Diffraction Photography

• Diffraction Limit Calculator
• Diffraction In Photography
• Diffraction Photography Definition
• Diffraction Limited Spot Size

First 500 get a 2-month free trial to Skillshare: is a bizarre property of physics that ruins the sharpness of your pict. Diffraction is a term that describes light waves interfering with one another. Lens diffraction is an optical interference that occurs when light passes through a tiny opening, such as an aperture with a small value f-number. Lens diffraction occurs when both the wavelength of light and the opening itself are roughly the same sizes.

1. Photographer Steve Perry of Backcountry Gallery sent in this 14-minute video he recently made to teach photographers about the topic of lens diffraction. He explains both what diffraction is.
2. Diffraction in Photography Clearly, diffraction is an important concept in physics. In fact, a similar experiment (with two slits rather than one) played a major role in proving that light can behave as a wave – one of the most important discoveries in scientific history. But how does this impact your everyday photography?
3. In this episode Don Komarechka explains everything you need to know about lens diffraction, what causes it, and how diffraction impacts your photos. (Spoiler: it can make them less sharp.).

Diffraction Limited Pixels? Really?
In Support of Depth of Field
We read on the internet how our digital cameras can become 'diffraction limited' as we stop down, worded in terms of the diffraction becoming larger than our digitalsensor's pixel size. But it's not about the pixels, they don't change.

Diffraction refers to various phenomena which occur when a wave encounters an obstacle or a slit. It is defined as the bending of light around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle.

Diffraction: When Smaller Apertures No Longer Mean Sharper Pictures
Conventional wisdom is that one can achieve a sharper image by stopping down to a smaller aperture, but this misses the mark in two fundamental ways. First, the image will always be sharp at the point of focus.

~
The change in direction of light rays when they pass close to an opaqueedge.
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LENS~ & PHOTOGRAPHY
~ is an optical effect which limits the total resolution of your photography - no matter how many megapixels your camera may have. It happens because light begins to disperse or 'diffract' when passing through a small opening (such as your camera's aperture).

~ is accurately predicted by both ray and wave theory.
Theoretical maximum resolution is limited by f/number. A perfect lens can do this under perfect conditions. A lens this good is called '~ limited.' Few lenses reach this level at large apertures.

The effects of ~ are clearly visible at f32 and significantly degrade the image. Use f22 only if you have no choice. Optimal sharpness depends on the lens.

Techniques Glossary ~
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~, Optimum ApertureRange and ISOSetting
Photographers often stop down lens apertures to gain greater depth-of-field in images and/or increased image sharpness.

~ - A phenomenon exhibited by a light's wave front when passing the edge of an opaque object (one that does not allow light to pass through it). The light becomes modulated, causing a redistribution of the light's energy within the wave front.

~ is a basic aspect of the behavior of waves passing through small openings which limits the maximum sharpness of all lenses at smaller apertures.

~
Bounced light. Light 'refracts' off opaque materials softening and blurring an image.
Diffuser
Material that softens and 'diffuses' light in order to soften the edges in an image.

~ Limited Aperture (DLA) is the point where on a specific camera, the sharpness begins to decrease with an increase in f-stop number (smaller aperture size). ~ is the point where light is bent when it passes through the lens opening or aperture.

~
When light is obstructed by an object and the wave front is changed, interference occurs between components of the altered wave front. The pattern formed by interference is called the ~ pattern.

-~ - light rays scattered and change direction when they are passed through a small hole or close to an opaque surface.
-~ grating - optical attachment that separates light into its constituent colors.

5. ~ causes lenses to
A. lose sharpness at smaller apertures.
B. be sharpest at their smallest aperture.
C. have greater depth-of-field.
D. overcome chromatic aberrations.

5 ~
Because of the wave nature of light, whenever light from a point source passes through a circular opening, there is an interference pattern generated. When projected on a screen, it consists of a central bright spot, and alternating concentric light and dark rings.

~ kicks in around f5.6-f8 on a 24MP sensor. No wonder it does not look very different at f11. Why not just compare the images at f22. At some point, a iphone will look just as good.
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Aperture ~ (3)- This is a photograph of a US postage stamp. Notice the box on part of the wing which is enlarged below twice, with different results.

Figure 1 - ~ Limit vs f Number
As you can clearly see, the resolution limit decreases as the lens speed decreases. All drops in MTF from the ~ limit are the result of aberrations.

