Questions tagged [autofocus]

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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289 views

Are electronically parfocal RF lenses parfocal enough for fireworks photography with zoom?

Within a month or so, it's the first time I'll see fireworks as an owner of a good camera and naturally I'm planning to take photographs of them. By researching various fireworks photography sources, ...
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108 views

Is there any benefit of “continue focus search” option?

Many Canon DSLR / mirrorless cameras have an option to choose whether the camera searches for focus if it cannot find focus. Especially on long lenses with no focus limiter, the lens can become ...
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Is there any test data available that characterizes performance of Canon's “AI Servo AutoFocus”?

I am of a certain opinion wrt Canon's "AI Servo AF". However, I'm aware that this is a Q&A forum, and not a discussion forum. Consequently, I'll pose my question as follows: QUESTION: Does ...
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AF Fine-tune zoom lenses?

How do you fix / fine-tune the focus on a zoom lens? Nikon states The D850 can fine-tune autofocus automatically. The results can be used with all lenses of the same type. But does it also mean ...
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55 views

AI Servo does not support Live View mode for Canon 1DX Mk ii

I've been doing some experiments with my AI Servo Autofocus system in my 1DX Mk ii. Basically, the experiments were intended to help me understand some of the rather confusing jargon used to describe ...
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106 views

Nikon D5200 no longer focuses

It used to be that on my Nikon D5200 camera holding down the shoot button halfway the viewfinder would show green dots and it would focus nicely. Now after resetting the camera settings, replacing ...
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3answers
89 views

Is it possible to use a follow focus to add AF to MF lenses?

I recently switched from a EOS 7D to a Sony a6400 and since I have to buy new lenses I saw the huge difference in price between compatible AF and manual focus lenses. I also stumbled upon this: ...
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6answers
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Why aren't faces sharp in my f/1.8 portraits even though I'm carefully using center-point autofocus?

I love my Canon Rebel T6 and take portrait pictures in Av mode with a 50mm in 1.8 Av. I'm using auto focus in the 'focus on center point' mode. I make sure that the center point focuses on the face so ...
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110 views

How can a subject stay in focus if the shot is recomposed afterwards?

I have a doubt about a procedure that I see many photographers continuously apply and they taught me. I see that, when they want to take a picture with their reflex, they do this sequence of steps: 1)...
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2answers
113 views

What lenses for a Nikon camera have both an AF motor and an aperture ring?

I have a Nikon FE10 35mm film SLR and a D5600 DSLR. I want a wide focal length prime or mid range zoom (nothing longer than 120mm) to use on both cameras. I need an aperture ring for the film SLR ...
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1answer
24 views

How to set AF area mode viewfinder if values are gray (can't be chosen) on Nikon D3500?

When setting AF area mode viewfinder on my D3500, I can only chose 2 options out of 4: single-point AF and auro-area AF. The remaining two: dynamic area AF and 3D-tracking are gray and the camera says ...
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91 views

What should I do when the results from Reikan FoCal show flaws?

I've done an AFMA calibration Reikan Software. Assuming this was properly executed, do I need to take the results seriously? All my lenses do suffer from astigmatism, and also my new Canon 24-70 f2.8 ...
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4answers
287 views

How do fixed lenses “focus” on things at different distances? [duplicate]

I'm trying to understand depth of field and I'm struggling. If I'm playing with a 50mm fixed lens, and I alter its focus using the little ring around the lens, what is actually changing in terms of ...
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1answer
95 views

Canon 50 1.8 STM: AF adjustment not possible?

My 50 1.8 STM back-focuses a little when focused through OVF. I visited Canon Service in Bangalore today. The technician there outright told me that there is no adjustment possible for 50mm 1.8 stm ...
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1answer
49 views

Could someone share AF calibration settings for Sigma 18-35mm lens on Nikon D3300?

