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56

The effect's name is parfocality, we are speaking of parfocal lenses. Lenses that change their focus when zooming are called varifocal lenses. Like reducing focus-breathing (change in focus also changes the focal length), parfocality is a premium-feature. Since photographers usually work with autofocus and since photographers tend to not recompose the image ...


53

How to zoom with Canon 77D with Canon 50mm 1.4 lens To zoom in, step forward. To zoom out, step back. It's often called zooming with your feet.


51

Who in the world buys large primes? Wildlife and sports photographers, mostly. I'm struggling to see how one would find use in a long focal length prime, 300mm and above for example: without zoom, isn't your shot composition always at the mercy of how close or far away your subject is, meaning heavy cropping is almost always necessary in post? It's the ...


42

You can’t. The 50mm f/1.4 is a prime lens, which means it has a fixed focal length, or fixed field of view. This is what some people call a “sneaker zoom” lens, where you as the photographer have to physically move to change what you see in the viewfinder. See mattdm’s great response in this question.


37

You can't. I don't care what you've seen on CSI, this just isn't possible in the real world. Even taking Canon's ridiculously big (and now discontinued. Oh, and $100,000) 1200mm lens, The Digital Picture say: faces were recognizable at distances up to a mile or more However, you're talking about six times that distance. You could think about mounting a ...


32

The answer to this question revolves around explaining how zoom lenses function because you are correct in your observation: As you zoom to higher and higher magnifications the image dims unless somehow compensation is applied. Suppose you zoom from 25mm to 50mm, should the working diameter of the aperture remain unchanged, image brightness would suffer a 4x ...


31

You are not required to purchase any lenses at all. It all depends on your photography needs and what you're willing to spend your money on. Regarding range, the superzoom 18-200 mm covers the same range as the other four lenses you mentioned. All of the other lenses focal ranges are parts of the large range of the 18-200 mm lens. The 18-200 can surely ...


26

do most photographers avoid using zoom No. If "most photographers" avoided zoom lenses with variable aperture, there'd be fewer zoom lenses with variable aperture on the market. Furthermore, there are plenty of fixed aperture zoom lenses available at a range of focal lengths, so it's safe to say that photographers don't have to avoid zooms just to have ...


25

By specifying that you want to do your surveillance photography in "good sun light", you have already shot yourself in the foot. The best time to do this kind of photography is at night or in the very early morning before the heat from the sun has time to create the "thermals" that make extreme telephoto photography almost impossible, even with the very best ...


24

The 24-70 is an incredibly good lens - it's as sharp wide-open as just about any prime at every focal length across just about its entire field. But it's only 24-70. As you're talking about a full-frame Canon, that's as wide (16mm * crop factor of 1.5 = 24mm), but you'll be losing a lot of length at the telephoto end - your 90mm on APS-C is equivalent to ...


21

The entrance pupil is limited by the diameter of the front element, and that is what usually restricts the maximum aperture of telephoto zoom lenses - not the physical size of the aperture diaphragm. The physical size of the diaphragm is only part of what determines the maximum aperture, expressed as an f-number, of a lens. Magnification between the front ...


19

Provided your lens isn't a power zoom (fairly rare, these lenses have motors that drive the zoom mechanism), then no you will not damage either camera or lens.


19

The general consensus in this thread is that detailed photography of a subject at a range of 10km is exceedingly difficult, and probably impossible using commercially available equipment — and there's plenty of evidence to support that in the other answers. However, there is a way to photograph extremely distant targets in extreme detail — it's just not ...


17

A prime likely still has several advantages over a zoom at a given focal length. (Well, depending upon your needs and habits.) A less complex optical design. All else being equal, a less complex design is likely to have fewer compromises, which means the prime is more likely to have less distortion of any sort -- pincushion, barrel, coma, and chromatic ...


17

The only ethical ways to get closer is to either use a lens with a longer focal length ("more reach"), or to view them in captivity, such as in a zoo. Trying to get closer to wildlife will only stress them (which you have observed their reaction — to run away). Without stalking the deer, you can use the approach favored by hunters: be in places they are ...


