Should I replace Nikon 24 120 f/4 VR

Sudipto

Senior Member
3fc308424356d14c15c0414a5bc805eb.jpg


This is 24 mm pics with 24 120.



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WayneF

Senior Member
This is 24 mm pics with 24 120.


You would like your images better if you would use less JPG compression....

Select only JPG FINE in the camera, and at least JPG Quality 80 in the editor, and as few times as possible. Everytime you edit and SAVE a JPG file, the JPG artifacts accumulate. They cannot be removed, you have to start over with a clean image.

This 80% number varies in different programs, it can't be stated exactly that way. Even Photoshop menus Save As JPG and Save for Web vary significantly. But do use much closer to Maximum Quality than to Minimum Quality.

That is one of the several advantages of Raw images, no JPG artifacts until the one final last save as JPG. If it should ever need more work, we simply discard that JPG (expendable), and edit the Raw and write one final last save as JPG again.

arti.jpg



These two are from the bottom, and from the top of your image. Greatly enlarged of course, to point out the JPG artifacts. Click it to show a bit larger. It doesn't show all that well here, you will see it more clearly in your own editor. We do need to learn to look for JPG Quality.

All of that scattered "clutter" or smudge around all of the edges is JPG artifacts, due to excessive JPG compression (due to JPG Quality setting being too low).

Less JPG Quality setting does makes the file smaller, but it harms image quality. What good is a poor small file?
More JPG Quality setting makes the file larger, but better image quality.
We typically prefer better quality. The setting is named JPG Quality.

A large file is good for JPG. Very High Quality JPG still will be relatively small.

The image you posted here is 1438x960 pixels. The RGB Data size is 3 bytes per pixel. So that's 1438 x 960 x 3 = 4,141,440 bytes, which is 4 MB, uncompressed.

But after your JPG compression, the file is only 223 KB, or about 5% of original size, about 1/20 size. IMO, that is excessive, and is visibily harming your image quality.

Take a new image of something, with FINE JPG selected in the camera, and examine it carefully at 100% size, and you will see these JPG artifacts are either gone or very insignificant, extremely hard to even detect.

A Large Fine D750 JPG will be around 12 or 13 MB size before it is resampled. Your 24 megapixels at 3 bytes per pixel is 72 million bytes. Every 24 megapixel image is 72 million bytes. That is simply the size of the data. Then JPG compression to average 12.5 MB is around 18% compressed size, near 1/5 size. That will be high quality. It is not actually large, because it is still about 1/5 or 1/6 size. We can't have too much quality. :) Large Fine is the way to go.

This compressed JPG size will vary a little with image content. Much fine detail everywhere will be larger (compresses less well), and much blank empty space (skys, walls, etc) will be smaller (low detail compresses smaller). Your picture had large areas of both, I'd guess it might be near average in that regard (degree of detail), but it is hard to predict.

Just try higher JPG Quality settings, I think you will like the 24-120 mm lens better.
 
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Iansky

Senior Member
Great analysis and explanation from Wayne about the hazards of JPEG compression and it is another reason why I personally only shoot in Raw but that is my personal choice.
 
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