Extracting pop from RAWs - and a quick rough and ready attempt

[George]

@Joanna

What I have presented here and in my apps is, in essence, a redefinition of depth of field. By this definition, the region of acceptable sharpness is determined by the combined effects of defocus and diffraction. This is not only more realistic, but also much easier to use. What’s not to like?

This is exactly the problem. Sharpness is not based on the sensor side, it’s based on the print side. Dof is based on that range that meets that definition. See @Wlodek , post 41 or any other. I miss the selection of the sensor in your app. The sensor size determines how many times that sensor has to be multiplied to get a print of A4. That sensor size has a certain CoC. They belong together.

If you want to know when diffraction is becoming visible use a diffraction calculator.
I did show you it before. https://www.photopills.com/calculators/diffraction. It depends solely on the sensel size and the f-nr.

I mentioned you as Joanna Meyers for we have been through this and I didn’t get an adequate answer. This is basic. And once one knows the basic, one can play with it.

George

[Joanna (Joanna Carter)]

@George

The sensor size determines how many times that sensor has to be multiplied to get a print of A4

And if one wants a print size of A0, that is to be viewed from close up?

@George

If you want to know when diffraction is becoming visible use a diffraction calculator.

So, why bother with two calculators when one does the job of both at the same time?

Just answer me one simple question - have you ever worked with large format cameras or printed to large sizes?

[mikemyers]

@Joanna

Since Joanna Meyers doesn’t exist in this forum and Mike’s name is Myers, I couldn’t dare to guess

Hey, from my little corner of the world, I understand the above about as much/little as I understand nuclear fusion/fission. I have no idea what you’re all talking about, and no idea of how it would benefit my photography. So, other than this, I’m out of here, again.

[George]

Joanna Meyers ,

@Joanna

And if one wants a print size of A0, that is to be viewed from close up?

I showed you how to calculate the desired CoC in post 49.

@Joanna

So, why bother with two calculators when one does the job of both at the same time?

I just don’t know what he is doing with it.

@Joanna

Just answer me one simple question - have you ever worked with large format cameras or printed to large sizes?

Last year I had an image from my D750 printed in A0, 118x84cm. Ok for me. I only don’t know what to do with it I was just curious.
Camera size is irrelevant for this dof discussion.

George

[mwsilvers (Mark - New Jersey, USA)]

@mikemyers

Hey, from my little corner of the world, I understand the above about as much/little as I understand nuclear fusion/fission. I have no idea what you’re all talking about, and no idea of how it would benefit my photography. So, other than this, I’m out of here, again.

Of course, you could always make a greater effort to understand this discussion and then see if it would benefit your photography. Maybe you’ll learn something.

Mark

[mikemyers]

@mwsilvers

Of course, you could always make a greater effort to understand this discussion and then see if it would benefit your photography. Maybe you’ll learn something.

When/if I ever get a “tilt” lens or a view camera, I will need to do so. Considering how long it took me just to learn the real story about “shift” lenses, and with no way to experiment, of what use would it be considering the photo gear I now have and use.

As I see it, there dozens, if not hundreds, of things about PhotoLab that are much more important for me to learn. I wonder what all of that has to do with the title of this discussion - which I am already trying to do. And I’m not sure why the title selected only RAW images, which I’ve been trying to do for years, and usually getting results I was satisfied with.

[Joanna (Joanna Carter)]

@George

I showed you how to calculate the desired CoC in post 49.

Why should I bother when TrueDoF-Pro gives me perfect results,

@George

I just don’t know what he is doing with it.

He is a physicist - he knows more than me - I learnt from him and benefitted by using that knowledge.

@George

Last year I had an image from my D750 printed in A0, 118x84cm. Ok for me. I only don’t know what to do with it

Hang it on the wall and enjoy it?

[George]

Sorry, I’m just disappointed about you at the moment. This is just a Mike Meyers answer.

George

[Joanna (Joanna Carter)]

@mikemyers

I wonder what all of that has to do with the title of this discussion

The title is about “pop” - something that can be enhanced by minimising diffraction.

[mikemyers]

@Joanna

The title is about “pop” - something that can be enhanced by minimising diffraction.

Agreed.
(…and why I rarely close my lens down to something smaller than f/10.)

[rsp]

In the film days, enlarging much more than A4 (A3 with 25 ASA films) didn’t allow to see much more details. So, looking at a photo was at an arm’s length, roughly the diagonal of the printing format, thus, the value of the CoC (defined by the average visual acuity with respect to distance from print). And it was enough because the grain of the film was generally bigger than the effect of diffraction in most cases (100 – 400 ASA).

Now we have high resolution sensors which allows for greater enlargements (either on print or zoom in on a display). But the physics remain the same:

• zooming on a display or looking at a part of a print is just like cropping, thus changing the “sensor” size. And thus changing the CoC in accordance to the crop factor.
• the diffraction spot is visible when it is roughly dual the pixel pitch / size.
• having a low-pass (anti-aliasing) filter or not may change the game. With an LPF/AAF things get more complex.

[mikemyers]

@rsp

Now we have high resolution sensors which allows for greater enlargements (either on print or zoom in on a display).

Hmm, use your imagination, and fast forward a year, or two, or ten. How many megapixels will we get? Is there a physical limit, beyond which more megapixels is no longer achievable? The current limit might be 100 million megapixels, but how long until a new camera or iPhone can approach that?

