Another Example of Sharpening
I had the opportunity to take the following photo recently with my Nikon Coolpix 950 (It's true - the CP950 was not widely in use during the civil war - excuse my jumping eras here).
Copyright 2000 William Lawrence
This photo of the Capitol Building was taken at night, but I couldn't bring a tripod with me, so this was done supporting the camera against a fence post. I had the 2x telephoto on, so this shot was taken with roughly a 35mm equivalent of a 220mm lens. I took enough shots that I got one relatively free of shake, but it still produced a reasonably soft image. The photo above was sharpened using Unsharp Mask, 100% full effect, with a radius of 3 and a threshhold of 6. Compare a closeup of the dome from the original image (left) with the sharpened image (right), below:
Even with the lower monitor resolution, and the jpeg compression, the effect of the sharpening stands out. I've made an 8x10 print of the photo before and after sharpening, and wound up throwing out the original photo after comparing it to the sharpened image. Note that there is no such thing as a free lunch, though. In the darker part of the Capitol below the dome, the sharpened image appears somewhat grainy (you can see some of this in the bottom edge of the two closeups). Overall, though, in this photo the grainy appearance is quite minor compared to the improvement that came with sharpening.
In the tintype, I did not apply the sharpening at full effect to avoid adding too much noise giving a grainy appearance to the background in general (didn't have to worry about this in the Capitol photo since the background is pure black) - so I tried to balance the impact of sharpening on bringing out the detail in the face on the tintype against the impact of increasing noise in the background.