Questions tagged [lens-design]

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

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2
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1answer
104 views

Does the type of lens adapter matter for manual focus?

Context I use a cheap adapter that has an Aperture Ring for the new Nikon G lens but also works for older lens as well. I use a Sony a6000 which has focus peaking and related. Question Assuming ...
1
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1answer
955 views

How do lenses focus? (and zoom?) [duplicate]

My understanding of focal length is that it is the distance from the lens to the sensor; in my observations: higher focal lengths make for longer lens. Then I started thinking about how a lens ...
0
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3answers
430 views

Why don't we have a single lens e.g. say a 18-200 f/1.2 lens for the SLR camera? [duplicate]

Right now we have multiple interchangeable lenses. So why don't we have a single lens, say a 18-200 f/1.2 lens? Are camera manufacturers deliberately avoiding that or it is that it is physically ...
22
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2answers
3k views

Are there any secrets in lens design?

Lens manufacturers usually share diagrams like this for their products. However, they conspicuously omit specifications that would allow one to completely analyze the optical system, like the power ...
3
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6answers
290 views

Should lenses of equal quality for smaller sensors be cheaper?

In theory do we expect lenses of identical specs and quality to be cheaper when designed for smaller sensors? My expectation is that the answer is yes, because all of the things that lenses struggle ...
5
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2answers
389 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!
4
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1answer
1k views

How is focus-breathing controlled in lens design?

Answers here note that minimizing focus-breathing is especially desirable for cine lenses, and that it is one of the common features of those higher-end lenses. How is it achieved? Also noteworthy ...
11
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3answers
845 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 ...
8
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4answers
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 ...
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2answers
8k views

What kind of lens are used in mobile phones?

Usually what kind of lens are used in mobile phones. I mean of the types similar to convex, concave etc.. Are they fixed focal length usually? How do we get the focal length of camera from digital ...
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4answers
776 views

What lens designs are sharper than a pinhole lens but also allow for multi-month exposures?

I have a homemade pinhole camera (film) that I use for taking super long exposures (multiple months). And while the results are fun, I would like to improve the sharpness of the image. Is diffraction ...
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3answers
1k views

Could a phone-camera have a medium-telephoto lens and still fit in a phone?

[to keep it simple, all focal lengths noted are 35mm equivalents; crop factors for phone cameras are about 7-8x, give or take] As far as I can tell most new phone cameras have a fixed, medium-wide ...
4
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2answers
2k views

What is the importance of the back focal length of a lens?

What is the effect and importance of the back focal length of a lens? For instance, if I look at these two lenses by Ricoh, they have the same focal length and aperture, but their back focal lengths ...
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1answer
1k views

Nikon 50mm 1.8g vs 1.8d? [duplicate]

What are some pros and cons of each? I use a Nikon D600 and am looking for my 50mm. I shoot a lot of video, so a smooth manual control is important to me. Besides that, I am unsure of what exactly I ...
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2answers
139 views

How much zoom does a lens need to have before we call it a superzoom lens?

I've read that superzoom lenses have poor image quality, but how much zoom does a lens need to have before we call it a superzoom lens? 3x is certainly not a superzoom, while 10x probably is. ...
6
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1answer
1k views

What makes the Zeiss Otus 1.4/55 so special?

The new Zeiss Otus 55mm f/1.4 is nearly $4000. With faster lenses from Canon (50mm f/1.2L) with autofocus, why is the zeiss lens more than twice that of the Canon counterpart?
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1answer
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 ...
0
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1answer
735 views

camera mobile phone takes pictures at constant focal length if 3.5 mm.supposed to have autofocus and touchfocus [duplicate]

This is a cheap Chinese landvo l200 Android mtk65xx mobile The onlything it keeps Changing is IS0 from 150 to 800 + And exposure time I wondered how can it autofocus and touch Focus when it keeps ...
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2answers
1k views

What are the differences between pictures shot with spherical and aspherical lenses? [duplicate]

I read about some differences between spherical and aspherical lenses. Mostly about geometry though. I was wondering what is the difference on the pictures. How are the pictures of an aspherical lens ...
14
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1answer
2k views

How does a macro lens focus so close?

How does a macro lens focus so closely and how is the system different to that of a non-macro lens?
0
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1answer
253 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 ...
2
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1answer
195 views

do mirrorless camera lenses have automatic diaphragms

Do mirrorless cameras have lenses with automatic diaphragms like DSLRs or are you able to focus and view through the working aperture because of their electronic viewfinders?
4
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2answers
619 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 ...
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3answers
2k views

How can the focal length of a lens be many times greater than the lens's physical length?

I bought a Tamron 16-300. Question is: how can it have a focal length 0f 300 mm when it is only about 30 mm long? Doesn't the lens have to be 300 mm from the sensing element?
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1answer
148 views

Does Sony DT 18-135mm SAM lens has Full-time Manual focus feature

I checked it in Len user-manual but Sony didn't mention about Full-time manual feature. I also checked it on Sony website but I didn't find any resources too. Does anyone know the Len has Full-time ...
8
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1answer
237 views

Can the method from the paper “High-Quality Computational Imaging Through Simple Lenses” compete with conventional lenses?

This answer to another question of mine linked to an interesting article: High-Quality Computational Imaging Through Simple Lenses. It proposes the use of simple optics and computational photography ...
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3answers
2k views

What is a pump zoom lens?

