Questions tagged [optics]

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.

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116 views

Looking for an iPad lens that makes it possible to capture a person head to toe from up close

I am filming golfers swinging at the driving range. Due to common video standards I want to film in landscape mode instead of portrait mode. However, to fit a whole person in I need to be quite far ...
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3answers
941 views

How can I find a compact camera where I can change the lens?

I would like to purchase a compact camera. But usually they are limited in optical zooming. So, I would like, if possible, to add/replace lens hardware with a different lens with better optical ...
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2answers
395 views

Point two cameras through the same lens, with the same perspective

I had an idea recently, that would involve two separate cameras, capturing at the same time, with the exact same perspective- Which I mean as, 1:1 the EXACT same perspective, as if both of the cameras ...
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2answers
292 views

Lens/Mirror system for stereo photography?

I am interested in exploring the viability of doing stereophotography using a single camera. The idea is that the camera would take images in pairs, first using one side of the lens system, then ...
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5answers
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What happens if anti-reflective coating is fully ruined or removed from lens' most outer surface?

Anti-reflective coating is sensitive to fingertips and extra care is needed when cleaning camera lens. I've heard a couple of stories where a camera owner used some organic solvents and ended up ...
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4answers
268 views

Why don't cameras ordinarily zoom by moving the whole lens as a unit?

Zoom lenses have a moving group of lenses within the whole unit. It seems to me that any lens could easily be made into a zoom lens by moving the whole lens unit towards/away from the film/sensor. ...
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1answer
319 views

Limits of camera lens capabilities [closed]

I read that the canon 35mm f/2 IS is the lowest aperture lens that also has IS. Is this because a stabilizer at any lower F-stop is not possible, or just because it is just currently outside of our ...
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3answers
332 views

Are points off-center from the lens axis out of focus? [duplicate]

If I take a picture of a flat surface perpendicular to the direction of the lens (i.e. the surface is facing directly at the camera), and I focus on the center, are the points off center in perfect ...
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908 views

What is the pre-computer version of Photoshop's blending modes?

Before computers, to blend two pictures into one, I'd imagine they'd have used some sort of mirror setup to reflect the one picture onto a mirror containing the reflection of the other picture. Does ...
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2answers
159 views

Clear-cut black corners with some superzoom photos

I've got a refurbished Panasonic DMC TZ40 which I consider to be very good value for money for my needs as amateur ignorant photographer. The camera is in good shape but was clearly used for some ...
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2answers
456 views

Will using a full frame lens with extension tubes on a crop sensor camera reduce the “crop”?

The question Will a macro extension tube eliminate the cropping of an APS-C lens on a full-frame sensor? is certainly related, though I'm not sure if it's a duplicate. As a follow up to my recent ...
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3k views

How can I test that the image is inverted in a pinhole camera?

I learned that a pinhole camera inverts the image on the film strip: Is it to possible to test if the image gets inverted without the film strip on which the image is projected? For example: I made ...
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2answers
590 views

Why doesn't an extension tube “crop” the picture?

Ever since I've heard of extension tubes I've been curious if they somehow crop the image that appears on the camera sensor. Based on this YouTube video, the answer is "no" (at least not that I can ...
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4answers
2k views

How to choose a good smartphone if the top priority of the user is photography?

At the current rate by which technology is improving, I believe that mobile photography is not far behind their DSLR counterparts, generally speaking. However, for amateurs like me, it is quite ...
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4answers
697 views

Why does illuminance stay the same for a given f-stop even when focal length changes?

I'm trying to wrap my head around the math/physics of how illuminance on the film/sensor plane remains equal for a given f-number regardless of the focal length of the lens. Since a longer lens will ...
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2answers
955 views

Why do modern aspherical lenses have so much coma?

The Nikon Noct 58mm f/1.2 from 1997 is famous for having excellent coma control wide open. Sources generally credit this to its being one of the first lenses that used an aspherical element, which had ...
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559 views

Why do mirrors give less sharpness, gamut, and contrast than lenses?

What is the scientific reason mirrors give less sharpness, gamut, and contrast compared to lenses? Ex. Is it an inherent property where light dissipates more when scattered compared to going through a ...
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3answers
501 views

How can I experimentally determine the size of my lens’s aperture?

I have a Canon FD 28mm f/2.8 that I shoot on my entry-level Canon DSLR using an adapter. You have to set the aperture manually, but only every second aperture is marked: between ƒ/2.8 and ƒ/4, for ...
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2k views

What causes lens flare along specific axes?

