Questions tagged [lens-design]
Of and relating to the specifics of lens construction and manufacture.
266
questions
0
votes
4
answers
588
views
Which is the cause of Barrel and Pincushion distortion?
Barrel and Pincushion distortion are due to the fact that the magnification of the lens changes as you get further off axis.
Let's consider a single thin lens with an aperture stop. These two pictures ...
- 504
0
votes
3
answers
168
views
Why do some lenses have a rounded front element?
I've noticed that some lenses, mainly wide-angle or fisheye (e.g. Samyang 14mm f/2.8, or Nikkor 8-15mm fisheye) have a rounded front element.
Which is the reason for it? It's of course limiting in ...
- 504
1
vote
0
answers
101
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
3
votes
1
answer
388
views
What determines the image circle diameter?
Anywhere in the web it's stated that the image circle diameter depends on the lens design. I'm curious to understand it a bit better.
Let's start with basics. Let's consider a single thin lens ...
- 504
3
votes
2
answers
240
views
Why are lenses of large-sensor smartphones so small? Could system camera lenses shrink as well?
The photo sensors of some recent smartphones are approaching sizes so far reserved for system cameras with interchangeable lenses. For example, the Google Pixel 7 has a 25 mm equivalent f/1.9 main ...
0
votes
3
answers
151
views
Do photographic lens show virtual image if the subject distance is less than focal length?
A convex thin lens produces a real inverted image if the subject distance from the lens is higher than the focal lens.
If it is lower, the image will be virtual. Of course a virtual image appears on ...
- 504
1
vote
3
answers
272
views
Why does Nikon Micro-Nikkor 55mm f/3.5 pre-AI show 1:1 markings when it can only get to 1:2?
I own this (mechanically and optically superb) lens since quite some time and was wondering why the blue marks that say 1:1, 1:1.5 and 1:2 don't actually correspond to the reproduction ratio that the ...
- 585
1
vote
1
answer
223
views
What lens would suit an A4 large format camera
I'm planning on building a scanner camera. The principle of which is simple: everything's built like a large format camera, except the film is a simple scanner controlled by computer.
Now, building ...
- 21
1
vote
0
answers
42
views
Smear/spread at the edges of a phone lens [duplicate]
My google-fu is failing me on this, because I don't know the term I'm looking for.
At the edges of a simple group shot of five or six people taken with a smartphone, there is a tendency for the faces ...
- 23.2k
2
votes
1
answer
186
views
Do third party lens manufacturers need the camera company's permission/licence to produce and sell compatible lenses?
I was wondering if lens manufacturers like Tokina, Sigma, Samyang etc, need some sort of permission from camera manufacturers in order to produce and sell their compatibles lenses or if any company ...
- 21
14
votes
5
answers
5k
views
Why isn't my camera body white?
If I leave it in the sun for a few minutes, even in winter, it gets pretty hot. In summer, I'd have to shade it as it has been too hot to touch. This makes remote-triggered wildlife photography and ...
- 809
14
votes
4
answers
3k
views
How would a curved sensor change camera and lens design?
I've read that lenses are designed to project an image onto a flat surface and that as image sensors grow larger, lenses will grow correspondingly larger and by some additional factor. Flat imaging ...
- 809
0
votes
1
answer
171
views
How does using more spherical lenses compensate for spherical aberration?
I've heard of three common ways to compensate for spherical aberration:
Small aperture (fewer non-paraxial rays).
Aspheric lens (compensate with lens shape/material).
Corrective spherical lens ...
- 111
1
vote
4
answers
188
views
Decrease FF lens focal length for use on APS-C and still have it focus?
Need to convert very cheap vintage FF 50mm f/2.8 lens to work as 35mm lens for for APS-C, for having wider angle of view.
Its kind of works by simply placing lens closer to camera sensor (without ...
- 197
1
vote
3
answers
263
views
Does the focal length on cropped lenses include a crop factor? [duplicate]
I'd like to be certain about the focal length written on the cropped lenses, e.g. I have a Sony NEX-5N with the original OSS 18-55mm kit lens. Is it actually an 18 to 55mm focal length with no "...
- 13
2
votes
1
answer
152
views
Is focus shift inherent in the Zeiss Sonnar lens designs (more so than other lens designs)
One of the common "criticisms" of the Zeiss ZM C-Sonnar 50 mm/1.5 is its pronounced focus shift. That got me curious if the similar-design Zeiss Sonnars for the Hasselblad V-system (e.g. 150 ...
0
votes
1
answer
1k
views
In general, should I expect better image quality from a 24-70mm f/2.8 lens than from a 24-105mm f/4 lens?
I'm in the market for a full frame EF-mount standard zoom lens, so I've been doing a lot of research about different 24‑70mm f/2.8 and 24‑105mm f/4 options. I understand the tradeoffs in terms of ...
- 699
1
vote
4
answers
414
views
Why is there an air gap between lenses and digital sensors, as opposed to continuous glass-like higher refractive index?
