Questions tagged [focus]

Focus is the mechanism of converging light from a point light source onto an imaging plane by a lens.

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1answer
186 views

Picture gets blurry when zooming in

My Nikon 3400's kit lens(18-55mm) works fine when I take pictures at 18mm. But when I extend lens beyond that, the picture gets blurry(no clarity). Though I can focus on extremely close distances ...
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1answer
242 views

Err 01 and no manual focus (Canon lens)

my Canon EF-S 18-55mm f/3.5-5.6 IS STM just stopped communicating with my DSLR (Canon EOS 77D). Furthermore, I can't even use manual focus anymore. Right before this happened, I tested some extension ...
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2answers
335 views

Modifying a film camera to display images

My dad passed recently and I would like a way to memorialise him and his photos. He was an avid photographer and never left home without his camera. The one I remember from growing up was an Asahi ...
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1answer
151 views

How can I produce high quality images of field ranges for training sets?

I am an Agronomic researcher assisting on a ML problem for identifying soy diseases. I would like to capture an image of a single range of soy (roughly 1' wide by 5' long) that is at least mostly in-...
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1answer
55 views

Mounting large format lens on PB-4 Bellows

I have a PB-4 bellows. I want to mount a large format lens on the bellows so it can focus to infinity and I will have a very versatile tilt/shift bellows. So I am just wondering if there are any ...
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8answers
4k views

How can I get sharp bird photos when the bird is further away?

I have Canon 1200D. I use the 55-250mm kit lens for bird photography. Laughing Dove ISO 400, 1/100, 250mm, cropped, shot late in day in overcast conditions, brightness increased in post processing ...
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4answers
182 views

Focussing on a star with wide angle 14mm lens

Has anyone discovered a better way than trial and error to focus on a star - (for Milky Way Astrophotography)? I am using a Canon 5D Mk2 with a 14-40mm lens at 14mm. My Settings are ISO 12800 and ...
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3answers
224 views

Why can't I reproduce a back-focus problem at home?

I'm a bit out of ideas. Lastly, my Nikon D7000 started to have severe back-focus problems. When I shoot photos of birds and other animals, or portraits of persons, in average, four out of five photos, ...
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1answer
116 views

Shutter activates when manual focus is achieved. How?

I have a canon 5D mk ii which I've been using for donkeys year. I was messing about with a new lens in the office today and somehow stumbled on a feature I've never noticed before. Using manual focus, ...
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2answers
88 views

Canon 250D not focusing on Self Timer [duplicate]

I want to take some smart photos of myself with my Canon 250D. I have it set to 18mm so I can stand a bit away from the tripod. I then put the camera on a 10 second self timer. Eye AF is on. When I ...
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5answers
237 views

Can digital zoom affect focus

I was always under the impression that digital zoom has little use since the same thing can be achieved on a computer afterwards by cropping. I recently purchased a point & shoot digital camera ...
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3answers
111 views

Is the sharpness of imaging different within the depth of field?

Is the sharpness of imaging different within the depth of field? Where is the sharpest? What I am asking is the distance from the lens to the object, not the image distance in the lens. How to ...
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3answers
223 views

Distant objects not in focus

This is almost certainly my fault, not the camera. I mostly shoot landscapes with myself in the foreground via a small tripod: My former camera was a Sony A5000 and for these kinds of shots (see ...
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2answers
57 views

Convex lens, object distance, distance, focal length, in what state is the hyperfocal state? [closed]

Suppose we have a convex lens for a middle school physics experiment, a screen, and an object being imaged, under what state will we find the hyperfocal state? The screen is the imaged screen. It can ...
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2answers
166 views

Using a modern lens (with electronics) manually?

Long story short: What I have: Panasonic GH4 Endless 3D printing options for making my own adapters Very, very nice japanese retro prime lens from almost 50 years ago (yeah, it really looks ...
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3answers
242 views

What is this style of photography called?

I am trying to learn a specific type of photography and am having a difficult time finding out the name for it. What I am most interested in, is a specific niche of high focus, minimalist, black ...
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5answers
442 views

Focussing with Extension Tubes

I bought a set of extension Tubes to use with my Nikon D5300 and 35mm f/1.8 lens. However, it seems that the only option to focus is to change the distance to the subject. This is very inaccurate and ...
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2answers
159 views

Why is my Nikon D5500 unable to lock focus while using Live View but works fine when using the ViewFinder?

