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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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1answer
947 views

Canon T2i doesn't seem to take crisp photos

I've been using my Canon T2i to do portraits for the last year now, and usually have really good luck with it. Most of my shots are up close, and turn out beautiful. However, it seems like when I ...
2
votes
1answer
395 views

Is Sigma 50-500mm EX DG HSM lens compatible with a Nikon D90 body?

Aloha, Can anyone tell me if the Sigma 50-500mm EX DG HSM lens (non OS model) is compatible with a Nikon D90 body? I recently purchased this lens on eBay but it seems that the lens will not ...
2
votes
2answers
140 views

Why doesn't autofocus work after using manual focus for a while on my Nikon DSLR?

I bought a Nikon D3200 DSLR with 18-55 and 70-200mm lens. I was taking photos for week in autofocus mode, where I have to press shutter button halfway to focus. And then I switched to manual, where I ...
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votes
2answers
80 views

How can I turn off auto focus when using the remote with my Nikon D7000?

I have a remote with my D7000 and it's hugely frustrating that it auto focuses when using the remote. The whole reason I want it is for speed and to not move the tripod. I have looked through the ...
2
votes
1answer
51 views

Why do phone cameras focus and defocus deliberately while clicking a macro shot?

I've tried this with many phone cameras and almost all of them focused well for macros but only for a moment before they defocus to focus something further behind. If the camera can focus on objects ...
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2answers
224 views

Why are some portion of my landscape shots totally out of focus?

When shooting landscapes, a single image (say 1 of 200) is totally out-of-focus. A typical setup might be: focal distance = 7.1 (x 3.9) f-number: 5 exposure time: 1/800 According to ...
2
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2answers
47 views

Does half pressing a RS-80N3 trigger autofocus if back-button AF is enabled?

I'm looking to invest in a remote trigger say the RS-80N3 or alike for my Canon DSLRs. I'm using them all with back-button AF enabled (and half press shutter autofocus disabled) and I wonder if half ...
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2answers
186 views

Why does my lens refocus when the f-stop is changed?

I have a prime Sigma f1.4 50mm lens on my Nikon D90 in P mode and focus mode on a set point of the field and notice that when I am using a tripod and change the f-stop that the camera changes the ...
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2answers
196 views

Is it possible for increased ISO to improve focusing in low light?

A member of a digital photo forum, to which I subscribe, stated that when she was photographing some badgers at night, the auto focus wouldn't work due to the lack of light. She then said she upped ...
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2answers
1k views

Nikon D5100 intermittent focusing problem

I'm having this intermittent problem that the camera does not want to focus in auto-focus. When this happens I try to switch to manual on the lens, (both 300mm, and 55mm) but the toggle button will ...
2
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1answer
774 views

Problem with TTL autofocus on Canon 450d - is there a way to adjust?

I have Canon EOS 450D, and it seems, that camera have problem with autofocusing, when i'm looking through optical viewfinder. If I switch camera to liveview - autofocus works correctly, but slow. The ...
2
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1answer
483 views

autofocus and maximum aperture of 60D [duplicate]

Possible Duplicate: What are the aperture limits for autofocus on Canon DSLR cameras? It is mentioned on page 79 of the EOS 60D manual that the center point AF is twice as accurate at ...
2
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1answer
2k views

How do I fix a lens with a problem returning to autofocus mode?

I bought a Canon EF 28-105mm f/3.5-4.5 II USM lens for my Canon 350D. It works mostly fine, except after switching from AF to MF, I can't return to AF mode. After I switch MF->AF, the lens doesn't ...
2
votes
1answer
8k views

Sony 18-250 or new Tamron 18-270 lens? Which has better autofocus?

I want to buy either Sony 18-250 F3.5-6.3 or the new Tamron 18-270 F3.5-6.3 as a travel lens for Sony A55. I have found good reviews that told me quite something about image quality of these lens. ...
2
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1answer
46 views

How do I achieve autofocus while zoomed in on a face, if surrounding elements hold more contrast?

I recently bought a new camera, a Panasonic FZ1000, and noticed on more than one occasion when I was photographing my wife in a posed situation, and I choose to zoom in a little for the shot, the ...
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2answers
347 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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1answer
303 views

Circular Polarization and Passive autofocus [duplicate]

Couple of weeks ago, I was assigned a homework in one of my Applied Physics master's course. My professor asked to explain why passive autofocus works only with circular polarizers. I am not a very ...
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2answers
1k views

Nikon D60: Autofocus of two AF-S lenses not working anymore after using another lens

I have used my Nikon D60 for about 6 years now, with AF-S DX NIKKOR 18-55mm f/3.5-5.6G, and AF-S 55-200mm Nikkor f/4-5.6G lens, and the autofocus has been working fine this entire time. However, I ...
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6answers
620 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 ...
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6answers
691 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 ...
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2answers
472 views

Is there a way to use phase detection AF with live view on a Canon EOS camera?

On any of the EOS xx(x)D model that has the live view function, can the camera make focus using the AF collimators (instead of using contrast detection), as it's possible on the old Nikon D300 ? If ...
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4answers
3k views

What low-cost ultra-wide angle DX lens will autofocus on my Nikon D5000?

