I assume an interest in making the chart as useful as possible. At present it shows that sharpening tools have an effect, but it is just one specific effect and it doesn't show when or if any given sharpen tool is appropriate. And since it basically only shows one effect it leaves the incorrect impression that different sharpening algorithms all have the same effect.

There are charts that show more. One chart that was not designed specifically to be used with sharpening tools, but that just happens to include most of what is needed, was designed by Norman Koren. There is discussion about the chart on his web page at

http://www.normankoren.com/Tutorials/MTF5.html

The chart itself can be downloaded from this URL

http://www.normankoren.com/Tutorials/Lenstarg_lin_720.png

It is a PNG image, but of course can be converted to TIFF or even JPEG.

Watching how that image is changed by various sharpen tools is really educational! But unfortunately it does not show one thing your chart does, which is the variation with contrast along an edge. The original point was that your chart combined with something like this is very useful, while your chart alone in fact just causes people to be more confused because the effects they see on the chart are not what they see when they sharpen an image.

It is also true that those two charts together do leave out one other effect that would be easy to add and is essential for an educational tool. There should be a contrast gradient for an edge that runs at an angle from vertical, rather than just horizontally. The would show the effects of sharpening on the "jaggies".

I have 2 months left on an extended warranty so I decided to send my Nikkor 18-200 mm lens to the Nikon repair center to get a cleaning, replace the zoom ring and focus ring. I get an email back stating that the lens unit, filter ring and the 2nd group tube had an impact damage. I asked what is exactly wrong with the 2nd group tube and their response was, "impact damage was found to the lens unit, filter ring and the 2nd group tube." I had called them back and ask again what is wrong with my tube and they said they will contact the repair center and email me back with the info. The response was, "the 2nd group tube has an impact damage, if you have any more question please contact us again." Naturally I did. Their response was "it is not covered under the warranty, it will cost approx. $290. The focusing mechanism it tight and grinding, the zoom rubber grip is also loose, if you have any more questions please contact us."
Well, it isn't sitting right with me. What should I do?

Need help from the hoggers. I have a Nikon d7000 body with a nikkor 300mm f4 afs attached. I have done a focus calibration of lens to body on my tripod . With static pics on the tripod I'm getting great in focus pics. When I shoot some free hand pics of say squirrels or small birds the focus is missing. Usually front or back then sometimes nails it. I've been using 800 to 1600 shutter speed with low ISO and f/4 to f5. I calibrated my 180mm sigma macro in the same way take the same shots at f/2.8 to f/4 and get tack sharp shots. Oh that's with the vr off on the Sigma. Why inconsistent focus with the Nikon lens? I read such great reviews about this lens and now I have it I'm not really liking it compared to any of my Sigmas.