Material on ~ includes the Melles Griot catalog, and David Jacobson's lens tutorial. In the latter reference, defocus and ~ are combined using the MTF. The resulting on-film resolution values were calculated by Bob Atkins. Using the formulas in this article, for c=0.035, at f32, D= 2 * 0.

~ Spreading or bending of a wave upon passing around an obstacle or through a narrow opening. digital A method of representing information in an electrical circuit by switching the current ON or OFF. Only two output voltages are possible, usually represented by '0' and '1.

F22? What about ~? Unless your digital camera has a full frame or larger sensor sharpness should actually decline beyond about f/11. the depth of field will be maximized at f/22 for sure but what is in focus will not be as sharp as when shooting with a wider apature.
Reply
Go Inspire says: ...

5 ~
Because of the wave nature of light, whenever light from a point source passes through a circular opening, there is an interference pattern generated. When projected on a screen, it consists of a central bright spot, and alternating concentric light and dark rings.

~ kicks in around f5.6-f8 on a 24MP sensor. No wonder it does not look very different at f11. Why not just compare the images at f22. At some point, a iphone will look just as good.
Like
0 ...

Aperture ~ (3)- This is a photograph of a US postage stamp. Notice the box on part of the wing which is enlarged below twice, with different results.

Figure 1 - ~ Limit vs f Number
As you can clearly see, the resolution limit decreases as the lens speed decreases. All drops in MTF from the ~ limit are the result of aberrations.

Material on ~ includes the Melles Griot catalog, and David Jacobson's lens tutorial. In the latter reference, defocus and ~ are combined using the MTF. The resulting on-film resolution values were calculated by Bob Atkins. Using the formulas in this article, for c=0.035, at f32, D= 2 * 0.

~ Spreading or bending of a wave upon passing around an obstacle or through a narrow opening. digital A method of representing information in an electrical circuit by switching the current ON or OFF. Only two output voltages are possible, usually represented by '0' and '1.

F22? What about ~? Unless your digital camera has a full frame or larger sensor sharpness should actually decline beyond about f/11. the depth of field will be maximized at f/22 for sure but what is in focus will not be as sharp as when shooting with a wider apature.
Reply
Go Inspire says: ...

Due to the characteristics of a PF (Phase Fresnel) lens that utilizes the photo ~ phenomenon, when there is a strong light source within the frame or when light enters the lens from outside of the frame, ring-shaped colored flare may occur according to shooting conditions.

-~. the index of refraction for that substance; for example, light travels about 1 1/2 times as fast in air as it does in glass, so the index of refraction for glass is about 1.5. Refraction, or change of direction, always follows a simple rule.

When very small apertures are used, the image quality will degrade due to ~. In other cases, even a small aperture will not reduce the light enough to produce a proper exposure. This is a fairly easy problem to solve. A neutral density filter or a polarizer can be put on the lens.

One form of flare is specific to digital cameras - '~Artifact'. With the sun shining on an unprotected lens, a group of small rainbows appears. This artifact is formed by internal ~ on the image sensor, which acts like a ~ grating.

It sounds logical, but because of ~ that comes into play when the aperture is too small, this may affect the quality of the image, ...

Typically, a small aperture such as f/11, f/16, or f/22 is necessary to produce an attractiveburst; the smaller the aperture the better the effect, although you may want to avoid extreme apertures such as f/16 or f/22 because of ~ (this same optical effect that produces the starburst effect also reduces ...

~ will start to blur the details. But don't get too hung up on this, it's only noticeable at very small apertures. Use F8-F11 for optimal image sharpness. See the results of my ~ tests on the 105mm lens, and read about aperture and depth of field in underwater photography ...

Diffraction Limit Calculator

There are two main things that affect how a lens resolves details, defocus blur and ~ blur. Defocus blur occurs most at wide apertures while ~ blur occurs most at narrow apertures.

Shooting at f/22 degrades image quality due to lens ~ but provides a sun star due to the optics of the lens.
F/22 is only recommended for the sun star effect or to change the overall exposure, such as an increase in shutter speed as taught in the Exposure Triangle Photography Guide.

â†' These calculations assume a maximum tolerable circle of confusion of 0.03mm and ignore ~; they are made at the DOFMaster depth of field calculator.
â†' Skinner, pp. 45-6. The 150mm Schneider lens on the example Skinner presents has a maximum aperture of f4.