When photographing bright objects, what causes lens flare along specific axes? First two images captured from Reds Rhetoric & Vincent Jones's video, last from SpaceX's feed. In reflecting ...
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1answer
941 views

Mirror vs Lens: do either or both invert the image?

Answers to this other Question on photo stackexchange have prompted me to seek clarification on this. consider for example the following images: Original scene How a mirror "sees" it (flipped ...
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2answers
2k views

How many times is the image inverted inside a DSLR camera?

How many times is the image flipped (inverted) inside a standard Digital Single Lens Reflex camera?
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138 views

What is the most general theoretical reason images out of focus appear blurry?

Don't know if I should ask here or physics for optics. But I am wondering how come images out of focus appear blurry? It seems to me that if a given lens geometry has a given focal length, then ...
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Does say a 35mm on an APS-C camera have the same facial/other deformations as a 35mm? [duplicate]

I am about to purchase a 35mm (Nikon 35mm F1.8 DX) for my APS-C camera, to get the equivalent of a 50mm lens. I want to use it for portraiture a bit, but I'm worried the facial deformations will ...
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3answers
1k views

What exactly “professional-grade” means in Nikon line of lenses?

I was researching a bit on Nikon 16-35mm f/4 lens. Both Nikon USA and India websites are silent about the build material of the lens barrel. There are a class of people, who either out of "frustration"...
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4answers
2k views

How can I increase the flange focal distance (back focal length) of DSLR lens?

I am working on a custom setup where I am using a DSLR lens (Canon 50mm f/1.8) to project an image onto an image sensor (image plane). For my application, I require a very large distance between the ...
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3answers
1k views

What determines whether chromatic aberration will be purple/green or red/cyan?

In my experience, both with my own photography and looking online, chromatic aberration is usually purple on one end and green on the other. However, I have also seen the same effect with red and cyan,...
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4answers
2k views

Why is my large format lens so much smaller (in length) than my 35mm-format lens?

In general I have found that as the focal length of 35mm (or APS-C) lenses increases, the physical length of the lens increases as well. However, my large format lens is much thinner than other 35mm ...
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1answer
241 views

Can you build a camera obscura indoors, to watch a play upside-down as it's performed? [closed]

I've seen Youtube videos of people who have converted a room into a camera obscura to capture images of skyline/trees/clouds, but couldn't you capture indoor scenes too? Or would you need bright ...
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1answer
92 views

What are the (dis)advantages of moving the entire lens for focusing vs. only parts of it?

There's a lens adapter available that adapts Leica lenses to Sony mirrorless cameras. It's called TECHART PRO. The key feature is that it allows to use autofocus with the manual lenses. This works by ...
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5answers
760 views

Aperture iris in front of lenses (in object space)

This question discusses the iris placed in camera body and this question does not reveal too much details about external iris. I recall from scattered information that I have read that iris placed in ...
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1answer
186 views

How is a lens distortion model performed? [duplicate]

So, as the title suggests, how is a lens distortion model (e.g. Brown-Conrady or pinhole camera model) applied on an image? I know it uses some calibration parameters (principal point's coords,focal ...
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2answers
742 views

How do lenses control “projection”?

How is a fisheye lens made differently from a normal ortholinear projection lens? How are real lenses acting differently from the ideal "thin lens" or pinhole, in terms of how the 3D scene in front ...
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1k views

Does sensor size impact the diffraction limit of a lens?

My understanding of diffraction, is that with a small aperture the 'airy disk' (which I understand is the pattern light from a given direction relative to the lens will form on passing through the ...
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4answers
758 views

Categorization of 14mm lens as rectilinear?

I used the Panasonic Lumix G Vario 14-42mm f/3.5 -5.6 Asph. / MEGA O.I.S. Lens to take a photo from my balcony. Here's the original RAW (ORF). The symptom I am experiencing is that different ...
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5answers
4k views

What is the shape of the focal plane?

This is something I just realised I don't entirely know the answer to, so I'm going to ask it here as I think it's interesting. In most non-scientific writing on depth of field, diagrams generally ...
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5answers
1k 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 ...
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1answer
889 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 ...
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1answer
263 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 ...
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2answers
497 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 (...
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4answers
8k 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 ...
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2answers
521 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 ...
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3answers
257 views

How is a lens's bokeh determined by its construction?

I'm buying a new lens and am interested in determining how the out-of-focus effects will turn out with it. How is a lens's bokeh determined by its construction, and can one get an approximate idea of ...
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2answers
368 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?
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2answers
963 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? ...
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4answers
603 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 ...
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4answers
331 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 ...
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1answer
278 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?
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1answer
133 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?
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3answers
243 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 ...
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3answers
2k 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 ...