Hot answers tagged aperture
49
It's an extra two-thirds of an f-stop, with all that comes with it:
Narrower depth of field (perhaps marginal in comparison to the f/1,8)
Brighter viewfinder; great in low-light situations
Might be the difference between getting the shot or not, also in low-light situations
Lenses tend to get sharper when stopped down. At f/1,8 the f/1,4 lens is stopped ...
45
TL;DR answer
In general, Canon DSLRs require a maximum aperture of at least f/5.6 to autofocus. Depending on the camera model, and with some exceptions, a maximum aperture of at least f/2.8 or f/4 enables cross-type and/or high-precision focusing. EOS-1 series cameras and the EOS 5D Mark III (with the latest firmware) can autofocus at f/8, but only with ...
37
An f-stop is kind of a combination of two terms. First off, f/x.y is generally the notation used to indicate the size of the diaphragm opening, or aperture, in a camera. Let me give a little detail about how that notation came about, before I go on to explain the meaning of a stop.
Aperture Values and f/Stops
Aperture openings are measured as fractions of ...
36
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 ...
25
Noise is better than blur (and much less of a problem than you might think from reading the internet), so don't hesitate to vigorously boost ISO.
Underexposing won't help; it's basically the same as increasing ISO w.r.t. noise. The only time to do this is when you've already maxed out the ISO adjustment.
Consider a "fast fifty" - you can get a 50mm f/1.4 ...
25
The aperture range on your lens only shows the maximum aperture for your lens at the extremes of the zoom range; i.e. f/3.5 at 18mm and f/5.6 at 55mm. There is nothing to stop you using a narrower aperture; remember a larger number is a smaller hole (the f number is the diameter of the hole as a fraction of the focal length).
24
Why the wide aperture blurs the background more
Let me start with Wikipedia figure:
Above we have a wide open aperture. Only point 2 is in focus. Points 1 and 3 are out of focus. Due to wide aperture, the rays coming from them through different parts of the lens intersect the screen 5 (a film or a digital sensor) in different points. We may also tell ...
22
First of all, it was an issue on film. If Bryan Peterson wasn't aware of it at the time, it just shows what he didn't know, not that it actually wasn't a problem.
There were differences though. First of all, we didn't have EXIF data, and most people didn't keep careful enough notes to really know why shot X came out quite a bit sharper than shot Y. Even for ...
21
This is normally referred to as something like "dual control dials", and you're right, it's a very desirable feature. Very few entry-level cameras have this, but it's common on mid-tier "prosumer" DSLRs, and universal on higher-end models.
You can find a list of models with this feature on a camera review / database site like Neocamera; try this search:
...
20
Yes, there are several reasons for this.
Larger apertures allow for a smaller depth of field, and generally better bokeh.
Faster/more accurate auto focus, because more light is available to the focus system.
Much more versatility, because more light falls on the sensor at a wide aperture, which opens up your options in lower-light settings.
Better image ...
19
The aperture affects not only the amount of time required to take a photo, but also the depth of field within it.
With a wide aperture (so a low number, like f/1.8) gives a shallow depth of field - sometimes less than a millimetre with a macro lens. Because a lot of light is reaching the sensor (be it film or digital), this allows for fast shutter speeds
...
19
I was recently trying to figure this out myself, and found this question. I didn't feel the accepted answer was quite complete, so here's my shot (no pun intended!):
The first thing to understand is that the light that reflects off any one point on a surface isn't one beam of light, but many, coming in at many different angles and reflected off at many ...
18
f1.4 will always be 2/3rds stops faster than f1.8.
The diameter has nothing to do with whether or not part of the sensor is hidden. That is a separate measurement referred to as vignetting, and not the image circle's light level. The image circle's light level/brightness is directly affected by the aperture of the lens design.
FF lens simply means the ...
18
There is NO difference at ALL because the physical aperture has not changed.
The Fuji Finepix S4000 simulates a small aperture using an ND filter. When you stop-down the ND filter slides into the optical path. The Aperture written in the EXIF data is adjusted to reflect the transmittance of the ND filter, but note that since the size of the opening has not ...
