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Optics is the science of light, and in photography often refers more specifically to to the properties and construction of lenses or the technical aspects of light sensors.

learn more… | top users | synonyms (1)

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5answers
222 views

Why does it seem like large sensors are necessary for good low-light performance?

Phone manufacturers have recently started advertising the size of the photosites on smartphone camera sensors. They argue that larger photosites lead to better low-light performance. I think a good ...
6
votes
2answers
160 views

Do nano coatings actually make a difference?

Nikon famously has "nano coatings" on it's higher ended lens, and many photographers online swear that this visibly improves their images. However, it's not clear what the actual improvement is ...
7
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2answers
3k 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 ...
2
votes
1answer
128 views

Does a lens exist that is parfocal, has a linear zoom throw, and is affordable?

I'm working on a project to create, essentially, a servo-powered zoom lens, using a (D)SLR zoom, a zoom ring gear, and a stepper motor. After mounting the zoom ring gear, I'll attach a pinion gear to ...
2
votes
0answers
99 views

How to obtain 180° FOV and little optical errors?

I'm thinking about building an all-sky camera, i.e. an automated camera that points straight up to the zenith and that captures the entire sky down to the horizon. The idea is to capture celestial ...
0
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2answers
46 views

Nikon J1, takes pictures but they are all black, doesn't seem to “see” things, lens not the problem

I have a nikon J1, it has always worked well. Today I wanted to take a picture and the screen appeared black, like something was blocking the light completely or I was trying to take a picture of a ...
36
votes
3answers
3k views

How do I interpret an MTF Chart?

As part of how Canon (and other lens makers) give technical information about their lenses, they supply an MTF (Modulation Transfer Function) chart. How do I read and interpret what the chart is ...
2
votes
2answers
104 views

How do universal clip-on iPhone lenses work?

So, recently I see a lot of clip-on Universal iPhone lenses like this (aliexpress link). I have a CCTV camera at home. It has a lens which looks like this from m12lenses.com. Can I clamp these iPhone ...
11
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2answers
6k views

Why is depth of field affected by focal length?

As the focal length decreases, the depth of field increases as well. Why is this? I'm not so much interested in a physics lesson as I am interested in a simple, down-to-earth explanation.
10
votes
2answers
143 views

What model does Lightroom use for lens correction?

I use Adobe Lightroom to remove the barrel distortion from GoPro images. Does anyone know if this software uses the Brown-Conrady model to achieve the lens correction? If not which model does it use? ...
0
votes
2answers
68 views

Distortion Removal=Parallax Removal?

So, as the title suggests: does distortion removal caused by lenses means that the parallax is also removed from the pictures?
1
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1answer
178 views

How do I design a secondary lens for my fixed-lens camera to narrow its field of view?

My goal is to put a lens or an array of lenses in front of my actioncam to use its high resolution for recording of undistorted normal-eyed footage, to avoid having to buy two cameras for the ...
34
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5answers
7k views

How do constant aperture zoom lenses work?

Cheaper zoom lenses usually are faster at the wide end and slower at the long end (for example, the $150 Canon EF-S 18-55mm f/3.5-5.6). More expensive constant-aperture zoom lenses have the same ...
1
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4answers
106 views

Does aperture effect the “depth” of faces in a portrait? Wide aperture make noses look shorter, wrinkles less pronounced?

Having a debate with myself that F/10 makes my portraits look better by making faces have less "depth." What I mean is I feel like wider apertures such as f/4 make my nose look longer and wrinkles ...
1
vote
5answers
3k views

Why image at 400mm is LARGER THAN DOUBLE of image at 200mm? (according to lens formula)

Like most of us, I thought it was yes. Until I really look into the Lens Equation: (1/subject distance) + (1/image distance) = (1/focal length) ...
16
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3answers
650 views

What is Chromatic Aberration?

