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

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7
votes
2answers
1k 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
1answer
573 views

What is the difference between microcontrast and sharpness?

I keep hearing the internet talk of this micro contrast from the famous Zeiss lenses. What is it? Is it the same as sharpness? And if so, why is it called differently for Zeiss? Does anyone have any ...
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 ...
6
votes
2answers
545 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 ...
6
votes
2answers
563 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 ...
6
votes
1answer
377 views

How do ultrasonic motors allow continuous manual focus?

I understand the basic pros and cons of ultrasonic lens motors — called USM by Canon, SDM by Pentax, or SWM by Nikon. One of the chief benefits is that they allow "always on" manual focusing — you ...
6
votes
1answer
133 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 ...
5
votes
2answers
825 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 ...
5
votes
1answer
874 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?
5
votes
7answers
6k views

Does the Nikkor 50mm f/1.4g perform better than the f/1.8d?

Looking into these two lenses, I'm getting the impression that for my Nikon D-90 with DX camera sensor that the f/1.8d would waste light that is cropped by the sensor whereas the f/1.4g would not as ...
5
votes
3answers
476 views

Does the imaging circle size change when a lens zooms?

When a zoom lens is designed for a cropped (APS-C) imaging circle, does the imaging circle necessarily stay that small throughout the zoom range? It is easily understandable that a prime lens ...
5
votes
2answers
287 views

Why aren't more lenses white?

So high end Canon lenses are white. This is to reduce heat, correct? If so why is this something that only appears in really high end Canon lenses. I wouldn't think that painting a lens white ...
5
votes
2answers
262 views

Can it damage a Canon L Series Lens (or a photographic lens with anti-glare lenses) if a powerful (Class IIIB or IV) laser is passed through it?

I would like to get a wide laser beam but a high quality one. That's why I'll make it go through a high-end Canon lens. But I would like to know if that is likely to damage my lens ! Maybe it will ...
5
votes
1answer
438 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. ...
5
votes
1answer
160 views

Where exactly would the focal length of a lens in the ray diagram fall?

If a lens is specified as (EF 50mm f/1.8), where exactly is the 50mm distance if I were to show it in a ray diagram? Considering that a lens is made up of multiple elements, I could not find a ...
5
votes
1answer
108 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 ...
5
votes
0answers
48 views

How does lens design affect the richness of color reproduction? [duplicate]

Comparing a kit zoom lens to a faster, 20-year-old prime it seems like the old lens produces richer, warmer color. I've noticed the same kind of comparisons elsewhere. What is the lens actually doing? ...
4
votes
4answers
248 views

How small can current SLRs get and still give comparable photo quality?

Let's take the full-frame Canon 5D as example. How small can this camera be and still give comparable picture quality? What are the design constraints? Besides the sensor, the body, can the lenses ...
4
votes
2answers
786 views

Are all DSLR lenses made of glass?

This question is about lenses to "big" DSLRs, not system or compact cameras with interchangeable lens. Are all lenses made of glass in DSLR? And if not, is there a notable difference between: kit ...
4
votes
2answers
228 views

Is having a lens with vignetting a real world negative for portrait lenses?

After reading this answer for another post: I don't mind the vignetting as it actually improves the look of portraits however if you're doing astrophotography what's the point in a lens that's ...
4
votes
3answers
779 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
votes
2answers
413 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 ...
4
votes
2answers
3k views

What does “Flat Field Focus” mean?

Looking at lenses, specifically sigma macro lenses, I noticed that it had a ""Flat Field" front lens element". What does this mean? And how is it different to the norm?
4
votes
4answers
1k 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.
4
votes
1answer
2k views

How to read a lens spot diagram?

How to read such a lens spot diagram?
4
votes
3answers
191 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 ...
4
votes
1answer
200 views

What factor determines the largest usable sensor size with a certain lens?

Reading this excellent answer about field of view, focal length and sensor size a new question came to mind. From the drawn diagrams it is clearly visible that for the same focal length an increase ...
4
votes
1answer
267 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 ...
4
votes
2answers
105 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 ...
4
votes
1answer
564 views

Why is anamorphic bokeh oval shaped?

I understand that an anamorphic lens "stretches" an image when it is recorded, but when it's played back, it's "un-stretched" so that it looks normal. But with images shot with anamorphic lenses, ...
3
votes
2answers
295 views

Why is there no apparent relation between focal length and physical lens size?

Why is there no apparent relation between focal length and physical lens size? For example, the Nikkor 20mm lens has a physical length of 42.5mm! That's more than twice the focal length! And if you ...
3
votes
3answers
2k 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?
3
votes
2answers
490 views

What influences the shape of a lens flare?

Most of the time the shape of the flare is close to a circle, but recently I saw a movie where the lens flare was elliptically shaped. The stills below, taken from the movie Die Hard, show the effect ...
3
votes
3answers
495 views

What are the difficulties with making a 10mm-300mm zoom lens?

I'd like to have a comprehensive explanation why such a lens doesn't make 'sense', whether economically, technically, ergonomically, etc. Please support each reason with some details so I can learn ...
3
votes
2answers
174 views

Why are lenses like the 40mm small and lightweight, but get larger and heavier as they get wider or narrower?

The 40mm/2.8 seems to be the smallest lens one can make. Also, why are f/2.8 lenses small and lightweight, but get larger and heavier as they get wider or narrower? Are these two things by ...
3
votes
4answers
162 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?
3
votes
2answers
230 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?
3
votes
3answers
250 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
2answers
592 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 ...
3
votes
4answers
551 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 ...
3
votes
1answer
121 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 ...
3
votes
3answers
118 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 ...
3
votes
2answers
133 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!
3
votes
2answers
151 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 ...
2
votes
3answers
304 views

Why not separate a tilt shift lens into two separate lenses?

When using a tilt shift lens I find myself using the two features of tilting and shifting for separate photos. If I want to control the depth of field such as in a portrait or macro shot I will tilt ...
2
votes
3answers
380 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?
2
votes
4answers
4k 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 ...
2
votes
1answer
1k views

How does the quantity of elements and blades in a lens affect the optics?

I am trying to get a greater understanding of how lenses work. Basically I bought this lens, the Sigma 10-20 f4-5.6: The construction has really fascinated me. 14 Elements in 10 Groups?! What ...
2
votes
4answers
1k views

When should I turn off image stabilization? [duplicate]

I've read a bunch of the questions here about image stabilization, but I don't see any concrete examples/proof or references with regards to the benefits of turning off image stabilization. I've got ...
2
votes
2answers
86 views

Resources for learning about digital cameras technical design?

I would like to learn more about the design of digital cameras in general, and DSLR in particular, from optics to sensors to mounts. Do you know any up-to-date resources (other than Wikipedia) where ...