It just keeps trying to find focus. If I press the half-click focus button I hear the motor moving and the numbers on my lens go from smallest to infinity and stop. If I press the half-click focus ...
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2answers
139 views

When the object is 50 meters away, how do you know that the camera is focused at a distance of 50 meters?

When the object is 50 meters away, how do you know that the camera is focused at a distance of 50 meters? Is it that we can only focus at about 50 meters?
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3answers
118 views

What is the acceptable CoC (Circle of Confusion) of the human eye to directly observe the object? [closed]

What is the acceptable CoC (Circle of Confusion) of the human eye to directly observe the object? The human eye has many cells and high pixels. Should the permissible circle of confusion be small?
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2answers
185 views

Is there an effect opposite of tilt-shifting?

Is there any effect that would make objects seem much larger than they actually are? I tried to google for it and the only thing I could find was a discussion on flickr where focus stacking is ...
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1answer
67 views

For the formula 1 / u + 1 / v = 1 / f, what is infinite depth of field or hyperfocal distance?

For the formula 1 / u + 1 / v = 1 / f, what is infinite depth of field or hyperfocal distance? In other words, when u, v, and f, we have infinite depth of field or hyperfocal distance?
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2answers
192 views

What does focusing mean? What does it have to do with the formula 1 / u + 1 / v = 1 / f?

What does focusing mean? What does it have to do with the formula 1 / u + 1 / v = 1 / f u is the object distance, v is the image distance, f is the focal length. Does focusing mean that both ...
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1answer
45 views

Measuring Change in Focal Length

I have a Nikkor 28mm f/2.8 prime lens. I understand that this focal length is only valid when the focus is held at infinity. Is there a way to easily measure how the focal length changes when I adjust ...
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2answers
83 views

Selective focus optical illusion [duplicate]

I have come across some shots from other people and they create something like an illusion to me and trick me of the scale of the actual scenery. For example, this shot by @chuttersnap on Unsplash ...
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3answers
126 views

Is the hyperfocal distance calculation outdated?

The hyperfocal distance H is calculated by H = (f^2)/(N*c)+f where f is the focal length, N the f-stop and c the circle of confusion limit. Lets assume we use a fullframe sensor. All those calculators ...
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1answer
112 views

What could cause the focus to be off in some images and not others?

I took a number of photos like the one here. Each was at the same settings but each time I asked the camera to focus (with a single focus point) and the focus point right on the girls face. The ...
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2answers
162 views

Calibrating a lens…is auto focus less reliable when zoomed?

So, I'm calibrating my lenses to a new camera body, a 5D Mark IV. When calibrating my 70-200 ƒ2.8 (version 1), I found that the focus was accurate at 70mm. However, when I calibrated it at the 200mm ...
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1answer
179 views

Is a Siemens star, printed with laser printer, suficiant for sharpness testing?

I have a Samsung SCX-4600 and I decided to make a Siemens star out of it using an A4 paper with vector to very high resolution PNG illustrations. Is it an decent choice? How will it compare to a ...
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1answer
157 views

Are internal focusing primes actually uncompensated varifocal lenses?

If I shorten the focal length of a lens without taking any other measures, that will reduce the required flange distance for infinity focus - meaning that if the actual flange distance is not changed, ...
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2answers
524 views

Why can't I turn the focus ring on my Vivitar 100-300mm far enough to get infinity focus?

I recently bought VIVITAR 100-300mm F5.6-6.7 macro zoom. I use it with Nikon D70S. Here is my problem. When distance between my D70S with VIVITAR and object of photography is 15meters and more, I can ...
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3answers
159 views

Does the autofocus system look through the lenses?

I have a doubt about the effect of putting a filter (polarizer, UV etc) on the autofocus system. In theory, a lens which is put in front of the lens will affect the focus (we must set a different ...
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2answers
373 views

Why doesn't lens focus after turning focusing ring while set to autofocus?

My brother tried my new camera and was turning the focusing ring quite harshly on auto focus. (50mm canon lens) I’ve read multiple similar questions but nothing is quite what I mean. Ever since my ...
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2answers
898 views

If I swap cameras, will my lens keep appropriate focus?

