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Autofocus is the ability of a camera/lens system to automatically adjust the focus of the lens via a motor attached to the focus group of the lens. Contrast with manual focus.

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60 views

Which image processing algorithm does the contrast auto focus use to check the sharpens?

My read is that the contrast auto focus is using edge detection algorithms like laplace or sobel.
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3answers
139 views

Why are my photos taken with the Sigma 18-50mm f/2.8 coming out blurred?

I'm new to photography, and I don't know why the pictures I'm taking are coming out blurred. Here's a sample image, taken with the Sigma 18-50mm f/2.8 on my Nikon D5200 at 18mm, 1/60s, f/2.8 and ISO ...
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0answers
65 views

What would cause an AF confirmation light to go on and off as I approach correct focus?

I'm using two cameras: Canon EOS 400D (Digital Rebel XTi) and Canon EOS 450D (EOS Rebel XSi). 450D was more heavily used than 400D. Not so long ago I noticed that 450D's autofocus system works not ...
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1answer
93 views

How to tell if a digital camera shoots quickly

In my experience, most (at least) older digital cameras take some time -sometimes even a second or so- from the moment you pressed the button to the actual taking of a photograph, especially when ...
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6answers
212 views

If I'm using only one focus point, am I doing it wrong?

Unless I have to shot a person or an object which moves, I set my camera to use only one focus point at the middle. It feels just more natural and so easy: when I need to focus on something which is ...
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1answer
30 views

Wireless Shutter Release Remote does autofocus before taking the snap?

I have Nikon D3000 and a wireless remote for it. I'm not sure about this thing: Suppose, I am keeping the camera on tripod where some birds will come. Then, I am setting my required zoom and other ...
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1answer
83 views

DSLR body without auto focus + auto focus macro extension tube set + lens without having auto focus motor but focusing screw = auto focus?

I've Nikon D3000. It died not have auto focus motor boot in its body. I've a lens having no auto focus motor within it. I saw some auto focus macro lens extension tube. Does that have autofocus motor ...
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2answers
109 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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2answers
193 views

Does a Canon STM lens autofocus more quickly and accurately on a high-end camera body?

There are incredible reviews on the new Canon STM lenses: https://www.youtube.com/watch?v=ho0hOhRSuHk Does autofocus perform better on a 7D body, compared to an entry-level 700D body, for example? ...
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2answers
110 views

What does it mean for a camera to be able to autofocus at EV 0 at f/2.8?

I know what it means for a camera to be able to autofocus at EV 0. As the answer to this question says, EV0 is the light level to achieve correct exposure with 1 second of exposure at F1 and ISO 100. ...
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3answers
224 views

What does the AE lock button do that half-pressing the shutter doesn't?

The Sony A6000 has an AEL button, while Nikon SLRs have an AE/AF lock button. What do these do that half-pressing the shutter to lock focus and exposure, and then recomposing, doesn't? I'm used to the ...
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2answers
157 views

Is it true that cameras with larger sensors are more likely to mis-focus under low light?

I use a Sony NEX-5R, and my single biggest problem with the camera is that it often mis-focuses under low light. I shoot a lot of low-light photos, and I work around it by using manual focus. I have ...
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0answers
25 views

AF points, focusing at f1.0-2.2 [duplicate]

I am considering the canon 5d mark iii or the 6d. Between the mostly negligible differences between those cameras, the AF point system of the 5d has many more "points". Having never really relied on ...
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1answer
1k views

Which Nikon DSLRs have an autofocus motor in camera body?

I have a Nikon D3000 and a lens which has no autofocus motor. But under the lens, I have found a screw which rotates with the focusing control. My D3000 does not have any autofocus motor inside the ...
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1answer
62 views

How can I confirm focus with a Nikkor 70-300 lens on a D3000?

Good day! I would like to have some suggestion from experienced photographers about following matter: I have a Nikon D3000 Camera. I bought a Nikkor Lens 70-300mm having not motor inside and unable ...
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2answers
209 views

Why can't I access Single Point Spot AF even when it is enabled on my 5D Mark III?

