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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.

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101 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
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1answer
42 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
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1answer
88 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 ...
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3answers
183 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. ...
53
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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 ...
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3answers
117 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 ...
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3answers
8k 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 ...
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4answers
191 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, ...
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12answers
21k 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 ...
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3answers
429 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 ...
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3answers
1k 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 ...
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6answers
211 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 ...
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3answers
300 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 ...
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3answers
541 views

What is the limiting factor in lens construction when it comes to f-stop values?

This widely praised Nikon 105mm macro lens has a maximum f-stop value of 2.8. I've held it in my hands, it's a big lens. Meanwhile, this 50mm Nikon lens can go up to f/1.2, despite being 25% cheaper ...
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4answers
108 views

What lens designs are sharper than a pinhole lens but also allow for multi-month exposures?

I have a homemade pinhole camera (film) that I use for taking super long exposures (multiple months). And while the results are fun, I would like to improve the sharpness of the image. Is diffraction ...
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1answer
130 views

Background warping through foreground defocus

I came across this effect the other day, and have spent the better part of the last week trying to figure out exactly what is happening. When photographing two layers, with the foreground in front of ...
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2answers
134 views

Is there a formula to calculate the physical size of an image?

I'm trying to figure out the size of the physical space an image represents (IE, how many meters long/wide the real world in the image is), but I can't seem to find a formula that works with only the ...
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4answers
22k views

How does a spherical lens differ from an aspherical lens?

Many lenses (like the Pentax DA 15mm f/4 Limited, or the Nikon AF-S 35mm f/1.4G) are described as having "aspherical lens elements". Does this mean that regular lenses are spherical lenses? What's the ...
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2answers
138 views

What causes barrel distortion?

Here are some scenarios for barrel distortion: When a target is too close to a camera, the photo will show barrel distortion. My flip cell phone's camera often produces barrel distortion. Some ...
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3answers
250 views

Equivalent focal length and aperture of 150mm medium format lens on a 35mm camera

I'm mounting a Hasselblad Sonnar C 150 mm f4 on a 35mm sensor (43mm diagonal) camera. What is the calculation to get the new angle of view and equivalent focal length? Does this also affect the ...
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7answers
663 views

Does lens speed still increase meaningfully when the physical aperture is larger than the sensor size?

This question came to me this morning, thinking about 50mm lenses. I have the Pentax 50mm f/1.7 (manual) and it's a very nice lens, but would be considered (relatively) slow on 35mm film, and many ...
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1answer
65 views

Why can a lens still function when subject to severe physical degradation?

Consider the following two modifications to a camera lens: Obstructing the about 75% of the lens's front element with an opaque filter as shown here: https://www.youtube.com/watch?v=43W159gPpdQ. ...
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0answers
85 views

Projector Design and lenses

I am working on a project where I need to project a single image onto an object, Originally I was looking at the digital projector route but due to cost and complexity this has been ruled out. I found ...
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2answers
6k 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?
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2answers
108 views

Why does the same f-number mean same amount of light? [duplicate]

Intuition tells me that a bigger lens will collect more light with the same f-number than a small lens. But photographers tell me I am wrong. I cannot understand why. There are quite a few posts both ...
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5answers
2k views

Do bigger focal lengths capture more light?

I never understood what the f really stands for in the f-stop values, like f/1.8. Wikipedia explains it in various articles, but I still find it very confusing. What I understand, though, is that it ...
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2answers
148 views

What is the importance of the back focal length of a lens?

What is the effect and importance of the back focal length of a lens? For instance, if I look at these two lenses by Ricoh, they have the same focal length and aperture, but their back focal lengths ...
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4answers
3k views

How can a super tiny iPhone 6 Plus lens produce significant DOF?

According to Apple specs the iPhone 6 Plus thickness is 0.28 inch (7.1 mm) and the lens length is only a part of that. And according to an article I found, Depth of Field is a function of "aperture ...
102
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7answers
8k views

What is bokeh, exactly?

