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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69 views

How can i edit my picture to meet verification requirement

How do i perfect my picture to suit a verification process. The error it gives me is "Make sure your picture is in focus, well lit, not too small and all 4 corners of it are in the picture". ...
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30 views

Nikon D750 erratic focusing [closed]

I hav been having focusing problems with Nikon D750 . When it tries to focus on a subject, it will take about 3 or more seconds to try and focus. I can hear the servos move in an out of focus several ...
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1answer
87 views

D7200 no longer autofocusing

AF on the body of the camera M/A on the lens Back dial is not locked I've tried clicking and holding the AE-L/AF-L button Tried two different lenses Battery is full In the viewfinder, I see two arrows ...
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89 views

Auto focus won’t work in viewfinder on Aperture priority mode

My camera (Canon Rebel t7i) won’t auto focus in manual or aperture priority mode in viewfinder. (It works perfectly in liveview) Maybe it’s important to say that I’ve never shot in manual mode so I ...
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4answers
253 views

Why I am unable to focus at all while using ND filters

Lately, I am unable to focus with ND8 AND ND10 filters put over the kit lenses of my Canon1300D camera. Whenever I try to focus, it allows me to only reach to a point where the subjects are only ...
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1answer
72 views

How to calculate depth of field at different resolutions

I have a DSLR (EOS 60D) and I use hyperfocal pro when setting up astro-photography. At lower resolutions though, such as in video mode, how can I calculate the depth of field? The field of view barely ...
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2answers
42 views

How can I measure the exact range of focus of a given fixed focus webcam?

By moving objects around the camera I can see that they get very blurry at 10cm and less sharp at 3-4m away from the camera but how can I measure the exact range of focus? If I check the sharpness of ...
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0answers
29 views

Nikon D5300 pictures are coming out blurry

When I'm taking pictures in Autofocus on my Nikon d5300 the subject's face comes out blurry. It's not the camera shaking, the shutter speed was on 1/200. It didn't help to zoom in, however, when I ...
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4answers
3k views

How do I tilt a lens to get an entire street in focus?

What is an efficient strategy to get a particular plane in focus by adjusting: the tilt (or in the example below, the swing) the focus distance (or rather the focus angle, for a tilted lens)? I'll ...
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1answer
108 views

K10D poor focus - manual or auto - with full-frame zoom lens

I'm getting very poor focus particularly at the long end of an 80-320mm tele lens that I am using with my Pentax K10D. The lens was originally bought for my 35mm Pentax SLR (maybe an MZ5 or something, ...
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1answer
88 views

Dismissing red frame in close up [Canon EOS M50]

Is there a way to take a shot even though the red frame indicating out of focus appears? When I am trying to take a picture few inches away from something the red frame appears. Someone asked similar ...
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4answers
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What causes images to have flat depth?

I am learning about photography and I remember reading about an effect that causes images to look like there is no depth but now I cannot find what it is called or what causes it. I remember an ...
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2answers
95 views

Would a screw in 2x converter double the minimum focusing distance?

I want to shoot some very zoomed in shots, my current lens has a 28cm minimum focusing distance. I want to shoot from 35-40cm away but more zoomed in. Sort of macro, but from a distance. If I bought a ...
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2answers
127 views

Focus problem with Opteka 500mm mirror lens

Ok, I'll lead with the fact that I know this is a cheap lens and they're notoriously difficult/impossible to focus well. But ... something is strange here. I took this lens out to try and get some ...
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2answers
63 views

How to properly focus using a Macro reverse ring?

Fourth question from me about this topic. I'm trying to digitize a large number of family slide films with a modified slide projector by taking photos of the slides (I replaced the original yellow ...
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1answer
215 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
383 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
343 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
154 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
68 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
294 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
247 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
137 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
259 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
249 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
119 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
230 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
61 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
171 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
249 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
494 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
198 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
160 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
219 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
327 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
94 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
193 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
47 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
86 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
139 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
117 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
174 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
242 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
192 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
559 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
161 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
567 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
903 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
321 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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