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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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How do I keep my Nikon D5100 from attempting to autofocus with every shutter press?

I have a Nikon D5100 and the auto focus works fairly well most of the time. But there are times when I have a subject in focus and want to fire off multiple shots fairly quickly. I do not need to ...
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382 views

Replacing my XXD with a 7D?

My goto camera is still my 5D Mark II. As I primarily shoot landscape, I love Wide Angle on a Full Frame body. That said, I do occasionally shoot animals and people running. The 5D Mark II's AF ...
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2answers
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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 ...
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What is the effect of the number of cross-type focus points on sharp focus?

Canon claims that EOS 6D has special capability to focus in low light, but it has only one cross-type sensor and overall only 11 focus points. Does only one cross-type focus point in the Canon EOS 6D ...
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4answers
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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 ...
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1answer
393 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 ...
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472 views

Do I need a better Camera or do I need to learn how to use the one I have?

Read some of the old questions. I figure that due to my wants you may be able to help me. Let me be clear about what I am doing, what I want to do, and see where we can go from there. I help run ...
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Why does my Nikon D3100 no longer auto-focus correctly?

I bought my camera on January 2011. Since a few months ago, I'm facing a problem with the autofocus. It happens with my two lenses 18/55mm and 55/200mm. I noticed that the focus light doesn't turn on ...
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1answer
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Why does the IR-Assist beam of Canon Speedlites not get used in AI Servo AF mode?

The IR AF-assist beam on the Canon Speedlites (I have a 430 EX II) doesn't seem to come on when the DSLR (I have the EOS 7D) is in 'AI Servo' AF-mode. It works fine if I'm in one-shot mode (comes on ...
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Does “the same” lens, with different autofocus systems, have the same optical quality?

I'll give examples with Nikon only, but the question is pretty general. So, is this a fact or not? Examples: Nikkor 50/1.8G AF-S, Nikkor 50/1.8 AF-D and Nikkor 50/1.8 AF 70-300 AF and 70-300 AF-S ...
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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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Shutter half-press to focus possible in Live View mode on EOS 50D?

When not in Live View mode and when the lens is set to AF mode, when I press the shutter button half way on my Canon EOS 50D it causes the camera to auto-focus, as expected. In Live View mode, I have ...
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1answer
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When is it really necessary to use AF assist light?

I find the AF assist light to be distracting at times when I'm trying to take a candid shot without disturbing the human subjects or taking pictures of pets (they hate getting the AF light in their ...
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1answer
1k views

Sigma 70-200mm vs. Nikon 80-200mm auto-focus speed

I'm considering the newest Sigma 70-200mm F2.8 EX DG APO MACRO HSM II and comparing it against the older (but still for sale) Nikon AF 80-200mm F2.8 D ED. These are roughly in the same price class, ...
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240 views

Converting cameras for infrared use: When does the filter have to be replaced, and when is simply removing it ok?

When converting a digital camera for infrared use, the general approach is to remove any filters that limit its sensitivity to the visible range of light wavelengths. Some conversions replace the ...
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What does the mirror do when shooting in Nikon Live View tripod mode?

When shooting with Nikon's Live View in tripod mode, the camera uses contrast detection to focus. It does this by using the sensor, which it would seem would raise the mirror similar to mirror lock ...
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218 views

How to Turn Off Custom Functions in Canon Film SLRs

So I adjusted the Custom Function settings in the dial, and then I noticed that my Autofocus is now controlled by the CF button. I am using a Canon EOS 50, a 1995 film camera (not 50D). How do I turn ...
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677 views

What is an auto-focus motor?

I recently bought a Canon 550D, and I read it has an auto-focus motor, which not all cameras possess. I'd like to know what it is, and what I can do to keep it running smoothly; AFAIK the manual ...
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4answers
2k views

Why does my Nikon D90 autofocus not work in rapid succession?

When photographing candid shots of my children at play with a Nikon D90, I have trouble with the autofocus system. I focus and shoot one shot, great. But a second later another shot opportunity ...
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Do point and shoot cameras have a metering sensor?

I have a Pentax point and shot camera and I tried to convert it to Infrared. I was successful to remove the front IR filter from CCD and then I had a 760 nm IR filter to kick start with the infrared ...
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Why does Nikon warn about banding at high ISOs when using autofocus on Nikon D4 or D800?

Nikon says that banding may occur at high ISO sensitivities with autofocus on the D4 or D800: D800 Noise in the form of horizontal lines may appear in pictures taken with AF-S Zoom Nikkor 24-85 ...
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Why is on sensor PDAF drastically slower than traditional PDAF?

Why is on sensor PDAF drastically slower than traditional PDAF? I assume the technology is the same, doesn't matter if the module is on the sensor or located behind a mirror. But the performance is ...
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Can I control if the in-body AF motor is used instead of the lens AF motor on my Nikon?

I have Nikon D7000 with 18-105mm. I know that the camera body has the AF motor and the lens itself has the AF motor too. I was wondering can I control which AF motor should be used while autofocusing. ...
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Why are there no autofocus tilt-shift lenses? or, why do tilt-shift movements appear to be incompatible with phase-detection autofocus?

