# Tag Info

51

You've run over the diffraction limit. Light rays passing through a small hole will diverge and interfere with each other and a pattern emerges--a sort of banding where different frequencies/placement can cause separate rays to add up or negate each other. The smaller the opening gets, the larger this divergence/interference becomes. This pattern is called ...

48

As mentioned in the other answers, diffraction has led to unsharpness. To put this to the test, one can attempt to sharpen the image using deconvolution by using the point spread function that corresponds to F/29. For diffraction, we have (up to an overall normalization) P(s) = {J1[ πrs/(λF) ] / [ πrs/(λF) ] }2 where J1 is the Bessel function of the ...

38

The small degree of defocus in the background is due to the focal length used being very short (18mm). The amount of background blur depends on the size of the entrance pupil, not the f-number. The entrance pupil size is the focal length divided by f number, so in this case it would be about 5mm. This is quite small. A 100mm lens at f/3.5 would have an ...

38

It's worth noting that sensor size plays a huge role in depth of field and behavior of the lens. A smartphone has a tiny camera sensor, often around 25 square mm. This gives the camera a crop factor of about 6. (For the Samsung S9, I'm not sure about the dimensions.) You can calculate the hyperfocal distance (or "depth of field") but you can also get a ...

37

What you are looking for is large depth of field. This is an optical property, not something applied as a special effect, so it's not something you can turn on or off. The raw image captures the light focused by the lens, and inevitably there will be parts of the scene which are either too far or too close — out of the range where the rays are tightly ...

33

If we start by just numbering them 1 - 6 for easy reference... Personally, I'd discount 5 altogether as it has none of the aspects we're looking for. 2 is a bit naïve & perhaps achieves a lot of its usable aspects almost by accident, however, because it does achieve some of them, let's keep it in consideration. 1 through 3 all have some element in the ...

31

Depth of field depends not only on aperture but also on distance to the subject. Depth of field increases as the subject gets farther away. If the wave and boats were all relatively far from the camera, but not terribly far from each other, then it's not surprising that they were all reasonably sharp. You can use DOFMaster to run the numbers yourself. Some ...

29

The easiest way to solve this problem is to use a neutral-density filter. They are essentially neutral grey filters that cut down on the light reaching the film or digital sensor. Good ones are fairly expensive, because they are surprisingly hard to manufacture. Another option is to shoot in more favourable conditions, like overcast days or really early ...

25

No - the aperture is set by the physical blades in the lens when you take the photo; a RAW "image" contains the readings from the sensor when the photo was taken, so there's no way you can go back and modify the light which was captured by the sensor. While it's not as obvious, this is equivalent to asking "Can I modify what the camera was pointing at from a ...

24

shutter speed 0.5 seconds This is likely to be a bit of your problem. The shutter causes vibration of the camera. So, too, does your hand pushing the release button. At faster speeds, this vibration does not affect the shot. Likewise, at very slow speeds (a few seconds +). But there’s a sweet spot somewhere between a second or two and ~1/30 where that ...

23

The camera usually keeps the aperture open as wide as possible while framing the shot. It is only closed to the setting you dialed in when the picture is being taken. This allows for a brighter viewfinder and more of the auto focus points to be used. As described in the manual of your camera on page 114, there's a dedicated button to stop down the aperture ...

22

There's only one distance that is in sharpest focus. Everything in front of or behind that distance is blurry. The further we move away from the focus distance, the blurrier things get. The questions become: "How blurry is it? Is that within our acceptable limit? How far from the focus distance do things become unacceptably blurry?" What we call depth of ...

20

Here's a really good case for the application of Okham's Razor. The simplest explanation is that the image was shot outdoors, under the midday sun. The blur was not added in post but is the result of the close shooting distance and relatively wide aperture of f/4. The fast shutter speed was required otherwise the shot would have been overexposed due to the ...

20

The effect is called field curvature. A good discussion comes from Nikon. It is a lens aberration that can reduce the resolution of the lens when coupled with a flat sensor. In the old days, the film could be bent a little to try to follow the image plane and reduce the effect, but our sensors today are rigid. It can be reduced with lens design.