17
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 ...
17
Shutter priority (Tv) gets used for a couple good reasons
You want to control the shutter speed (obviously) and don't care about the aperture. You'd use this to have creative control over the shutter speed which mostly involves motion blur. Some techniques that use this are 'dragging the shutter' with flash to create motion streaks and a final 'flash' to ...
17
There are probably more formal answers, but for me it boils down to what kind of shot I am looking for.
If I want to register something in time (either frozen or moving) then shutter speed is more important than aperture.
If I want to register something in space (meaning a deeper or shallower area in focus) then aperture is more important than shutter ...
17
Lenses with the aperture ring were originally designed for older SLR's which did not control aperture via the camera body.
Newer SLRs and DSLR control aperture via the body, so these older lenses must be stopped all the way down in order to be used. Your lens is working as it should, and is not defective.
To select aperture using your camera, ensure the ...
17
Although the relative aperture numbers — the ƒ stops — are the same regardless of format, the actual focal lengths of the lenses on small cameras are quite low: 5mm or 6mm at the wide end. That in turn means that the real aperture is small, which is why the diffraction limit kicks in sooner.
The smaller format also means that depth of field is hugely ...
17
The wider a maximum aperture, the more prevalent optical aberrations will tend to be (given a "simple" lens.) Wide aperture lenses become increasingly difficult to manufacture at reasonable cost, as you have to put more effort into correcting those optical aberrations. Additional lens elements are necessary to mitigate chromatic aberration (which can become ...
17
If I understand your question correctly, stopping the aperture down to its narrowest ensures that light is focused as tightly as possible. If you take a photograph at a wider aperture, excess non-incident light will still make it to the sensor, and mitigate the effects of sensor dust.
To put that in more precise technical terms...with a narrow aperture, the ...
17
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 ...
16
Lenses don't shine light directly through, they focus it, if you forgive the lousy ray-tracing:
The green lines represent the cone of light striking the lens with a narrow aperture, the red is the cone of light allowed by a wide aperture. In this case you can imagine the aperture immediately in front or immediately behind the lens (there's not much ...
16
Those kind of apertures often show up in macro work because the DoF is razor thin, so every fraction of a mm you can get matters. However, you also can be diffraction limited at such a aperture and actually end up with less sharpness. Cambridge in Colour has a good article on this very topic.
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It's now more common to control aperture through the camera.
The mechanical aperture ring adds cost, mechanical complexity which can lead to equipment breaking, and it can be confusing to users (if it's set to something other than the smallest aperture many cameras will give a confusing error on a lot of modes).
It also prevents Nikon from putting a seal ...
16
When they talk about increased sharpness, they're talking about the blades' edges, not their plan shape. The actual edge of the blade is shaped to be somewhat like a dullish single-bevel knife blade:
That does two things: it means that there is only one edge in play (rather than two, as would be the case with an iris blade that is stamped or otherwise cut ...
15
Here's the Thom Hogan review: http://bythom.com/Nikkor50AF-Slensreview.htm
His take is: yes, the f/1.4 is somewhat better, but not by a whole lot, so save your money unless you really do need the extra 2/3 stop. Consider boosting the ISO by a stop instead (and you should be ignoring the pixel-peepers and their 100% crop noise tests anyway).
Also note that ...
15
Aperture simply means "opening", and in photography we use the term to
refer to the diameter of the opening in a special adjustable diaphragm
within each lens. When this diaphragm is constricted, there's less physical
space for light to get in, so naturally the exposure is darker, and a
more-open aperture allows more light and results in a lighter exposure.
...
15
I have about 10 years experience shooting pro-rodeo from inside the arena. The standard lens is a 70-200 f2.8 with high-speed focusing, either a Canon 70-200L f2.8 USM or the Nikon equivalent will be on 90% of the bodies. Rodeo action is extremely random and can change the distance to the camera very fast so having a fast focusing lens is essential.
I ...
15
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 ...
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