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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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Why is AF slow in Live View on DSLRs?

Why is AF so slow in Live View on SLRs ? On compacts, the AF works very smoothly and quickly.
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2answers
2k views

Why is my Canon 500D with kit lens having trouble focusing at higher focal lengths?

I have a Canon 500D with the kit lens. Recently I have observed that its not able to focus at higher zooms but it works at min zoom. To get it to focus, I have to zoom out or recompose and it works. ...
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2answers
1k views

Why are my pictures blurry/soft?

Ok so I shoot basically one thing....real estate. I am in the market for a new camera so I borrowed a friends canon 50d. I have been using a Rebel xti and been getting good results but I want to ...
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2answers
3k views

How to eliminate auto focus noise in video mode when using NIKON D7000?

You can hear the noise when taking a video w/ NIKON D7000 w/ normal lens. Is there any way to get rid of the noise? Will shotgun mic help? Thanks in advance!
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1answer
1k views

Why did my 50mm f/1.8 Canon lens deactivate autofocus on Canon EOS 1000D?

I recently lent my 50mm f/1.8 lens to a friend who owns a Canon EOS 1000D. Afetrwards he told me that the camera had deactivated autofocus when he switched back to his kit lens (18-55). Is this ...
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1answer
236 views

Why is DSLR autofocus much faster than Mirrorless autofocus?

When DSLRs are not using Live View they autofocus much faster than Mirrorless cameras. Why is that? Why can't Mirrorless cameras use the same autofocus mechanism that DSLRs use?
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3answers
542 views

How does autofocus point selection relate to manual focus?

Every lens I have comes with an auto-focus / manual focus switch. How should it be used if I am shooting on AV mode? If I were to select one of the focus points, do I need to have the lens on ...
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2answers
6k views

Why does Nikon D3100 locks Shutter in Autofocus mode?

So I just got this Nikon D3100 Camera. And I am trying to take a picture using autofocus with the kit lens(18-55mm). The system is in Auto mode, AF-A, single frame and the lens A-M switch is on ...
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2answers
734 views

Why is my lens focusing sound lounder than before?

I'm new to DSLR camera. I didn't mount a lens properly. The camera still allowed me to take photos, so I didn't notice the error. After I had been using it for 10 minutes I noticed my error and ...
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1answer
161 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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1answer
147 views

Does using multiple batteries (via grip) improve AF speed?

I want to say I read somewhere that, particularly with heavier lenses (such as the 70-200 F/2.8), having two batteries in the portrait grip would provide extra juice to the AF motor and help it ...
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2answers
4k views

Do I use the camera or lens switch to change between auto and manual focus?

I own Nikon D7000 with 18-105mm lens. I am bit confused how the auto focus and manual focus switching works, particularly with my gear. The confusing part is both the camera and lens have an A-M ...
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1answer
967 views

Why does my D70s no longer focus my Nikkor 70-300, but still focuses the 18-70?

At first I thought my lens was dead but after switching to my other D70s it worked fine. So, here's the issue: One of my D70s bodies can no longer auto-focus my Nikkor 70-300 lens. Switch to a 18-70 ...
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1answer
814 views

How do I make the focus point indicators stay long enough to select on the Canon 60D?

I have just switched from the Canon 500D to a 60D. Most of my work is property based, and this is therefore 90% internal flash shots where I often wish to pick out a particular spot for best focus. ...
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2answers
428 views

Is there a secret way to make the Fujifilm X-Pro 1's autofocus point selection faster?

I think the answer to this is "no", but it may actually be available and I'm just not figuring out how to toggle the setting. The X-Pro 1 has a wealth of AF points — 49 in EVF mode and 25 in OVF ...
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1answer
444 views

Why is my Canon Powershot A1100 focusing only on the bottom part of scenes?

I've been using a Canon PowerShot A1100 IS camera for the past year and it had been working just fine until I decided to change its settings. After I had serious trouble with it, I reset the settings ...
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2answers
64 views

Canon 5D - Focus viewfinder indicators in Manual focus mode

On a Canon 5D MkIII, is there anyway to see the autofocus lock boxes on screen while manually focusing (showing the areas the camera detects as in focus)? This might just be an insane product of my ...
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1answer
160 views

A recently acquired lens will focus automatically, but won't manually, why?

I have recently acquired a Sigma 70-200mm f/2.8 (Canon mount, relatively old), and it focuses perfectly in auto mode, but in manual mode the focus ring simply won't budge at all. What could be causing ...
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1answer
1k views

How can I make phase-detection AF more accurate with a Canon 650d and 50mm/1.8?

This is what I get pretty much every time when shooting in Live View mode using the Canon 50 1.8: This is what I get when I'm lucky when focusing through the viewfinder: This is what I get when ...
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1answer
1k views

Is back-button autofocus possible on the Nikon D7000?

A while back I asked about the purpose of back-button autofocus and got several answers. The Nikon D7000 lacks the "AF ON" button that's present in some higher-end cameras. Is it possible to use ...
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1answer
335 views

Do AF-S lenses work with bodies with in-built motors?

I have D-5000 body (without AF motor in the body) and two AF-S lenses. If I upgrade my body to more expensive body one with built-in AF motors, will AF-S lenses work (do autofocus) with new body ? ...
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1answer
61 views

5D Autofocus - disable tracking after lock?

I recently got a 5Dmk3 and it's been a really fun toy so far. I'm coming from a Canon 7D, so I'm trying to adjust to the much more complicated autofocus system. I've read the manual and looked around ...
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1answer
207 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 ...
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1answer
334 views

What Ever Happened to Hologram AF?

I'm currently using it in my Sony DSC-F828 and I think works very well especially in low light condition. I've read a lot of hypothesis about it but anyone know for sure why modern cameras don't use ...
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1answer
223 views

Why is my ISO so high in auto mode?

New user of a Canon 7D - less than 50 shots taken. Last night, I needed to take a quick picture of something that was on my cell phone with my Canon 7D I propped the phone up against a white pillow ...
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2answers
1k views

EOS 60D manual focus/exposure selection only after half press

The 60D only lets you select exposure compensation (with the round wheel on the camera back) and AF point (using the 8-way button or the AF point selection button, depending on your settings) only ...
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1answer
782 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 ...
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2answers
6k views

Why does my Nikon D3100 no longer auto-focus via the viewfinder?

My Nikon D3100 out of the blue cannot focus correctly. It seem the that the focus motor always stops at the end of the run (Infinity) and cannot lock on the target, thus cannot release the shutter. I ...
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1answer
372 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 ...
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2answers
129 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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1answer
142 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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2answers
907 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 ...
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1answer
411 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 ...
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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 ...
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2answers
169 views

Can changing metering mode change focus?

I've Canon 600D and I use the back button to focus and the shutter to meter, I've been using spot metering for over 2 years for now and I understand what's the difference between it and evaluative, I ...
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2answers
276 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
184 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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1answer
624 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 ...
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6answers
356 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
452 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
402 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
2k 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
493 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
263 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
853 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
631 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
185 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
150 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
187 views

can i transform my manual focus lens into an autofocus lens?

I have a Nikon D3300 camera. And I bought a 55-300mm nikkor lens but this lens is not an autofocus lens, so when shooting I should manually focus and sometimes the photos are blurry. Is there any ...
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2answers
160 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, ...