What is Chromatic Aberration? Is it a physical part of the lens, or just an optical illusion?
2
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4answers
135 views

How can I fire two cameras simultaneously with different settings but the exact same view?

I have an idea I want to play around with and I was hoping something already exists for it but google has turned up nothing. I want to use two cameras synchronized to fire at the exact same time and ...
1
vote
0answers
78 views

Could someone please give simple explanation of “Principal plane” & “Nodal plane”?

I have read "cardinal point" on Wikipedia for number of times but still I can't get it. My English is not perfect. could someone please explain it in simple English?
1
vote
1answer
54 views

If a lens has a 4% Barrel Distortion, what does that mean for images?

I know what barrel distortion is, but how do I take a 4% rating and relate that to an image?
19
votes
13answers
24k views

How does the lens diameter influence photo quality?

I have tested two different 50mm lenses in my camera. One was a Nikkor 50mm ∅52mm. The other one was a Sigma 50mm ∅72mm. I took some pictures with both lenses using the same setup for aperture and ...
1
vote
4answers
600 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 ...
26
votes
3answers
7k views

What is a zone plate?

I was looking into alternative methods of photography and I happened upon something called a 'zone plate.' Three questions: What is a zone plate? How does it work? What can I do with it?
3
votes
2answers
287 views

How to compare the speed of lenses taking transmission into account?

When comparing the speed of two lenses, you almost exclusively hear about the maximum aperture. This of course makes sense, since at a certain lighting condition, a larger aperture in general allows a ...
16
votes
2answers
1k views

Does a specific f number across all lenses denote same amount of light?

When we say a light source emits 1500 lumens of light, it does not really matter if the light source is incandescent, CFL, diode etc. Similarly, when I say f/1.8 can I assume that all lenses pass the ...
1
vote
1answer
80 views

What is the fastest T Stop available?

What is the widest T Stop possible We are having f stops of below even 0.7 NASA lenses What will be the T stop of such lenses with f stop below ONE?
10
votes
2answers
4k views

How can a lens with a single focal length focus on more than one plane?

By definition, a prime lens is a fixed lens system with a fixed focal length. Then, simple physics tells us that it should be able to focus only on one plane (at a fixed distance) in front of it. But ...
2
votes
3answers
118 views

Light Capture of Full-Frame Lens on Crop Body [duplicate]

Given two lenses: a full-frame lens and a crop lens, both at focal lengths necessary to capture the same frame on their respective systems and at the same f/stop. The physical size of the aperture ...
12
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3answers
14k views

What is the Chief Ray Angle (CRA)?

I want to select image sensors for a particular application. One term that I have come across regularly in their datasheets is the CRA. I was comparing 2 image sensors and although they were of ...
1
vote
3answers
168 views

What factors make a lens brighter? [duplicate]

Let's say I have two lenses of 50mm, one with maximum aperture f/1.8 and another with f/1.4. I understand that when using maximum aperture, for the latter lens more light will get to the film or ...
2
votes
2answers
163 views

What is the “airy disc”, in simple language?

In my understanding, this is relevant to photography because if you are shooting light of a certain wavelength (or primarily so, and such as: a blue scene), your aperture size can affect the sharpness ...
21
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2answers
2k views

Why is infrared light's focus point different from that of visible light?

When reading about infrared photography, it's often mentioned that IR's focus point is slightly different from visible light. Why is the focus point of infrared light point different from the focus ...
1
vote
1answer
135 views

How do wavefronts/wavelets propogate in three dimensions, and why is this important for photography?

The photography book I have talks about waveforms, but it doesn't do a good job of explaining them. So, here's my understanding from the book and google searches (it could be unbelievably wrong.) In ...
3
votes
1answer
122 views

Is it possible to make your own focus distance scale?

I'm using a Nikkor 18-105mm kit lens and it doesn't have a distance scale on its focus ring, is it possible to create your own distance scale by knowing the 0 and the infinity focusing points on the ...
2
votes
1answer
224 views

Why does the “fisheye effect” look stronger or weaker with different scenes taken with the same lens?