I'll be going to a place where the night sky is quite nice to photograph. I plan on taking a star trail long exposure shot with a Canon 3000N, an analog camera. I'm pretty sure it won't be able to ...
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3answers
269 views

Reason for offset in lens/sensor and tripod mount?

I have noticed that my Canon Powershot G11 tripod mount is more in the center of the body of the camera and not aligned with the lens/sensor. Is there a reason for this? My concern is that as I rotate ...
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1answer
235 views

Why is there a maximum focus distance when using an extension tube? [duplicate]

I am using the Nikon D850 together with the Sigma 50mm/1.4 Art and the MEIKE MK-N-AF1-A extension tube(s). During first shots I found out that the combination not only has a minimum focus distance (...
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2answers
395 views

Are electronically parfocal RF lenses parfocal enough for fireworks photography with zoom?

Within a month or so, it's the first time I'll see fireworks as an owner of a good camera and naturally I'm planning to take photographs of them. By researching various fireworks photography sources, ...
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5answers
503 views

Is it best to use a wide aperture when I'm focusing at infinity and depth of field is not a concern?

If I shoot at f1.4, I can easily separate my subject from background due to the shallow DoF. In the case where I turn the focus to infinity at f1.4, I will have everything in focus, except the ...
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6answers
225 views

Can we prove that the object is not tilted from photo(s)?

This is an image of Al-Masjid an-Nabawi. Can we from this image, or from combination of images available online say with a certain degree of confidence (prove?) that this red circled minaret is ...
4
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1answer
135 views

AF Fine-tune zoom lenses?

How do you fix / fine-tune the focus on a zoom lens? Nikon states The D850 can fine-tune autofocus automatically. The results can be used with all lenses of the same type. But does it also mean ...
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3answers
214 views

Focus in Analog and Digital Cameras [duplicate]

Why a subject not in focus in the viewfinder of an analog camera is seen as two misaligned half circles, while in that of a digital camera is evenly blurred?
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5answers
4k views

Why can't my custom camera body focus to far distances?

I have built a custom optical device that uses a standard C-mount lens as found on CCTV cameras. Wikipedia states that the flange-to-film distance of a C-mount lens is 17.526 millimetres. I have ...
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3answers
192 views

What affects tripod stability?

I have a Vanguard Veo 2 265 CB tripod. I really like it and it has been performing, but lately I am trying to get my pictures as sharp as I can get and I noticed something. It must be trivial to ask,...
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4answers
110 views

Would it be viable to use my camera as a low power microscope?

I sometimes do pcb soldering and it is useful to have a microscope on hand with zoom of anywhere between 7x-12x to view the tiny components. I don't really want to spend several hundred dollars on a ...
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1answer
151 views

Back-focusing with Canon 7D2 body and Sigma 50mm art lens: is the Sigma USB dock the solution?

I just bought a second hand Sigma lens (50mm Art f/1.4) for my Canon 7D2 body (Mark II). This combination yields a very serious back-focus problem: With no micro-ajustements correction on my body, ...
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2answers
158 views

How to focus old manual viewfinder cameras?

I recently got two really old cameras, and I'm lost. The cameras are an Agfa Silette, and a Welta Weltax. I expected the cameras to have a focusing mechanism similar to rangefinger cameras, or split-...
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2answers
858 views

Nikon D5200 no longer focuses

It used to be that on my Nikon D5200 camera holding down the shoot button halfway the viewfinder would show green dots and it would focus nicely. Now after resetting the camera settings, replacing ...
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2answers
99 views

Focus issues even when using Single-Point [duplicate]

I have been noticing, even if I use AF-S with Single-Point focus and set the focus on the eye of the bird, still the final photo either comes out blurred or has less details. Someone in a response to ...
16
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6answers
8k views

Why aren't faces sharp in my f/1.8 portraits even though I'm carefully using center-point autofocus?

I love my Canon Rebel T6 and take portrait pictures in Av mode with a 50mm in 1.8 Av. I'm using auto focus in the 'focus on center point' mode. I make sure that the center point focuses on the face so ...
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2answers
222 views

How do I find infinity focus with a kit lens when there's not enough light for optical verification? [duplicate]

I have a D7200 which I want to use at long distances in low light photography. The kit lens, a 18-140 does not have focus markers on it. Furthermore, the focus ring does not stop hard at any point. ...

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