Photography

Questions tagged [focus]

Ask Question

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

489 questions
Info Newest Frequent Votes Active Unanswered
1
vote
3answers
61 views

Is there any mirrorless camera that can mark areas within DoF in the EVF?

All mirrorless cameras have the image in the rear LCD and the electronic viewfinder (EVF) fully generated by a computer, making many utilities such as noise removal, text overlays, histograms, etc ...
0
votes
1answer
51 views

Detecting changes in focus [on hold]

I have a process where a DSLR camera takes a photo of an identical and flat (nearly 2D) object every few seconds. I am hoping to build a QA step that involves checking a control or test card every 50 ...
2
votes
2answers
155 views

Would adding an external lens allow one area outside the focal plane to be in focus?

I’m doing high speed scientific imaging. I have a camera mounted in a fixed location with a Micro Nikkor 105mm lens. It’s viewing a fixed subject that has a small mirror oriented 45 degrees underneath ...
0
votes
0answers
43 views

How can I tell whether or not a lens has focus breathing?

So recently I got a 90mm macro lens, installed a focus bracketing app onto my camera and let it run. Unfortunately, turned out that this lens has focus breathing which means the actual zoom level in ...
0
votes
2answers
85 views

Is the Canon EF 24-105mm f/4L IS USM lens parfocal or not?

I read a review of the Canon EF 24-105mm f/4L IS USM lens. It said: Focus shifts while zooming. Zoom before you focus. Surprised by this (I don't recall ever seeing the focus scale shift while ...
1
vote
3answers
132 views

Does image quality of the lens affect “focus and recompose” technique?

As I understand it, 'focus and recompose' is often used to ensure the subject is in focus and at the same time composition is right. It has been estimated that some lenses are best in terms of image ...
1
vote
2answers
94 views

Is this the limit of the camera image quality or is the subject out of focus?

I'm using the "macro" mode in the Powershot G9X II. The macro mode is simply a shorter focus range, there is no magnification in place, like in aftermarket macro lenses for DSLR's. I've shot many ...
0
votes
1answer
47 views

What units are used for zoom and focus distance for the varifocal Dahua camera? [closed]

I've been working with an industrial Dahua camera and since I do not have a full model of how the camera works (and because I'm a complete newbie to cameras in general), a few elements are still ...
2
votes
2answers
133 views

How to perform non-center focusing using common film SLR camera?

I have a Nikon FM2 camera with Nikkor 50/1.4D lens. Is there a way to focus on the area that is not center? This can be easily done with digital camera as Nikon D750, where we can just use focus ...
1
vote
2answers
338 views

How to find an angle and a distance for clicking picture of a distorted artwork to achieve 3D effect?

If you know about 3D pencil artworks, you would know people draw it distorted (generally length is enlarged i.e., stretched from bottom to top) first and then click a picture at some angle (30-40 ...
1
vote
1answer
76 views

Everything in focus with d750 [duplicate]

as you can see the flowers are not focused, I cannot focus everything, I have to chose the squirrel or the flowers, is it normal? THANK you D750 28-300
1
vote
2answers
184 views

New camera won't focus while zoomed in, old one focuses perfectly. Why? [duplicate]

I take photos of computer hardware for sale on ebay. I had been borrowing a camera for photos (Olympus SZ-16) and the camera will be able to focus while very zoomed in to a device while relatively ...
1
vote
1answer
108 views

How can I preview depth of field on my Canon M50?

I recently bought a Canon M50, and it's actually my first time ever taking pictures with a camera other than my phone, so I'm super noob. Today I was playing around with my M50, trying different ...
-2
votes
2answers
158 views

My camera won't focus on close objects [duplicate]

Hi my EOS 6d mark ii camera will not focus when I am trying to get a close up photo but will focus on a far away object. Please help.
4
votes
3answers
169 views

Why is that the wider the aperture of a lens is, the more we can see through narrow cracks and crevices?

Example I took at 85mm f/1.4 on APS-C sensor:
0
votes
1answer
53 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 ...
0
votes
3answers
66 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 ...
7
votes
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 ...
0
votes
3answers
112 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 ...
1
vote
1answer
39 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, ...
3
votes
3answers
460 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 ...
0
votes
3answers
148 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 ...
43
votes
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 ...
7
votes
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 ...
0
votes
5answers
196 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?
0
votes
1answer
68 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 ...
1
vote
2answers
419 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 ...
3
votes
2answers
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 ...
0
votes
1answer
52 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. ...
1
vote
3answers
177 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 ...
2
votes
2answers
141 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, ...
2
votes
1answer
140 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 ...
-1
votes
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 ...
5
votes
2answers
524 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 ...
1
vote
2answers
87 views

Is it necessary to use focus point selection if I use back button focusing?

I'm a beginner in photography who just started using back button focusing.
2
votes
2answers
64 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 ...
0
votes
1answer
633 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?
0
votes
1answer
86 views

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 ...
4
votes
2answers
256 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,...
3
votes
2answers
100 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 ...
4
votes
5answers
442 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 ...
1
vote
4answers
199 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 ...
6
votes
4answers
197 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 ...
3
votes
1answer
246 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 ...
4
votes
3answers
133 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 ...
1
vote
1answer
79 views

DSLR cannot focus after short drop

Have an old Canon 300D which suffered a drop onto hard floor from less than half a metre. It was in a bag, with a lens attached, and there is no visible damage. However, it seems to have lost the ...
1
vote
4answers
459 views

Wondering about the metering mode and focus area? [closed]

I just learn about the metering mode and focus area on youtube. But i am wondering about are they on at the same time? I got a sony a6300 camera.
3
votes
2answers
142 views

Pentax K-x with kit lenses problem producing sharp photos [duplicate]

Hey guys I have recently dug out old Pentax K-X with kit lenses, but I noticed I struggle with sharpness of the photos. No matter what settings I try I get my photos blurry when I crop it to make ...
1
vote
2answers
116 views

How to accurately determine the size of a nearby object (~15cm) using the autofocus focus distance?

The problem I'm trying to determine the size of an object using the focus distance determined by the autofocus of a smartphone camera (Galaxy Note 8). But I don't seem to be able to get an accurate ...
1
vote
1answer
176 views

Is it normal for focus to “drift” in timelapse mode?

I use a Canon 77D with a 24mm 2.8 STM lens. If I set the camera to back-button focusing, focus, then take a short series of shots, everything looks fine. But if I leave the camera in timelapse mode (...

1 2 3 4 5 … 10