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Focus is the mechanism of converging light from a point light source onto an imaging plane by a lens.

learn more… | top users | synonyms

26
votes
6answers
5k views

Can I damage the focus system by turning the focus ring when the lens isn't mounted?

I have a couple lenses that don't have an internal focusing system, and whenever I want to put them back in my bag, I turn the focus ring to make the lens shorter. I noticed that when the lens is set ...
7
votes
1answer
23k views

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

Recently I bought a Canon 60D and I am uncertain about when and how to use/activate the AI Focus and AI Servo functions. I understand the One Shot autofocus function for still subjects. You press ...
14
votes
5answers
11k views

What is “infinity focus”?

I have been reading a bit about astrophotography and the term infinity focus keeps coming up. What is infinity focus and how do you set the camera to infinity focus?
4
votes
2answers
100 views

Why is the battery required to manually focus through the viewfinder?

Is it normal that I can't manual focus any of my lenses on my 5D MK iii without having a battery inserted? I can focus on an object, and while looking through the view finder, remove the battery and ...
1
vote
3answers
2k views

Nikon D3100 Won't Take Photo — says light is too low

I've had my Nikon D3100 camera for about 3 years. I recently accidentally reset my shooting options. Since I've done that, I'm having a hard time getting the camera to focus and take photos in lower ...
12
votes
1answer
5k 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 ...
2
votes
1answer
71 views

Nikon 18-55 mm Lens Focus Wheel Jammed

I accidentally dropped my Nikon D3200 with a 18-55 mm lens about a foot onto a hard carpet. It originally looked ok, however I soon realised it wasn't focusing. I saw that the focus wheel was jammed ...
2
votes
1answer
226 views

Nikon 16-85 VR focus noise problem?

My 16-85 VR is doing some weird noise during focus, manual or auto. It's like an hiss. I asked in a local shop and they said it can be some microdust inside the lens. But I'm a little worried it can ...
5
votes
4answers
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 ...
1
vote
1answer
87 views

What is the difference between touch focus and autofocus?

I have a cheap Chinese Android phone, a Landvo l200 based on MTK68XX chip. It claims to have a 13MP touch & autofocus camera. I wanted to know how this autofocus feature differs from touch focus ...
3
votes
1answer
53 views

Why is manual focus off after installing a 45° split-prism focus screen?

I recently bought a new focus screen for my D5100. I installed it without any problems. But, if I manually focus with the screen it is not correct. A picture of something 30ft away is about a foot ...
3
votes
1answer
106 views

Diagnose a damaged lens from focus test results

I have a lens that gives perfectly decent results at f/22 and f/32. Here's its capture of an ISO 12233 test chart: It's not the sharpest lens I own, but whaddaya want, it's a quarter century old ...
4
votes
3answers
132 views

Does hyperfocal distance only apply to manual focussing?

At any given aperture and focal length, I can still focus on something near or something far away by simply touching the lcd on my dslr. Does that mean that because I may not be focussing at the ...
0
votes
2answers
72 views

Find focus and effective range of single focus camera

I have a cheap camera that is supposed to take videos underwater. It is a camera in a case that is set to a single focus. I checked the specs and it is a manual set focus camera. When I asked the ...
2
votes
0answers
183 views

Canon EOS SL1 - Manual focus stopped working

I recently purchased a Canon EOS Rebel DSLR SL1. My 18-55 mm lens shoots amazingly, and I have been using it in auto and manual focus. About a week ago, my manual focus randomly stopped working. The ...
97
votes
7answers
8k views

What is bokeh, exactly?

I understand that "bokeh" refers to out-of-focus areas of an image — but there is obviously more to it than that. What does the term mean exactly? How well is bokeh really understood? Is it purely ...
0
votes
0answers
97 views

Samsung NX1000 focus ring does not work, can't get off manual focus mode either

I bought a used Samsung NX1000 last night, everything is great but it's stuck on Manual Focus mode. The Single Auto-Focus [SAF] and Continuous Auto-Focus [CAF] are greyed out no matter what I try. ...
6
votes
2answers
424 views

How does autofocus confirm work with manual lenses?