I need a wide angle lens for low-light/club photography with my Nikon D5000. I was going to pick up this one, but then I realized that it won't autofocus on my body. What is the closest equivalent ...
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4answers
537 views

Autofocus performance of different brands at night

Are there huge differences in the ability to focus in low light between different brands and models? I have a Pentax Kx with a Sigma 30mm 1.4. My problem is, that the camera's autofocus does not work ...
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3answers
322 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 ...
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2answers
1k views

Why can't AF-S lens (with broken auto-focus) work with bodies that have build-in motor?

Background: I have a Nikkor 70-300 AF-S G. Somehow, the VR and AF systems stopped working.. It was working perfectly fine, then for 2-3 months it stayed inside the bag, in a wardrobe, without even ...
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3answers
820 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
195 views

Why does my autofocus fail in windy conditions?

When I say windy, I mean inside 100+mph prop-wash, shooting from an open cockpit aircraft. The camera is an Olympus C-765 UltraZoom, which features a retracting zoom lens. It may be that manually ...
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2answers
284 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
236 views

Pictures start in focus then go out of focus?

I was recently shooting some surf after a session with my 7d and Tamron 18-270MM F/3.5-6.3 Di II VC PZD. I started shooting while he was in focus, then as he got to the main part of the maneuver the ...
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3answers
9k 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
114 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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2answers
239 views

How does aperture/DOF affect continuous autofocus?

When the autofocus system is deciding to adjust the focus, say in a situation of the subject getting closer to or farther from the lens, does it take into consideration the current depth of field, ...
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1answer
17k views

Why isn't my Canon 70D autofocus accurate in manual zone AF mode with a 50mm f/1.8 lens?

I recently purchased a Canon 70D for its dual pixel autofocusing system and ISO performance. I am in love with this feature rich-camera; however I found the camera's autofocus fails to function ...
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2answers
2k views

Using old, manual focus lenses with a new Pentax DSLR

I have an old Pentax ME SUPER with three lenses, all of which have manual focus rings and no autofocus motors. Do new Pentax DSLRs have built-in focus motors that can deal with old lenses? FYI, ...
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1answer
381 views

What happens when a Sony SLT camera is operated with mirror up?

What happens if you attempt to operate a Sony SLT (pellicle mirror) camera with the mirror up? Does the camera detect this condition? Will the camera shoot? What happens to autofocus--can the ...
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1answer
123 views

Where do we focus when shooting cars in a street?

f I just want to put the camera at night at the corner of a street to get long exposure effect of the cars that are moving for their car lights, What is the focus settings I should use? Should I also ...
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1answer
186 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
4k views

Why are images with my Nikon D7000 and 70-200mm lens soft?

I'm having trouble getting sharp pictures with my D7000. I've tried it with a 70-200 and 18-70 and produce the same results. I've tried AF Fine Tune with one of those focus charts, but the value of 0 ...
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1answer
172 views

The future of AutoFocus [closed]

I bought a Nikon D5000. Back then I didn't know anything about photography, but it sounded like a really good intro camera. And so far it has been. I don't mind the DX format, and have invested in ...
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1answer
546 views

Which of the following lenses do fit on a Nikon D 3100

I've been given the following lenses from my neighbour; which ones will fit a Nikon D3100? Sigma 28-200 mm F F3,8 - 5,6 Nikon Af 70-210mm F/4,0-5,6 Nikon Af 28-85mm F/3,5-4.5 Nikon 50 mm F 1.4 Nikon ...
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1answer
497 views

Is continuous autofocus in video a software or hardware function?

My camera (Sony alpha A580) does not natively support video autofocusing. When I was buying camera, I didn't think that was such important feature for me. Now I want my camera to be able to autofocus ...
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1answer
137 views

Why doesn't my “Nikkor AF” lens autofocus on my Nikon D3300?

I recently got a new lens for my Nikon D3300. I now have 3 lenses; the other two that I have came with the camera and work great but when I put my new lens on, it will only manually focus. If I go to ...
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1answer
448 views

What should I do if my Canon 24-105 f4 L is making focus-seeking noises but not focusing?

I have a Canon 24-105 f/4 L lens. Just today, it started having focusing problems. The problem does not manifest if the focus is easy: bright light and centre focus point is on a good contrasty ...
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1answer
151 views

Why is my Fuji X camera stuck in manual focus?

I have a Fujifilm X series camera with one of the nice prime lenses, and it seems to be stuck in manual focus mode. The switch on the camera is on S, and I flipped it back and forth several times, but ...
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2answers
1k views

Is the “One shot” mode more accurate than “AI servo” using back-button focus?

By using back-button focus you don't have to switch from "AI servo" when photographing stationary subjects. I tend to do this anyway since I have the feeling it's more accurate even when I can ...
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2answers
2k views

DSLR in AF mode. Do we need to use Focus ring on lens?

My camera is in Auto Focus mode (AF). As my understanding, the camera will focus on subject automatically. But when I rotate the focus ring, the focus subject points will change, too. I don't ...
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2answers
565 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
166 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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1answer
960 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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1answer
388 views

Finding the distance of object from camera to the point of autofocus

Is it possible to find the distance to which the camera is auto focussing ? Camera auto focuses itself to view a particular plane in the real world in front of it. Is it possible to estimate the ...