I have auto focus problems with Sigma 18-35 which I recently bought on D3300. I would like to see other's AF adjustment/calibration settings. I am having a hard time with setting it up. Are the ...
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1answer
171 views

Focusing issues on live view - Nikon D750 w/ AF-S NIKKOR 24-70mm f/2.8G ED

On a heavily used Nikon D750 w/ AF-S NIKKOR 24-70mm f/2.8G ED: When using live vision, ussualy while holding the camera up over my head, autofocus focuses nowhere. This happens right after having ...
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2answers
81 views

Focussing area is different in live view than when viewed in viewfinder

When I use the AF-S mode or any other mode through the view finder, I can see an area in which the focus point can be moved. It is relatively small. What if I want to focus out of that area or focus ...
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3answers
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What should I do when autofocus is not working after i dropped my camera? [closed]

Yesterday i had dropped my camera and everything is working except Auto focus while using view finder but on LCD it is working fine and pictures are coming good. All is good except Auto focus, I ...
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1answer
50 views

Nikon D5100 struggling to autofocus on screen, but fine through viewfinder? [duplicate]

hope you can help me and my frustrating issue I have a D5100 with a Sigma 18-250mm f/3.5-6.3 dc os lens which will AF no problem at all when I'm looking through the viewfinder but when I change to ...
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2answers
110 views

When using Back Button Auto Focus, do I release the button before shooting a sequence, or hold it down?

When shooting moving subjects (Sports), am I suppose to keep the back button AF pressed during a sequence of shots? Or do I press til it focuses, and then let go and shoot a sequence? Thank you in ...
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1answer
51 views

Question on f-number and exposure [duplicate]

Is there any mathematical proof to show that the exposure in a camera is independent of the focal length used, if the f-number (ratio of focal length to lens diameter) remains constant?
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68 views

Relationship between f-number and amount of light being let into the lens system [duplicate]

Why does smaller f-number imply greater aperture diameter and consequently, greater amount of light entering the lens of a camera? As evidenced from my study across a number of resources, an absolute ...
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1answer
78 views

Does EOS RP support recomposing with servo AF?

My EOS RP has two AF modes: one shot AF and servo AF. With one shot AF, the camera focuses once and allows recomposing the picture. With servo AF, the camera keeps looking at the selected AF point, ...
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1answer
72 views

Auto-focus in Nikon D3100 doesn't work and i can't take pictures

When on autofocus my camera will not focus. The lens will do the twisting movement, go in and out of focus and then stay out of focus. Then it won't even take a photo. In addition, when on manual ...
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1answer
2k views

Why do even high-end cameras often still include normal (non-cross-type) AF sensors?

Modern cameras often use two kinds of AF sensor: normal, and cross-type. While normal-type AF sensors notably struggle focusing on high-contrast vertical lines, cross-type sensors, though more ...
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3answers
234 views

Why don't any cameras use time-of-flight systems (like ZCam) for autofocus (and allow extra raw creativity with z-data)?

After reading Why don't DSLRs use laser rangefinders for autofocus? This question come in my head : Why camera don't use z-cam for autofocus (and allow extra raw creativity with z-data) There is ...
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1answer
106 views

Canon Rebel T6 won't autofocus after taking photo

I'm trying to repair a Rebel T6 with a strange problem. All settings are stock, AF One Shot, center point selection. I've tested with 3 lenses including the 18-55 kit lens. After turning the camera ...
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2answers
52 views

Focus motor problem in lens due to fine dust particles

I have a Sigma 18-250mm F3.5-6.3 DC Macro OS lens that I use exclusively with my Nikon D5300. I went to Denmark last year, and visited Rubjerg Knude Lighthouse. If you've ever been there, you know ...
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1answer
108 views

Why won't the autofocus on my Nikon 200-500 work?

I can't seem to get the autofocus on my brand new Nikon 200-500 f/5.6E lens to work. All the settings (on the camera and lens) are set to autofocus. Trying other lenses on the camera, the autofocus ...
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1answer
38 views

Autofocus glitches in Nikon menu for Sigma 18-50 f2.8-4.5 lens

I have sold a Sigma 18-50 f2.8-4.5 OS HSM to an internet buyer. The lens worked fine, but after receiving it today, he said that whenever he turns on autofocus on the lens the camera has a glitch in ...
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252 views

Can I get this nikon d750 repaired or replaced?

I searched for answers on why my autofocus stopped working for my Nikon D750. I found that someone posted: “Note that when using AF lenses that are not AF-S lenses the AF/M switch on the camera ...
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1answer
48 views

Nikon Ch and AF-S mode - what controls whether the camera will try or not try to refocus during series?

Experimentally, on a D200 that was at hand, set to CH (continuous-high) drive mode, AF-S (autofocus-single), release priority, center focus point only, tracking:Normal (should not affect AF-S?) there ...
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1answer
567 views

Canon 50mm 1.8 lens not autofocusing on *one* camera

I have a Canon EF 50mm f/1.8 STM lens than when attached to my 100d doesn't autofocus. I presumed the motor had gone on the lens, as it had previously worked fine A friend has recently let me ...
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3answers
76 views

Are focus-peaking MF and contrast-based AF susceptible to being misled by metallic reflections?

