Hot answers tagged zoom
38
No, it does not have much use.
Digital zoom is a restricted form of cropping:
It is always done around the center.
It is constrained to certain fixed increments.
It is limited in quality by the firmware of the camera.
On the other hand, cropping can:
Be of arbitrary size.
Be taken from any part of the image.
Be processed using a variety of ...
29
The "times zoom" notation is simply the big number divided by the small one, so the examples you give are correct. "3x zoom" simply means the longest focal length is three times the shortest.
This number really isn't very useful, though. On point and shoot cameras, it became popular because the starting focal length was generally about the same across all ...
23
The biggest reason for difference in the two lenses is aperture. The 80-200mm is a constant f/2.8 throughout the focal range and the 18-200mm varies from f/3.5 to f/5.6, so substantially slower, especially at the far end. All this really means is that the 80-200 can let in more light at the same focal length over the other.
Also, generally, zooms with ...
22
These letters refers to zooming depth as follows,
W = Wide angle
T = Telephoto
Read more about wideangle and telephoto in the tags.
21
A range of focal lengths indicates a zoom lens. There are two major classes of lenses. Primes, or primary lenses, have a single focal length. They tend to be higher quality, as there can be fewer lens elements, and fewer moving element groups. One exception to this rule is super telephoto prime lenses, particularly faster lenses (f/2.8), which are some of ...
20
There is no simple relationship between the physical length of the lens
and its focal length. For example, a retrofocus wide angle is generally
longer than its focal length, while a telephoto lens is shorter than
its focal length. Inside a zoom, you have several lens groups that move
independently. The focal length of the zoom depends on the relative
...
18
At 50mm on your 18-55, the max aperture is f/5.6. On the 50mm f/1.8, the max aperture is - obviously - f/1.8. It is perhaps not immediately obvious, but f/1.8 lets in 10-12 times more light than f/5.6. That is the difference between shooting at 1/10 second shutter speed (which is absolutely a no-go for moving subjects) and shooting at 1/100 (which is a ...
16
Focal length is a measure how the lens focusses the light into a point. When light enters a 50mm prime lens, the light converges into a point the camera sensor after 50mm.
In addition the focal length determines the magnification of the object you photograph. A long lens (e.g. 300mm) magnifies the images a lot (useful for birding) while a short (wide angle) ...
16
As you've pointed out, the question is meaningless in absolute terms. People whose exposure to photography starts and ends with point-and-shoot cameras don't really know what the term means.
They'll be thinking in terms of compact cameras, and the "zoom" on those goes from a moderate wide angle (about the 20mm mark on your lens, which is about 32mm ...
16
Since your question is "What am I supposed to tell them?", I'm going to go a little bit off the literal math with my answer. What you should say is:
The more "times-zoom" a lens has, the more compromise on image quality it has to have. Since my camera allows me to change lenses, I can have the flexibility of a huge zoom range without compromising on the ...
16
Same photo will result from using digital zoom or cropping.
Advantage of digital zoom: you don't need a computer to crop it. You can upload straight to Facebook, print it out, etc. Cropping is a very common post-processing technique and this lets you do it easily, on the fly.
Advantages of cropping after the fact: you can take more time to compose the crop ...
16
I think an important advantage is saving time. When you happen to shoot hundreds of photos in a row stuck with a lens wider than would be optimal, cropping each one of the images into a smaller size in post processing would be quite tedious - usually you can't do that in batch unless you really don't care about resulting framing. Framing on spot, on the ...
15
I'll tackle this from the assumption you're looking for the best lens, money no object (as you indicate).
The best lens will be the Canon 500L f4 IS, 600L f4 IS or 800L f5.6 IS mounted on a gimbal mount on a very solid tripod rated in the 20+lbs area. Which of these is the one for you comes down to a couple things.
Focusing speed: The 800mm will have ...
14
The focal length of a lens determines its field of view on your camera. If it has a long focal length, it has a narrow field of view, making the things in front of you appear large in the photograph. If it has a short focal length, it has a large field of view--it's a "wide angle" lens that takes in a large area, making objects appear small.
A "zoom lens" ...
14
The W stands for Wide angle. The T stands for Telephoto.
This has been asked around the web, for example here:
Yahoo! Answers: What does W T button (zoom) stands for in zoom lens cameras?
Tech-Recipes: Why are Camera Zoom Buttons Labelled W and T?
13
As an owner and user of both the 450D and the EF 100-400mm, I can offer some help here. From a construction, durability, and handleability perspective, using the 100-400mm on the 450D will definitely not be a problem. Both the camera and the lens are durably built, and the lens mount can handle a considerable amount of rugged use and rough handling.
