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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.

learn more… | top users | synonyms

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1answer
473 views

Why doesn't the focus assist light get triggered on a flash connected via a Pocket Wizard TT1?

I have a Pocket Wizard TT1 and TT5 which work fine. I mount the TT1 on the camera shoe and the TT5 fires my remote flash ETTL fine. I now want a focus assist light, so I set a flash (580, 430 or ...
7
votes
1answer
7k views

Can I fine tune the autofocus on my Canon 60D to be more accurate?

I noticed that some of my lenses auto-focus more accurately then others. (Assume perfect light conditions and fast shutter speed) Zooming-in on say the center focus point (if only the center focus ...
2
votes
1answer
412 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 ...
2
votes
4answers
2k views

Why can't I take a photo in dark with auto focus, manual mode?

I'm dorking around with a Nikon D80 and I am a total beginner. I am trying to shoot some light trails but the darn thing doesn't even take a picture. I am in manual mode with the bulb setting. For ...
6
votes
2answers
509 views

What is being set with Micro Focus Adjustment?

An autofocus system is system based on a feedback loop, where the AF sensor error reading if fed back to the lens focus motor. Being a closed loop, then theoretically there should be no focusing ...
7
votes
3answers
4k views

What do the AF-A, AF-C, and AF-S autofocus settings mean?

My camera has these settings for autofocus, and I don't know what they mean. I suspect "A" is "Auto", and "C" is "continuous", but I have no idea what "S" is.
3
votes
2answers
636 views

What does this switch do on my macro lens?

There is a switch on my Canon 100mm USM Autofocus Macro Lens that switches between 0.32 mm and 0.48 mm (I think those are the numbers I dont have my camera near me). What do these numbers mean and in ...
2
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3answers
2k views

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.
5
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3answers
2k views

Are there cheap or DIY focus assist solutions for the Canon 5D?

I want a better autofocus system for low light. Low light auto focus is my biggest bane. I use a 5D so the options are AF on a flash like the 430 or 580. I happen to use the Pocket Wizard TT1 so I ...
0
votes
1answer
388 views

Is there a way to make auto-focus more smooth while filming with Sony A55?

Wondering if anyone can help with this. I have a Sony SLT-A55, and when in video recording mode it is able to auto focus. My issue is that it does this "too quickly". For example, if I'm shooting ...
0
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3answers
2k views

How can I get better focus results with my Nikon D90 at a fashion show?

I shot at a fashion show last week, and had focus problems. I used my Nikon D90 with a Sigma 70-200mm f/2.8, with no flash. I tried many autofocus settings but none of them worked. I also tried ...
5
votes
5answers
2k views

What is the best camera for concert photography? [closed]

I am interested in camera recommendations with a fast shutter and which are able to focus well in low light. The camera will be used for indoor concert photography where no flash is allowed.
18
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4answers
833 views

How to speed up autofocus on moving subjects under low-light conditions?

Since I am usually taking pictures under low light ambient conditions I have discovered the nifty 1.4 lenses (such as the Sigma 30mm/1.4 or the Canon 50mm/1.4 or also the Canon 85mm/1.8) for my Canon ...
4
votes
2answers
1k views

AF-D vs AF-G: is the aperture ring necessary?

I just purchased a Nikon D7000 with an 18-105 f/3.5-5.6 AF-S lens. I'm also looking at purchasing a lens around the 200-300mm focal length range, and I found the 70-300mm f/4-5.6 AF lens. As far as I ...
5
votes
5answers
3k views

Why am I getting poor AF results with my Pentax K10D?

I've been using Pentax K10D for a while and I'm a bit frustrated with performance of auto focus on that camera. Very often the images are not sharp enough despite taken in with decent lens (e.g. ...
9
votes
3answers
1k views

Is the color of the AF assist light important?

What are the differences between white and this darkroom red/orange active autofocus assistance lights?
1
vote
1answer
7k 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. ...
4
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2answers
307 views

What's a Typical “In-Focus” Rate for Portraits with an 85mm?

I have a lot of experience doing travel, landscape, product, ... in short, things that don't move much. Models? Not so much. I have a beautiful 85mm portrait lens for my Canon 1Ds Mk III DSLR, and at ...
2
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2answers
1k 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. ...
15
votes
4answers
2k views

Why can't my SLR autofocus on certain parts of a scene?

I had my Nikon D7000 on single-point auto focus and it just would not focus on the spots I wanted. I have marked the spots that could not be focused on with red circles, and the parts that could be ...
24
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9answers
3k views

Why would I want to select an autofocus point?

I'm trying to understand why I would ever want to select an auto focus point other then the center point. I have a Canon XTI Rebel DSLR which has 9 auto-focus points, but I'm also looking into getting ...
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vote
0answers
151 views

What benefits are there from autofocusing with the lens rather than with the body? [duplicate]

Possible Duplicate: How do camera body motors compare to in-lens motors for focusing? I have read in this question that the lens motor will be the one doing the focusing if both the body ...
2
votes
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 ...
17
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3answers
1k views

How can I get better focus when a subject is moving towards or away from the camera?

When shooting events or action photos, engaging people, I often find that frontal (or rear) perspective may be very expressive, but my problem is focusing when the subject moves towards the camera (or ...
9
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2answers
1k views

Can lens focus speed affect continuous shooting speed?

I was using a 50mm f/1.8 II lens on my Canon 40D yesterday, and I was trying to capture some action shots using continuous high-speed drive mode and AI Servo autofocus mode. I was using a shutter ...
17
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5answers
2k views

When would one need manual focus override?

In lens reviews, ability to override auto-focus manually is often referred to as a good (and important) feature. I have rarely, if ever used that feature, so I feel I might be missing out on an ...
5
votes
1answer
20k views

What is the difference between Al Focus and Al Servo autofocus modes?