I have been using Canon 5D Mark III since long but somehow never been able to get across this thing. With the advanced 61 point focus system which the Mark III has, I have always missed the ability to ...
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0answers
29 views

Nikon Lens Won't Autofocus [duplicate]

My Nikon Lens will manually focus but not auto focus. I have tried another lens on my camera body without issues and I have put this lens on another body and it will not auto focus there either. I ...
2
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2answers
230 views

How to tell whether a lens has an autofocus motor or not?

I have to buy a lens and I have a Nikon d7000. I want to know which lenses have AF motors and which do not, as the D7000 has an AF motor built into the body. How do I tell whether a lens has a motor ...
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2answers
92 views

Learning from one's blurred photos: where was the focus point set?

After some shooting, I inevitably find that some photos (and by Murphy, often the best ones) have a blurred subject. Even if the shots are spontaneous and hence the subject is hardly static, I ...
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1answer
135 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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2answers
238 views

Do separate autofocus motors exist for entry level Nikon DSLRs?

I have a Nikon D3200, which doesn't have an autofocus motor. Therefore, I'm mostly deterred by lenses that don't have focus motors in them. But the ones that do have it are much more expensive. Take ...
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2answers
122 views

Autofocus icon is missing in Canon 650D, please help

Can anyone please help me in getting this icon back in my canon 650d
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2answers
111 views

Why are phase detect lenses adapted onto contrast detect bodies so much slower?

The Sony A7 is able to adapt almost any type of auto-focus lens (Canon/Nikon/etc) and use autofocusing, but the auto-focusing is much slower than the same focal lengths native for the A7. Why would ...
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4answers
267 views

Which one is better - more cross-type sensor or better sensitiveness of cross-type sensors?

What makes better sense for situations like: low light, sports/action, wild life? More cross-type sensor on AF (like Canon does) Or more sensitive cross-type sensors (like Nikon does)
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1answer
222 views

What to do when autofocus on Canon 85mm f/1.8 not working?

My Canon 85mm's AF isn't working. But here's the thing, it recognizes there's a lens mounted, it gives focus confirmation, and I can even set the aperture, but it does NOT recognize that it's an AF ...
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0answers
32 views

Help is needed in Fixing Canon lenses USM's focus motor [duplicate]

I have the Canon EF lens, but the USM motor looks dead. I need help in order to get it fixed so I can use this lens again. Unfortunately a "focus by wire" system is used in this lens and I have no ...
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1answer
125 views

Why doesn't my Sigma lens autofocus if the subject is initially way out-of-focus?

I have a Sigma 150mm F2.8 EX DG OS HSM APO Macro lens mounted on my Canon 6D. Even if AF mode is set to minimum-to-infinity range, if my subject is way out of focus (too far or too near), like, say, ...
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3answers
939 views

Why don't cameras have autofocus points in the edges and corners?

On all the DSLRs I've used, there are never any autofocus points near the edges and corners. Why is that?
3
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1answer
87 views

How to test the autofocus system before asking for support?

For outdoor usage I got an Olympus TG-2 compact camera. Various tests claimed autofocus: 'quick and mostly accurate' - at least I could not find any that described problems. Now, I know that I cannot ...
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2answers
179 views

Why does my Nikon D5100 suddenly have a 30-60 seconds delay before auto focus starts working?

I have a Nikon D5100 with the 18-55 kit lens. It was working fine till a few days ago. The auto focus used to work from the very next second after turning ON the camera. But now the auto focus does ...
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3answers
277 views

canon 6d or 5d II for macro?

At the mo I have a 550d and a 60d. my lenses are 17-35 2,8L, 24-80 2,8L, 70-200 2,8L, 100-400 4,5-5,4L sigma 150 2,8 and looking for the canon 50 1,2. The obvious next step is a FF Body. My main ...
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3answers
173 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
80 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 ...
3
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1answer
218 views

Do mirrorless cameras focus less or more accurately than SLRs under low light?