The ...
13
Nobody is saying that you must choose an 80-200 over an 18-200. An 80-200 (f/2.8) has some severe drawbacks compared to an 18-200, price, size and weight being among them besides the obviously limited zoom range. On the other hand, an 80-200 is far better behaved optically; it will tend to focus faster and more accurately (on a given camera body, and ...
13
Warning: this is yet another of my "book length" answers... :-)
Let's start by a quick review of how a zoom lens works. Consider the simplest possible lens design -- a single element. One big problem with a single element lens is that the focal length of the lens determines the distance the element has to be from the film plane/sensor to bring a scene into ...
12
Technically 'Telephoto' means that the focal length [the mm] is longer than the lens is. In my experience, people in the photography world usually don't talk about it under that definition.
Most of the time people say 'Telephoto' they just mean 'zoomed in' or in other words 'high mm' or 'long focal length' As has been mentioned, Nikon seems to say that 85mm ...
12
The short answer is because it is cheaper to manufacture such lenses. The longer the lens and the wider the aperture, the larger the optical elements in the lens - thus larger the expense to produce them.
A lens like 70-200/2.8 must have a front optical element of 200mm/2.8=72mm, which is quite a chunk of glass. On the other hand, the 70-300/4-5.6 needs to ...
11
The notion of "complementary" lenses takes for granted that the focal length is the only characteristic that's different between the lenses in question. In reality, that's rarely the case (probably never, really).
To make sensible selections, you need to look at quite a bit more than that, such as speed, size/weight, optical quality (sharpness, aberrations, ...
11
If you're only going to shoot your 50 f/1.4 at f/2.8 then yes it is redundant.
but as with all primes you have to stop it down to get sharp results
I'd replace "primes" with "f/1.4 lenses", plenty of primes are sharp wide open. Few ultra wide aperture lenses are really sharp. The Sigma 50 is actually pretty good. #Certainly sharp enough to consider ...
11
Not speaking for any company/lens designer, but I think it's a lot less practical now than it was in the manual focus days when one hand on one ring controlled both zoom and focus. The push/pull zoom was less precise than a rotating ring (it took some small force to move from any rest position, so overshooting was easy for critical composition), but managing ...
11
There is no answer to your general question.
Prime lenses are usually sharper than zooms at the same focal-length and aperture, mostly at wider apertures when the sensor out-resolves the lens. At one point lenses can out-resolve the sensor and then you will see equal sharpness in your images despite a potential difference in lens sharpness.
If someone were ...
11
It is simply the ratio between the longest focal-length and the shortest focal-length of the camera. For example, if the camera has a 25-100mm range, its zoom is 4X because 100 / 25 = 4.
It does not matter if this is computed based on the actual or equivalent range because the answer will be the same. More importantly, is that two cameras with 10X zooms can ...
11
The EF-S 15-85 can be used only on APS-C cameras, where it will have an full frame equivalent focal length of 15 * 1.6 to 85 * 1.6 = 24-136mm. As such, it's approximately equivalent to a "normal" zoom on a full frame camera.
The EF 17-40 when mounted on a full frame camera has the stated focal lengths (17-40mm) and is an ultrawide zoom. However, if you ...
11
The lens is a varifocal lens. Basically, it's a lens that changes focus as the focal length changes and it's quite common. Parfocal lenses, ones that maintain focus on zoom change, exist but are typically more expensive as a result.
Long story short, it's normal for a large number of consumer zoom lenses.
10
Executive Summary: I really like the prime over the zooms.
I've shot Hapkido (very similar to TKD) using an 85mm f/1.8 prime and with a 60 mm f/2.8 prime on a D200 and D70-- the D90 has better lowlight capabilities than those two cameras.
Here's the 85mm on the D200 at f/2.5:
This might be a bit of a cheat, however, since there was light from the ...
10
It depends heavily on what qualities in the final picture you care about. An f/2.8 lens won't simulate the depth of field of an f/1.4 lens -- ever. Even if the zoom was sharper, it still wouldn't give the shallow DoF of the f/1.4 primes. For portraits, that can (and often will) matter a lot. For landscapes, you'll typically use a fairly small aperture in any ...
10
In your example, assuming you kept the same distance to the subject, the 24mm picture would have more depth of field than the 70mm picture. To keep the same depth of field, you'd need to stop the 70mm lens down until it has the same absolute aperture diameter (so that 24/f-number = 70/other f-number).
In this picture, you can see that a 210mm f/11 lens ...
Only top voted, non community-wiki answers of a minimum length are eligible
