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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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Is there a way to auto-focus shooting video then lock it on a sony rx100 iv? [on hold]

I have so many focus problems with this camera it is driving me mad. There is no focus assist when in video mode, so I have trouble setting it up just trying to squint at the tiny screen. It's also ...
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1answer
50 views

How do adjustments to flange focal distance affect front focal distance?

I am using a Nikon Micro-Nikkor F-mount lens with 105mm fixed focal length in a custom optical set-up (F-mount adapter to custom optics). This means that my flange focal distance is only an ...
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9answers
29k views

How to nail focus for DSLR astrophotography?

I've been doing a bit of astrophotography and the problem that I almost always have is nailing focus. I'll manually focus on a bright star or the moon (which hopefully isn't an option!) by magnifying ...
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3answers
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How can I take a photo with everything in focus with my DSLR?

I am quite new to DSLRs and one of the first things I noticed was the incredible focus points and appearance of depth that you can achieve. That is great in a lot of scenarios, but not in all. When ...
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7answers
17k 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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3answers
41 views

Are focus-peaking MF and contrast-based AF susceptible to being misled by metallic reflections?

Wondering about some shots that went wrong, which were shot with focus peaking and manual focus, and where there were metallic/mirror-reflective highlights (think scenes with crumpled car wrecks or ...
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4answers
2k views

Is camera lens focus an exact point or a range?

I have often wondered if the focus of a lens at a particular focal length is an exact point or a range within a few millimeters. This becomes all the more important when manually focussing. How far ...
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3answers
100 views

Is it normal to see focus inconsistency frame-to-frame with an f/1.4 lens?

I have the Nikon Sigma 85mm 1.4 and I've noticed some inconsistency with focus. I setup a tripod, and a lens calibration card in an attempt to micro adjust the focus. However, what I noticed was that ...
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2answers
656 views

What is being set with Micro Focus Adjustment?

An autofocus system is system based on a feedback loop, where the AF sensor error reading if fed back to the lens focus motor. Being a closed loop, then theoretically there should be no focusing ...
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1answer
29 views

Mavic Pro 1 Infinity focus problem

1 Hello everyone, I am very new to flying drones. I have bought a second hand Mavic Pro 1, and it has this strange issue of focusing at night. Whenever I try to focus to infinity to get a broad DoF, ...
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421 views

What is “focus distance lower/upper” and how is it different from depth of field?

I have taken two photographs on a Canon crop sensor camera: 18mm f/9 with the following exiftool output (the focus was approximately at 3.5 meters): Focus Distance Upper : 5.27 m Focus ...
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119 views

Does shift based perspective correction have any effect on focus?

Consider a photographer with an SLR camera and a PC lens attached in its default, unshifted position, standing on the ground at the base of a columned building whose height is X times that of the ...
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3answers
3k views

Why am I allowed to turn my focusing ring beyond infinity?

Is there a good reason why I can turn the focusing ring on my lenses beyond infinity mark on focusing scale? Following recent questions about focusing in the dark (here and here), it sounds like a ...
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5answers
1k views

Can you determine if focus is sharp without diopter adjustment if your sight is imperfect?

I've already encountered this question about wearing glasses as a photographer. A more specific question I have is as follows. If your eyesight is not perfect, or your glasses and/or contact lenses ...
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8answers
7k views

Can you tell from a blurry photo if focus was too close or too far?

If you focus on a focal plane that is sufficiently in front of your subject, or past it (relative to depth of field), the subject will appear blurry. Is there some way of telling purely from the ...
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3answers
136 views

How to make pictures lots of kids so everyone's face isn't blurry?

I have a Nikon D850 with portrait lens AF 105mm f/1.4. I'm just learning how to make good pictures. We purchased this camera not for business — we have kids and want to make every possible memory. I'm ...
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3answers
881 views

Why is the Canon MP-E 65mm F/2.8 Macro Lens not called a zoom?

