperture correction:
Technical Difficulties - Lookin' Sharp

[Alister Chapman]

Warning: These details may not be accurate, so don't take them as gospel.

If I remember right aperture correction used to be generated using a simple circuit that boosted high frequencies in the analog video signal giving the overall image a sharper or crisper look. The down side was that it also boosted noise levels by the same amount. Detail correction however used delay lines to detect areas of high contrast where the video level rapidly went from light to dark or vice versa, which would normally indicate an edge and then boost both the light and dark sides of the transition to make the edge more square. This worked but if overdone added black or white borders around edges and it would always try to square off all areas of high contrast.

Neither method actually increase resolution. Aperture correction was always my preferred method as if used in moderation could make pictures look sharper but it really does bring up the noise floor. Detail will also make an image appear sharper and has less of an impact on noise, but I hate black edges.

In the digital world I'm not sure how it is done. It may still be very similar as the read out from the actual CCD or CMOS sensors is still an analog signal. Certainly detail correction looks similar to the way it used to be done, but now you have more control, as for aperture correction, well I'm just not sure whether it's still the same thing or not.

[David C. Williams]

I don't have an F300 series, but I think your talking about Knee Aperture? I hate the way jargon changes from camera to camera. This explains it very clearly.

http://pro.sony.com/bbsccms/assets/f...ture_Edges.pdf

[Alister Chapman]

Knee aperture only affects the knee area. It uses the same methods as aperture correction but only in the highlights. Aperture correction affects the entire image.