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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18
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5answers
10k 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
23 views

Canon EOS80D would not focus

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
99 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
97 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
votes
1answer
88 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 ...
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0answers
28 views

Canon eos rebel 2000 ef focus points [on hold]

The FP’s are only visible in brigt sun. Are they meant to glow or something ?
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2answers
105 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
105 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 ...
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3answers
138 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 ...
0
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2answers
96 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 ...
2
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2answers
167 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
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0answers
47 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
95 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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2answers
341 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 ...
2
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2answers
137 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 ...
0
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1answer
56 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 ...
1
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1answer
79 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
7
votes
3answers
4k views

Since it's not “focal length”, what is the term for the distance at which things are in focus?

I was under the impression that the “focal length” of a lens is the distance at which stuff appears in-focus. (E.g., perhaps I set the camera so that objects 3 meters away appear sharp, ...
0
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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 ...
1
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1answer
164 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 ...
1
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2answers
185 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 ...
-2
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2answers
206 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
170 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:
7
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2answers
1k views

How can I get more of this macro photo in focus?

I want to make a full focus on the body, for example: I need to have a clear focus on the each balls in the photo. I used just single point focus. In this picture I used: shutter speed: 8 aperture: ...
0
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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 ...
36
votes
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 ...
11
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3answers
65k views

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 ...
12
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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, ...
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
118 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 ...
7
votes
2answers
659 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
48 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
483 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 ...
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 ...
24
votes
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 ...
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 ...
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 ...
0
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3answers
150 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 ...
9
votes
3answers
906 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 ...
0
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5answers
223 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
69 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
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2answers
421 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 ...
8
votes
3answers
4k 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 ...
0
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1answer
54 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. ...
3
votes
4answers
18k 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 ...
1
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3answers
185 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 ...
1
vote
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 ...
2
votes
2answers
143 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
149 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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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 ...