Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [focus]

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

6
votes
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 ...
11
votes
3answers
63k 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 ...
41
votes
7answers
6k views

What is “Hyperfocal Distance”?

I'd like a clear & easy-to-understand (especially for non-physics-types) explanation of what Hyperfocal Distance is, how it affects photographs, and what determines its value.
120
votes
7answers
12k 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 ...
76
votes
15answers
18k views

How does one focus for landscape photos in very dark conditions?

Tonight I tried my best to take some night landscapes in the darkest of dark conditions. Hoping for an epic composition of the Milky Way and a landmark. Of course, none of my glass could auto focus ...
8
votes
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 ...
33
votes
8answers
5k views

What is the advantage to back-button autofocus?

I've heard some advanced photographers talk about using back-button autofocus. As I understand it, this involves changing one of the camera's custom setting to engage the AF when a button on the rear ...
28
votes
5answers
4k views

What tips and advice do you have for photographing the Aurora Borealis?

A friend has been kind enough to lend me a DSLR for a few months. It's my first foray into DSLR photography, or indeed any kind of photography beyond simply aiming my Canon IXUS at something and ...
11
votes
4answers
120k views

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
15
votes
4answers
16k views

How can a lens with a single focal length focus on more than one plane?

By definition, a prime lens is a fixed lens system with a fixed focal length. Then, simple physics tells us that it should be able to focus only on one plane (at a fixed distance) in front of it. But ...
12
votes
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, ...
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 ...
18
votes
1answer
5k views

Why do some lenses focus past infinity? [duplicate]

On the kit 18-55 lens that came with my Nikon D5100 I have noticed that when trying to focus on infinity for shots in dark conditions (star-trails, etc) the lens tends to move past infinity out of ...
28
votes
5answers
3k views

What are the best practices for DOF stacking?

What are the best practices for DOF stacking? How do you get the frames with focus just right amount apart? How do you stack them in post processing?
18
votes
5answers
2k views

Why can't my SLR autofocus on certain parts of a scene?

I had my Nikon D7000 on single-point auto focus and it just would not focus on the spots I wanted. I have marked the spots that could not be focused on with red circles, and the parts that could be ...
29
votes
3answers
7k views

Does changing the focal length change focus?

When using manual focus or back focus on D60, I sometimes zoom in the lens, set the focus, and then zoom out. Does changing the focal length (zooming out), also change the focus? In case the answer ...
7
votes
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: ...
30
votes
9answers
5k views

Why would I want to select an autofocus point?

I'm trying to understand why I would ever want to select an auto focus point other then the center point. I have a Canon XTI Rebel DSLR which has 9 auto-focus points, but I'm also looking into getting ...
8
votes
2answers
3k views

Is it normal for focal length to change while focusing?

When I change the focus distance on my Pentax 55-300mm lens, the focal length appears to change. More specifically, the lens appears to zoom in as I focus towards the minimum focusing distance. This ...
3
votes
3answers
2k views

How can lens cause consistent front or back focus?

I can understand body focusing problems, but I can't imagine why lens might cause front or back focus. I have two third party manufacturer lenses for my Nikon: one is front-focusing, the other is back-...
6
votes
2answers
2k views

What is the reference plane used when the minimum focus distance is measured?

Once you know the MFD (minimum focus distance) for a particular lens, is that the distance from the subject to the front of the lens or to the camera sensor?
18
votes
5answers
11k views

How does changing focal length affect depth of field?

I'm curious about how my "area of acceptable focus" changes when the focal length of the lens I'm using changes as I zoom (or switch lenses). In particular, I'd like to know how the front & back ...
29
votes
13answers
16k views

How does one get manual focus right with a fast-aperture lens?

I have got an old lens (f1.4) that I have to use only with manual focus on a DSLR. Well, it is difficult for me to get the subject on focus. Although on focus according to the viewfinder, the actual ...
15
votes
5answers
32k views

What is “infinity focus”?

I have been reading a bit about astrophotography and the term infinity focus keeps coming up. What is infinity focus and how do you set the camera to infinity focus?
12
votes
3answers
51k views

How do I keep both the background and foreground in the image in focus at the same time?

How do you have both the background and foreground in the image in focus at the same time? Last week I was attempting a shot where I had the back of a hat in focus and in the distance you could see a ...
3
votes
2answers
8k views

Do the issues with sharpness I am seeing require AF fine-tuning?

I own a nikon D7000 with 18-105 lens. I am not happy with sharpness I get with autofocus in portraits. I read about front/back focusing, but I am not sure whether my gear has this issue. Is this issue ...
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 ...
37
votes
4answers
90k views

What is back-focusing?