Thinking about ultra-fast lenses (ƒ<1), it would seem useful to have a solid+liquid medium between lens and sensor. This wouldn't have been very practical (presumably) at the time of film, but with ...
- 73
5
votes
4
answers
319
views
Seeming contradiction on wikipedia about rear nodal points and how the principal plane is related to focal length
There are two lines on the wikipedia pages for "cardinal points" and "focal length" that seem to contradict each other, and I would be extremely grateful if someone could explain ...
- 51
0
votes
2
answers
621
views
Canon 18-55mm lens giving err01 after it fell down
Sometime back I accidentally dropped my canon EFS 18-55mm lens (open caps); I cleaned the contact areas and any kind of dirt I could see on it. After that it was a bit jittery whenever I zoomed, but ...
3
votes
2
answers
324
views
How to use spacer rings to change the behaviour of the Nikon 35-70 f/2.8 lens
I recently bought a Nikon 35-70 mm f/2.8 lens with some scratches on the front element. I exchanged the front element with the element of an old lens I had lying around. Everything works fine, but now ...
- 1,530
0
votes
3
answers
227
views
Is it possible to commission a custom lens that would significantly outperform stock lenses?
I know that to get better image quality often requires aspherical lenses, which are expensive to make, so at some point it becomes non-economical to have a lot of aspherical elements in a camera lens.
...
- 1,834
3
votes
3
answers
227
views
Différence between a long lens design and a telephoto
I was looking at the Leitz Hektor and Ken Rockwell says
"This is a conventional long lens design, not a telephoto. Its diaphragm sits right at 135mm from the image plane.
The Nikkor lens shown ...
0
votes
1
answer
145
views
Laowa 7,5 mm F2 Lightweight Micro 4/3 vs. Laowa 7,5 mm F2 Standard Micro 4/3
I am interested in buying a wide-angle lens.
The Laowa 7.5mm F2 Micro 4/3 seems to be the best option for my purpose.
I have found it in an online shop and was wondering why the lightweight version (...
- 3
6
votes
4
answers
424
views
Why are flatbed-scanned images warped when compared to itself scanned & rotated 90 degrees?
This has been absolutely baffling me. I scanned an image both vertically and horizontally on the flatbed of my HP Color LaserJet Pro MFP M277dw using Windows Fax and Scan. I then used Gimp to rotate ...
- 206
-3
votes
2
answers
506
views
What is the advantage to not use names, but only descriptions as unique identifier for lenses? [closed]
If I want to buy a new camera, I use its model number to look at review sites and videos, compare photos on photo websites e.g. flickr and search on price comparing websites and market places where I ...
- 140
2
votes
1
answer
398
views
Are internal focusing primes actually uncompensated varifocal lenses?
If I shorten the focal length of a lens without taking any other measures, that will reduce the required flange distance for infinity focus - meaning that if the actual flange distance is not changed, ...
- 7,182
1
vote
2
answers
256
views
What's the best choice of lens from an optics surplus shop to get a Stanhope Lens-like magnifying function?
I am looking to do some experiments with my cellphone and a lens, holding the lens in contact with my cellphone lens. I'm looking for a lens that has the shortest back focal length length possible, so ...
1
vote
3
answers
517
views
Why are adapters for slightly too-short backfocus lens mounts not made with just a thick glass window instead of a lens element?
Infinity-correcting adapters tend to incorporate a weak teleconverter usually.
It would appear that a thick, planar optical glass window is also capable of lengthening back focus - and would probably ...
- 7,182
0
votes
1
answer
168
views
What is behind this symmetric coma like effect, and literally odd-ball bokeh, in a triplet lens?
The example picture, shot with a vintage triplet (Staeble Kata 45mm/f2.8, wide open, on APS-C, no further crop), shows a curious shape of coma-like cross pattern in the right- and leftmost sculptures -...
- 7,182
3
votes
4
answers
156
views
Do strongly vignetted parts of a lens imaging circle gain depth of field?
Usually, vignetting in a lens (when not caused by glass losses, intentional graded filters or sensor issues) is explained as being a consequence of the effective aperture being smaller in corner areas,...
- 7,182
1
vote
3
answers
305
views
Protective shell for Nikon 200-500 f5.6 lens?
The Nikon 200-500 f/5.6 lens has a zoom mechanism that makes the lens physically longer or shorter depending on the zoom level, but is there an enclosure that will accommodate the lens across its ...
- 223
2
votes
3
answers
427
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 ...
- 6,598
1
vote
1
answer
338
views
Are front lens focusing and unit focusing equivalent in triplet/tessar style lenses?
Some vintage tessar or triplet type lenses (eg such intended for viewfinder cameras) implement focusing by merely moving the front element or front cell.
When adapting such lenses to other cameras, ...
- 7,182
-2
votes
4
answers
158
views
Why is zoom provided in Tokina 11-16mm?
I wonder what's the use of providing zoom in the Tokina 11-16mm.
Why not make it an 11mm prime lens instead? It would contain less elements, so will produce sharper images. Also at such wide angle, ...
0
votes
3
answers
172
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
3
votes
2
answers
560
views
Is there any problem with this camera not having a lens cover?
