Questions tagged [lens-design]

Of and relating to the specifics of lens construction and manufacture.

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4 votes
1 answer
262 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 ...
2 votes
1 answer
415 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, ...
0 votes
1 answer
53 views

What is the lens diagram of this Pentacon 50mm F1.8 multi coating lens?

I'm trying to find detailed lens diagrams (showing the lens elements) of this old prime lens I have but I can't seem to find anything. Does anyone know where could I find it? Here are some photos of ...
-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 ...
12 votes
6 answers
7k 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 ...
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 ...
9 votes
4 answers
19k views

Which impacts the speed of focusing more, the lens or the camera body?

Speed is the larger concern, but a description of accuracy would be appreciated as well.
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 ...
2 votes
3 answers
433 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 ...
33 votes
8 answers
4k views

What is the difference between in-lens image stabilizing and sensor-based image stabilizing?

And which one is more effective?
0 votes
4 answers
863 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 ...
9 votes
1 answer
2k views

Why are so many kit-lenses parfocal if it's an expensive feature?

According to this answer, parfocal lenses (lenses that can zoom in/out without losing focus) are relatively rare and more expensive. However, the original poster's kit-lens is parfocal. Additionally,...
0 votes
3 answers
184 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 ...
3 votes
1 answer
515 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 ...
1 vote
0 answers
201 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 ...
3 votes
2 answers
265 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
186 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 ...
1 vote
3 answers
312 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 ...
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 ...
2 votes
1 answer
188 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 ...
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 ...
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 ...
0 votes
1 answer
213 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 ...
1 vote
4 answers
208 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 ...
1 vote
3 answers
320 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 "...
2 votes
1 answer
163 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 ...
2 votes
3 answers
6k views

What does a megapixel designation on a lens actually mean?

I know that in a CMOS sensor the megapixels give you an idea of how many pixels are actually there to capture the light. In terms of a lens however, I cannot find any relation between the megapixels ...
10 votes
2 answers
39k views

What is the difference between the Canon 55-250 IS II and 55-250 IS STM lenses?

I am a beginner in DSLR, and would like to purchase another lens other than the kit lens (18-55mm STM) that came with my Rebel T5i/D700. After much googling, and reading of blogs, I have decided to ...
8 votes
4 answers
4k views

Why did manufacturers stop including DOF scales on lenses?

Seriously why? I hate it and I hate memorizing it or check my phone app for the depth of field of the current aperture. I find it so useful in old lenses. The DOF preview doesn't help that much ...
15 votes
5 answers
4k views

How can a lens like a 18-55mm have more than one focal length?

How can a lens have a range of focal lengths? Shouldn't it be a single number? Isn't focal length supposed to be fixed for a lens of a particular shape and geometry? What am I missing? How many ...
8 votes
3 answers
3k views

What are the production cost breakdowns for lenses?

I am very curious to know what the breakdown is for lens production costs. This information is hard to come by, and I am unable to find any reliable sources. Obviously, I can't just email Canon to ...
6 votes
1 answer
11k views

How to read a lens spot diagram?

How to read such a lens spot diagram?
1 vote
2 answers
264 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 ...
5 votes
3 answers
7k views

Are there lenses that exhibit absolutely no focus breathing?

As noted here focus breathing can be problematic, especially for macro focus stacking. Are there lenses that exhibit absolutely no focus breathing? Is there some way to find lenses that minimize ...
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 ...
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 ...
44 votes
4 answers
43k views

What does the number of elements and groups in a lens mean?

All lens specifications include a statement of how many elements the lens contains, and in how many groups, for example: Nikon AF-S VR Zoom-NIKKOR 70-300 mm 1:4,5-5,6G: 17 elements in 12 groups (two ...
1 vote
4 answers
433 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 ...
10 votes
5 answers
2k views

Why there are so few lenses with small minimum focus distance?

My superzoom compact camera Canon Powershot SX60 HS has advertised minimum (closest) focus distance of 0 cm, and many other compacts have this in a couple cm range. But for my micro four thirds ...
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 (...
18 votes
8 answers
9k views

Will using a lens at max aperture ("wide open") result in poor images?

I’m looking to add a second lens to my kit lens I got with my Nikon D7000. I have read several reviews on both the 35 and 50 mm lenses made by Nikon in particular that said using either lens at the ...
5 votes
4 answers
331 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 ...
0 votes
2 answers
639 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
340 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 ...
19 votes
11 answers
4k views

Are all kit lenses poor? (And if so, why?)

Kerri Shotts says (emphasis mine): Also, if you already have great glass, there is little reason to get more (unless you need it for a certain reason). E.g., if you have a 70-200 f/4, don't rush ...
0 votes
3 answers
238 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. ...
3 votes
3 answers
244 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 ...
6 votes
4 answers
464 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 ...
8 votes
5 answers
21k views

Which Zeiss lenses are actually made in Germany?

Recently, I used a Zeiss Makro-Planar T* 2/100 ZE only to find a big "Made in Japan" marking on it. Which of their lenses are made in Germany, and does it matter if it's made there vs. Japan?
7 votes
3 answers
1k views

50mm mirror lens. Does one exist?

I like the bokeh and limitations of mirror lenses. I however, also love my 50mm 1.4. Does a 50mm mirror lens exist? I searched but could not find one. If not 50mm what is the closest to 50mm one can ...

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