It seems that the fisheye effect can look different with the same lens. So I want to understand how it works. For example, I use a Dji Phantom vision 2 drone to take pictures, all of my pictures have ...
4
votes
3answers
331 views

Does focal length change when I adjust the focus? [duplicate]

When I adjust the focus of my camera, in general, does this affect the focal length? I have heard that it does.
33
votes
4answers
22k 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 ...
4
votes
1answer
163 views

Can a teleconverter make lenses designed for a “crop” sensor cover full frame?

I have a crop lens. Can I fill a full-frame sensor adding an appropriate tele converter (focal length extender? Specifically, I have a 1/2" C-mount lens and terrible vignetting on a full frame camera. ...
3
votes
1answer
264 views

What could cause this visible artifact which seems to a be a glowing inverse of something outside of the frame overlayed on this photograph?

An acquaintance recently posted an image to FB from his recent trip to the JFK Historic Site asking for an explanation of a visible artifact he states was not visible to the naked eye but was visible ...
1
vote
1answer
119 views

Is the Panasonic Leica Summilux the same quality as a non-Panasonic Leica summilux?

Is there an advantage to having a Leica Leica lens vs. a Panasonic Leica lens? To my ability to examine them, they look like the same on the inside. Would this be correct? The Leica Leicas are ...
0
votes
1answer
45 views

Recommended F-Stop for older Canon 35mm F/2 [duplicate]

I have a few year old Canon 35mm F/2 lens (Here it is on Amazon). I've been shooting wide-open, but I realize that doesn't make for the sharpest photos. What would you say would get me the sharpest ...
3
votes
1answer
155 views

How can I calculate the effect of a supplementary close-up lens (a.k.a macro filter)?

If I have a +1, +2, +4, or +10 close-up lens which attaches to the front of my regular lens, how can I calculate its effect on close focusing distance, figure out how much magnification I can get from ...
2
votes
3answers
239 views

Is a quartz lens necessary to prevent UV blocking on full spectrum enabled cameras?

I have read that in order to operate a "full spectrum" camera properly, so as to not block light in the ultraviolet portion of the spectrum, that one needs to acquire quartz lenses for one's camera. ...
54
votes
4answers
5k views

Why aren't all viewfinders 100%?

We often see that a manufacturer's high-end (D)SLR models offer a "100% viewfinder," which shows the entire exposed frame, and allows precise composition with regard to objects near the edge of the ...
0
votes
3answers
170 views

Why don't we have a single lens e.g. say a 18-200 f/1.2 lens for the SLR camera? [duplicate]

Right now we have multiple interchangeable lenses. So why don't we have a single lens, say a 18-200 f/1.2 lens? Are camera manufacturers deliberately avoiding that or it is that it is physically ...
21
votes
3answers
9k views

What makes a Carl Zeiss lens so special in a smartphone?

There are smartphones on the market that have a focus towards photography. Some are equipped with a Carl Zeiss lens. I have looked into Wikipedia, which tells me that they are a brand who produces ...
1
vote
4answers
210 views

How can I compare different lenses in terms of quality?

I am currently looking to buy a new lens to replace with kit lens, having an extra reach, faster, better image quality and also better video quality. Without buying all the lenses I have shortlisted, ...
11
votes
3answers
668 views

Why are superzoom lenses small but giant telephoto lenses huge?

This week I've read two news stories about two different camera lenses that can magnify things that are very far away. The first is the Nikon Coolpix P900, which is a point-and-shoot camera that ...
8
votes
3answers
2k views

What is the cause of this non-uniform bokeh effect?

A friend of mine is thinking of buying a used medium-format film TLR camera (a Mamiya C330), and he showed me some of the test shots he'd taken with it. I was struck by the curiously non-uniform ...
2
votes
6answers
221 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 ...
14
votes
3answers
322 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 ...