When I was a kid my dad had an Olympus OM10, he had a bunch of lenses for it and I remember focusing was done with a special circle in the middle of the viewfinder, where you pointed it at the thing ...
4
votes
2answers
721 views

Why do I get blurry pictures at far distances, but sharp results up close?

I took this picture: https://www.flickr.com/photos/91552641@N06/15828810701/ and if you look at the details (like the trees on the right side) they are all kinds of muddy. I had the same experience ...
0
votes
3answers
118 views

Image in focus at the back (LCD) but not when shown in computer

I take pictures of fishes in my photo tank. But every time the photos come out a little blurry and never totally sharp. I only get to know that my photos are useless is when I see them on the computer ...
0
votes
1answer
104 views

Making the whole photo in focues using Nikon D7100 with nikkor 18-105 mm

Can anyone help me in how to make the whole photo in focus ?? I'm using Nikon D7100 with Nikkor 18-105 mm. Updated
1
vote
2answers
280 views

Why Focus Assist activating in full outdoor light on my Canon EOS Rebel?

Trying to understand why the focus assist feature is activating in full outdoor light on a sunny day. I have a Canon EOS Rebel T-3. Recently, the 18-55 stock lens was replaced free by Canon. Since I ...
1
vote
1answer
36 views

How can I avoid the “Low Light!” warning with Samsung S1050 compact camera in Night mode?

I am wanting to take photos in dark conditions using the Night scene mode. For example, a carved Halloween pumpkin in the dark with a candle in it. However, I get the "Low Light!" warning message ...
0
votes
2answers
828 views

Auto-focusing problem on a Canon 500D with a EF-S 18-55mm 1:3.5-5.6 IS(standard kit lens)

I'm having problems with the lens. I've tried auto-focusing with my other lenses, and it works fine. It can only auto-focus one way, i.e. the focusing ring is still able to move, but only able to turn ...
13
votes
2answers
16k views

How does focus work on mobile phone cameras?

How does focusing work on mobile phone cameras? Aren't their optics simple enough to not have any moving parts whatsoever? If so, how come most smartphones have an auto-focus, and with various ...
21
votes
9answers
3k views

How do I focus in low light for long exposures?

I've been trying to take some long exposure shots at night with my Canon 450D. The problem I'm having is that I can't seem to get a shot in focus. The low light conditions prevent AF from working at ...
12
votes
7answers
2k views

How can I get perfect sharpness when shooting still art?

I've been trying to shoot some marble sculpture that are well lit on a studio wall. The photos are coming out well and perfectly useable.. but I'm striving for something better. My issue is with ...
2
votes
1answer
60 views

How do you focus a shot with an IR/UV passfilter?

I'm researching the world of photography outside of the visible spectrum and I'm really curious to get my hands on some filters, the Baader-U for example, to try shooting in these spectra. However, I ...
2
votes
2answers
125 views

Programmable cameras that can take multiple shots at different focus settings

To do focus stacking in case of moving subjects, it would be useful to have the ability to preset different focus settings and let the camera take the pictures with the different settings in fast ...
0
votes
3answers
204 views

Why can lenses only focus from so close? [duplicate]

I have always wondered, why is it that a lens can only focus from so far away from the subject? I know some lenses have a kind of macro switch which basically allows them to focus closer but why are ...
31
votes
4answers
47k views

What is back-focusing?

What is back-focusing? Is it something I need to be worried about, or can I just live with it? How can I tell if my camera/lens is sufferring from it?
0
votes
3answers
220 views

Auto focus vs Single Continuous/Point focus

I'm using a D600. Sometimes, having the ability to select my focus point is good. However, in certain situations, moments can be lost when you're framing or moving the focus point to the subject in ...
5
votes
3answers
192 views

How do waterproof lenses focus underwater?

Our eyes need air in front of them to be able to focus properly, that's why when we go swimming using goggles, our surroundings are much clearer than without. So my question is, how do waterproof ...
5
votes
1answer
400 views

Is it possible to get tethered focus and aperture control with any current DSLR?