I am considering buying the Fujifilm FinePix XP140, shown here: https://www.fujifilm.com/products/digital_cameras/xp/finepix_xp140/.
I notice that most other cameras either have some form of lid that ...
- 131
10
votes
3
answers
283
views
What useful information can one gain from a lens element diagram?
On many photo gear review sites, cutaway diagrams of lenses are featured which show the layout of the elements in each lens. Here's the style of diagram I'm talking about, taken from Nikon's website ...
- 202
4
votes
3
answers
292
views
How commonly do constant-aperture manual zooms actually influence the aperture mechanically when zooming?
I have seen a few examples of constant aperture zooms (eg a 28-100mm f/4 Ricoh.) in the secondhand markets where the aperture appears to be not fully open (visibly non-round hole) at some zoom ...
- 7,182
14
votes
2
answers
998
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 ...
- 143
6
votes
3
answers
1k
views
What enables the Canon RF 70-200 f/2.8 to be much smaller than the EF version?
Canon announced the RF 70-200 f/2.8L in February 2019. This is notable for being much smaller than the equivalent EF lens, being perhaps two thirds of the length, yet maintaining the speed of the EF ...
- 21.8k
2
votes
1
answer
167
views
Are "moustache" distortions in rectilinear ultrawides the result of a fisheye+pincushion construction?
If I wanted to try and build an ultrawide, I guess I would try building a fisheye first, then try tearing the frame back into shape with a group that introduces pincushion distortion.
The kind of "...
- 7,182
1
vote
2
answers
575
views
How can a lens produce better (or worse) colors than another one?
So I was looking the Lomography Lomogon 32/2.5 Lens, which looks pretty cool. However in the copy they claim that it produces images with great color.
Now if the lens glass is slightly tinted, then ...
- 880
2
votes
1
answer
103
views
Is ROHS environmental theater the reason some lenses are only available as manual focus versions?
Classic lens designs often used glasses containing lead, thorium, cadmium and similar dopants.
These materials are rather taboo in what counts as electrical equipment and accessories in many ...
- 7,182
1
vote
1
answer
632
views
How wide does the front element of a lens have to be, given the focal length and the aperture?
Clearly, a lens with focal length F and aperture 1/f has to be at least F/f mm wide. Maybe a little more to accommodate the angle of view.
However, lenses tend to have wider front elements than F/f. ...
- 339
5
votes
4
answers
6k
views
Why we can't use telephoto lens for macro objects?
As I know the focal length of macro and tele lenses are the same, which is around 200mm. Now I wonder, why we can not use tele lens for macro photography?
P.S: Both macro and tele lenses have a focal ...
0
votes
2
answers
206
views
What would a 10-300 f/1.4 lens (such as for a spacecraft) look like?
My basic question is, what would a fast lens with a huge zoom range look like?
This question has been asked and answered for photographers on the ground - the answer was basically (rightfully) "no ...
5
votes
1
answer
153
views
What kind of lenses with a "slightly different diffraction behaviour" were used in "large format photography in the 1980s"?
Referring to an interview with a lens expert (Krolop&Gerst Objektivreihe 17/32), discussing diffraction limits.
"Es gibt ein paar Spezialobjektive die haben ein bisschen anderes Beugungsverhalten,...
- 7,182
1
vote
6
answers
2k
views
What is the relationship between lens diameter and exposure?
All of the online calculators for exposure, I have seen, factor in time, film speed, and aperture (which is a function of the iris diameter and the focal length of the lens).
However I would have ...
- 880
3
votes
2
answers
200
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 ...
- 7,182
Hot Network Questions
- A question about Lie groups
- What "extra protection" from ammonia is needed during an EVA?
- Is science fundamentally based on the binary testing of hypotheses? (according to the scientific method)
- Why expansion of real gases lead to cooling?
- Request for explicit character tables of conjectured, non-existent finite simple groups
- Realistic protection for spaceships against kinetic projectiles
- chemfig -- \charge writes into surrounding text
- How long is a life sentence in GA?
- Modify text file with command
- Mortality statistics: Ski touring vs rock climbing
- Is it true that "in Singapore, you should assume all rules are implemented at all times"?
- "How far back was the deer? - Does "how far back ...." make sense when the driver actually run into a deer in front of the car?
- Positive cone in Haagerup L²-space: how much information does it contain?
- what algorithm does numpy and scipy use to calculate matrix inverse?
- If I chose to make a game engine with GPL license, does anyone who build a project with it have to disclose the license or is that for distros only?
- Did Henry Kissinger say "it may be dangerous to be America's enemy, but to be America's friend is fatal"?
- how to remove holes in sparse file on Linux?
- Soda from non-kosher restaurant
- Sci-fi short story in which a dictator loses authority by being attacked/blinded by laser
- Can my boss sue me for handing in my notice
- Sketchy looking electrical outlet
- Why does Genesis 19:24 distinguish between the Lord and the Lord out of Heaven?
- What is this humming machine in my basement hooked up to a pipe?
- What's the character limit of this text field?