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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13
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6answers
5k 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. I'...
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3answers
151 views

Does the autofocus system look through the lenses?

I have a doubt about the effect of putting a filter (polarizer, UV etc) on the autofocus system. In theory, a lens which is put in front of the lens will affect the focus (we must set a different ...
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1answer
165 views

Confused about AF, AF-S (Nikon Autofocus)

I have a Nikon D610. I thought it would work with AF lenses, but my Nikkor AF 50 mm 1.8 D doesn't autofocus, Same for the Yongnuo 50 mm 1.8 AF (the Yongnuo has a MF/AF switch on the lens). Are these ...
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3answers
3k views

My viewfinder won't autofocus but live view focuses well

I have a Canon EOS Rebel T5 camera and I've been running into an issue lately that I do not know how to solve. The autofocus while using viewfinder does not work at all; I could not even take a photo....
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3answers
287 views

Why doesn't lens focus after turning focusing ring while set to autofocus?

My brother tried my new camera and was turning the focusing ring quite harshly on auto focus. (50mm canon lens) I’ve read multiple similar questions but nothing is quite what I mean. Ever since my ...
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2answers
149 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....
8
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1answer
3k views

Where is the AF sensor located in a DSLR?

As I understand every DSLR has a separate, smaller sensor that handles phase detection focusing. Where is it located? If this location is different for every DSLR, and therefore this broad question ...
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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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4answers
118 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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2answers
126 views

Is there any test data available that characterizes performance of Canon's “AI Servo AutoFocus”?

After trying numerous recommendations for setting Canon's AI Servo AF, I am getting only the rare in-focus picture of small birds in flight in their native environment. Based on this I have formed an ...
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3answers
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What is the advantage of the huge number of AF points?

If the camera has only 1 central AF point, it is difficult to focus on an off-center subject (without recomposing after autofocus) so having 3 AF points seems really useful. Similarly I understand the ...
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2answers
315 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, ...
3
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2answers
414 views

Are there autofocus-enabled adapters for Olympus lenses on Canon EOS cameras?

Fairly new to photography so forgive my foolishness before calling me out, I already know. I bought a Olympus 50mm F1.8 lens thinking it was a manual focus but when I received it I realized I misread ...
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2answers
5k views

Why isn't a Sigma HSM lens autofocusing with my Nikon D5600 — is there a compatibility problem?

Today I had a chance to try a Sigma 70-200mm f/2.8 EX DG OS HSM, a 2013 model lens, on my Nikon D5600. Everything was okay. I was able to take pictures with it. But auto focus didn't work as it should....
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0answers
77 views

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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7answers
9k views

How did photography work before auto-focus was invented?

Having just spent some time reading questions about auto-focus, I came up with a question of my own: How did cameras even work before auto-focus technology was invented? Presumably everybody used ...
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2answers
86 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 ...
17
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2answers
13k views

Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?

One thing that I've noticed with Canon DSLR camera is they will disable or limit autofocus when the lens' maximum aperture is narrower than certain values, which are specified in my answer to What ...
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1answer
40 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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1answer
124 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
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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2answers
157 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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6answers
8k views

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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1answer
166 views

When does the Sony NEX-5R use release priority?

As I understand it, focus priority delays the shot till focus is achieved, while release priority potentially takes a mis-focused shot. Wikipedia says that release priority is usually used in ...
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2answers
111 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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5answers
568 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 ...
2
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2answers
122 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
30 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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2answers
113 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 ...
2
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2answers
171 views

What equipment would be best for a new photographer, interested in macro nature photography?

I recently started a photography class and I really like it, and I want to start taking photos outside of school with my own camera but I don’t know what to get. I love taking close up pictures of ...
0
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3answers
194 views

Why does my autofocus sometimes set the aperture, after the lens was in the rain for several minutes?

I'm using a Canon EOS 60D with a Canon 40mm f/2.8 STM. I bought both used about a week ago. I've had no problems except for one: sometimes the autofocus only jumps between two apertures, and the ...
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4answers
402 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 ...
0
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1answer
247 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 ...
0
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1answer
53 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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2answers
117 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 ...
6
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1answer
1k 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 ...
54
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5answers
23k views

What methods can be used to micro-adjust autofocus of a camera body to a particular lens?

I have a Canon 7D with a 50mm f/1.4 lens, and I think the auto-focus of the lens is off. How can I test and adjust this reliably? Will this approach work with all of my lenses? If I had a different ...
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3answers
82 views

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
76 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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1answer
53 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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1answer
75 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 ...
3
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4answers
24k views

Why does my Nikon D3100 not fire the 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 "A"...
3
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1answer
1k views

How to set “release priority” rather than “focus priority” on Canon DSLR?

FujiFilm X-Series cameras can be set for focus priority or release priority. This controls the camera behavior when AF cannot lock. On focus priority, the shutter will not release. On release priority,...
2
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2answers
111 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 ...
0
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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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2answers
75 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 ...
2
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1answer
3k views

Why won't my Fujifilm X-E3 focus or take photos?

I’m new to photography but I bought an X-E3 today, pressed some buttons, and I’m not sure what happened but my camera won’t focus now. In the photo, it’s on auto and I’ve tried changing the settings, ...
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1answer
2k views

Why is the autofocus not working on my Canon EF 70-200mm f/2.8 L IS II USM?

I bought the EF 70-200mm f/2.8 L IS II lens and the autofocus is not working. It's non-functional. I can use the lens in manual mode but not in autofocus. What could be the cause?
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2answers
641 views

Nikon D3200 focus problem when using viewfinder, but not live view

I have a problem on Nikon D3200 with autofocus, using viewfinder it works in cca 70% cases, sometimes it has a problem to focus on objects (which distance is relevant). Using liveview it works ...
2
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1answer
111 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, ...