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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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4answers
165 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 ...
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0answers
41 views

Technical question about aperture and lens [duplicate]

F stop = focal length / iris diameter So for example, my Lumix 20mm pancake, f1.7, has iris diameter of 12mm at that f stop, correct? So if Panasonic wanted to make a faster lens, could they do it ...
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0answers
44 views

What defines camera's size? [duplicate]

Smartphone cameras are small while others are big. I know some functions like zoom can change physical size, etc. So, ignoring a zoom lens, what defines a camera lens? I want to get the general idea ...
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1answer
55 views

Pentax k-30: can i buy all lens not stabilized?

I'm interested to buy a Pentax K-30. I'm wondering : can I buy not stabilized optics because of body' stabilized sensor ? Is the overall image quality comparable to an optic with stabilizer (like ...
6
votes
2answers
282 views

How does an apodization filter improve bokeh?

The new Fujifilm Fujinon XF56mmF1.2 R APD has an "apodization" filter, which Fujifilm says "smoothes the outline of the subject to create a more natural bokeh effect". The Wikipedia article on ...
2
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1answer
97 views

How does a focus ring bring a subject in or out of focus?

When you manually adjust your focus ring on the lens, what actually happens inside the lens? Is this changing simply the point at which the lens is focusing, so that anything at this distance away ...
4
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1answer
63 views

maximum aperture consistent with the nikon F mount

In a related thread, it's been debated whether there is a hard limitation to maximum possible lens aperture ; it seems there is none. However, using the example of the nikon F mount, this technical ...
2
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4answers
130 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 ...
4
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1answer
186 views

In what way does the lens mount limit the maximum possible aperture of a lens?

In many answers to questions about different aspects of really large aperture lenses it's pointed out that the lens mount sets a hard limit on the maximum possible aperture of the lenses to that ...
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1answer
60 views

Is there an “optimal” background distance when striving for a minimally distracting background?

Let's assume a thin lens and an object O in focus at a distance of dO from the lens. Further, let's assume there's a large out-of-focus background object B at a distance of dB. Now, we know ...
4
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2answers
151 views

Use of DOF adapters in stills photography

The camcorder guys figured out long ago how you can get the shallow DOF of a larger sensor system (typically full frame) on a camcorder equipped with a much smaller sensor (typically 1/2.8") by doing ...
2
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1answer
93 views

How to find numerical aperture of lens

I need to find the precise collection cone angle of an arbitrary objective at an arbitrary (but known and finite) object-side focal length. This is typically given as the "numerical aperture", defined ...
4
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3answers
765 views

Why do circular fish eye lenses create circular images?

I'm trying to understand the physics of circular fish eye lenses. As far as I can see circular fish eye lenses create an circular image because the area of the sensor is larger than the projected ...
6
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0answers
104 views

Can the method from the paper “High-Quality Computational Imaging Through Simple Lenses” compete with conventiona lenses?

This answer to another question of mine linked to an interesting article: High-Quality Computational Imaging Through Simple Lenses. It purposes the use of simple optics and computational photography ...
7
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2answers
555 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 ...
3
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1answer
96 views

Do lenses have focal planes or focal spheres/ellipsoids?

The title says it pretty much all. I'm asking this because I find myself always using the focus point in the center, and after I focused, I rotate my camera to make the framing right. However, if ...
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3answers
408 views

35mm vs 40mm: Does it matter?

I want to buy the lens Voigtlander Nokton 40mm F1.4, $449 Voigtlander Nokton 35mm F1.4, $629 I am asking, why the slightly difference in focal length, the price difference in so much as $180? ...
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3answers
513 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) ...
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1answer
85 views

Aperture and field of view - percepted by eye vs camera

I very well informed and I know about how aperture works and why is it not restricting field of view, but I somehow cannot get around the following: Aperture doesn't restrict field of view for the ...
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0answers
180 views

How is it possible for bridge camera with 50x zoom to cost so little? [duplicate]

i state that i'm a completely beginner in the wonderful world of photography. Last year i bought a Fujifilm FinePix S2980 ...
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votes
1answer
124 views

Is it possible to make an image which is only photographable in black or white?

Not sure if this is the right forum to ask this. Here is what I'm looking for: Example: I have a color photo could be text could be an image What I would like: if someone photographs this ...
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2answers
196 views

How can I build an underwater camera housing?

I'm thinking about building simple waterproof housing for camera. I don't expect high quality I want to record some videos good enough to identify fish species, nothing more for now. My housing will ...
2
votes
1answer
213 views

What is the largest aperture on a commercially available lens? [duplicate]

Out of pure curiosity, what is the largest aperture, or lowest f-stop, a commercially available lens has. I have seen the 50mm prime lens from canon with 1.2, but not lower than that. What are the ...
3
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2answers
201 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 ...
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0answers
35 views

What causes the rays surrounding strong lights? [duplicate]

I've noticed, especially in long-exposure city lights photos, that strong light sources are surrounded by rays. The number of rays seem to depend on the lens being used. What causes these rays and the ...
3
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4answers
294 views

Differences between canon 17-85mm and 18-55mm

I was given a 450d with a canon 17-85mm lens, it has USM and image stabilzing. It has always seemed okay to me but after a few years i have decided to upgrade to the 700d, which has now come with a ...
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2answers
128 views

Why human eye doesn't exhibit aberrations?

Eye's optical system is composed of single lens and is capable of producing very sharp results, but if I use single lens (monocle) with my camera I'll get soft image.
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2answers
498 views

Does wide angle equivalent in crop sensor skew image?