Wondering about some shots that went wrong, which were shot with focus peaking and manual focus, and where there were metallic/mirror-reflective highlights (think scenes with crumpled car wrecks or ...
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3answers
157 views

How does autofocus micro adjustment (AFMA) really work?

One of my answers was edited to include autofocus micro adjustment (AFMA) as a camera choosing criterion. The edit linked to another answer explaining the AFMA more. My understanding of autofocus is ...
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1answer
90 views

Which camera (and lens) mode or settings for moving subjects?

So for the first time, I've been shooting moving subjects. I've got a new camera and a lot of stress, so I barely had time to set it up completely before the shoot (nothing professional though anyway)....
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266 views

Is it normal for EF 24-105/4L IS to autofocus when switched to manual focus?

I'm using a Canon 6D mark II. I recently got a Canon EF 24-105mm f/4L. I wanted to try using manual focus, so I switched the lens to manual focus, but it keeps auto focusing when I half press shutter ...
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1answer
643 views

Canon EOS 60D will not focus accurately [duplicate]

I have an EOS 60D that has had intermittent focusing issues since a purchased it. I primarily use the Canon 28-135mm f/3.5-5.6 IS kit lens. I also have a new Canon 70-300mm f/4-5.6 IS USM and a ...
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1answer
99 views

Does near infrared AF assist light work with sensor based autofocus?

Some flashes, cameras and wireless flash triggers (like Canon ST-E2) have a near infrared AF assist light that is invisible to the human eye. My understanding is that his AF assist light works at ...
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134 views

What to do with a Nikon D750 body that when switching lenses won't autofocus?

There was another similar question out there and one of the responders commented there was and he got his camera body replaced. I've been having the same issue with my new nikon just bought in January....
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1answer
87 views

How does a DSLR measure brightness and sharpness of an image?

In mirrorless cameras, light reaches the image sensor all the time, so this data can be used by the camera to determine the correct focus, shutter time, aperture and ISO. Makes sense so far. However ...
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3answers
164 views

Is it normal to see focus inconsistency frame-to-frame with an f/1.4 lens?

I have the Nikon Sigma 85mm 1.4 and I've noticed some inconsistency with focus. I setup a tripod, and a lens calibration card in an attempt to micro adjust the focus. However, what I noticed was that ...
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1answer
261 views

How to change auto-focus point in Auto mode on Fujifilm X-T20?

When I set my Fujifilm to AUTO mode, the focus points area seem to be only at the center of the screen. Is there a way to make this to cover the whole area? So that if my subject is at the edges, it ...
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3answers
627 views

What is “focus distance lower/upper” and how is it different from depth of field?

I have taken two photographs on a Canon crop sensor camera: 18mm f/9 with the following exiftool output (the focus was approximately at 3.5 meters): Focus Distance Upper : 5.27 m Focus ...
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2answers
61 views

Are the autofocus parameters independent from the selected case?

The behavior of Canon's AI Servo AF autofocus can be modified by choosing one of six presets, and can be customized further by adjusting the Tracking sensitivity, Acceleration/deceleration tracking ...
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1answer
73 views

What can I do when a PK-EOS ring adapter with AF conformation chip gives “communications error” with my Canon 650D?

Recently bought a PK-EOS ring adaptor for my older Pentax K lenses. I went with one that has an AF confirm chip. But, this chip causes "Communications error" and locks all camera functions. I've ...
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3answers
1k views

How sharp are RAW photos before processing?

Are RAW images by nature slightly blurry prior to processing? If I open them up in Lightroom and zoom into the photo, my photos are not tack sharp but a bit blurry. Once I process, it comes out ...
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1answer
236 views

Best settings to focus in low light and low contrast condition

I have been shooting for several years in the north of Canada and I notice that I don't get a really high percentage of keeper when using my Canon 100-400 Mk II or 70-200 F2.8 Mk II with either 5DIV ...
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1answer
692 views

Nikon D750 Lens Mounting Issue

I bought a Nikon D750 during the 2017 Black Friday and the camera is just out of manufacturer warranty. I am having a weird issue with my Nikon D750. With the original 24-120mm Nikkor lens, I am ...
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1answer
81 views

Does EOS utility fully work with other (non canon) lenses?

I only used canon lenses with EOS Utility before and now I'm looking to buy a new sigma lens. My question is: would fine focus adjustments when shooting tethered still work with other lenses? Edit: ...