The Canon MP-E 65mm works differently than my other macro lenses. Compare: With a standard 35mm macro, I can frame first and then adjust focus which only changes framing very slightly with. With the ...
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5answers
150 views

What is the point of the infrared focus markers?

I am talking about the red values that comes after the infinity value. Why do they exist and how do you use them properly?
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1answer
62 views

Why does some lenses have red focus points on their focus rings? [duplicate]

A typical lens have white focus indicators on their lenses [5m 50m and infinity] but some have red points for 85m and farther and some lenses have a red curve instead of numbers. What are these red ...
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2answers
415 views

Why can't I auto-focus on semi-close subjects with my new Nikon 50-300?

I just got a new lens (Nikon DX 55-300) for my Nikon 3300 camera. I am just a beginner, however when I try to focus and capture something semi- close by (in the same room) it does not allow me to ...
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3answers
3k views

I'm having trouble getting sharp pictures while shooting a concert from a press pass location

I am a bit of a noob when it comes to photography. But I recently got the opportunity to shoot John Mayer this past weekend in Wisconsin. Upon getting home, I noticed the pictures weren't as sharp ...
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2answers
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What lense and flash should I get to take pictures of kids?

I'm new to having a camera and I'm not sure how everything works with my DSLR. I have a T6, and I would like to take pictures with flash without the kids squinting and that it is fast when I shoot. I ...
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1answer
51 views

Viewfinder shaking in my sigma 18-200 lens with Canon eos1100d

So, I dropped my camera yesterday wasn't a big drop and it was in its bag but today when I tried to use it the viewfinder has got an almost constant shake on it and all the photos are out of focus. ...
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4answers
17k views

How can I get correct focus when taking a self portrait with a DSLR?

Recently I purchased a Canon Rebel T5. I'm a high school student so this was in my budget. I enjoy taking picture of myself and putting them on Instagram... taking photos for my friends' parties and ...
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3answers
164 views

A projection of a real-image is one fixed perspective, but looking through the lens with my eye, I see many perspectives. Why?

Assume that I have a camera obscura (with a large lens - something like a magnifying glass) setup projecting an image of some still life. I look at my projection on my projection plane and I see one ...
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2answers
2k views

70-300 AF-S Lens Won't Autofocus on one of my D7100's

I recently purchased a used Nikkor 70-300 AF-S VR lens used from B&H that is in "Excellent" condition. I have 2 Nikon D7100 bodies that I shoot with and both autofocus just fine with all of my ...
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2answers
136 views

Why can my eye focus on the real image of a convex lens at many distances from the lens, but a projection only works at a specific distance?

Say I have a single convex lens. I set it up like a camera obscura, shine a light on my object and project the image onto a projection plane. Given the focal length of my lens, the projection plane, ...
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1answer
130 views

How to adjust focus without changing zoom?

I'm taking pictures of a D&D miniature. I'm using an iPhone with an app called VSCO that allows me to change the focus point. I've taped a 10x jeweler's loupe over the camera. My goal is to focus ...
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1answer
126 views

Sentimental photo taken by an iPhone out of focus

First let me say I am not a photographer, however I have a photo that was taken of my mom, myself and niece that is very dear to me. The photo was not properly focused I don't think. Could a ...
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1answer
1k views

What is a focusing rail?

In What are the best practices for DOF stacking? I noticed a mention of a "focusing rail". I've never heard of such device. What is it, and in what circumstances is it useful?
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Focus Mode issue with the Nikon 7200

It is my understanding that to change the Focus mode you press and hold the AF - Mode button next to the lens and then rotate the knurled dial on the back of the camera. Then you select your desired ...
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2answers
523 views

One camera unable to focus in low light, different camera, same brand model, has no problem

With a Canon T3i mounted in a camera/flash tower, the camera cannot focus in low ambient light with dark complected subjects. All the settings are preset as this is being used in a drivers license ...
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1answer
2k views

How can I fix an out of focus photo? Is there an app for that? I don't have Photoshop [duplicate]

Someone else took this picture of me and didn't focus. :( How can I fix this? Is there an app for that? I don't have Photoshop.
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4answers
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How can I fix an out-of-focus blurred photo in Photoshop?

