Westminster fountain at sunset

by Jorge Córdoba

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

learn more… | top users | synonyms

21
votes
9answers
3k 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 ...
10
votes
7answers
2k views

How can I get perfect sharpness when shooting still art?

I've been trying to shoot some marble sculpture that are well lit on a studio wall. The photos are coming out well and perfectly useable.. but I'm striving for something better. My issue is with ...
2
votes
1answer
141 views

Nikon 16-85 VR focus noise problem?

My 16-85 VR is doing some weird noise during focus, manual or auto. It's like an hiss. I asked in a local shop and they said it can be some microdust inside the lens. But I'm a little worried it can ...
2
votes
1answer
50 views

How do you focus a shot with an IR/UV passfilter?

I'm researching the world of photography outside of the visible spectrum and I'm really curious to get my hands on some filters, the Baader-U for example, to try shooting in these spectra. However, I ...
2
votes
2answers
80 views

Programmable cameras that can take multiple shots at different focus settings

To do focus stacking in case of moving subjects, it would be useful to have the ability to preset different focus settings and let the camera take the pictures with the different settings in fast ...
1
vote
1answer
247 views

Why Focus Assist activating in full outdoor light on my Canon EOS Rebel?

Trying to understand why the focus assist feature is activating in full outdoor light on a sunny day. I have a Canon EOS Rebel T-3. Recently, the 18-55 stock lens was replaced free by Canon. Since I ...
0
votes
3answers
190 views

Why can lenses only focus from so close? [duplicate]

I have always wondered, why is it that a lens can only focus from so far away from the subject? I know some lenses have a kind of macro switch which basically allows them to focus closer but why are ...
28
votes
4answers
42k 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?
0
votes
3answers
86 views

Auto focus vs Single Continuous/Point focus

I'm using a D600. Sometimes, having the ability to select my focus point is good. However, in certain situations, moments can be lost when you're framing or moving the focus point to the subject in ...
5
votes
3answers
156 views

How do waterproof lenses focus underwater?

Our eyes need air in front of them to be able to focus properly, that's why when we go swimming using goggles, our surroundings are much clearer than without. So my question is, how do waterproof ...
5
votes
1answer
385 views

Is it possible to get tethered focus and aperture control with any current DSLR?

I'm looking to get into some photography work and I had a couple questions. I'm quite an amateur at this, unfortunately, so I would appreciate any and all assistance! I want to be able to control the ...
0
votes
1answer
33 views

Find focus and effective range of single focus camera

I have a cheap camera that is supposed to take videos underwater. It is a camera in a case that is set to a single focus. I checked the specs and it is a manual set focus camera. When I asked the ...
0
votes
2answers
104 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 ...
0
votes
1answer
92 views

1/30 shutter speed with film camera

If you take a photo with a 1/30 shutter speed, but the objects in the photo were not moving, will the picture appear blurry? Or will they appear clear?
0
votes
1answer
103 views

When should I consider an image sharp? [duplicate]

Recently I am worried about the functionality of my Pentax K-50, i.e. I am not able anymore to get real sharp images. Thus my question arose, what I should see as "sharp". So I took several pictures ...
0
votes
2answers
118 views

How can I focus on the moon [duplicate]

I'm technically a beginner when it comes to anything other than point and shoot photography so I apologise if I don't explain myself clearly. I have a Pentax Q with an 85-200mm K lens, I'm using a Q ...
1
vote
2answers
115 views

How does auto focus tracking work in DSLRs

I thought auto focus tracking comes from the computation of image on the image sensor when I was using GF1, a MILC. The auto focus tracking was good. However when I use canon 6D, a DSLR the auto focus ...
11
votes
2answers
402 views

Does focus breathing make a lens slower when close focusing?

I've heard that focal length of some lenses will become noticeably longer when focusing to a close distance, an effect called "focus breathing". Since f-number is focal length divided by diameter of ...
5
votes
2answers
1k 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 ...
0
votes
2answers
98 views

does depth of field travel with the focal plane?

for simplicity it can be assumed all of the following discussion is relative to a prime lens i recently learned about the technique of hyperfocal distance focusing. that is, by using the method to ...
6
votes
2answers
4k 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 depth that you can achieve. That is great in a lot of scenarios, but not in all. When filming a ...
2
votes
1answer
97 views

How does a focus ring bring a subject in or out of focus?

When you manually adjust your focus ring on the lens, what actually happens inside the lens? Is this changing simply the point at which the lens is focusing, so that anything at this distance away ...
0
votes
1answer
65 views

Noise reduction before or after deconvolution?

NR before or after sharpening has been asked and answered, but deconvolution is much more complicated than simple USM. Many deconvolution algorithms have their own methods of handling noise, so I'm ...
1
vote
1answer
72 views

Which mirrorless have the best live view for night photography?

Which mirrorless camera are best suited for focusing (manual is OK) and framing in low-light? I have an Olympus e-pm2, and I can't see anything on the LV when its really dark, and have to resort to ...
1
vote
2answers
191 views

Focus in night photography

Another question related to the Olympus OMD EM5. I bought this camera to replace my Nikon D90 and I'm very satisfied with it. However, I find very hard to do the focus at night. With the Nikon D90, ...
9
votes
2answers
6k views

How do I determine focus points in Adobe Lightroom?

