Berislav Horvatic wrote:I think Mario is right, jpeg compression usually does not impact image sharpness.
But I've never mentioned any JPEG COMPRESSION (meaning transforming anything else to a jpeg file),
what I meant is the mere REDUCTION of a cca. 6 MB original JPEG file to a less than 500 kB JPEG file,
which can be done in many ways, some better than the others...
These two things are basically the same. Transforming a file type to jpeg INVARIABLY involves compression, reducing file size USUALLY does too. There are just 2 main parameters you can fiddle with in order to reduce file sizes of jpegs. Parameter number one is image resolution, either by cropping (cutting away unwanted portions of the image) or by resampling (calculating a lower resolution image).
The first option usually deteriorates image quality for a plethora of reasons, the latter almost always improves image sharpness. Parameter number two is (further) compressing the image - usually done with a "quality" slider or number while saving the image. Most of the time you will have to combine these two methods to get the desired file size while retaining optimum image quality.
There is a third parameter for reducing file size, color depth, but no sane person would use this option unless one wants to create a cartoon-like look. I'm not aware of any other of the "many ways" you mentioned, but I am curious to learn about them....
The visible softness in these images is usually produced by bad (misaligned) lenses or too much noise reduction
applied by the camera - or the raw converter. Supertelephoto-lenses like 18-300mm tend to be soft at their long
end wide open, and give the exact look of the images seen here.
Yes, BUT:
Mario had a problem of his own (with his HARDWARE, as he says) and Thomas (maybe) a quite different problem,
(with the SOFTWARE, as he says), yet the results seem to me to be the same...
And like I said, in this forum you may encounter a whole report by a good photographer that is "too soft" (at least
to my taste). Not just some of the pictures, under some special (unfavourable?) conditions, but dozens of them,
all of them. How should one explain that? Some people just like it that way, or they miss something, or what?
as far as I understood Thomas did not check the parameters of the camera, that's got nothing to do with software. Another very common cause for image softness is diffraction of light due to a very small aperture (above f/11 or f/16). Just speculating, but this might be one of the parameters not checked by Thomas.
Combine aperture 16 or higher (to have a lot of depth of field) with a mediocre "consumer" lens and some image cropping (to fill the frame with the subject), then add some minor camera shake (not uncommon with exposure times resulting from f/16) and the image will often be as soft as seen in some of the examples above.
There are just too many parameters affecting image sharpness to tell exactly why a given photo might be out of focus, soft, fuzzy or whatever you call it without knowing the model of camera and lens, focal lenght, aperture, exposure time and ISO used capturing and post processing steps applied to the image.
And there might be one easily corrected cause for image softness at the viewer's side - be sure to hit ctrl-0 in your browser to view images at 100%.
btw: i prefer a slightly soft photo of a beautiful specimen to no photo at all, and that's why I often deliberately make a compromise when taking pictures knowing if I could/would spend thousands of euros for a better lens i would get much sharper photos. But that's not gonna happen And maybe others (the good photographers you are referring to) subscribe to this point of view and rather take suboptimal pictures than none at all...