Set your cameras aperture to f/16; going any higher than this can cause problems of lens ~ and f/16 is more than enough for front to back sharpness with a wide angle lens typically used for landscapes. Focus manually about a third into the shot.
Fire off first Exposure
Step 6 ...

Small apertures bring more light ~, degrading the image resolution and they reduce the light transmission, forcing the use of longer exposures, which leads to motion blur in the pictures. Also, even using the smallest aperture is sometimes not enough to capture the entire scene sharply.

Smaller Apertures like f/11, f/16, f/22 (remember that smallest apertures tend to introduce ~ and soft effect)
Shutter Speed based on the Aperture setting and the available light
Low ISO like 100, 200
Use Tripod ...

You'll also have to select a low ISO to compensate for the longer exposure. You could also select a small aperture. Though, ~ could be a problem in these situations.
And finally, you might need a solid ND filter to top it off.
Take Some Macro Shots ...

Are there any recommended lens apertures? Best at f/2.0 or does it improve at f/2.8 and f/4.0? Do you see general softness due to ~ already at f/4.0?
How does the image stabilization work? IBIS only for still photos, and EIS for video I suppose?

High Image Quality-Even in Low Light ConditionsThe 12.1-megapixel High Sensitivity MOS Sensor in combination with the Venus Engine excels in ~ compensation, yielding images that are crisp and free from artifacts associated with small aperture settings.

Critical Aperture is the f-stop setting where a lens provides the optimal image quality; critical aperture finds the best balance between ~ from small apertures and lens aberration from large apertures.
C
Cropping ...

The point of Hyperfocal Disntance is to be able to capture an image with a depth of field just deep enough to make sure everything is in focus, while using an aperture that isn't so small as to introduce unwanted artifacts like ~. It was commonly used in landscape photography in the film days.

A few months ago we wrote an extensive article on sensor crop factors and equivalence. In that post we covered several topics: the history of the cropped-sensor formats, brightness of the scene, perspective, depth of field, noise and ~.

Because of their wide viewing angle and large apparent depth of field, wide angle lenses generally produce photos which are sharp throughout. However, this can be slightly reduced when shooting at very wide apertures, as with any lens. At very narrow apertures, light ~ can also cause edges to appear slightly ...

Because the pinhole is so small, exposures made with this type of camera tend to be longer than on a regular camera and the depth of field of the image tends to be nearly infinite, although the edges tend to be soft due to ~.

Focus stacking allows us to blend together a set of images that all have slightly different focus points, enabling us to cover a much larger range of depth of field than a single shot. Moreover, it enables us to shoot each individual image at a more optimal aperture, ie: f8, so that ~ never becomes an issue.

Large format sensor seem to have more depth of field because depth of field is judged off the print, not the sensor. Bigger sensors don't have to be magnified as much resulting in smaller circles of confusion on the print. Very small sensor cameras operate at ~, thus everything is in focus, ...

The small water droplets like to adhere on to the filter and lens, especially when the lens is pointed upwards towards the sky. A lens hood provides some protection, but often not enough. In picture no. 8 below this additional 'coating' created a nice ~ effect mostly visible on the lower half of the picture.

When starting out in photography, we're taught to narrow down our aperture for greater depth of field. Then again, we're also told not to narrow it down too much. This is because the images will come out softer due to a phenomenon called diffraction. So what actually is diffraction and why does it negatively impact our images? In today's video we have photographer Don Komarechka who explains everything you need to know about diffraction:

Diffraction In Photography

Light undergoes diffraction due to its wave nature. When waves pass through narrow openings, they tend to bend and deviate from their original path. Komarechka demonstrates this beautifully in the video with the help of water waves. And interestingly, the narrower the opening is, the effect of diffraction gets more prominent. This is exactly why it's not recommended that you narrow down your aperture too much.

Due to diffraction, the light bends away from its actual path and does not reach the photosite on the sensor where it's supposed to go. The image thus seems to be out of focus and appears soft.

'Light that should be hitting one particular pixel will be hitting multiple pixels at the same time and that just blurs the results.'

Although a more narrow aperture might give you a greater depth of field, you will have to compromise a lot when it comes to image quality. And another important thing to keep in mind is that cameras with higher megapixel count are more susceptible to issues from diffraction.

Be sure to keep this information in mind before stopping down on your aperture settings. Hopefully, this understanding of diffraction will help you take better photos.

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