What is back-focusing? Is it something I need to be worried about, or can I just live with it? How can I tell if my camera/lens is sufferring from it?
25
votes
9answers
8k views

How do I focus in low light for long exposures?

I've been trying to take some long exposure shots at night with my Canon 450D. The problem I'm having is that I can't seem to get a shot in focus. The low light conditions prevent AF from working at ...
13
votes
3answers
16k views

What is the technical difference between focus and zooming?

This may look like a silly question but I don't know what the difference between zooming and focusing is. Zooming in will usually let me have fewer subjects in the scene while zooming out will allow ...
7
votes
4answers
13k views

How can I find infinity focus on a kit lens with no markers?

I have a kit lens which has no markers. What would be a recommended way to find infinity focus on this lens? I plan to shoot objects at night -- not necessarily stars or the moon. So, adjusting the ...
3
votes
4answers
2k views

How to focus on an area correctly, while still blurring everything else?

I made a picture (see below) of an almond cake with the following settings: 4/3 sensor 25mm focal length Aperture f1.4 Shutter speed 1/30 sec I chose an appropriate shutter speed with the biggest ...
3
votes
3answers
30k views

What does infinity focus mean and when should I use it?

All my lens have focus ring where at the end there's an infinity symbol. What does that mean? If I'm taking landscape shot and what everything from near to far to be in focus, do I use infinity? Or am ...
12
votes
4answers
3k views

How close can a lens focus?

From my understanding, if you want to do some macro photography it is better to have a lens that can focus when it is really close to the subject. Sometimes people buy extension tubes to help them ...
9
votes
5answers
5k views

How can I get maximum DoF with no distance markers?

I am aware of what hyperfocal distance is and the general principles behind it. However, most of the tutorials I have seen and read regarding it make use of lenses with focus distance indicators. ...
26
votes
18answers
3k views

What are some techniques for hand-held image stabilization?

My zoom lens (75-300mm) is fairly slow: 5.6 at its farthest point. (I think it's 3.5-5.6, and it's not image stabilizing. I'm on a budget, sadly!) Unfortunately, my primary use for it is hand-held ...
13
votes
4answers
1k views

Where to focus when shooting landscapes?

When I am shooting landscapes, where (at what point) should I focus when using Auto Focus? Or if I am shooting the lit up skyline of the city, what should be my focus point? The reason I ask is that ...
4
votes
5answers
3k views

How could I achieve stock quality sharpness?

I am using Canon 600d equipped with 18-55mm kit lens and also I bought 50mm 1.8. I am trying to take pin sharp pictures to upload them for sale.I am shooting still objects and models time to time. I ...
8
votes
4answers
2k views

How can I take photographs with a large depth of field without diffraction?

I was looking at some pictures by TSO Photography, and I was struck by how everything in the image seems to be sharp and in focus. I do realize that to achieve huge depth of field, you set the ...
4
votes
1answer
555 views

Do lenses have focal planes or focal spheres/ellipsoids?

The title says it pretty much all. I'm asking this because I find myself always using the focus point in the center, and after I focused, I rotate my camera to make the framing right. However, if ...
4
votes
2answers
353 views

How can I more consistently focus on the point I want?

I've had so many wonderfully composed images turn out lousy because my AF isn't as accurate as I'd like (or I don't know how to wield it). Despite using single-point AF, my focus point is often ...
1
vote
3answers
5k views

Why does this lens lose focus when you zoom in but not when you zoom out?

This is regarding the Sony 18-105 E-mount constant-aperture zoom. I took at photo at 18mm, focusing manually: I then zoomed to 105mm, and took another photo, keeping the same focus: Notice that the ...
17
votes
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 ...
22
votes
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?
7
votes
4answers
2k views

Are there macro focusing techniques for handheld shots?

I know that when doing much macro work that the autofocus system is nearly useless. When hand holding and trying to manually focus, I find myself continually going a little too far or just not far ...
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, ...
3
votes
2answers
1k views

What could be causing focus problems in low light?

I am not a professional photographer but shoot outdoor and indoor pictures, weddings, and portraits as a hobby. I use a Nikon D750 with a 70-200mm 2.8 VR lens and a 35mm 1.8 ED lens. I have been ...
2
votes
1answer
3k 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.
2
votes
1answer
980 views

Is it possible to get bokeh in cellphone photos?

I have wondered how to get some parts of the image out of focus when using smartphone cameras (or if it can even be done). Recently found out about the concept of bokeh, and am interested in ...
1
vote
6answers
1k views

How to ensure sharp focus when shooting with an open aperture?

I've bought a Canon EF 50mm f/1.8 to use with my EOS 200D and while I love the wide aperture, it appears to be quite difficult to achieve sharp focus on people's faces when shooting at f/1.8. I've ...