57 votes
Accepted

Why do photo cameras lose focus when you zoom, when movie or TV cameras keep it?

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 ...
flolilo's user avatar
  • 6,468
53 votes

How to zoom with Canon 77D with Canon 50mm 1.4 lens?

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.
Michael C's user avatar
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52 votes
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Why buy prime super telephoto lenses instead of zoom super telephoto lenses?

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, ...
inkista's user avatar
  • 52.1k
43 votes

How to photograph distant objects (10km)?

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 ...
Philip Kendall's user avatar
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42 votes
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How to zoom with Canon 77D with Canon 50mm 1.4 lens?

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 ...
NoahL's user avatar
  • 904
32 votes
Accepted

Why doesn't the picture become darker the more you zoom in?

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 ...
Alan Marcus's user avatar
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30 votes

How to photograph distant objects (10km)?

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 ...
Mick's user avatar
  • 1,047
25 votes

Is replacing all my Fujifilm gear with this Canon zoom lens an upgrade?

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-...
Philip Kendall's user avatar
  • 21.9k
21 votes

How to photograph distant objects (10km)?

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 ...
Jules's user avatar
  • 658
18 votes

How should I approach deer to photograph them?

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 ...
scottbb's user avatar
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16 votes
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Is replacing all my Fujifilm gear with this Canon zoom lens an upgrade?

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 ...
Michael C's user avatar
  • 175k
16 votes
Accepted

What does "AUTO-ZOOM" mean on my Zuiko lens?

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 ...
Mike Sowsun's user avatar
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15 votes
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Any tricks to escape the zoom lens trap?

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, ...
mattdm's user avatar
  • 143k
15 votes

How to photograph distant objects (10km)?

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 ...
CaffeineConnoisseur's user avatar
15 votes

How do manufacturers get to high (83x) zoom levels on hybrid cameras?

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: ...
Alan Marcus's user avatar
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14 votes

Why do photo cameras lose focus when you zoom, when movie or TV cameras keep it?

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 ...
Michael C's user avatar
  • 175k
13 votes

Why does my first picture have a dark area and the next is fine?

This phenomenon entirely depends on how backlight of the LCD works. The brightness of LEDs is controlled with very frequent pulses (Pulse Width Modulation) which are mostly unnoticeable to humans. PWM ...
Euri Pinhollow's user avatar
12 votes

Longer Zoom Lens

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 ...
StephenG - Help Ukraine's user avatar
11 votes
Accepted

Is it exactly true that doubling the focal length makes everything look twice as big?

Your intuition is right. To validate it, we can dig into basic high-school geometry. Although a camera lens is actually a complex lens made from many elements, conceptually and mathematically for ...
mattdm's user avatar
  • 143k
11 votes

How can I magnify ≤1mm objects onto a display for under $200?

There are a few considerations here: How are the objects illuminated? Small objects typically need quite good illumination to see them properly. Without good light ...
bob1's user avatar
  • 255
11 votes

How can I get more magnification when shooting wading birds?

Shooting from the same point of view will always result in the same image (in terms of magnification) with every 300mm lens you can get (zoom or prime doesnt matter). To achieve a higher magnification ...
Arji's user avatar
  • 1,633
10 votes

How much zoom would make a camera suitable for imaging railcar seals from 100 feet away?

As the other answers do a good job of giving you the fish, seeing as you're an engineer, this answer will teach you to fish. The angle of view of a lens & camera combination is simply determined ...
scottbb's user avatar
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10 votes
Accepted

Are there any lens hoods with zoom-moveable petals?

There are a few zoom lenses that effectively do what you envision, but it is not due to movements of the hood. Rather, it is due to a retrofocus design that extends the lens barrel fully at the widest ...
Michael C's user avatar
  • 175k
9 votes
Accepted

Zooming in meters

It's impossible to say. This is because a "zoom factor" is a relative measurement, not an absolute one. 10x zoom doesn't mean the picture is enlarged 10x. All that the zoom factor is telling you is ...
inkista's user avatar
  • 52.1k
9 votes

Can I convert binocular zoom to equivalent lens focal length?

Binocular zoom and lens focal length just aren't equivalent and can't be converted in any meaningful way. A camera lens is an image-forming system. It has a focal length. Binoculars and telescopes (...
mattdm's user avatar
  • 143k
9 votes

How should I approach deer to photograph them?

Short version : you need more shutter speed. Crank up ISO, use widest aperture and trade both for shutter speed. they still either naturally wander off or hop and run away whenever I get within ...
StephenG - Help Ukraine's user avatar
9 votes
Accepted

How do I choose a lens for my first DSLR to replicate the capabilities of my bridge camera?

The entire point of an interchangeable lens system camera is to allow you to use different lenses that are better or even great at one thing but unsuitable for other things. Fixed lens cameras force ...
Michael C's user avatar
  • 175k
9 votes

Is replacing all my Fujifilm gear with this Canon zoom lens an upgrade?

You might also want to take into account the following: That 24-70 mm doesn't cover even half your current range. You really like the 90mm for portraits, and 90 mm is outside that recommended ...
remco's user avatar
  • 3,161
8 votes
Accepted

Why do zooms have small apertures even around 50mm?

Update 2023: some of the elements of my answer below assume a DSLR, and in some cases mirrorless system make some of these issues less of a challenge. The points about zoom lenses requiring a more ...
thomasrutter's user avatar
  • 13.6k

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