# Tag Info

## Hot answers tagged sharpness

51

There have been some very good answers, however there are a couple details that have not been mentioned. First, diffraction always happens, at every aperture, as light bends around the edges of the diaphragm and creates an "Airy Disk". The size of the airy disk, and the proportion of the disk that comprises the outer rings, and the amplitude of each wave in ...

50

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 ...

40

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

Technique is typically at fault with "fuzzy" images 99% of the time with someone new to dSLRs with only an 18-55 kit lens. The lens is not the problem. 18-55s are limited, and they are cheap, and there are much nicer lenses around, but how you use one is more likely to be the fault than what glass is in the lens. People will often blame the lens because ...

31

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 ...

29

There are several factors to getting a sharp image, the lens is only one of them. Lighting If you have a well-lit shot it will be much easier to get the crispness you want because you can get higher contrast lines. Shutter speed This is actually pretty closely related to a well lit shot, but you want to make sure your shutter speed is fast enough to ...

26

Stopping down is suggested because many lenses are considerably less sharp when wide open. This does not change on a crop-camera, since it is a property of the lens. There is however for most lenses a difference between center sharpness and corner sharpness. Most of the time, the center sharpness is substantially better than the corner sharpness. The ...

25

First of all, sharpening isn't (at least primarily) to compensate for pictures that weren't sharp -- it's primarily to reverse (or least ameliorate) the effects of interpolation that's inherent in converting the data from a typical Bayer-pattern sensor into a recognizable image. There's also (at least typically) interpolation done when you resize an image. ...

24

Clarification: Firstly, you are correct in stating that sharpness is subjective, but the ability of a camera system to resolve small details can be measured, and this measurement is strongly related to the perceived sharpness. As you image black and white lines that get closer together they will eventually merge into a grey blob. By measuring how close ...

22

General Rule The general rule of thumb for 35mm (full frame) has been the reciprocal of the focal length. This means that for a 50mm lens, the minimum shutter speed when hand-holding is 1/50 sec. 1/(focal length) = 1/50 Since this is usually not an option, 1/60 sec is the next option. Since the move to digital and multiple sensor sizes, the generally ...

22

The sweet spot of a lens is probably just as dependent upon the type of image capturing surface used as the lens itself. Both film and digital sensors have a limit of detail they can resolve (although large-format film has the tendency to capture FAR more detail than 35mm or digital sensors at much tighter apertures, around f/22.) Assuming you have a lens ...

22

Looking at your samples, the answer seems clear to me: that's not grainy, that is, actually, out of focus. Here's a 1:1 crop of your wide-open image: It seems pretty apparent that the wooden sign is sharp but the dog isn't, and the appearance of the blur looks completely in line with what one would expect from out-of-focus blur, not noise or grain. ...

21

To an extent, yes. There are several ways in which the camera body can affect sharpness and image quality in general: Autofocus If your camera's autofocus is inaccurate, your subject might just be slightly out of focus, causing a loss of focus. The 550d has a cross-type center AF point which can focus more accurately with lenses faster than f/2.8; as far ...

20

While you can get some freezing with speeds around 1/300 (see the first photo below), I would recommend going with faster shutter speeds if you want to take shots of water drops falling or moving away from wet dogs. One thing to keep in mind is that most flashes have a limit on their sync speed, which means that the use of flash will limit your fastest ...

20

Smoothness often comes from a large lightsource (i.e. a softbox or umbrella) The first link you posted isn't what I'd call crisp fashion photography so I'm not entirely sure what you're after. Crispness comes from the lens, and from post processing. The balance switches as you reduce the image size. Don't be swayed by sharp looking but tiny images! For ...

20

Without a doubt the fact that you're using a prime lens (fixed focal length) on the nikon is causing the difference in sharpness, especially if you're comparing it to the Canon 18-135 kit lens or Sigma 17-70 DC. Not that those are horrible lenses but the gulf in sharpness between them and the NIKKOR 35mm f2 fixed would be very wide. I'm assuming you're ...

19

f/8.0 is often the "sweet spot" for lenses on 35mm SLRs however on a small sensor camera like a Canon PowerShot that aperture is probably causing diffraction - there's a good reason the aperture doesn't go any smaller than that! Light spreads out when passing through a small opening like the aperture on a camera and this results in loss of sharpness. The ...

18

Think of a scene as comprised of many small discrete points of light. A lens is supposed to convert each point to another point at an appropriate place on the image. Diffraction causes every point to spread in a circular wave-like pattern, the Airy disk. The diameter of the disk is directly proportional to the f-number: that's the "diffraction limit." As ...

18

You've hit the diffraction limit. That link has some amazing answers with a lot of detail, so I won't be redundant, but in short, once the aperture gets to be below certain physical size, diffraction causes inevitable blur. For your camera (and any other camera with an APS-C-sized sensor), the limit is a little beyond f/11. The amount of light let in doesn'...

17

Sometimes a polarizer helps cut through haze. Otherwise, you can tweak the contrast/brightness in the camera if you want the jpegs to be better, or do it in the RAW program you use. 3rd option is the embrace the smog and make it part of your composition to tell the story. You could make a series to bring attention to problems with pollution and sell them as ...

17

Given that you have explicitly disqualified fungus and dust inside the lens, then the answer is no. A lens will not "naturally" lose sharpness with age. Glass is glass. It is a fixed medium, and assuming a 100 year old lens is in good condition without any extraneous wear and tear like fungus, dust, or a strong enough jolt to misalign one of the internal ...

16

The sharpness differences are probably due to the lenses, not the cameras. In general, you will find that prime lenses are sharper than zoom lenses, and lenses with short zoom ranges are sharper than lenses with long zoom ranges. So I'm not surprised that the borrowed 7.5x zoom lens is not as sharp as your 4x zoom lens, which in turn is not as sharp as the ...

15

You can determine the minimum shutter speed to avoid camera shake by 1) applying the following approximate rules of thumb. (See Wikipedia article - rule of thumb) 2) or carrying out careful measurements, as I did. 1) The rules of thumb a) With NO image stabilisation The approximate rules of thumb are: Full frame cameras : min shutter speed = 1/...

15

Yes, you can tell what went wrong: out of focus (entire frame) This can be a problem because of close-focus, i.e., the lens and camera never did find something to lock onto before you fired and was focusing ahead of everything in the scene. Sometimes this is because your lens focuses too slow, sometimes it's because there wasn't enough light to provide ...

15

The short answer is that all else being equal FX will give sharper images, at least in the centre of the frame (possibly not in the extreme corners with wide lenses). The long answer is here. The typical argument that gets rolled out against full frame is that lens sharpness falls off toward the corners, so using the same lens on a crop body avoids the ...

15

This looks like the effect of noise reduction at high ISOs. Heavy NR is common in compact cameras with small sensors. Fujifilm does it better than most, but there's only so much blood you can get from a stone. On most modern high-megapixel point and shoot cameras, you'll see this even at low-ISOs if you pixel peep. It's important to note that in most cases, ...

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