16

The lens is not parfocal in either direction. What you have discovered is the difference between narrow Depth of Field (DoF) at longer focal lengths and deeper Depth of Field at wider focal lengths. The focusing error you introduce when you focus at 18mm and then zoom to 105mm is greater than the shallow DoF at 105mm even at f/8, so you notice how out of ...


15

A greater zoom range means a more complex design at greatly increased cost. There are some excellent lenses make for broadcast with incredible zoom ranges, like the Fujinon 8-832mm (yes that's not a typo!), but you don't want to know the price. Designing a lens with a larger zoom range at a lower price does lead to compromises on quality. Finally lens ...


15

It just means you push / pull the front of the lens to zoom, rather than twisting a zoom ring. The mechanism is simpler to design/manufacturer but is less precise and has a reputation for sucking dust into the lens due to the large change in volume when zooming.


15

Would switching to full frame Canon and getting that lens be an upgrade over my Fujifilm gear? For some shooters it would be. For others it would not. For a true photographer it shouldn't make a ton of difference either way. They'll do good work with either. One system may make doing that work easier than the other, but the work you are describing can be ...


15

Your lens dates back to a time when some lenses were still completely manual, and the aperture had to be manually closed for stop down metering. Your zoom lens has a more modern feature that allowed for wide open metering and then the lens would automatically stop down to the desired aperture just as the photo was taken. By the 1970’s most lenses had this ...


14

I think this is a great exercise and can really help you with your photography — even if you end up using zoom lenses in the future. And, there is a commonly-used "trick" here — it's called One Lens, One Camera, One Year, suggested by longtime prime-lens enthusiast Michael Johnston (also see his The Case Against Zooms). A Method The original suggestion was ...


14

I think the use of the term 83X while true, is most misleading. The Coolpix does a remarkable job when it comes to its optical range which is 83X. This is actually called the zoom range. The math is: The power of the camera’s lens is adjustable from 4.3mm wide-angle to 357mm telephoto that’s 357 ÷ 4.3 = 83. In other words the span of the zoom is 83X.To ...


13

There is definitely something very wrong here. That's not a focus or DOF issue, but looks like the lens suffers from extremely strong field curvature. It's normal for a lens to be sharper in the center than around the edges, and this effect gets stronger with wide open aperture and at the extreme ends of the zoom range (your last sentence indicates that you ...


13

In my career as a VFX supervisor, I've helped supervise several miniature shoots. Shooting miniatures in substitution of a full size scene has been a common technique for almost as long as films have been produced. There are several important steps to make the photograph convincing: Use a small aperture Consider a 1:10 scale model, and put your camera in ...


13

As others have said, 10 km is not feasible due to the physics of light and atmospheric distortion. However, I'd like to address another aspect of this that hasn't been mentioned yet: if someone is standing 10 km from you and you're both at the same altitude you won't be able to see them because they'll be behind the horizon! If a person is 1.8 meters (~6 ft)...


13

A lens that maintains the same distance of focus as it is zoomed is said to be parfocal. This is a highly desirable quality in a lens if one is shooting film or video and wishes to maintain focus while zooming in or out during a continuous shot. Some zoom lenses that are not really parfocal, particularly those with smaller maximum apertures, can appear to ...


12

Just because you buy a zoom lens doesn't mean it is the only lens you are now allowed to use! And just because you are using a zoom lens doesn't mean you can't still alter the composition of your photographs by using your feet! The advice you have been given is primarily a warning not to stand in one place and stop exploring shooting angles and perspectives ...


12

Let's start with what is similar with all three of these lenses: They all have a focal length of 50mm. You should also be able to have a lot of overlapping focusing distances and aperture values. Now, to what's different. When it comes to a zoom lens, they tend * to have a different maximum aperture values that are smaller than with a prime. The advantage ...


11

The rule is learn to get closer. Really the best wildlife shots are made by people who have learned to get closer to wildlife ( a tricky skill ) and to wait ( find a spot you think they'll come near and wait there, usually partly hidden ). These are like hunter's skills. Also note that 40x is a factor from widest focal length on a zoom to longest. It's ...


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