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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

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28 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 ...
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2answers
93 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 ...
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1answer
90 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?
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1answer
99 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 ...
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2answers
100 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 ...
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2answers
135 views

Why can lenses only focus from so close?

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 ...
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2answers
91 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 ...
2
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1answer
94 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 ...
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1answer
56 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 ...
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1answer
69 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 ...
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1answer
125 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 ...
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1answer
81 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 ...
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1answer
334 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 ...
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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 ...
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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 ...
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2answers
117 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 ...
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2answers
181 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 ...
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1answer
160 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 ...
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2answers
118 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. ...
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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
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1answer
92 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 ...
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1answer
75 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 ...
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2answers
184 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 ...
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3answers
100 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 ...
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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?
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2answers
105 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?
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2answers
117 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 ...
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2answers
172 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, ...
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3answers
167 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 ...
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1answer
125 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 ...
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2answers
80 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 ...
3
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3answers
198 views

Do focus area modes matter if shooting in manual focus?

It seems my camera lets me change the focus area modes (e.g wide, center or spot) even when I am shooting in manual focus so I am trying to understand if area modes matter even if the camera is in ...
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2answers
86 views

Nikon d7000 will not auto focus

Nikon D7000: When I press down on the shutter release my camera does not auto focus with any lens. I have checked and it's NOT on manual I have tried resetting my camera I want to shoot nightlife so ...
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2answers
736 views

Focusing on hyperfocal distance with Nikkor 35mm f/1.8G prime lens [duplicate]

I have a Nikkor 35mm f/1.8G lens on a Nikon D7000 body. I have a theoretical understanding of hyperfocal distance. And it seems like the lenses with an clear indication of "infinite" focus point are ...
1
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1answer
77 views

Is there a way to avoid focus searching? [duplicate]

While using my camera in a relatively low light scenario I noticed some shots I missed because my camera was struggling to focus. I use a Nikon D7100 and noticed that the AF assist light only came on ...
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2answers
432 views

Why does my Samsung NX1000 zoom way in when manually focusing?

I bought a Samsung NX1000 this week, and I have the 20-50mm lens. However when I put it on manual focus, the picture keeps jumping from standard zoom to "mega zoom" — it zooms a lot further in then ...
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2answers
324 views

What is the difference Focus mode and AF-Area mode?

I am using Nikon D5100. To shoot a subject which is: Stationary: we can set AF-area mode to Single Point AF we can set Focus mode to AF-S Moving: we can set AF-area mode to Dynamic-Area AF we can ...
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1answer
197 views

What is the purpose of Quick Mode focusing in live view?

What is the purpose of Quick Mode (found on some Canon DSLRs) focusing in live view? To me it seems like a bad blend between live view and viewfinder mode that really doesn't cut it. Of course it's a ...
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3answers
590 views

Nikon D3100 Won't Take Photo — says light is too low

I've had my Nikon D3100 camera for about 3 years. I recently accidentally reset my shooting options. Since I've done that, I'm having a hard time getting the camera to focus and take photos in lower ...
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4answers
381 views

Why can't my DSLR with kit lens focus on objects close to the lens?

I have a Nikon D5200 with the 18-105 kit lens. I cannot focus the objects which are 15-20 cm away from the lens. Can anyone tell me how to manipulate the settings so that i can focus those objects? ...
1
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1answer
173 views

Why do I see different focuspoint in my DSLR's viewfinder and screen with old lenses?

I've had an old completely analog Praktika SLR with a set of lenses for a few years now. The camera and lenses are still quite good but I wanted to go digital. Having recently acquired a Nikon D5200, ...
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1answer
98 views

Which lenses show focus shift?

Some lenses, because of a design that includes uncorrected spherical aberration, shift their plane of focus backwards as the aperture is narrowed. This is most apparent at close focusing distances and ...
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1answer
75 views

Compensating for Focus Shift?

Some lenses, because of a design that includes uncorrected spherical aberration, shift their plane of focus backwards as the aperture is narrowed. This is most apparent at close focusing distances and ...
3
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2answers
512 views

What might make focus points blurred/gone from viewfinder on Canon T2i after cleaning?

The red lights are all but lost in my T2i now....barely a haze of a blur. The focus points work fine, and I get the audible beep, but I have to check my focus point on the back before shooting and I'm ...
4
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2answers
135 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?
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1answer
154 views

How can i get AF confirmation working with Samyang 500mm f/6.3 with dandelion chip?

I've put a dandelion chip (4th gen) on my Samyang 500mm f/6.3. I shoot a Canon 6D by the way. So, that's cool now I've set the chip to return f/6.3 and I can get a correctly exposed LiveView, EXIF ...
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4answers
312 views

How much does a drop in temperature affect focus?

In an answer to question "What lens characteristics are important in astrophotography?" there was mentioned "If the temperature changes drastically, you may need to refocus as different materials in ...
0
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1answer
150 views

Canon 50mm F1.4 focus problems

I've had this lens for a couple of years, but am really struggling to get sharp pictures now. I've tried it on a 400D and a 7D and both show the same results. I had the problem with it getting stuck ...
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2answers
77 views

Science Fair Project Relating focus to pinhole size

I am doing a science fair project in which i want to see how the size of a pinhole effects the light diameter, and i would like to also relate this to focus and focal point. How would i do this?
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1answer
78 views

Tricking compact's camera autofocus

I'm trying to get some bokeh using a compact (almost premium) camera, a Nikon Coolpix p300 (although the question is general). Since the camera hasn't got a manual focus option, I'm trying to use the ...