# Questions tagged [theory]

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### Why doesn't a shorter shutter time cause less capture time/ readout time?

If I make a video @ 120 FPS and a shutter speed of 1/12000 from my pwm controlled lamp, which flickers at around 1300 Hz, I get those 11 rolling shutter bars: (11 Cycles in 1/120s equals around ...
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### How can I measure the flicker frequency of a light source with my phone?

I have a Hue light and want to measure the flicker frequency (due to the PWM) without buying an expensive photometer. Is it possible, to calculate it with such an Image, by counting the bars from the ...
• 155
91 views

### Lateral blur in digital images

I would like to know if is there any term or concept to refer to the effect of lateral blur of the objects which reflected rays enter the optic surface tangencially. Is there any specific term for the ...
1 vote
189 views

### luminance range for camera

According to this article, luminance is proportional to pixel measurements via the following: $$L = \frac{N_d f_\text{s}^2}{K_\text{c}tS} \tag{1}$$ Where: $N_d$ is pixel value $f_\text{s}$ is f-...
583 views

### Would there be a noticeable difference between long exposure and brighter light?

If I take one photo with long exposure and dimmer lights (e.g. constant lighting) and then another photo with short exposure but lights brighter to the level enough to compensate for the shorter ...
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1 vote
885 views

### Longer or shorter focal length for good IQ for low light portrait photography?

I have a theoretical question. Consider two lenses with same f-ratio but one has a larger focal length than the other (say 200 mm vs 50mm). Which lens would give better image quality when shooting ...
26k views

### Aren't all digital images ultimately just pixel values between 0 - 255?

I have a few incredibly basic (stupid?) questions about images; specifically, image formats and pixel values. Forgive me, I'm not a photographer. I'm just someone that works with images, and to me, ...
285 views

### How close are we to the theoretic limits of sensor low-light performance?

Consider a low-light, high-ISO, short-exposure shot. We all know the image will be noisy. I understand that the image noise is dominated by the photon counting noise (shot noise) that is caused by ...
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2k views

### When do straight lines become curved when talking about projection?

This in not a question directly pertaining to photography, but the theory of projection in general. Imagine that I'm drawing my surroundings, say, in a city with straight lines everywhere. I start ...
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522 views

### Where can I learn the theory behind photography and camera engineering?

While I do have a basic understanding of the concepts of photography, it would be great to also understand the theoretical background behind the optics and the engineering of modern cameras. E.g. to ...
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### Capturing and stitching images without distortion/perspective correction given perfect control

I'm working with a virtual scene and camera. Unfortunately, the program locks the render resolution at 1920x1080 with no direct workarounds. This is significantly lower than I'd like. Given the ...
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433 views

### Why are specular highlights sharp when focusing on close object?

I am trying to understand how specular highlights work. As I understand specular highlights are created by reflecting light-sources in a mirror-like fashion. Because faraway reflected objects are out ...
• 1,003
4k views

### Large Sensor vs Large Aperture [closed]

Both increasing the sensor size and increasing the aperture size (in terms of f-stop) increases low light performance and decreases depth of field. Given, say, an equivalent of a full frame and f/1.8 ...
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### From a user perspective, is a stopped down variable aperture zoom lens equivalent to a constant aperture zoom lens?

Let's say that I have a 24-70 F3.5-4.8 variable aperture zoom lens. If I were to stop down that lens to 4.8, would it then be equivalent to a 24-70 F4.8 constant aperture zoom lens from a user ...
• 131
1k views

### What processing is done on RAW files in the camera?

Recently I came across a debate about whether it's fair to call RAW 'unprocessed' or 'unaltered' sensor data of a DSLR. As far as I know, the analog sensor data is processed into a digital RAW file ...
• 1,002
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### Why are rangefinders not directly above the lens?

It seems the biggest gripe about rangefinders (vs SLRs) is that your shots are not quite what you see, there is a parallax error due to not seeing through the lens. Which makes me think, if you put ...
• 315
346 views

### Why "plane of focus"? [duplicate]

The spatial locus on which a lens/camera focuses (and so appears sharpest in the resulting image) is always referred to as the "plane of focus". My question is why does it have to be a plane? As I ...
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1 vote
589 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 ...
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### Are Ansel Adams's theory books relevant today?

With the decline of film photography, it seems that there is no use for "The Negative" anymore. But what about "The Print" and other books where Adams teaches about light, technique and, well... ...
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16k views

### Is vector photography possible?

Of course any bitmap image can be vectorized, but might we ever reach a point where a camera can make an outline image that looks exactly like a photograph? Could the resulting image even be ...
• 223
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### An intro to "conceptual" fine-art photography?

In many photo clubs and professional fine art photography, is very common to show "conceptual" photo essays or photo series. That is, there is a unifying idea behind a compilation of images, and ...
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### Rule of thirds -- is there any scientific proof behind it?

I learned about rule of thirds only recently, and it excited me a lot, and it seems to apply to a lot of situations. But my question is why does it make pictures look more appealing? Does it have ...
• 159
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### Do full frame sensors gather more light than crop sensors?

Lots of people say that full frame sensors receive more light than cropped sensors. I have never found a proof of this claim so I tried to do the computation by myself, and proved the contrary! Could ...
• 418
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### How can a high resolution camera matter when the output is low resolution?

The question is inspired by this question showing these pictures. The accepted answer suggests that these pictures were taken by a 8x10 view camera, and the use of a 8x10 camera was confirmed in the ...
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### Is there such a thing as a filter for circularly polarized light for photographic use, and what would be the effect of using one?

I was under the assumption that a circular polarizing filter would filter circularly polarized light. I now understand that what is commonly called a circular polarizing filter only filters based on ...
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