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

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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?
3
votes
2answers
594 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
votes
1answer
162 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 ...
8
votes
3answers
626 views

Why are Zeiss lenses heavier and larger for Canon EF than Nikon F mounts?

We recently acquired specifications for all DSLR lenses by Carl Zeiss and almost always the Canon EF-mount version is larger and heavier than the Nikon F-mount version. The difference ranges from ...
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 ...
0
votes
1answer
334 views

What is the infinity lens by Jim Frazier? [duplicate]

I know who Jim Frazier is and what he has done, but I only have basic knowledge of his invention. Could someone please explain what he has done further?
0
votes
1answer
67 views

Can I remove the tiny amount of wiggle in the focus ring of my brand new lens?

I just purchased a Samyang 24mm T1.5 lens and the focus ring is not 100% solid and smooth, there is a tiny amount of give in the vertical direction (perpindicular to the horizontal direction the ring ...
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 ...
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 ...
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 ...
11
votes
4answers
639 views

Why aren't lenses designed with extra large apertures for autofocus beyond what's used for imaging?

Historically, designing large-aperture lenses has been difficult because correcting the optical aberrations that arise from large apertures requires complex designs and very large amounts of glass. ...
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 ...
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. ...
2
votes
2answers
1k views

Why are large aperture lenses so expensive? [duplicate]

Why are lenses with very large apertures so expensive? For example, generally speaking, there is a significant price difference between a f/1.8, f/1.4 and f/1.2 lens of the same focal length. Doesn't ...
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 ...
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 ...
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 ...
7
votes
7answers
1k views

How come there are no 24-70mm f/2.8 lenses with image stabilization?

There definitely aren't any Canon or Nikon lenses. I also have not seen any third party lenses. I can think of two reasons for this: There is some technical limitation (which I tend to doubt since ...
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 ...
5
votes
2answers
826 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 ...
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 ...
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
497 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 ...
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
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 ...
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 ...
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 ...
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?
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 ...
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 ...
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.
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 ...
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.
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 ...
-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 ...
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?
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 ...
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 ...
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 ...
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 ...
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 ...
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
378 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 ...