I have never seen or heard of an autofocus tilt-shift (perspective control) lens. It seems like perspective control movements prevent phase-detection autofocus from working correctly; for example ...
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Why isn't the gain on phase-detect autofocus sensors increased in low light?

Modern phase-detect sensors can focus in pretty low light. However, the limit for low light focusing tends to be reached much before the camera can no longer capture images using a high imaging sensor ...
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What is the “AF Stop” button on some Canon lenses?

When looking at custom functions in Canon camera manuals, I've come across mention of setting functionality to have happen when the "AF Stop" button is pressed - a button that, apparently, exists on ...
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548 views

Does having the AF points bunched up in the middle make a big difference?

I was looking into the new Nikon D600, which looks like a pretty compelling camera. I however noticed that its 39 AF points though quite a lot are all bunched up in the middle. I am used to having AF ...
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2answers
339 views

Control and option comparison between the Nikon D7000 and the D300s?

I'm looking to purchase a new camera for both photoshoots and videos. I know all the technical differences like resolution, speed,...and all that. But I went to a shop where the sales lady told me ...
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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 ...
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Which Nikon DSLRs have an autofocus motor in camera body? [closed]

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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EOS Rebel T3i 18-55mm lens won't take a picture - happened with two lenses

I'm a reporter for a small town paper - Early in 2012 we had a body of a T3i go bad and it was replaced new body and we used the old 18-55mm lens. It worked fine for 7-8 months. I do a lot of sports ...
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1answer
354 views

What autofocus zone selection mode should I use for action/event shooting?

I have a Canon 7D, and typically shoot everything I do in its single-point autofocus zone select mode, because I usually want fine control over exactly what the camera is focusing on and I often find ...
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390 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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What can I do if autofocus does not work but manual focus does?

Recently, the autofocus on my Nikon D3100 stopped working. The ring of the lens wouldn't even turn when I tried to focus. However, when switched to manual focus, the camera works fine. When I used a ...
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462 views

Are of cross-type focus points more accurate, or just faster?

Do cross type focus points achieve sharper photos than horizontal points or do they just grab focus faster.
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Is it safe to manually-focus the Nikon 18-105 while in autofocus mode?

There are only A and M settings, no A/M. but I just noticed that Nikon website has mentioned three focus modes for this lens: Auto, Manual and Manual/Auto I'm confused if this is only a typo or is it ...
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262 views

How much did the v2.0 firmware update improve the Fujifilm X-1 Pro's autofocus?

I really liked the Fujifilm X-1 Pro when I tried it for a couple of weeks — enough that it made me think seriously about switching from my much-loved DSLR about five years earlier than I thought the ...
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321 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 ...
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891 views

Force AF assist light on body / flash to come on with Nikon DSLRs?

I have a Nikon D-40 and D-90 with a wide assortment of prime lenses. I like fast primes for low light photography. Some of my lenses are sufficiently old that they do not auto focus at all. Others ...
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Why is the AF confirmation chip needed?

I've read that adapter rings for manual lenses in Canon and Nikon might incorporate an Autofocus Confirmation chip... With my old Pentax K10D all manual Pentax-K lenses had AF confirmation, and they ...
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Could autofocus of the Canon t4i be improved with a firmware update?

I am trying to decide between the Canon t4i (650D) and the t3i (600D). Initially I was going for the t4i because of the autofocus. But the sample videos I have seen did not really impress me. Can I ...
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1answer
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What factors influence whether a lens and camera combination front or back focus?

I know that sometimes a lens/body combo needs to be micro-adjusted to attain ideal focusing behavior, and that this is usually because of sample variation, but which parts of the lens and/or body are ...
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Why eye-controlled focus is gone?

I tried to google, but only semi-decent answer was that ECF didn't work for some and was a nightmare for support group. But are there any reasons modern Canons (or other major camera-makers) lack ...
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Where can I find information on the Pentax Q lenses serial protocol?

I'm searching for detailed information on the Pentax Q lenses (any, but I'm especially interested in the 5-15mm-lens) serial protocol, which controls focus/zoom/aperture. So far I have found nothing ...
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Halos on images taken with a Panasonic Lumix DMC-FS35 [closed]

Every image I take with my DMC-FS35 shows a halo around the subject. (See below) This is true in all light conditions with or without flash. INSERT IMAGE HERE
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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 ...
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5answers
379 views

Do all cameras with autofocus need motors?

Do all autofocus cameras need motors to drive the lens? I would have thought today's modern electronics rendered motors obsolete.
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Which focus mode should I use for a portrait shoot?

I have to do a portrait shoot for a friend. My camera (Pentax K-30) allows me to focus in the following modes: 1 focus point (center) 11 auto focus points 5 auto focus points I haven't yet ...
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Which lenses typically don't focus properly on the Canon 60D?

I currently have the 18-200mm kit lens for my canon 60D. I am thinking of getting the 10-22mm wide angle lens as a second lens. So far with my kit lens I havent experienced any focusing problems or ...
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Why my “action” shots are blurry even shooting on AF-C, is this a lens or camera limitation?

I'm currently using a Nikon 28-200mm AF-D with my D7000. While trying to take action shots (e.g. my dog running or sports) none of the shots seem to be in focus even on AF-C mode. Would this be a ...