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 ...
- 6,468
52
votes
Why aren't faces sharp in my f/1.8 portraits even though I'm carefully using center-point autofocus?
You're not doing anything wrong. You're just finding the limits of the camera/lens combination you are using.
The EF 50mm f/1.8 (in various versions) has been known as the "plastic fantastic" for a ...
- 175k
46
votes
Accepted
What are the best (ethical) ways to keep insect still for outdoor macro photography?
A focus rail + stacking software will help you achieve deeper depth of field.
However, if you don't have a focus rail (or time to set one up), try to pick an optimal angle to capture as much of your ...
- 657
40
votes
How can a smartphone take pictures of a landscape with everything in focus?
It's worth noting that sensor size plays a huge role in depth of field and behavior of the lens.
A smartphone has a tiny camera sensor, often around 25 square mm. This gives the camera a crop factor ...
- 830
40
votes
Accepted
Can you tell from a blurry photo if focus was too close or too far?
It depends. In many cases, it may actually be possible without any further visual aids in the picture.
Many lenses, if not most, will show different longitudinal chromatic aberration in front of and ...
- 3,282
40
votes
Accepted
Why can't my custom camera body focus to far distances?
If I have built my device with the correct distance between the flange and the optical plane, does this mean the (inexpensive) lens I am using is bad?
If you had built your device using the proper ...
- 175k
32
votes
Can I post-process this out of focus image?
Yes of course it can be post processed. It might make it “better.”
But it will never make it the picture you wish it was.
The good news is that there will be other snakes on other days. Plenty of ...
- 4,936
28
votes
Why focus on the eye closest to the camera instead of the eye in the middle?
There's more depth of field behind the focus than in front of it. So focussing on the near eye gives you the best chance of getting the whole face in focus. If you can't do it focussed on the near eye,...
- 3,812
28
votes
Accepted
Do convex lenses make parallel light rays of different wavelength converge to different points?
Do convex lenses make parallel light rays of different wavelength converge to different points?
Yes. The separation of different wavelengths of light is called dispersion. Different wavelengths of ...
- 32.7k
25
votes
Why do people not use large f-numbers (small apertures) when shooting landscapes, when you want large depth of field?
First people want to have (when making photos of landscape) almost all in focus. But they do not use F22-32 because on such aperture diffraction degradate the quality of images.
Second, when shooting ...
- 12k
24
votes
What is it about this albatross photograph that makes it look like it might either be faked or actually a photorealistic drawing (to me at least)?
IMO, the primary cause of the effect is differential lighting. The birds and grass have hard bright frontal light from high right. Whereas the foreground and background appear to have softer/dimmer ...
- 17.2k
23
votes
Any cameras move the sensor instead of lens elements for focus?
Not a digital camera/sensor, but the Contax AX film SLR was able to move its film plane forward and back via a ceramic rail and ultrasonic motor in order to be able to autofocus the normally-manual-...
- 12.1k
23
votes
Accepted
How to reposition subject in the same place and pose in a series of images over time
Fun idea. That could be called hyperlapse.
If you use a specific memory card for that project, you can always switch from viewing the first photo of the project to live view.
Another option is that ...
- 24.8k
22
votes
Do convex lenses make parallel light rays of different wavelength converge to different points?
Light from a far distance object, like a star, arrive at the lens, as parallel rays. As they transverse the lens, they are forced to change their direction. They bend inward, we call this refraction ...
- 39.2k
22
votes
Is camera lens focus an exact point or a range?
There's only one distance that is in sharpest focus. Everything in front of or behind that distance is blurry. The further we move away from the focus distance, the blurrier things get. The questions ...
- 175k
21
votes
Accepted
How can I take a photo through trees but focus on an object behind the trees?
You can focus manually.
To do that with the Nikon AF-S DX NIKKOR 18-55mm f/3.5-5.6G VR II supplied as the kit lens with the D3300, you need to slide the switch on the lens to M for manual focus. It's ...
- 2,893
21
votes
Accepted
How do I diagnose the source of blurry photos?
The question is extremely broad. There are a lot of questions and answers here that address particular aspects of blurry pictures. Putting all of that in one answer would be excessively long as well ...
- 175k
21
votes
How can a smartphone take pictures of a landscape with everything in focus?
If by "landscape" you mean something like this:
then the answer is simple: at very large distances, depth of field is extremely large even at large apertures. That is, at any aperture if you focus at ...
21
votes
Can you tell from a blurry photo if focus was too close or too far?
When the aperture is positioned to minimize vignetting, the bokeh shapes for objects that are too far is rotated by 180° compared with objects that are too near. (The aperture image is reflected ...
- 251
21
votes
What is it about this albatross photograph that makes it look like it might either be faked or actually a photorealistic drawing (to me at least)?
Late addition
To me, the jury's still out on whether it's fake, but I do come down on the side of 'real, but worked up [too] hard'.
In the photographer's defense, I do get the feeling the guy only got ...
- 23.3k
20
votes
How can I get sharp bird photos when the bird is further away?
Several possibilities:
In the examples shown, it could be a problem with the subject. The center of the picture is a rather fuzzy plumage for the dove and sharp lines for the white-eye.
Your 55-250mm ...
- 21.3k
18
votes
Why do we need a DOF preview button?
Hitting the DOF preview with a stopped down aperture should make it obvious: what you see can be very dim, dim enough it can be very difficult to compose and focus.
That's why cameras have the lens ...
- 1,192
17
votes
Accepted
Since it's not "focal length", what is the term for the distance at which things are in focus?
Focal length is the distance between the lens and the sensor when the subject is in focus, not the distance to the subject.
The term for the distance to the subject in focus is the focus distance ...
- 17.9k
16
votes
Accepted
How to take sharper photos
The first image was shot wide open with what is essentially the lowest cost Canon lens (50mm f/1.8), in demanding low light conditions, and at ISO 1600. I'd say your results are exactly what I would ...
- 46.5k
16
votes
Accepted
Why does wider aperture make snowflakes look bigger?
The use of a large diameter, f/3.2 aperture allowed you to set the shutter at ½ second. You captured snow as it tumbled down. The shutter speed is insufficient to freeze the falling snow. The flakes ...
- 39.2k
16
votes
How can I reproduce a myopic effect on a picture?
I don't know how a myopic person sees, but an effect similar to that of the paintings described in the comment can be achieved with Photoshop.
Starting from this image:
Duplicate the layer
Change the ...
- 1,769
16
votes
What is it about this albatross photograph that makes it look like it might either be faked or actually a photorealistic drawing (to me at least)?
Complementing Steven Kersting´s answer:
The photo looks like a diorama.
Look at the images at this google search
You put some stuffed animals with a printed photograph as a background, then you add ...
- 24.8k
15
votes
How can a lens with a single focal length focus on more than one plane?
First, focal length is a property of a lens (by lens I mean a piece of plastic or glass that's inside your camera's photographic lens system). If you just have a single lens (think magnifying glass) ...
- 251
15
votes
Why focus on the eye closest to the camera instead of the eye in the middle?
Because the way human vision perceives a two dimensional representation of the three dimensional human face if the nearest eye is in focus it looks to us more like the whole face is in focus.
Even if ...
- 175k
14
votes
Accepted
Can focus stacking (or a similar technique) also be used to reduce depth of field?
Yes, it's possible
With the focus stack you could estimate a depth map of the scene. Then this map is used to selectively blur the image to emulate the effect of shallower depth of field.
See for ...
- 278
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