How do the following compare in terms of autofocus accuracy for night photography: Mirrorless cameras like the Sony NEX-5R, in hybrid autofocus mode. The NEX-5R, in contrast-only autofocus mode. A ...
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6answers
290 views

What would be the right way to shoot a portrait in a very dark room with flash?

I have several flash units. Both the shoe-mount type and the "studio" type. The portrait has to be taken in a room that happens to not have windows. It is always dark in there. I can bring a light ...
2
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4answers
340 views

How to take a photo of defects on a mirror?

Taking a picture of a reflected image of object is depicted in this image. Camera focus is on the image of a piece of paper. Besides the depth of field (cheap Panasonic DMC-FX8 in makro mode, ...
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2answers
74 views

Are extra auto focus points expensive for the manufacturer?

Having a lot of auto focus points is a feature associated with expensive camera bodies. There are of course different types of points like crosstypes and also different sensitivities, but lets ...
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1answer
145 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 ...
2
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1answer
130 views

How to get tack sharp portraits with shallow DOF when lacking an AF point where I want to focus?

What is the best way to get tack sharp portraits with shallow depth of field when lacking an auto focus point where I want to focus. I don't want to crop and "focus and recompose" is not an option ...
2
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2answers
192 views

How AF works with lenses f/2.8 vs f/4

I read following in a web site (http://realphototips.wordpress.com/tag/ai-servo/) Lenses with maximum apertures of f2.8 allow the camera to use all high precision sensors. In low light or other ...
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2answers
113 views

Should I always use point-autofocus and spot metering while shooting a small restless bird in a bush?

I am a beginner and I am finding more and more images to be out of focus or grainy when viewed on a computer screen, compared to the camera LCD. Could anyone give a step by step listing of the ...
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0answers
85 views

Nikon 300mm autofocus makes noise and stops working temporarily

I have a Nikon D5100 and a used Nikkor 300mm AF-S f/2.8D IF-ED II, where the two usually work great together. However, if I use autofocus a few times in a row (usually when the change in focus ...
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1answer
168 views

What can I do about Pentax superzoom 18-270 autofocus problems?

I use a Pentax K200 and have been satisfied with the original Pentax 18-250 superzoom, for travelling, outdoors, family types of use. However the autofocus gradually failed, the motor going to and fro ...
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3answers
210 views

Why is micro 4/3 autofocus so much faster than DSLR live mode focus? [duplicate]

Both a DSLR in live view mode and a micro 4/3 system camera use the main sensor for autofocus. However, on a DSLR it's embarrassingly slow. This can't just be a software thing. How is it that one is ...
3
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1answer
364 views

What does AF -0.5 EV sensitivity mean? Or -3EV in Canon 6D's case? [duplicate]

I know that it stands for Exposure Value, so my 6D focuses in 2.5EV worse light than a 600D. But it's relative to... what? What makes it meaningful? What's the "base unit" for AF sensitivity?
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1answer
71 views

Why are OVF and Liveview focus dots in different locations in my Nikon D800?

I put my camera (D800) on a tripod to check for any focusing issues ,and if I switch from OVF to Liveview the focus dot is in a different location.I tried two different lenses and they both give the ...
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1answer
139 views

Can I filter by autofocus in Lightroom?

Does Lightroom let me filter photos by whether they were manually focused? Or is this information not even stored in the ARW metadata? (I'm assuming they were not lost during DNG conversion in ...
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6answers
245 views

Is it normal for autofocus to produce blurry photos under low light?

I use a Sony NEX-5R. I find that the autofocus often fails during low light, as in produces out of focus photos. Sometimes it's clearly out of focus, and I can see that on the LCD, in which case I ...
5
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5answers
282 views

With the advantages of an AF-ON button, why don't all DSLRs have one?

I've just updated my body from Nikon D40X to Nikon D300 and realized that the D300 has a AF-ON button on the rear of body. That button's feature do the same as half-pressing shutter button, which ...
6
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2answers
266 views

When do you not want to use continuous autofocus (C-AF)?

This Nikon promotion website sums up when to use single autofocus and when to use continuous autofocus. (http://imaging.nikon.com/history/basics/16/03.htm) So, basically if you want to ...