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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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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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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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99 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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28 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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416 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
135 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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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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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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148 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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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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412 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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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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93 views

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
50 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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162 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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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
128 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
125 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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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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72 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.
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56 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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408 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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85 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 ...
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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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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
439 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
172 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
173 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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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 ...
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78 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 ...
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350 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.
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2answers
126 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 ...
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2answers
105 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 ...
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156 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 (...
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29 views

Focus highlighting thumbnails

Is there any software that will analyze the photos in a directory and create thumbnails with the areas most in focus highlighted in color? I know my camera (Sony a99ii) can do this real time. It ...
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1k 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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1answer
747 views

Panasonic Lumix TZ100 - how to stop autofocusing and just get everything in equal focus?

I’m an amateur photographer and would like to ask for some help! I’ve recently bought a new camera, a Panasonic Lumix TZ100. Before that for 5 years I was using a Canon Ixus 255 HS. So far I haven’t ...
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2answers
178 views

Manual focus in A mode can harm my lens? [duplicate]

I use 18-140 Nikkor . This lens have two A & M focus mode and this lens is AF-S that mean when auto focus is enable the focus ring dose't move. If i do manual focus when the lens is at A mode , ...
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1answer
250 views

Manual focus lens on fixed focus camera?

Hello i have bought this camera: It is a lens type camera, but it has a FIXED focus. I read on the internet that if I buy and put a manual focus lens it will work? Is that true ? If it is true ...
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4answers
354 views

Is recomposing ideal rather than changing focus point?

As a beginner in photography I’ve stumbled across several videos stating that the center point is the sharpest and most accurate point as apposed to the others. I’ve seen many photographers take ...
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3answers
1k views

How to avoid the grainy background in sunset picture?

I was taking this picture of the sunset. I used auto focus, but the trees are not really that focused. Also, the red background is grainy. Any tips if I get this opportunity again? I was using a ...
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2answers
252 views

Focal length measurement and definition in DSLR cameras [duplicate]

So i am a bit confused when it comes to focal length in DSLR cameras. According to multiple sources online i found and as per NIKON "It is a calculation of an optical distance from the point where ...
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2answers
162 views

How to take a macro photo, but with the subject completely in focus [duplicate]

I love macro photography, it gives an insight in the small world around is. Unfortunately, I'm really not good at it. When I came across an artificial beehive, I took a chance to get into the bees and ...
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1answer
87 views

Are focus and resolving power optically equivalent?

Limited "resolving power" or "sharpness" is a problem one can see with many lower-quality lenses, especially with higher-resolution camera bodies. Playing with my cheap 500mm mirror lens, I often get ...
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1answer
749 views

Do 49 focus points mean the camera will focus on 49 different areas at the same time?

I've read a lot but could not find a clear explanation. As I understand, a lens can only focus physically on one point since the focus depends on the physical position of the lens vis-a-vis the sensor....
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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
2k views

Tamron lens focusing problems?

I own a Tamron 18-270mm F/3,5-6,3 Di II VC PZD lens - a fabulous lens, but since I got it (around Christmas time), the autofocus has been playing up; see below image. EXIF is as follows: 270mm, ...
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4answers
612 views

After I dropped my lens, focus locks but images are blurry — what could be wrong?

I have a Tamron 24-70 2.8 on a D610. I usually go for small apertures (F11 to 16) since I work with flashes on studio setups, my lens gives sharp images on those appertures but anything below F5.6 ...