All Questions
Tagged with aperture lens-design
34
questions
1
vote
0
answers
292
views
Why won’t the aperture adjust on my Sony A camera? [closed]
I recently bought a telezoom objective without built-in AF. I did not bother because my camera has an AF which could handle the focus on such lenses.
I always had used lenses with built-in AF so I did ...
- 11
2
votes
3
answers
440
views
Is diffraction limited aperture independent of lens?
I have always understood diffraction limited aperture as a property of the camera and its sensor, not of the lens. The camera has a certain sensor size and a certain megapixel count, which together ...
- 6,835
0
votes
3
answers
173
views
Does a camera have to have a contiguous housing?
The lens group in this picture would have its own protective lens tubes like the one on a camera but one for each lens group. What would be an issue having a gap between the lens group and stray light ...
- 1
14
votes
2
answers
1k
views
How do apertures which seem too large to physically fit work? [duplicate]
A 400mm f4.0 lens is supposed to have a maximum aperture diameter of 10cm. Looking at such a lens they don't seem big enough to fit that kind of aperture including all the mechanics for control inside ...
- 243
3
votes
2
answers
210
views
Are bokeh (ball) shapes a result of vignette or aperture action?
The effect of getting shaped out-of-focus highlights (bokeh balls) from both non-circular apertures inside the lens, and masks applied in front of it (where an external aperture would presumably also ...
- 7,232
1
vote
1
answer
200
views
Why is Auto on aperture rings near the smallest aperture?
This is something that has puzzled me for a while and it always seems counter-intuitive. When a lens has an aperture ring with an auto position (A), it is always (at least on 3 systems that I have ...
- 103k
9
votes
4
answers
1k
views
What motivated lens makers to now use 1/3 f-stops rather than say 1/4 or 1/2 stops?
I've noticed that many older lens have just hard f-stops for lens (2, 2.8, etc). However, since the aperture wheel for some is continuous you can "stop" are some arbitrary point and shoot. From my ...
- 2,063
3
votes
1
answer
452
views
Limits of camera lens capabilities [closed]
I read that the canon 35mm f/2 IS is the lowest aperture lens that also has IS. Is this because a stabilizer at any lower F-stop is not possible, or just because it is just currently outside of our ...
- 1,135
5
votes
2
answers
2k
views
Why do zooms have small apertures even around 50mm?
A 50mm f/1.8 prime from one of the major manufacturers can easily be found for $200 or less, but zooms that include 50mm in their range always seem to have much smaller apertures even at 50mm until ...
- 185
15
votes
3
answers
2k
views
How do zoom lenses restrict their widest aperture at the telephoto end?
Does the aperture ring lock the apertures beyond, say 5.6 at length lens's telephoto end?
Does the lens introduce an obstacle to the aperture ring so the lens can't be opened anymore beyond the ...
- 1,515
2
votes
1
answer
969
views
Why don't all zoom lenses have variable f-numbers? [duplicate]
As I understand it, the f-number is a ratio between the focal length and the aperture diameter. A zoom lens can change focal length, but shouldn't the maximum aperture be a fixed size? If so, that ...
- 123
0
votes
1
answer
1k
views
Do mobile cameras ever vary f stops?
I've been trying to get my head around the camera in my newly-bought Chinese mobile phone.
I wonder how focusing actually works in these kind of phones. I imagine that in the standard context of ...
- 111
0
votes
1
answer
295
views
How are aperture changes implemented on D-series Nikkor lenses?
Nikkor G lenses have a built-in USM motor that permits auto-focusing on bodies with or without the focus motor. They also permit changing the aperture from the aperture dial on the body. Nikkor G ...
- 115
4
votes
2
answers
808
views
What is the maximum aperture consistent with the Nikon F-mount?
In a related thread, it's been debated whether there is a hard limitation to maximum possible lens aperture; it seems there is none. However, using the example of the nikon F mount, this technical ...
- 196
18
votes
2
answers
3k
views
In what way does the lens mount limit the maximum possible aperture of a lens?
In many answers to questions about different aspects of really large aperture lenses it's pointed out that the lens mount sets a hard limit on the maximum possible aperture of the lenses to that ...
