Luminous Landscape Forum
Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: stamper on December 31, 2007, 06:14:11 am
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I have read a lot about lens softness and I am wondering about a couple of points Softness is lack of contrast in a similar way that an image is soft ( lack of contrast ) Is this correct? Assuming that a lens is soft all across the lens from corner to corner then the resulting image can be satisfactorily sharpened in photoshop? Again is this correct TIA
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Crap in, crap out.
Rob C
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Crap in, crap out.
Rob is basically correct. Small corrections in post-processing might not be very noticable but the little fixes add up and you'll see loss of gradation if nothing else. For the best quality work do the best you can at each step of the process which means if you want a sharp picture use a sharp/contrasty lens (and good technique, a good camera or film, yada yada yada... ).
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I have read a lot about lens softness
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Lenses all have a distinct character. Even among different example of the same lens there can be differences. Softness/sharpness is just one characteristic that lenses specifically exhibit. It is also often true that people mistake smoothness (of tonal transition) for softness.
Anyway, the above posters are correct. Once an image is actually created "soft", it can only be made to appear sharper. Sharpening puts new artifacts, edges, on your image. These edges emphasize the appearance of detail but do not actually add detail, unless you count the edge artifacts as detail.
There is no substitute for great lenses. If you make an image with a great lens and you want to degrade it in Post Processing to create the effect you want you can easily do this. However, when you make images with bad lenses and later want to enhance them in Post, your job is not so easy and the effect is usually not as satisfying.
Peace and Happy New Year to all.
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Lenses all have a distinct character. Even among different example of the same lens there can be differences. Softness/sharpness is just one characteristic that lenses specifically exhibit. It is also often true that people mistake smoothness (of tonal transition) for softness.
Anyway, the above posters are correct. Once an image is actually created "soft", it can only be made to appear sharper. Sharpening puts new artifacts, edges, on your image. These edges emphasize the appearance of detail but do not actually add detail, unless you count the edge artifacts as detail.
There is no substitute for great lenses. If you make an image with a great lens and you want to degrade it in Post Processing to create the effect you want you can easily do this. However, when you make images with bad lenses and later want to enhance them in Post, your job is not so easy and the effect is usually not as satisfying.
Peace and Happy New Year to all.
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Thanks to all for their replies If someone has a 10mp camera and takes images wide open and the lens is soft at the edges then does a little cropping of the image a viable method of getting round the problem?TIA
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Thanks to all for their replies If someone has a 10mp camera and takes images wide open and the lens is soft at the edges then does a little cropping of the image a viable method of getting round the problem?TIA
No. Cropping, or throwing away pixels will never increase overall image quality. If you use a different camera with a smaller-format sensor (say a 40D instead of 1D-MkIII) but a similar pixel count, you may increase image quality, depending on the MTF curve of the lens. But cropping away pixels from the same camera is not a useful approach to increase image quality.
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I have read a lot about lens softness and I am wondering about a couple of points Softness is lack of contrast in a similar way that an image is soft ( lack of contrast ) Is this correct? Assuming that a lens is soft all across the lens from corner to corner then the resulting image can be satisfactorily sharpened in photoshop? Again is this correct TIA
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It depends upon the source of the softness. There are two concepts: (i) focus, and (ii) edge contrast. If the lens is not capable of focusing sharply, or if the photographer failed to focus the image (intended parts thereof) properly, this can be "fixed" to a limited extent in post-capture processing. Deconvolution methods such as FocusMagic have more strength here than acutance sharpening techniques which to a limited extent can cover-up lack of focus with increased acutance. But beyond a certain point this looks artificial. If, however the softness is not really due to lack of focus, but due to low acutance, post-capture sharpening processes which increase acutance are quite effective at redressing this issue. It is usually fairly easy to tell which kind of problem you have. A blurred image does look different than an image suffering from inadequate edge contrast.
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It depends upon the source of the softness. There are two concepts: (i) focus, and (ii) edge contrast. If the lens is not capable of focusing sharply, or if the photographer failed to focus the image (intended parts thereof) properly, this can be "fixed" to a limited extent in post-capture processing. Deconvolution methods such as FocusMagic have more strength here than acutance sharpening techniques which to a limited extent can cover-up lack of focus with increased acutance. But beyond a certain point this looks artificial. If, however the softness is not really due to lack of focus, but due to low acutance, post-capture sharpening processes which increase acutance are quite effective at redressing this issue. It is usually fairly easy to tell which kind of problem you have. A blurred image does look different than an image suffering from inadequate edge contrast.
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Thanks I am new to slr lenses and still learning I was looking for a wide lens about 20 or 24 to 50 or 60 Something in that range It is for low light so the wide setting at f 2.8 is what I am interested in Because my budget is limited the reviews that I looked at stated for various brands that wide open at f 2.8 they suffered from softness and I was wondering if the softness was correctable in Photoshop It looks like I will have to increase my budget Thanks for the replies