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
70 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
41 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
28 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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3answers
7k views

My DSLR's autofocus doesn't work after I dropped it — how can I narrow down the problem?

If I try to focus by the shutter button the image doesn't change, even in live view (and I'm not be able to shot a picture). But if I hold the "AE-L/AF-L" button and click the shutter button I'm able ...
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2answers
541 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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0answers
24 views

AF point focus shifted Rebel T5i/700D [duplicate]

I have a rebel t5i/700d and focus via touching live view works fine. But using the focus points via view finder does not work properly. I manually selected the center one and the picture is blurry in ...
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4answers
347 views

How to take a photo of a close-up object without focus stacking?

I'm trying to get into product photography and took some fun shots. I'm talking about shots of my iPhone and things like that. What I quickly realize is that I am unable to get enough DOF. I'm using ...
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1answer
85 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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1answer
189 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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7answers
3k views

How can I meter and focus on different places of an image with a Canon DSLR?

I have a Canon 700D. I use the P mode (this way I can select a single focus point; I use the center one most times). I haven't changed any other setting. I raise the camera, focus on my subject (...
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4answers
2k views

When a camera auto-focuses, is the current focus distance reported from the lens to the camera?

The question says it all -- does the camera "know" how far the subject is from the lens, i.e. what is the current exact focus distance set at the lens?
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4answers
1k views

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
125 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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2answers
5k views

How can I cause red eye in photos I take with my iPhone 6s?

How do I cause red-eye in my photos? I had no trouble causing red-eye in my old iPhone 4; but having issues with the 6s, even with [right & left] circular polarising filters over the flash and ...
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4answers
278 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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1answer
361 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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1answer
64 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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2answers
196 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
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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5answers
323 views

Can hyperfocal distance be used to keep everyone in focus in group photography?

If you have different sets of people standing at different linear distances from the camera can we use the theory of hyperfocal distance to ensure sharp focus on all subjects? Conversely does being "...
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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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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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3answers
137 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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3answers
246 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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4answers
7k views

how to focus with a ND filter

I've just bought a ND3 filter (-10 stops) and was looking for recommendations on how to focus the camera. Basically many recommendations are around focusing WITHOUT the filter, then switch to manual ...
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2answers
169 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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8answers
19k views

How can I get everything in focus? (Why can't my camera just use all of its focus points at the same time?)

I have a Canon 550D with 70-200 f4 and 50mm prime lenses. Although the camera has built-in 9 focal points, I sometimes face a strange problem. Here's a sample photo: In reference to the above pic, ...
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1answer
128 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
240 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
247 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
229 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
60 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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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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2answers
4k views

How to use focus points in manual focus mode on Canon EOS 6D?

I just got my first DSLR, a Canon EOS 6D with 50mm f1.8 lens. I'm tring to learn by watching YouTube, but have some questions. When I use the lens on MF and the body on MF, I can't focus using the ...
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1answer
167 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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5answers
483 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
155 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
209 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
312 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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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
90 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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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
1k views

Can focus stacking (or a similar technique) also be used to reduce depth of field?

Instead of using multiple images focused at different points to extend the depth of field, can I also reduce it? Does a technique exist to achieve a shallow depth of field by stacking multiple images ...

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