I understand that "bokeh" refers to out-of-focus areas of an image — but there is obviously more to it than that. What does the term mean exactly? How well is bokeh really understood? Is it purely ...
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1answer
116 views

Lenses round ..Photographs square shaped why? [duplicate]

If camera lenses are round then why is the photograph taken by the camera is square-shaped? photography
18
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5answers
2k views

How does a circular lens produce rectangular shots?

Is it something like the sensor captures a circular image and then what we get is the cropped version? Something like this: Or did I get it completely wrong?
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6answers
16k views

Why do light sources appear as stars sometimes?

See for example this photo: From my experience, the longer the exposure the stronger can this effect be observed. Is this correct? Are there any other factors that influence the creation of these ...
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6answers
3k views

Can a smaller sensor's “crop factor” be used to calculate the exact increase in depth of field?

If APS-C and similar crop-sensor digital cameras have a focal length multiplying effect such that a 50mm lens has an apparent focal length closer to the field of view of an 80mm on a full frame ...
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1answer
1k 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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2answers
284 views

What do resolution figures mean in lens specifications?

I'm working in computer vision and choosing the right lens is obviously as critical as having a good sensor if you're going for quality inspection (for example). Sadly I have very little experience ...
48
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6answers
10k views

What is a “diffraction limit”?

I've seen the term used, but what is a "diffraction limit", when should I worry about it, and what undesirable effects are a result of it ?
5
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4answers
8k views

Why are objects far away inverted through a lens but not through the viewfinder?

When I look through a lens the image of objects far away are inverted but when looking the the viewfinder on my camera they are not. Why is this? I am having a hard time understanding why objects far ...
3
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2answers
372 views

How to determine if a new lens is a subpar copy?

I have read some posts like the ones below about testing a lens to determine how well it performs optically. What I didn't see was anything on determining whether the lens performs as it should and is ...
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5answers
14k views

What is “infinity focus”?

I have been reading a bit about astrophotography and the term infinity focus keeps coming up. What is infinity focus and how do you set the camera to infinity focus?
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1answer
173 views

Explanation of the fisheye phenomenon

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 ...
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0answers
34 views

Technical book or resource (non-creative) [duplicate]

I'd like a resource from which to learn about technical, non-artistic/technique aspects, such as: Onion ring bokeh, and what causes it. Choosing of lens hoods, Why chromatic aberration happens/why ...
7
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1answer
276 views

How is Nikon's PF optics different from and similar to Canon's DO optics?

Nikon has just announced a new 300 mm lens featuring a new technology called "PF" or "Phase Fresnel." This has been compared to Canon's existing DO (Diffractive Optics) lenses such as the 400 mm f4 ...
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4answers
2k 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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1answer
94 views

Why do I need an add-on lens to take smartphone macro photos?

Why do you need an external macro lens for a smartphone to take macro photos. Why can't the smartphone lens itself take macro photos?
41
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2answers
20k views

What is the difference between a pentaprism and a pentamirror?

Higher-end SLR cameras include a pentaprism to transmit the image from the lens to the viewfinder, whereas lower-end SLR cameras use a pentamirror to accomplish the same task. What are the ...
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1answer
223 views

How do add on macro smartphone lenses allow you to take macro photos?

It may sound obvious, but how exactly does an add on macro lens allow you to take close up photos? Can someone give technical reasons? I'd like to know the physics behind add on macro lenses and how ...
14
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1answer
903 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?
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1answer
111 views

Where do rays of light from one point strike the film?

I am a programmer and I am doing a camera simulation, I am stuck in a matter of how to know where does every ray of light incident after traveling through the lens, every point of the object will give ...
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3answers
153 views

How to estimate the minimum magnification to capture features of a certain size?

What is the correct way to estimate the minimum magnification (maximum subject distance) at which features of a certain size are resolved? My thinking is that given a system capable of resolving a ...
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0answers
61 views

Where is the focal point of a camera lens? [duplicate]

If the distance between the center of the lens and the film is called Focal length, does that mean the focal point of the camera lens is located on the film?