How can I fix this picture? Somebody else took this picture and well he wasn't able to do it very well, and it's blurred. I have photoshop
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7answers
11k 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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How can I effectively use the focus points (of Canon DSLR), to get accurate focus on a small subject?

I'm shooting birds with my Canon 1200D and 55-250mm lens. I know this is not ideal lens and focal length for bird photography. But I am new to this field and before investing on expensive equipment, ...
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2answers
57 views

Focussing 100mm Auto Bellows Minolta lens on Bellows I with slide duplicator

I have a Minolta Auto Bellows 100mm lens (no focussing functionality, just aperture), that I am trying to use to duplicate slides with a A7R III and Minolta bellows I, focussing rail and slide ...
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4answers
6k views

How to calculate the size of the image circle at infinity focus?

How can I determine the diameter of the image circle (i.e. the diagonal size of CCD required to fully utilise a telescope's optics) at near-infinity focus? I have looked around online and found this ...
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5answers
9k views

Can software auto-detect image focus?

I was wondering if there was any photo management software out there that could auto detect and "rate" images on how in focus they are. This comes up for me quite commonly when i am looking through a ...
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1answer
424 views

How to enable back button focus on a Canon EOS 1300D?

I have recently switched cameras to a Canon EOS 1300D and I am unable to find how to enable back button focus. Does anyone know how to enable it?
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2answers
4k views

How do I diagnose the source of focus problem in a camera?

Probably a novice question, but how do I correctly diagnose from a photo for what reason that camera wasn't able to focus properly? It can be any 1 of the following Unsteady hand Lens issue Metering ...
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2answers
253 views

Is there really a trend of portraits where the subject is not in focus?

My wife told me is a trend to aim out of focus on portrait shot. Maybe like focus on the background and let the main subject look blurred. Is there such trend? What kind of photography is this? Anyway,...
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2answers
99 views

Focus on near eye in backlit situation

As far as I am aware, for a portrait of a single person, focus should be on the eye closer to the camera, as a rule. Does the same apply in more or less backlit situations, i.e., when the near eye is ...
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5answers
440 views

Why use ultra-wide with short focus?

I have a Samyang F/2.0 12 mm for the Sony E Mount, so the 35-mm equivalent focal length is 18 mm (crop sensor 1.5×). I use it mainly for landscapes and architecture in order to fit more in my frame ...
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4answers
175 views

Are all prime lenses designed so that the same DoF scale applies at any focusing distance? If so, why?

This question is about the mapping between the angular position of the focusing ring and the focusing distance. This mapping could be anything but the design of prime lenses seems to be such that a ...
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4answers
194 views

Why does this thin plate disappear when changing focus

I am photographing a very thin plate (0.01" thick) that is partially submerged in a tank of water. My goal is to find the angle that the water surface makes with plate. When I focus on the front edge ...
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1answer
176 views

Focusing techniques with old folding camera (Agfa Isolette/Jsolette V)

I inherited one of these from my grandmother recently. Bought new in Romania in the 1930s or 1940s, can't remember. Anyway, I've been shooting all kinds of films with it, and have gotten ...
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1answer
345 views

Why is my Nikon 18-300 lens not focusing at higher focal lengths?

I found a similar question about the 18-200. Someone suggested screwing the front element tighter. Is it possible to do the same with the 18-300? My problem happens at 200-300mm. I am not sure how to ...
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3answers
132 views

How can I focus on someone who is in motion and still get them in focus with a wide aperture?

I'm trying to figure out the best technique to use for photographing people in motion. I would love to do weddings one day - but for now I’m concentrating on just getting my focus down (with a very ...