I'm looking to get into some photography work and I had a couple questions. I'm quite an amateur at this, unfortunately, so I would appreciate any and all assistance! I want to be able to control the ...
0
votes
2answers
322 views

Why does this lens lose focus when you zoom in but not when you zoom out?

This is regarding the Sony 18-105 E-mount constant-aperture zoom. I took at photo at 18mm, focusing manually: I then zoomed to 105mm, and took another photo, keeping the same focus: Notice that ...
0
votes
1answer
126 views

1/30 shutter speed with film camera

If you take a photo with a 1/30 shutter speed, but the objects in the photo were not moving, will the picture appear blurry? Or will they appear clear?
0
votes
1answer
138 views

When should I consider an image sharp? [duplicate]

Recently I am worried about the functionality of my Pentax K-50, i.e. I am not able anymore to get real sharp images. Thus my question arose, what I should see as "sharp". So I took several pictures ...
0
votes
2answers
132 views

How can I focus on the moon [duplicate]

I'm technically a beginner when it comes to anything other than point and shoot photography so I apologise if I don't explain myself clearly. I have a Pentax Q with an 85-200mm K lens, I'm using a Q ...
1
vote
2answers
318 views

How does auto focus tracking work in DSLRs

I thought auto focus tracking comes from the computation of image on the image sensor when I was using GF1, a MILC. The auto focus tracking was good. However when I use canon 6D, a DSLR the auto focus ...
11
votes
2answers
414 views

Does focus breathing make a lens slower when close focusing?

I've heard that focal length of some lenses will become noticeably longer when focusing to a close distance, an effect called "focus breathing". Since f-number is focal length divided by diameter of ...
5
votes
2answers
2k views

Is it normal for focal length to change while focusing?

When I change the focus distance on my Pentax 55-300mm lens, the focal length appears to change. More specifically, the lens appears to zoom in as I focus towards the minimum focusing distance. This ...
0
votes
2answers
142 views

does depth of field travel with the focal plane?

for simplicity it can be assumed all of the following discussion is relative to a prime lens i recently learned about the technique of hyperfocal distance focusing. that is, by using the method to ...
6
votes
2answers
6k views

How can I take a photo with everything in focus with my DSLR?

I am quite new to DSLRs and one of the first things I noticed was the incredible focus points and depth that you can achieve. That is great in a lot of scenarios, but not in all. When filming a ...
2
votes
1answer
139 views

How does a focus ring bring a subject in or out of focus?

When you manually adjust your focus ring on the lens, what actually happens inside the lens? Is this changing simply the point at which the lens is focusing, so that anything at this distance away ...
0
votes
1answer
109 views

Noise reduction before or after deconvolution?

NR before or after sharpening has been asked and answered, but deconvolution is much more complicated than simple USM. Many deconvolution algorithms have their own methods of handling noise, so I'm ...
1
vote
1answer
91 views

Which mirrorless have the best live view for night photography?

Which mirrorless camera are best suited for focusing (manual is OK) and framing in low-light? I have an Olympus e-pm2, and I can't see anything on the LV when its really dark, and have to resort to ...
1
vote
2answers
308 views

Focus in night photography

Another question related to the Olympus OMD EM5. I bought this camera to replace my Nikon D90 and I'm very satisfied with it. However, I find very hard to do the focus at night. With the Nikon D90, ...
9
votes
2answers
6k views

How do I determine focus points in Adobe Lightroom?

Not sure if this is possible or not in Adobe Lightroom. I would like to see the focus points chosen by my Canon DSLR. I am guessing this is stored somewhere in the EXIF, but I'm not certain. I find ...
6
votes
3answers
1k views

I'm having trouble getting sharp pictures while shooting a concert from a press pass location

I am a bit of a noob when it comes to photography. But I recently got the opportunity to shoot John Mayer this past weekend in Wisconsin. Upon getting home, I noticed the pictures weren't as sharp ...
4
votes
1answer
145 views

Is the distance scale on a lens linear?

I have Nikon lenses with distance scales on them so I can set the lenses to the hyperfocal distance when I need. Say now the focal length is 28mm and the aperture is f/16. The corresponding ...