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 ...
- 6,478
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.
- 176k
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 ...
- 22.1k
42
votes
Accepted
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 ...
- 904
33
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 ...
- 39.5k
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 ...
- 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-...
- 22.1k
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 ...
- 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 ...
- 33.2k
17
votes
Accepted
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 ...
- 176k
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 ...
- 12.3k
15
votes
Accepted
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, ...
- 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 ...
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: ...
- 39.5k
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 ...
- 176k
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 ...
- 5,525
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 ...
- 6,384
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 ...
- 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 ...
- 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 ...
- 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 ...
- 33.2k
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 ...
- 176k
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 ...
- 52.7k
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 (...
- 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 ...
- 6,384
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 ...
- 176k
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 ...
- 3,181
9
votes
Why doesn't the picture become darker the more you zoom in?
Why doesn't the picture become darker the more you zoom in?
If the entrance pupil size remains constant, it does.
But very few zoom lenses, even those with variable maximum apertures, maintain the ...
- 176k
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 ...
- 13.6k
Only top scored, non community-wiki answers of a minimum length are eligible