Recently I bought a Canon 60D and I am uncertain about when and how to use/activate the Al Focus and Al Servo functions. I understand the One Shot autofocus function for still subjects. You press ...
8
votes
5answers
3k views

How to get focused pictures for action shots?

My daughter just started playing Tee-Ball and I was out there with my Digital Rebel XT and a Sigma 300mm. I know enough to be dangerous and I was shooting in "Auto mode" with the action preset (the ...
8
votes
4answers
748 views

Which is better - autofocus and recompose vs. manual focus?

In some occasions autofocus doesn't focus what I intend it to. What is the better option - to use autofocus, focus what I want and recompose, or use manual focus in that situation?
18
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4answers
9k views

How do camera body motors compare to in-lens motors for focusing?

What is the difference between using a motor on the camera body and the motor built into lenses? Aside from how both compare in terms of speed, what differences would I notice if I use a body with a ...
18
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2answers
46k views

What's the difference between cross-type autofocus points and regular ones?

What's the difference between different autofocus point types (cross vs point and such)? Cross points seem to be a "feature" — why?
5
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3answers
2k views

What causes auto-focus “freezing”?

On occasion, the auto-focus system in my camera and/or lens just stops working. I'll be holding down the shutter release halfway and tracking a subject and I can feel/hear the auto-focus system ...
7
votes
1answer
2k views

How do you trap focus on DSLRs without native support for it?

I came across the term trap focus on the autofocus page of wikipedia, and it seems to be a very handy feature that triggers the shutter release when a subject moves into the focal plane. This feature ...
13
votes
7answers
1k views

How can I improve focus using both manual and auto on a candle flame?

I got my new tripod and 50mm F/1.4 sigma on my Nikon D7000 and was testing it out doing some shots of a flame on a candle. The below image is the sharpest i was able to produce. In review of my 50+ ...
13
votes
4answers
767 views

Why doesn't auto-focus work with an all-white subject (like a wall)?

I am trying to compose a shot using my Nikon D60 and 18-55mm lens towards a white wall in a auto-focus mode. It looks like I am not able to take the photo. I feel the camera is not able to find any ...
5
votes
2answers
1k views

Can't auto-focus at full zoom

I have a Canon 1000d, and the standard lens EF-S 18-55mm. Recently I was out taking photos and I've noticed that if I zoom in fully, the lens can't auto focus. I can still take shots using manual ...
27
votes
8answers
3k views

What is the advantage to back-button autofocus?

I've heard some advanced photographers talk about using back-button autofocus. As I understand it, this involves changing one of the camera's custom setting to engage the AF when a button on the rear ...
31
votes
5answers
3k views

Focus problem vs. motion blur vs. camera shake - how to tell the difference?

I'm not sure if the title of the question captures what I mean, but it's hard to be succint in the space allowed. Suppose you have a picture that is not as sharp as you think it should/could be. ...
9
votes
8answers
3k views

Should auto-focus need adjusting?

I own a Canon XTI, and it always seems my shots are slightly out of focus. I usual have my camera set to the center focus point, and usually half press the shutter button to establish the focus on the ...
13
votes
3answers
1k views

How does the lens influence the autofocus?

I think I've more or less understood how AF works now. However, I'm not sure how the lens influences the whole process. In my recent research for my next lens I found reviews stating the one lens' AF ...
8
votes
2answers
622 views

Why the AF confirm lights won't blink when the spot is in-focus while using an all-manual lens with an adapter without any connectors?

I understand that my Canon 450D's (XSi/Kiss X2) passive autofocus system knows a spot in the view is in-focus when its nearby contrast is adequate. Then the camera blinks AF confirm lights to inform ...
9
votes
2answers
770 views

What is manual-priority autofocus?

I have been looking at the Nikon AF-S 35mm f1.8 lens and it has two focus settings: Manual Focus Manual-Priority Autofocus What is "manual-priority autofocus"?
12
votes
1answer
4k views

What is a focus limiter?

What is a focus limiter and how does it work? What is the advantage of it? For instance Tamron 90/2.8 Macro has a focus limiter. According to the documentation: In the limit position, the Tamron ...
5
votes
1answer
361 views

AF switch on lens vs. AF switch on camera

Is there any difference between using only the AF/MF switch on my camera (Nikon D90) or using the AF/MF switch on my lens (18-105mm)? Could having autofocus on my camera switched to manual focus ...
7
votes
5answers
500 views

Precise focus in self-portraiture

I've been trying to take some self-portraits, but I often have to struggle with the auto/manual focus. I don't miss by a lot, but I really want sharp focus in the eyes. I'm using a 50mm/1.8 around ...
29
votes
3answers
3k views

How does autofocus work?

How does auto focus work on modern cameras? How accurate is it?
7
votes
3answers
2k views

How should I chose a manual focusing screen for my Pentax K10D?

I am considering buying a split focusing screen, replacing the original one. I would like to use some split/microprism screen to ease the focusing of the manual lenses. I own both kit lenses (18-55, ...
3
votes
2answers
4k views

Are there solutions to limitations on using back-button AF on Nikon D3100?

I have started to use my D3100 with my AE/AF-L button set to AF. So in other words I use this button instead of the half press shutter button to AF. I'm new to this technique and came across it here ...
0
votes
0answers
345 views

Need help focusing at night with DSLR [duplicate]

Possible Duplicate: How to focus in complete darkness I have a Canon 20D, when I shoot outdoors at night I have a very hard time getting images in focus. I primarily shoot landscapes, so ...
10
votes
3answers
1k views

What type of lens will auto-focus on Nikon bodies without a focus motor?

I know my D40 doesn't have a motor in it to auto-focus lenses. What type of lens has the motor in it? How can I know which lenses will and will not work?