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

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2
votes
2answers
151 views

Why do superzoom designs keep expanding on the telephoto rather than wide-angle end?

Why do bridge/semipro/superzoom camera manufacturers keep increasing the telephoto end rather than the wide-angle end? For example, the Nikon P900 has a 35 mm-equivalent focal length of 24 to 2000 ...
-1
votes
1answer
41 views

Need Code V tutorial (optical design software) [closed]

I'm working on Code V the optical software designer which is used to model, analyze, optimize, and provide fabrication support for the development of optical systems (lenses, cameras, telescopes..) ...
1
vote
2answers
94 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 ...
0
votes
1answer
99 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 ...
-1
votes
2answers
77 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. ...
5
votes
1answer
966 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?
0
votes
1answer
80 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
votes
1answer
79 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 ...
1
vote
3answers
127 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 ...
14
votes
1answer
854 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
votes
1answer
136 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 ...
20
votes
3answers
3k 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 ...
2
votes
1answer
108 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
votes
2answers
151 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 ...
8
votes
2answers
362 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 ...
3
votes
3answers
217 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?
13
votes
3answers
457 views

What is the Leica look?

What is the Leica look that fans of the company claim is unique to them? What concrete differences are there that are most obvious to a layman?
2
votes
1answer
57 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 ...
6
votes
1answer
149 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 ...
8
votes
3answers
762 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 ...
2
votes
2answers
312 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 ...
1
vote
4answers
348 views

Why does crop factor apply with APS-C lenses, and why aren't these brighter than FF ones at same aperture?

I know that the image circle of FF-lenses is bigger than it needs to be on APS-C sensors, thus the FOV spears narrower. I've heard that APS-C lenses sit closer to the sensor, thus projecting a smaller ...
0
votes
3answers
206 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 ...
3
votes
4answers
1k 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 ...
7
votes
3answers
3k 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
votes
4answers
370 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 ...
12
votes
2answers
416 views

Does focus breathing make a lens slower when close focusing?

I've heard that focal length of some lenses will become noticeably longer when focusing to a close distance, an effect called "focus breathing". Since f-number is focal length divided by diameter of ...
4
votes
3answers
234 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 ...
30
votes
3answers
16k 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 ...
6
votes
2answers
1k views

How does an apodization filter improve bokeh?

The new Fujifilm Fujinon XF56mmF1.2 R APD has an "apodization" filter, which Fujifilm says "smoothes the outline of the subject to create a more natural bokeh effect". The Wikipedia article on ...
2
votes
1answer
149 views

How does a focus ring bring a subject in or out of focus?

When you manually adjust your focus ring on the lens, what actually happens inside the lens? Is this changing simply the point at which the lens is focusing, so that anything at this distance away ...
2
votes
4answers
136 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 ...
0
votes
1answer
82 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
votes
5answers
1k 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 ...
4
votes
3answers
828 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 ...
3
votes
3answers
306 views

Variable focal length for macro lenses?

True macro lenses come in fixed focal length. Are there any macro lensens which have variable focal lengths? And please explain why yes or why not?
3
votes
1answer
130 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 ...
24
votes
2answers
3k views

What characteristics make a lens good or bad?

When reading lens reviews on the Internet, I often find subjective statements about the image quality that a lens produces, such as "good contrast" or "sharp". The problem is that I don't think I am ...
4
votes
2answers
490 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 ...
25
votes
3answers
2k views

When you zoom in with a lens on an SLR why does the lens go in then out?

I guess this is more a question of optics than photography but I just got an SLR with a basic 18-55 lens. I noticed that when going from 18 to 55 or 55 to 18 the lens physically comes back in and ...
3
votes
2answers
206 views

Why are phase detect lenses adapted onto contrast detect bodies so much slower?

The Sony A7 is able to adapt almost any type of auto-focus lens (Canon/Nikon/etc) and use autofocusing, but the auto-focusing is much slower than the same focal lengths native for the A7. Why would ...
19
votes
4answers
11k 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
vote
1answer
156 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 ...
4
votes
1answer
294 views

What is meant by 'centering quality'?

I'm reading lens reviews and I have encountered the term 'centering quality' a few times (e.g. http://www.photozone.de/sony_nex/720-sony50f18nex?start=1). What does this term mean? What are the ...
8
votes
2answers
1k 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, ...
5
votes
1answer
129 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 ...
0
votes
2answers
508 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 ...
3
votes
4answers
9k views

What is the difference between Nikkor D type and G type lenses?

I recently bought a Nikon D5100. And along with this camera, I got the AF-S DX NIKKOR 18-55mm f/3.5-5.6G VR lens as kit. It's "G" type lens, right? One of my friend suggested to buy a 50mm f/1.8D ...
7
votes
2answers
2k 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?