20

If by "landscape" you mean something like this: then the answer is simple: at very large distances, depth of field is extremely large even at large apertures. That is, at any aperture if you focus at infinity, objects 20m, 200m, and 2000m from you will be sharp. However, focal length of the lens also influences depth of field, see answers below. Smaller ...

18

Depth of field depends on two factors, magnification and f-number. Focal length, subject distance, size and circle of confusion (the radius at which blur becomes visible) jointly determine the magnification. Depth of field does not depend on lens or camera design other than the variables in the formula so there are indeed general formulas to calculate ...

18

All lenses can really only focus at one distance from the camera. Everything in front of or behind that point is increasingly blurry. In practice, there is a range of distances where the blur is imperceptible, or close enough. We call this the depth of field. It sounds like you are looking for a very large depth of field. Your older camera had a very high ...

18

Hitting the DOF preview with a stopped down aperture should make it obvious: what you see can be very dim, dim enough it can be very difficult to compose and focus. That's why cameras have the lens wide open until actually taking a picture, so you can get the brightest image by which to setup your shot.

17

You wanted the math, so here it goes: You need to know the CoC of your camera, Canon APS-C sized sensors this number is 0.018, for Nikon APS-C 0.019, for full frame sensors and 35mm film the number is 0.029. The formula is for completeness: CoC (mm) = viewing distance (cm) / desired final-image resolution (lp/mm) for a 25 cm viewing distance / enlargement ...

16

Short answer: The digital photography revolution has pretty much eliminated any idea of a standard display size and viewing distance. Depth of Field calculations are always based on several variables including the display size and viewing distance. First, a word about what depth-of-field is and is not: In a way, depth-of-field is an illusion. There is ...

15

Background blur, as an intrinsic element of a lens, is related to the physical diameter of the aperture as observed through the front of the lens. This is often called the "physical aperture", however it is more appropriately termed the entrance pupil. The size of the entrance pupil is really what determines how blurry OOF content will be, as it is the ...

15

The D5300 and D5500 bodies do not have the depth of field preview button. Whether it matters is a personal preference. I never use the DOF preview on my camera (ok, maybe occasionally when shooting macro). With digital you can just shoot and review on the LCD. There are some limitations around how accurate DOF preview is with wider apertures. See these ...

15

Because of diffraction. f/29 is way too much for you to expect a sharp image. Try shooting the same thing at f/8 and you'll see the difference.

15

The aperture ring is engraved with f-numbers duplicated; the duplicates are color coded the same. The lines you are asking about are also paired, same color. The idea is to graphically display the zone of depth-of-field. As an example, you focus on an object at 10 meters (32 feet) as indicated by the thick center white line. Setting the aperture at f/8 (...

14

Focus stacking allows you to create an image with a greater apparent depth of focus (i.e. more of the subject in focus) than would otherwise be possible. This is used in fields like macro photography where you are often working at the limits of the capabilities of the lens.

14

I gather from the aspect ratios (top one is 3:2, bottom one is 4:3), that the top image is the dSLR one, and the bottom image is the one from your TZ40. And at web sizes, while there's some improvement in image quality with the dSLR, it's not a huge amount better, and some could be compensated for with post-processing, rather than using straight-from-the-...

14

No photoshop necessary for that background. That's simply what happens when shooting a telephoto lens, f/2.8 or larger, and having the subject closer to the camera and much further from the background. I don't see anything inherently special about the tone. We'd expect cool tones from the shade and that's what we've got. The nice part, imo, is the contrast ...

13

There is a point where lenses transition from being aberration limited to being diffraction limited. This means that peak sharpness will increase up to a point as you stop down but will then start to decrease again. If you don't care about depth of field then use of an ND filter is preferable to stopping down past this point. Of course ND filters aren't ...

13

Many older or cheaper phone cameras use a "fixed focus" lens. ie it is always set to focus a specific distance away from the camera. This is usually set to the "hyperfocal distance", ie everything from half that distance out to infinity is in focus. This depends on just what is acceptable as 'in focus'. But most photos from these cameras will be sharp ...

13

Yes, it's possible With the focus stack you could estimate a depth map of the scene. Then this map is used to selectively blur the image to emulate the effect of shallower depth of field. See for example: https://graphics.stanford.edu/papers/focalstack/ You could of course use other methods to generate the depth map, such as moving the camera (as the ...

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