fish sticks
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Iancraig10 Posted at 10-28 04:13
Just answering someone’s question and the topic is about lens sharpness. You could be more helpful and correct it.
This forum seems to be full of uptight people.
Yes, sorry about that. I didn't want to nit-pick, but I shouldn't have answered the post characterizing the post as "spot on". Your intuition is correct, and it sounds like you have the right idea about how an (over)sharpened looks like.
There are some inaccuracies: blurry is how an image or a region in the image looks like. "Out of focus" is one cause for an image to be blurry and appear without edges/detail, but there are many others. For example, with the OA3 you can digitally zoom, use slow shutter speed, rotate frames to "electronically stabilize", and so on.
The following explanation of oversharpening is alright, imo, if everyone understands what is meant with "edges" and "detail". Strictly speaking, "lack of detail" is "missing edges" or "edges being too soft", so some sort of edge enhancement can in theory correct for that. The problem is that simple sharpening methods only increase contrast at edges that are somewhat well defined, while leaving less pronounced ones as is.
For example, if you take a picture of a tree, and don't capture the edges defining individual leaves, increasing the sharpness (most of the time) will increase contrast between the silhouette of the tree, without emphasizing the edges around individual leaves, leading to what people will describe as oversharpenned image.
In the post you were replying to, I argued that blurry and overly sharp is the opposite thing: take a small enough region of an image and it will either be blurry (without edges, i.e. big differences in pixel values) or it will contain an edge (i.e. there will be difference or contrast between neighboring pixels). So, yes, an image can contain both blurry and "overly sharp" regions, but I would describe it as oversharpenned, not as "both blurry and oversharpenned".
Anyway, as I already (impolitely) said earlier, I can see that you were trying to help, and I think your post is already very helpful for people trying to understand possible issues with digital images. |
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