Not sure if this is possible or not in Adobe Lightroom. I would like to see the focus points chosen by my Canon DSLR. I am guessing this is stored somewhere in the EXIF, but I'm not certain. I find ...
5
votes
3answers
781 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 ...
4
votes
1answer
126 views

Is the distance scale on a lens linear?

I have Nikon lenses with distance scales on them so I can set the lenses to the hyperfocal distance when I need. Say now the focal length is 28mm and the aperture is f/16. The corresponding ...
32
votes
7answers
2k 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.
0
votes
1answer
109 views

Sony 3.5-5.6/18-55 SAM (SAL1855) lens broken

I have a Sony 3.5-5.6/18-55 SAM (part no. SAL1855) lens that has taken a knock and the zoom ring is now stuck fast at 55mm and the focus ring doesn't want to pull all the way in. Are there any guides ...
5
votes
1answer
366 views

How do disposable cameras work without exposure and focus control?

Before I got into photography, I used to use disposable cameras with ISO 400 film. I've gotten some decent results in various lighting, both inside and outside and at different focus distances. How do ...
24
votes
4answers
2k 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 ...
3
votes
1answer
106 views

Why is it harder to focus using LiveView?

I have a Canon EOS 650D with 18-135 f/3.5-5.6 IS STM. When shooting in LiveView, I find it harder to achieve focus when it's in the dark, and sometimes it can not lock focus despite my touching the ...
11
votes
4answers
302 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 ...
0
votes
2answers
200 views

Is a Canon 50mm 1.4 lens only meant to focus close range?

Ok, so I currently shoot with a canon Rebel which of course has a 1.6x crop factor. My primary lens is Canon's mid-level 50mm f/1.4. I love this lens for close up portraits and can get a very sharp ...
1
vote
1answer
182 views

Nikon D3000 Blurry Pictures. Focus Issue?

Here are two examples: Both pictures are in NEF format here. The pictures have not been modified in any way except except for being resized and converted to PNG. Just for kicks (and to prove I'm ...
1
vote
2answers
120 views

How to focus manually with a Nikkor AF-S DX VR 50-200mm f/4-5.6G zoom lens?

I have a Nikon D3100, for which I just bought a Nikkor AF-S DX VR 50-200mm f/4-5.6G zoom lens. This is a CPU lens and works very nicely in auto-mode, i.e. when you let the camera set the focus. ...
8
votes
1answer
547 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 ...
-4
votes
1answer
93 views

Why do my photos appear more in focus when I use a long exposure?

Why does an unfocused lens still give a focused view with a longer exposure? For example, I took an out-of-focus photo with a ¹⁄₁₀th second exposure (at f/7.1), but when I change to 10 seconds (at ...
3
votes
1answer
95 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 ...
3
votes
1answer
2k views

Nikon D5100 Focusing Issue

The issue I have had is where the camera tries to focus and cannot focus. It just zooms in and out constantly and no matter what I do it will not focus and fire. The only way I have found around this ...
0
votes
1answer
78 views

Why does the focus light come on in manual focus mode?

When I'm in the manual focus mode, I find that the focus light (the red blinking light) sometimes still comes on before it takes a photo. Why is this? I thought the purpose of the light is to ...
1
vote
2answers
185 views

How can I increase the amount of 'keepers' from my Nikkor 50mm 1.8D

I have been using this lens for a while, mostly for portraits and have noticed that for some reason the outdoor pictures where I most likely had to quickly compose and take the shot have had something ...
8
votes
3answers
5k 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 ...
2
votes
3answers
102 views

Precise focus information in metadata

I am trying to get the precise focal length used for a stack of photographs taken with various focal length. See the following link. My problem is that even if the photographs are obviously focusing ...
1
vote
2answers
111 views

What determines the sharp parts in an image: the DoF or the focus point?

I am a little bit confused between depth of field (DoF) and focus points. Which of them is responsible for making part of the image sharp?
0
votes
0answers
58 views

How to get accurate focus at night? [duplicate]

I've tried focusing shots at night, but never get a perfect click. Are there any tips that might help?
4
votes
2answers
120 views

Light-field shots entirely in focus?

A light field camera can be used to make shots which can be truly refocused after the shot, however if I understand the technology correctly it would be just as easy to process the "image data" in ...
0
votes
2answers
87 views

Wide aperture in low-light results in muddy image on Powershot G16?

I have a Powershot G16 that I'd like to use as my standard camera for its light weight. It takes amazing photos in the day, but I'm having some problems with handheld at night. I'm still a photography ...
1
vote
3answers
172 views

Why can't I get a sharp macro image when shooting handheld, even with IS?

These days I shoot macro handheld, using the focus and recompose technique. I used AF-one shot. I used a Canon 100mm 2.8 on my Canon 550D. My shutter speed was 1/100s, but it was quite frustrating ...