84
votes
Accepted
Does this telescope only have a 4 blade aperture?
What you're seeing isn't the result of an iris aperture like in a camera. The 4-point diffraction spikes in the telescope are caused by the four struts holding the reflector in the mirror telescope. ...
- 32.3k
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
35
votes
Accepted
What makes the difference on partially and fully visible moon?
What makes the difference on partially and fully visible moon?
In a word: shadows.
I cannot understand why the IQ is extremely diminished when doing the same with an almost fully visible moon.
...
- 32.3k
29
votes
Accepted
How did this note "19/65 21/90 22/130" help previous owner of this old Zenit 12XP film camera?
Those look like DIN speeds that match values on the GOST meter dial.
GOST was the Soviet film speed standard; it was on the same scale as ASA speed, but 90% the value (so GOST 360 was equivalent to ...
- 7,113
27
votes
Do photographers avoid using zoom?
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 ...
- 31.7k
27
votes
Accepted
Why are aperture settings visible when previewing photo on camera screen?
Assuming this is only on the LCD screen (it is in this case, I can see part of the viewfinder in the top of the photo), then it may be image burn from using the screen to display shooting settings. ...
- 2,815
25
votes
Accepted
Is it possible to change depth of field in RAW images?
No - the aperture is set by the physical blades in the lens when you take the photo; a RAW "image" contains the readings from the sensor when the photo was taken, so there's no way you can go back and ...
- 21.8k
25
votes
How can I avoid this blur during taking indoor party pictures?
The blur is caused by the people moving while you were taking the photograph with a slow shutter. Honestly, I think it improves this particular photo a lot: it shows that the people are dancing, ...
- 1,340
25
votes
Accepted
Do f-stop and exposure time perfectly cancel?
This is normal behavior, caused by:
Imperfections of aperture. Usually there are variations from
technology process which cause not to have exact size of the hole.
On 50mm lens f4 you should have 12....
- 11.5k
23
votes
How do zoom lenses restrict their widest aperture at the telephoto end?
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.
...
- 175k
22
votes
How to focus on long distance with object in front and blur the object?
One way is to simply use manual focus. Since the landscape is very distant, there is only one thing to focus on once, then you frame and shoot multiple pictures as you like.
- 17.4k
21
votes
Accepted
What is the relationship between ISO, aperture, and shutter speed?
The Factors
There is an equation, and by convention, it's set up to be really simple. There are basically five factors to consider together:
Aperture — the size of the opening which lets light in,
...
- 143k
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 ...
20
votes
Accepted
How do XMP files encode aperture?
The Exif:ApertureValue is stored as an APEX value as mandated by various EXIF standards.
The APEX system is a way to calculate exposure and works using base-2 logarithms. The use of base-2 means a ...
- 9,539
20
votes
Accepted
How to focus on long distance with object in front and blur the object?
There are (at least) four ways to do this:
Use manual focus: This is (one of the reasons) why good cameras still have that feature. For this specific scene, there are other ways to achieve ...
- 4,703
19
votes
Why is the background bigger and blurrier in one of these images?
The easiest way to think of this is with an image. When you use a wider lens, you have to be closer to your subject, which emphasizes the distance between the subject and background by making the ...
- 500
19
votes
Accepted
How do apertures which seem too large to physically fit work?
Your observations of the lens leads you to both a correct, and incorrect, conclusion.
Correct: the aperture (i.e., mechanical iris) of the lens is substantially smaller than the 10 cm it supposedly ...
- 32.3k
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
18
votes
Nikon D3400 aperture
In order to control the aperture from the D3400 with an older 'D' type lens that has an aperture ring, you need to set the lens' aperture ring to the narrowest (highest f-number) and lock it there. If ...
- 175k
18
votes
Why is Nikon 1.4g better when Nikon 1.8g is sharper?
1) Sharpness is complicated.
Lens sharpness is just one aspect of the overall resolving power of a camera system. The appearance of crispness is separate from the rendition of detail. And a lens can ...
- 143k
18
votes
Accepted
What are the benefits of the classic f-number scheme?
What is the purpose ... for the existing convention?
Math. It's because in many equations regarding simple optics, the ratio \$N = f/D\$ (where \$N\$ is the f-number, and $D$ is the lens (or more ...
- 32.3k
17
votes
Accepted
Landscapes: why *narrow* aperture?
Or am I misunderstanding how aperture works?...I thought the further away something is, the greater the depth of field. So when an object is three and a half miles away, it's going to have a huge ...
- 31.7k
17
votes
Accepted
What are the practical advantages of fast lenses when shooting landscapes?
When used at the same aperture and focal length, a faster lens will have less vignetting than a slower lens.
For example if you choose to shoot at 35mm f/4.0, then a 24-70mm f/4.0 lens will have the ...
- 751
17
votes
Accepted
Does a lens with a bigger max. aperture focus faster than a lens with a smaller max. aperture?
During focussing, the lens is left at full aperture. It's only when you take the picture that it closes down to the appropriate f-stop. That's so you can see what's going on and so that the camera has ...
- 658
17
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 ...
- 11.5k
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 ...
- 38.7k
16
votes
Do f-stop and exposure time perfectly cancel?
In theory, yes — stops are interchangeable. In practice, they do not perfectly cancel to complete precision.
the standard deviation of the raw counts is ~5% of the mean
In photographic terms, this ...
- 143k
15
votes
Accepted
Simply bad focus or too big aperture?
Your question seems to reflect the idea that a lower aperture number is for closer objects and a higher aperture number is for distant objects. This is not the case. Either aperture may be used to ...
- 175k
14
votes
How can I avoid this blur during taking indoor party pictures?
Honestly, the biggest problem I see in your picture is not the blur, but the badly clipped highlights. Next time, try shooting at, say, -1 EV (which will also reduce the exposure time, and thus the ...
- 4,703
14
votes
Accepted
Does aperture affect field of view?
Answer with an image : the guy on the left represents your (vertical) field of view and its image on the sensor is inverted on the right (in other terms, the guy fills your entire image).
As you can ...
- 4,163
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