alanr0

Yes. If you see a strong sunstar, the image of the source at the sensor is likely to be saturated. A smooth apodisation of the lens aperture will reduce the proportion of light diffracted through ...

Jack, I believe that should work. I have not gone back to your references to check all the scaling factors, but it looks about right and somewhat familiar.  If (as I expect) it lines up with the ...

<snip> This is because Goodman assumes a substantially planar wavefront at the aperture.  Any wavefront curvature associated with defocus is assumed to cause an image displacement which is small ...

Goodman says " In most cases it is the intensity across the focal plane that is of real interest ", and this equation is for the PSF in the focal plane . I assume that the pupil function describes ...

If you are calculating the absolute size of the Airy disk at the image plane, that is determined by the image-space numerical aperture , equal to the sine of the half-angle subtended by the exit pupil.

The idea is that we can swap object and image sizes and locations, and the rays follow pretty much the same (reversed) trajectories. Is your N the nominal F-number, or working f-number (my Nw ) ? I ...

<snip> As presented 4.3-11 describes the radiation field from an aperture illuminated by a plane wave. You will see a Fraunhofer diffraction pattern in the far field where the Fresnel blur sqrt ( λ z ...

Hi Jack. The Fresnel number used in figure 4.3-7 applies where a parallel beam of light is incident on an aperture. Fraunhofer diffraction broadens the far-field roughly as λ z / D Fresnel ...

<snip> DM, Looks like we have similar expressions, but different interpretations. You have: DOF ~ 2 ( c / m ) * N *(1 + m/p ) / m In terms of image-space working F-number, Nw , this becomes: DOF ~ 2 (

Hi DM,  I am not entirely clear how you are scaling the Circle of Confusion diameter as sensor size and image magnification vary. For macro photography, what matters is the image blur as a fraction ...

As Erik said, diffraction by a circular aperture broadens the angular spread of light by an amount proportional to the ratio of wavelength to aperture diameter. More specifically, the angular ...

Don't you mean kibibyte ? :-D

Sure. I have attempted to highlight the approximations and assumptions in this approach, and suggested some resources for Jack to follow up. The Shannon Hartley theorem is widely used to estimate ...

Jack, I don't claim to be an expert, but this Wikipedia page offers a useful overview, https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem. In particular, the historical development secti ...

That is essentially what I did to get the factor 1/3. If you treat the square root of the electron count as the signal, noise variance is approximately constant with mean square value 1/4.  That ...

Let's take a closer look at the information rate ( not the data rate), using the pointers provided by bobn2 and Jack .  Assume The Shannon Hartley theorem tells us that for an analogue channel ...

At the risk of derailing - or is it re-railing the discourse ... We don't seem to have a good definition of microcontrast, but there is an IEEE standard for texture blur. Is this the same thing? CPIQ ...

<snip> That is rather the point. The second moment is the " Unique blur measure ". But where? Is there a truncation radius which "does not make a visible difference" for a useful range of ...

Line spread function is the intensity profile measured normal to an extended line source. Step response (also referred to as Edge Spread Function) is the convolution of the line spread function ...

<snip> Let's look at intensities in the neighbourhood of point, line and step sources, against an ideal black background. Fig. 5. Point and line spread functions plus step response for ...