While browsing for cheap second hand lenses I found the Cosina 70-210mm f4.5-5.6. The seller notes that it's a pump zoom. Googling the term does yield some results, but these simply state that a ...
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2answers
2k views

How effective are the rear weather sealing rings on lenses?

I am kinda torn between buying a Sigma 18-35mm f1.8, Nikkor 17-55 f2.8 and Sigma 17-50 f2.8 for my D3100 and D7100 cameras. The reason for confusion is that the Nikkor one has a weather sealing ring ...
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3answers
511 views

Why can lenses only focus from so close? [duplicate]

I have always wondered, why is it that a lens can only focus from so far away from the subject? I know some lenses have a kind of macro switch which basically allows them to focus closer but why are ...
4
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4answers
11k views

Differences between canon 17-85mm and 18-55mm

I was given a 450d with a canon 17-85mm lens, it has USM and image stabilzing. It has always seemed okay to me but after a few years i have decided to upgrade to the 700d, which has now come with a ...
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4answers
2k views

What did the “macro” switch/mode do on older zoom lenses?

I remember that a number of older (80s to maybe mid 90s) zooms had a "macro" mode where you would throw a switch that allowed the lens to focus closer. What was that? was it just a built in extension ...
4
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3answers
633 views

Why do macro lenses have such recessed front elements?

This is a 90mm Tamron SP Di macro lens. Like other macro lenses in this focal range I've seen, it has a deeply recessed front element — more than 1.5", and that's without the optional lens hood!...
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1answer
182 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, ...
6
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5answers
3k views

What about lens construction influences bokeh?

I can understand how certain elements of a lens can correct an aberrations or make it sharper - but specifically, how do lens manufacturers influence the bokeh - the quality of the blur? There's a ...
5
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3answers
2k views

Why do circular fish eye lenses create circular images?

I'm trying to understand the physics of circular fish eye lenses. As far as I can see circular fish eye lenses create an circular image because the area of the sensor is larger than the projected ...
4
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1answer
530 views

What is the reason that the materials of the lens barrels changed from metal to plastic?

Most of my older lenses have a shell of metal instead of plastic that is common today on all lenses even the expensive ones (with the possible exception of expensive tele lenses). When I compare the ...
23
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4answers
22k views

Why is the aperture ring removed from new Nikon lenses?

Maybe I'm wrong, but I notice that Nikon's newer lenses don't have an aperture ring. For example, an older AF 35 mm f/2D is now replaced by AF-S DX 35 mm f/1.8G, or AF 50 mm f/1.8D is replaced by a ...
1
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1answer
572 views

What's with these petal-shaped lens hoods? [duplicate]

In the last decade or so, I've seen more and more lens hoods for long lenses that aren't simply round in front. I was reminded of that by this answer, which shows the inside of a neatly packed camera ...
9
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2answers
4k views

Do cine lenses have any significant advantages for still photography?

A number of manufacturers, including Canon and Zeiss, make cine-optimised lenses for still photography mounts (e.g. EF). For reasons well-covered elsewhere, these lenses are stupendously expensive, ...
6
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1answer
613 views

Which lenses show focus shift?

Some lenses, because of a design that includes uncorrected spherical aberration, shift their plane of focus backwards as the aperture is narrowed. This is most apparent at close focusing distances and ...
4
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3answers
42k views

What is the relationship between “macro” and “telephoto” lenses? [duplicate]

Can anyone explain the difference between "macro" and "telephoto"? I know that a macro lens will give you a magnification of 1:1 but how does it differ from a telephoto lens?
6
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2answers
1k views

Why are there no fast APS-C zooms beyond 55mm?

I am looking to add a longer lens to my current zoom (a Tamron 17-50) for my Nikon D300 (but I believe this question is relevant across aps-c lens manufacturers). There is just one currently in ...
19
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5answers
10k views

What's the difference between the Canon and Nikon lenses mounts?

I was wondering what, if any, are the technical differences between the two mounting systems. Does one auto focus faster? Can one hold more weight? Things along those lines that make them different.
3
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3answers
144 views

Suggestion for books tracing the evolution of photographic equipment [closed]

Could you please suggest a book that Tracks the evolution of photo equipment from inception to modern times Has diagrams and cutaways of equipment and mechanisms, including shutter and aperture ...
9
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1answer
700 views

Why do certain lenses increase angle of view upon close focus?

I recently picked up a superzoom lens, the Nikon 28-300mm. Although I got it primarily for its versatility, my intuition was that a lens that can do 300mm focal length at 50 cm, as indeed it can, ...
9
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1answer
518 views

What kind of mirror in a mirror lens?

A normal mirror, that we see for example in an elevator, is a glass sheet with thin metal coating on the backside, so light reflecting from the metal surface goes first thru the glass. Metal mirror (...
2
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3answers
1k views

Are polarizing filters as useful on normal lenses as they are on wide-angle lenses?

I have seen people using Polarizing filters on many wide angle lenses. Is it worth using a Polarizing Filter on a 40mm 2.8f STM Pancake lens or any other prime lens?
3
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2answers
3k 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 ...
2
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1answer
889 views

Canon 40mm STM - The focus cannot be adjusted in manual mode

I bought a new Canon 40mm STM lens and in the Lens Manual it says The focus cannot be adjusted in manual mode. Does it mean that its harmful to rotate the focus ring when the focusing mode is set ...