The world's most powerful camera is complete | BBC Science Focus Magazine

Twenty years ago, 12 megapixels on a $5,000 Nikon D2X were a lot.
Today’s cameras can reach and exceed 50 megapixels.
How soon will that be 500?
…or 5,000 ?
Or, 2024: https://www.kfconcept.com/blog/highest-megapixel-camera.html:
Fujifilm GFX 100 II

Then there are discussions about camera lens capabilities, and Leica needing to constantly create better lenses to match the increase in what can be captured by a “camera”.

I’m sure I’m not the only person here who feels that older lenses have a quality all their own, because they’re not trying to win a megapixel war, which might be part of the reason why old Leica lenses are skyrocketing in price.

I’ll get dumped on for saying this, but those 12 megapixel cameras, when used carefully, created excellent results, even by today’s standards.

OK, I will crawl back into my hole, and not get involved any more in this topic. I jumped in only because I saw my name in a post.

[George]

@rsp

zooming on a display or looking at a part of a print is just like cropping, thus changing the “sensor” size. And thus changing the CoC in accordance to the crop factor.

And here is where @Joanna is fooling herself. She thinks she can select a CoC/blur circle but that’s not. She is selecting a smaller sensor. The given dof belongs to that smaller sensor. Now what happens when she will print? The FF sensor has to be magnified 8.3 times. But that smaller sensor should be magnified 25 times. By using these settings in the calculator she will get a much larger dof. The dof shown in the calculator is just wrong.

George

[rsp]

You can’t always get what you want!
You will have to use focus stacking or tilt, as Joanna has written.
But we are far from the subject (adding pop…).

[Joanna (Joanna Carter)]

I do think you are missing something here.

CoC, blur spot, call it what you will, is directly related to how light rays are focused, or not, on the image plane.

Diffraction has nothing whatsoever to do with a lens. It is caused as light rays pass through an opening or aperture…

So, even with the most perfectly focused lens, when those light rays pass through an aperture that is too small, they are dispersed, as they touch the edge of the hole.

Defocus blur is caused by the lens not being at its correct distance from the image plane.

Separately, diffraction blur is caused by the diameter of the opening in the aperture blades.

One is acting on the “front to back” axis of the lens, the other is acting on the “side to side” axis of the diaphragm.

Up to a certain point, the aperture can be closed down to reduce defocus blur without causing diffraction blur, so the image gets progressively sharper over a greater DoF.

But, continuing to reduce the aperture size, beyond a certain point, may continue to increase the DoF but it then starts to incur the totally separate phenomenon of diffraction blur caused by the edge of aperture blades, which has the effect of reducing sharpness, even on a totally focused image.

In the top diagram, at f/10, there is no diffraction blur, just defocus blur, in front of and behind the DoF.

In the second diagram, at f/16, diffraction from the physical diaphragm opening, is starting to have an effect and, although the DoF continues to increase, now, diffraction blur takes over and decreases sharpness again.

[George]

Please don’t jump to another subject. We’re talking about the dof-calculator. Diffraction only limits the practical use of that calculator.
Look again at your screen where you can set the “blur circle”. That’s a regular list of sensor sizes and the there by belonging CoC. Used in every dof calculator. CoC, sensor size ,print size and viewing distance belong to each other. That’s simple geometry. You’re not able to select another CoC/blur circle for your FF sensor.
So, what are you doing?.
You’ve a FF sensor, the there by belonging CoC is 0,03. When printing a A4 that CoC will become 0.03*8.3=0.25mm. That’s the extreme what is experienced as sharp.
But now you select 0.01. That belongs to a sensor much smaller as your FF. To get the same print it must be enlarged 3x8.3=24.9 times. But you don’t do that, you’ve a FF sensor which has to be enlarged only 8.3 times. So your dot of 0.01 will be printed as 0.01x8.3=0.083mm. Much smaller as the 0.25mm under regular use of the dof calculator.

If we agree on the dof we can proceed with diffraction.

George

[Wlodek]

@Joanna has a wider angle of view

[Joanna (Joanna Carter)]

@George

Please don’t jump to another subject.

i am not. Diffraction is different to defocus blur and has to be factored into the calculation in order to get the sharpest image on the sensor, so that any print is as sharp as it can be.

@George

So, what are you doing?.

I’m using TrueDoF-Pro as it is intended to be used, not as a simple CoC-based calculator, but one that takes diffraction into account in the overall calculation.

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Hey! If you want to work in a different way, fine. But, as I’ve now said countless times, George Douvos’ calculator works perfectly and saves me the effort of having to do separate DoF and diffraction calculations.

I’ll bet you still haven’t read his papers

[George]

Please read my posts more carefully. And look at the diffraction calculator I linked to you.

@George

Diffraction only limits the practical use of that calculator.

George

[Wolfgang ([ Win10, PL+VP+FP, Nik7 / 3.3 ])]

I highly doubt the OP follows this discussion.

The OP tried Hi res mode and obviously has problems with it, while there is endless discussion about diffraction here.

Let the OP try out for himself what works – including when it comes to choosing the “right” aperture.

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In German we have a nice expression for it:
“You should leave your teeth to something to the rats.”