I see many posts on both this forum and elsewhere the discuss the use of a wide angle on a crop sensor. For example, they discuss how at 14mm lens is 14mm on a 35mm film or full frame, but with a ...
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1answer
66 views

Exact specification of N1-CL1 Nikon Closeup lens

On nikon site (and everywhere else) I've been unable to find any exact specification of tne N1-CL1 filter lens -- only thing I need is to know the exact focal distance of this lens (or dioptres, or ...
2
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2answers
144 views

Huge distortion with the 16mm lens

Today I've tried my new lens, but the image was very distorted in the right side. Here's the image: Is this normal? (The building on the right is very skewed) Bigger image: link
2
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3answers
881 views

What does “maximum aperture” mean in a camera spec? Where can I get the full aperture range?

I own a Canon S95, and am considering getting a newer model (e.g. Canon S110 or S120), and I'm comparing the specs. According to DPReview.com, the S95 has a maximum aperture of F2.0-F4.9, and the S110 ...
3
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1answer
156 views

Why is the center of image smudged with magenta/white at a small aperture?

I took two pictures with a Nikon D300 and a 17-55mm f/2.8G lens. Both pictures have been taken at ISO 200, aperture f/22 and shutter speed 1/8s. I used a tripod. The only difference between the two ...
5
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1answer
99 views

Which lenses show focus shift?

Some lenses, because of a design that includes uncorrected spherical aberration, shift their plane of focus backwards as the aperture is narrowed. This is most apparent at close focusing distances and ...
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4answers
2k views

What is the most versatile lens for the Sony NEX-6? [closed]

I received a Sony NEX-6 body (no-lens) over the holidays this year and I am looking to find the right lens to match. I am searching for the most versatile lens available for this camera. In other ...
5
votes
1answer
846 views

What makes the Zeiss Otus 1.4/55 so special?

The new Zeiss Otus 55mm f/1.4 is nearly $4000. With faster lenses from Canon (50mm f/1.2L) with autofocus, why is the zeiss lens more than twice that of the Canon counterpart?
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1answer
92 views

Optical focal length [duplicate]

i have a quick question. We have a machine which has a camera mounted above a board at 75cm. The cameras ability to focus on an object at 0 zoom is 1cm, and all full zoom 120cm. The zoom is build ...
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1answer
348 views

Size of the entrance pupil vs size of the aperture

I understand that the entrance pupil is the image of the aperture as seen from the front of the lens. However, is the size of the entrance pupil the same as the size of the effective aperture? In ...
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3answers
233 views

Can I estimate the light gathering power of a lens by measuring size of entrance pupil?

Supposing I have an unknown lens of which I don't know f/# and focal length. I want to estimate the total amount of light that my lens can collect which, I believe, is given by the solid angle that my ...
2
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1answer
139 views

What lens is needed to change the minimal focus distance length of my camera?

Here is my problem, I Have a scientific camera, a Sony Block FCB-EH6500, which has an automatic focus. The minimum focus distance is 1 cm when completely zoomed out and 120 cm when fully zoomed in. ...
2
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1answer
348 views

How do anamorphic lenses produce lens flare “streaks”?

For example: What contributes to this streaking? Why doesn't spherical lenses have this effect? How is it used in photography?
0
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1answer
121 views

How do focal distance reductors affect image quality?

I have a bunch of lovely old full frame K mount lenses (like the 50mm f1.2 and the 135mm f2.5) and the idea of using them in a proper mirrorless body (I have the K-01 and that's a hell of a brick) ...
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1answer
178 views

What's the difference between a diopter and an extension tube?

It seems both allow close up shots of a subject but what are the differences both physically and in use cases?
0
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1answer
68 views

Should a fisheye converter be sharp when I look through it directly?

I bought a fisheye converter some days ago. Now, I am unsure if such a converter should create a clear image if I look with my eye straight through it. I found a video on youtube with the hint that ...
12
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6answers
764 views

What lens characteristics contribute to attractive lens flare?

Some lenses give really harsh and unwanted flares. Some gives beautiful flares that add depth to an image. What's the science behind this?
4
votes
2answers
368 views

What are the theoretical minimum and maximum apertures?

Is there such a thing as a maximum aperture that a lens can be open to? What about a minimum aperture that it can be closed to? Do these concepts even make any sense? Is there a lens with the ...
8
votes
1answer
174 views

What kind of mirror in a mirror lens?

A normal mirror, that we see for example in an elevator, is a glass sheet with thin metal coating on the backside, so light reflecting from the metal surface goes first thru the glass. Metal mirror ...
4
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2answers
733 views

How can I get the image/sensor dimensions in mm to get Circle of Confusion from EXIF?

I need to get calculate some formulas based on Circle of Confusion and/or image dimensions (diagonal) in millimeters based on EXIF data only. IOW, I cannot say "this photo was shot with Canon 5D3 ...
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1answer
595 views

How to calculate the magnification factor of an object to its image?

I have an object of size 37.5um x 37.5um, and captured a 640 x 480 resolution image of the object with a CMOS sensor. I see that the object is around 200 x 200 pixels in the image. How do I calculate ...
3
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0answers
148 views

Is this a Fata Morgana? [closed]

I took this photo. Above the horizon there is a thick line that looks like a cloud, but it surely isn't. Is this a Fata Morgana? What do you think? The Image
11
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4answers
607 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. ...