650D, 18-55mm STM - Depth of Field issue or??

brightcolours wrote:

R2D2 wrote:

brightcolours wrote:

You will get the same detail back you lost in the first place.

I made an example for you that illustrates this.

An image where the blue channel image projects bigger than the red and green channel image, resulting in blue/yellow CA:

This is an image with absolute contrast (two values). Of course it'll work. Most folks will need to use it on real scenes though.

Of course with contrast, it is the perfect example because nothing can hide in the mirky midtones this way. It demonstrates perfectly that CA correction restores lost sharpness and contrast.

If you want I can make a similar example, from a real scene, with for instance red/blue-green CA (and then provide a corrected sample).

I made an example where the green channel is projected bigger due to CA. This results in magenta/green CA artifacts, plus loss of sharpness and contrast due to edges being smeared out over several pixels near the borders.

Now a version where the CA is corrected, by shrinking the green projected image to the size of the projected image from the red and blue channel:

That is the only thing done to the image, shrinking the green channel. No other action has been applied. No sharpening, no contrast tinkering, nothing.

And in the example provided by the OP, I say there's more gains to be had.

the lens is more or less working as expected.

That's where we disagree. You still see a silk purse...

We can leave it at that, no?

R2

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