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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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383 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
votes
1answer
183 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
votes
3answers
455 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 ...
2
votes
2answers
346 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
150 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 ...
2
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0answers
121 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 ...
3
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4answers
2k views

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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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. ...
1
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3answers
240 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 ...
4
votes
1answer
270 views

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 ...
3
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1answer
725 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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6answers
18k views

What is the practical difference between phase-detect and contrast-based autofocus?

What are the main differences in field use between phase detect AF and contrast based AF? I understand the technical differences, but I am not sure what the implications from a photographer ...
18
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2answers
51k 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?
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3answers
1k views

Where is Canon 1100D autofocussing in low light low contrast conditions?

It's obviously my fault for living in the UK and expecting to want to enjoy my bird photography in grey January afternoons, but, I would appreciate some opinions on the following. I took 150 shots ...
6
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1answer
9k views

Why isn't the focus indicator light showing when focused on my Canon 5D Mark III?

I've been working with two different Canon EOS 5D mark III cameras, and had the same problem with both. When auto-focusing I have two kind of indicators when the image is focused on a certain point. ...
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 ...
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1answer
92 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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6answers
310 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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1answer
176 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 ...
1
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1answer
7k views

How to troubleshoot a Nikon D5100 that will not autofocus at all?

A good friend of mine has a d5100, which was working perfectly fine yesterday. Today, however, it refuses to autofocus at all - it makes no effort to move the focusing ring etc. I have tried ...
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5answers
444 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 ...
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3answers
197k views

What does STM mean on a Canon lens?

The Canon EF 40mm f/2.8 has a designation of STM on the lens. What does this mean? What are the advantages of having it and does it replace an older technology? We have a terminology thread that ...
6
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2answers
457 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 ...
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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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1answer
83 views

Tricking compact's camera autofocus

I'm trying to get some bokeh using a compact (almost premium) camera, a Nikon Coolpix p300 (although the question is general). Since the camera hasn't got a manual focus option, I'm trying to use the ...
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1answer
564 views

Has D600 AF fine tune option? Can I fix backfocus of my lens on D600?

I know that the D800 has an option to tune AF. Does the D600 have this option, and does it work as well as it works on the D800? Can I fix a back-focus issue with my lens on a D600 without sending it ...
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2answers
121 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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2answers
51 views

Superzoom unable to autofocus at infinity at mid-zoom focal lengths

I have an inexpensive "superzoom" camera that functions properly and fills my needs but has one problem I seem unable to resolve. It is a GE Power PRO X500 camera with which I have taken several ...
3
votes
3answers
200 views

Why won't Nikon V1 autofocus with a close up filter attached?

I have a Nikon V1 with a 10-30 mm lens and recently purchased a +10 filter for close up work, but the camera won't focus when i use the filter. Am I doing anything wrong or is this a limitation of the ...
4
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2answers
353 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.
1
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1answer
348 views

What is broken on my Canon 450D? Edit: Missing focusing screen and submirror: fixable?

I recently aquired a used Canon 450D, which the previous owner said was broken. I'm new to photography and SLRs so please excuse some of the ignorance following. After digging a bit around the last ...
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3answers
289 views

How to take clear photographs with DSLR

I just bought a Nikon D5200 with the 18-105mm lens and I have taken this flamingo photograph but can't see their faces properly and If I zoom in a little bit the image is pixelated. I have tried ...
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1answer
316 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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2answers
1k 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, ...
18
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4answers
10k 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 ...
2
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1answer
156 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
128 views

Canon camera DIY repair

I have a digital rebel XT, an 18-55mm, and 75-300mm lens, all by Canon. Everything has saltwater damage. I'm aware that it's cheaper to just replace it all, but I was fiddling around with it, testing ...
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5answers
1k views

Why don't most cameras use infrared for focusing?

All auto focus assist lights are either red or white. Why do DSLRs not use infrared instead? It seems it would be beneficial to a photographer to not blind their subject before taking a picture. ...
0
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1answer
464 views

Nikon AF-S Nikkor 70-300mm 1:4.5-5.6 G ED Lens will not autofocus

I have a Nikon AF-S Nikkor 70-300mm 1:4.5-5.6 G ED Lens that I purchased in Feb of 2013. I have been using this lens with my Nikon D3200. Up until this point my lens and camera have been completely ...
0
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1answer
3k views

How to fix inoperative autofocus in Canon 70-200 F4 L USM?

This lens has been sitting on the shelf for years and I recently hauled out my DSLR to play with it. Turns out the autofocus no longer works. I'm wondering if there's any kind of remedy for this short ...
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2answers
5k views

How to enable Canon AF with teleconverter?

Canon DSLR bodies prevent poor auto-focus performance by disabling it completely when the lens reports maximum aperture at chosen focal length smaller than f/5.6. This implies that some lenses will ...
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2answers
147 views

Quiet video autofocus on a consumer level SLR? [closed]

I bought a Canon Rebel T3 a while back before doing my homework on the features. The video quality looks very good to me. However, I have to hold down the shutter button to keep focus. The auto-focus ...
4
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0answers
113 views

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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4answers
853 views

Will the Canon 5D MK II with 100-400 1:4.5-5.6 work properly with Kenko 1.4 converter?

I'm using 5D MKII body and 100-400 f/4.5-5.6 lens. I want to use a 1.4 converter; will the Kenko converter work and autofocus properly?
6
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1answer
929 views

Which offers better results: FoCal or LensAlign Pro?

I am in need of microadjusting my autofocus for a couple of my lenses with my Canon 7D. Namely, I need to adjust the 100-400 L lens, which seems to consistently AF a bit softer than I've seen from ...
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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 ...
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1answer
308 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 ...
4
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2answers
1k views

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 ...
3
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2answers
3k views

What is a Dual pixel autofocus?

I have seen the term "Dual Pixel CMOS autofocus" used by Canon (specifically in relation to the 70D). What is it? Is this Canon specific technology? Are there equivalents in other manufacturer's ...
5
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3answers
1k views

Enable Auto focus after timer on Nikon D800?

I'll start with an apology if everyone knows this but me. I bought a Nikon D800 about a month ago (adore), but the wireless remote I used for the D7000 is not compatible. No worries, I'll just ...