- 8,288
1
vote
1
answer
213
views
what is the barriers of making fast lenses? [duplicate]
I know there are lenses like f/0.7
However as a beginner I'm wondering what's the barrier of making ultra fast lenses like f/0.01 ?
Also if lens manufacturers willing to make wide aperture lenses, ...
- 241
5
votes
2
answers
416
views
How does the Sony 135 F2.8 [T4.5] STF twin aperture lens design work?
I stumbled across the Sony 135 F2.8 [T4.5] STF other day.
I have read through the review but I can't for the life of me figure out what the twin-aperture setup is supposed to do!
- 9,070
12
votes
6
answers
8k
views
What are the theoretical minimum and maximum apertures?
Is there such a thing as a maximum aperture that a lens can be open to? What about a minimum aperture that it can be closed to? Do these concepts even make any sense? Is there a lens with the ...
- 673
16
votes
4
answers
2k
views
Why aren't lenses designed with extra large apertures for autofocus beyond what's used for imaging?
Historically, designing large-aperture lenses has been difficult because correcting the optical aberrations that arise from large apertures requires complex designs and very large amounts of glass. ...
- 2,366
3
votes
2
answers
4k
views
What's the difference between real and effective aperture?
I understand that the simple idea that f-stop is focal length divided by aperture really applies to a simple single-glass lens, not the compound lens systems used to provide good image quality in ...
- 143k
8
votes
1
answer
781
views
Why does my Zeiss Hasselblad Distagon lens have a 5 blade diaphragm?
As we are all aware, the more blades there are in a lens’s diaphragm, the rounder the resulting hole can be made, and in turn this gives a more natural looking bokeh.
So on receiving my recent ...
- 9,070
3
votes
2
answers
323
views
Is there a difference in sharpness between aperture stops?
Is there a notable difference in sharpness between aperture stops of a lens?
If so, where can I find that information for my Canon 550d Kit lenses?
- 1,147
11
votes
3
answers
900
views
What is the limiting factor in lens construction when it comes to f-stop values?
This widely praised Nikon 105mm macro lens has a maximum f-stop value of 2.8. I've held it in my hands, it's a big lens. Meanwhile, this 50mm Nikon lens can go up to f/1.2, despite being 25% cheaper ...
- 2,465
12
votes
4
answers
7k
views
Is overall light gathering of a lens only dependant on aperture?
My impression is that the aperture value of a lens determines its light gathering ability, but I'm not sure I understand how it works...
When considering light gathering in telescopes, it is ...
- 223
31
votes
3
answers
9k
views
Why do wide angle prime lenses have relatively small apertures?
I've noticed that many of the wide angle prime lenses (at least for Canon) have somewhat smaller apertures than their normal or telephoto counterparts. E.g. the regular Canon 24mm prime is f/2.8 while ...
- 4,655
9
votes
4
answers
1k
views
Why do filter sizes vary for lenses of the same focal length?
I have a Nikkor 18-55 kit lens that has a 52mm filter, and recently I was looking that the 17-55 lens has a 77mm filter.
Is it because the latter is a better quality lens? I assume a bigger circle ...
- 393
22
votes
2
answers
5k
views
Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?
Why does a camera's maximum (allowed) aperture get smaller when you increase its zoom?
- 641
6
votes
2
answers
1k
views
What's the base f-stop when counting an ideal f-stop for lens?
I've read a lot around this site that an ideal quality of the lens is achieved when using f-stop roughly 2 stops slower than the fastest value of the lens.
Firstly, I'm not exactly sure what "2 stops"...
- 2,683
9
votes
3
answers
6k
views
What are the advantages of a lens having a fixed maximum aperture?
What are the advantages of a lens having a Fixed Maximum Aperture? Previous answers have indicated that "pros tend to want constant apertures in zoom lenses".
While in general lenses with a fixed ...
- 2,641
26
votes
5
answers
8k
views
What is special about lenses with f-number < 1?
Talking about fast lenses, Wikipedia mentions
Nikon TV-Nikkor 35mm f/0.9-Fastest Nikon lens ever made
Why don't, for example, f/0.5 lenses exist?
Is there some special construction that comes ...
- 4,049
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