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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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3
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3answers
612 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
109 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
83 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 ...
2
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1answer
63 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
78 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
80 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
87 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 ...
0
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2answers
113 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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2answers
109 views

How can a subject stay in focus if the shot is recomposed afterwards?

I have a doubt about a procedure that I see many photographers continuously apply and they taught me. I see that, when they want to take a picture with their reflex, they do this sequence of steps: 1)...
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2answers
138 views

How to set focus when subject is more than one object?

I have taken a photo with men dancing in a group. It was rejected by an agency stating: "The main subject is not in focus and grain noticed in the photo". Below I am giving the cropped image. Since ...
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3answers
94 views

How to identify main subject of the photo and set focus?

I am using Nikon D5600. While on street photo shoot, I clicked a couple of photos and submitted on one of the stock photo website. Few photos got approved whereas few were rejected with a comment. ...
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2answers
186 views

What makes these white stars appear black?

This is partial screenshot from an episode of the TV (Netflix) show Daredevil (season 2, episode 7): Note how the normally white stars of the US flag are showing up as black - albeit quite out of ...
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4answers
199 views

How do fixed lenses “focus” on things at different distances? [duplicate]

I'm trying to understand depth of field and I'm struggling. If I'm playing with a 50mm fixed lens, and I alter its focus using the little ring around the lens, what is actually changing in terms of ...
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2answers
166 views

Why do I get so many unsharp pictures with my Canon 70-200 IS f/2.8?

Please take a look at the picture below. You can see where the focus point was thanks to a LR plugin. But the image is unsharp - again. And yes, I'm sure the dog was standing still enough for 1/250 ...
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1answer
113 views

Focusing issues on live view - Nikon D750 w/ AF-S NIKKOR 24-70mm f/2.8G ED

On a heavily used Nikon D750 w/ AF-S NIKKOR 24-70mm f/2.8G ED: When using live vision, ussualy while holding the camera up over my head, autofocus focuses nowhere. This happens right after having ...
0
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2answers
86 views

Is minimum focus distance (MFD) really minimum?

On my prime lense the barrel shows the "minimum" focus distance (MFD). According to the definition you find on internet you cannot focus an object closer to this distance (measure from the sensor ...
0
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1answer
25 views

Canon EOS80D would not focus [duplicate]

While in manual mode with auto focus, could not get the camera to focus for night astrophotography. Tried different combinations of ISO, TV and AV. I noticed that the EV was all the way to the right....
2
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2answers
108 views

When using Back Button Auto Focus, do I release the button before shooting a sequence, or hold it down?

When shooting moving subjects (Sports), am I suppose to keep the back button AF pressed during a sequence of shots? Or do I press til it focuses, and then let go and shoot a sequence? Thank you in ...
2
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4answers
113 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 "...
3
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1answer
95 views

What is the Job of second lens in dual camera Mobile phones

Somewhere I read that two lenses are required to create a DSLR effect- Blurring the background. But today I read, the Aperture size is responsible for blurring the background, So any lens (single ...
0
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2answers
109 views

DSLR lens image inversion?

 Out of simple curiosity, do DSLR cameras produce an inverted image on the sensor, with the image being flipped by software?  I've dabbled with astronomy prior to my current interest in ...
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3answers
111 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 ...
2
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2answers
169 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 ...
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1answer
81 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 ...
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2answers
152 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 ...
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3answers
232 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 ...
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2answers
103 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 ...
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1answer
80 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
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2answers
169 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 ...
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2answers
356 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 ...
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1answer
105 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
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2answers
191 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
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1answer
431 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 ...
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2answers
525 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
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3answers
172 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
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1answer
65 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
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3answers
72 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
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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 ...
0
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3answers
153 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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1answer
81 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
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3answers
586 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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3answers
157 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
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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 ...
7
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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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5answers
341 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
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1answer
82 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
427 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
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2answers
129 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
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1answer
61 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. ...