Of and relating to the specifics of lens construction and manufacture.
4
votes
1answer
81 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
280 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. ...
10
votes
6answers
658 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 ...
0
votes
0answers
7 views
Digital video cameras optical zoom vs lenses [migrated]
If you read at digital video cameras specifications, you will probably read that camera has 20x optical zoom or even greater.
If you compare this camera with my Nikor 18-200 lens, the lens itself is ...
6
votes
3answers
290 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
1answer
213 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
130 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
332 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
46 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
108 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 ...
4
votes
4answers
230 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
117 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 ...
6
votes
7answers
901 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
116 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 ...
9
votes
2answers
629 views
What characteristics make a good lens good?
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 ...
6
votes
2answers
169 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 ...
4
votes
2answers
573 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
116 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
228 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
275 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 ...
2
votes
3answers
214 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
753 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
194 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 ...
18
votes
3answers
619 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
5answers
449 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
328 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
275 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 ...
12
votes
2answers
471 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
118 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
147 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
384 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.
9
votes
3answers
385 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
431 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.
3
votes
1answer
113 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
272 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 ...
12
votes
1answer
411 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?
-1
votes
1answer
184 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 ...
2
votes
2answers
133 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
247 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 ...
13
votes
4answers
2k 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.
...
0
votes
2answers
170 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
175 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?
23
votes
3answers
5k 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 ...
1
vote
3answers
247 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 ...
44
votes
5answers
889 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
...
12
votes
1answer
202 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
281 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
594 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
2answers
731 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, ...
5
votes
1answer
262 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 ...
