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

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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? ...
3
votes
2answers
593 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 ...
12
votes
6answers
1k views

Do lenses lose sharpness when they age?

I was reading this answer where it mentions, "..it's a lens that can lose sharpness as it ages.." and was wondering if this is true and if yes, true for all lenses. Reasons as to why this happens and ...
1
vote
2answers
181 views

What happened to multi-focal lenses?

Apparently multi-focal lenses such as the Tri-Elmar 16-18-21mm went out of fashion but I was wondering if the reasons for that were technical or commercial. Are multi-focal harder to build compared ...
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 ...
7
votes
1answer
321 views

What are the constructional differences between a macro and a regular lens?

I understand that to reduce minimum focusing distances, macro lens design must focus on maintaining certain distances between the lens and the sensor. However, is the placement of the lens and its ...
1
vote
1answer
135 views

Is the size of the rear opening of a lens related to image quality?

I purchased a Sony NEX F3, and it came with a 16mm lens and a 18-55mm lens. It seems to me that the 18-55mm lens produces better picture. Does the bigger lens opening in the 18-55mm lens produce ...
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 ...
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 ...
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 ...
20
votes
3answers
1k views

Is it physically possible to build a long zoom (17-300 mm for example) at an aperture value of around 1.4 or 1.2?

I'm curious if the physics allow a company to build such a lens of course with good IQ, minimal color aberration, maximum sharpness, and little to none lens vignetting or edge softness
4
votes
2answers
787 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
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?
2
votes
1answer
125 views

How are lenses made?

How are lenses and lens elements made? Also how are the lens elements and groups etc. arranged in the lens? In regards to the glass, are the elements ground, moulded or are there other techniques ...
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.
1
vote
1answer
2k views

What are screw drive lenses?

Are lenses known as screw drivers actually available?If so what are their features and why are they called so.Name some of the lens and their manufactures.
10
votes
3answers
734 views

Why are 50mm Lenses Cheaper?

There is no doubt that 50mm lenses, if all other variables are held equal, will beat any other lens when it comes to value for price (lower f/number). I want to know why. Possible theories I have ...
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 ...
8
votes
1answer
381 views

Why does my Zeiss Hasselblad Distagon lens have a 5 blade diaphragm?

As we are all aware, the more blades there are in a lens’s diaphragm, the rounder the resulting hole can be made, and in turn this gives a more natural looking bokeh. So on receiving my recent ...
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 ...
14
votes
1answer
718 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?
13
votes
2answers
2k views

Retrofocus lens? What's that?

I saw that in Why do some people prefer 50mm to 35mm prime lenses? , in @MattGrum's answer: ... The 50mm is a simpler design compared to the retrofocus 35mm ... What's retrofocus?
-1
votes
1answer
413 views

Below which focal length are lenses considered to be wide angle?

Focal length is the only factor that decides whether a lens is described as being normal or wide angle. Below which focal length are lenses considered to be wide angle? Is this focal length the same ...
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 ...
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 ...
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 ...
23
votes
2answers
2k 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 ...
0
votes
2answers
240 views

Does number of elements and groups of lens affect bokeh shape? [duplicate]

Possible Duplicate: What about lens construction influences bokeh? Does the circular or hexagonal shape of the bokeh depends on the number of elements and groups of the lens?? If not then ...
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?
7
votes
3answers
1k views

What are ED elements?

I find that some lenses are indicated with the letters "ED", referring to some special type of lens element. What are ED elements, and what advantages do they bring? Note that this question isn't ...
1
vote
3answers
263 views

Do lenses need to be made with more precision for Hasselblad's 60MPix camera?

One of Hasselblad's cameras has a Double-Full-Frame sensor. Does that mean that the lenses needed for it are incredibly complex to build (to have a sharp, high quality, abberation free image on the ...
14
votes
1answer
249 views

What lens design limits derive from the width of the lens mount?

I'm familiar with the lens design limitations imposed by the flange-to-focal-plane distance. But what constraints are caused by the width of the lens mount (that is, the size of the hole in the ...
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 ...
10
votes
1answer
480 views

How do I design a conceptual lens schematic?

I would like to attempt to create a schematic for a simple or small compound lens, but the process seems very daunting. I have thoroughly read 'Science for the Curious Photographer: An Introduction to ...
13
votes
2answers
2k views

What is the benefit of an internal focus lens?

The "IF" in Pentax DA★ 200mm f/2.8 ED (IF) SDM stands for "Internal Focus". I know what this means: the lens doesn't change in size as I focus. (And it's true; it doesn't.) What's the point of this, ...
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
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
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 ...
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 ...
8
votes
3answers
460 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 ...
11
votes
4answers
2k views

Is overall light gathering of a lens only dependant on aperture?

My impression is that the aperture value of a lens determines its light gathering ability, but I'm not sure I understand how it works... When considering light gathering in telescopes, it is ...
4
votes
1answer
2k views

How to read a lens spot diagram?

How to read such a lens spot diagram?
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 ...
11
votes
2answers
410 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 ...
19
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 ...
51
votes
5answers
1k views

Is there development in the world of lenses?

Now, I'm not an expert, so if this post makes you laugh, you're welcome. Still, as far as I know there are basically two components that determine the potential quality of a camera's photos: Sensor ...
9
votes
4answers
544 views

Why do filter sizes vary for lenses of the same focal length?

I have a Nikkor 18-55 kit lens that has a 52mm filter, and recently I was looking that the 17-55 lens has a 77mm filter. Is it because the latter is a better quality lens? I assume a bigger circle ...
30
votes
3answers
13k 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 ...
14
votes
2answers
2k views

Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?

Why does a camera's maximum (allowed) aperture get smaller when you increase its zoom?