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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

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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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4answers
1k views

What's the difference between holding a half-pressed shutter button and pressing the AE lock?

As I have been looking around today the AE lock button is supposed to lock in the focus and exposure settings (aperture and shutter) so that the picture can be recomposed before taken. I also believe ...
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votes
2answers
874 views

Is it possible to Zone Focus with a DSLR?

I have a Canon 1000d. Is the zone focusing technique applicable in a DSLR? If yes, how do we do it?
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1answer
21k views

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

Recently I bought a Canon 60D and I am uncertain about when and how to use/activate the Al Focus and Al Servo functions. I understand the One Shot autofocus function for still subjects. You press ...
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2answers
654 views

How can I quickly tell without testing if my lens is parfocal or varifocal?

I have read a couple of related questions, but I am curious to find out if there is a list of parfocal/varifocal lenses out there. I'm most concerned with the lenses I have and I would like to know ...
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1answer
108 views

Which lenses show focus shift?

Some lenses, because of a design that includes uncorrected spherical aberration, shift their plane of focus backwards as the aperture is narrowed. This is most apparent at close focusing distances and ...
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2answers
188 views

Why do the Nikkor non-AI 135mm vs 50mm f/1.8 work differently when I look directly through the lens?

I recently purchased an old Nikkor 135 f/2.8 non-AI lens. Beautiful lens, but the closest focal distance is about five feet. I noticed that it will 'focus' at about 4 inches as well. If I hold the ...
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1answer
390 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 ...
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3answers
176 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 ...
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5answers
282 views

Should I refocus if I change the aperture in a DSLR?

The title pretty much says what I want to ask.
4
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5answers
852 views

How could I achieve stock quality sharpness?

I am using Canon 600d equipped with 18-55mm kit lens and also I bought 50mm 1.8. I am trying to take pin sharp pictures to upload them for sale.I am shooting still objects and models time to time. I ...
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4answers
229 views

Doubt about focusing in the lens?

I usually find after blowing out my pic in computer that at one point (where I wished to focus) image is very sharp, then as I inspect the picture I see that some more part of the image either ...
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2answers
675 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 ...
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2answers
162 views

What is the reference plane used when the minimum focus distance is measured?

Once you know the MFD (minimum focus distance) for a particular lens, is that the distance from the subject to the front of the lens or to the camera sensor?
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votes
4answers
1k 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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2answers
975 views

What is the meaning of having 9 focus points and how to see where they are?

Canon PowerShot SX210 IS is said to have 9 focus points. I haven't seen any setting which shows all those points on the screen or anywhere. How and what are those remaining 8 focus points used for? ...
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2answers
3k views

What does “Flat Field Focus” mean?

Looking at lenses, specifically sigma macro lenses, I noticed that it had a ""Flat Field" front lens element". What does this mean? And how is it different to the norm?
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3answers
309 views

how to focus with a ND filter

I've just bought a ND3 filter (-10 stops) and was looking for recommendations on how to focus the camera. Basically many recommendations are around focusing WITHOUT the filter, then switch to manual ...
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2answers
444 views

How can I achieve well focussed and sharp images at long focal lengths?

Well I guess this is a question every newbie asks. I have a Canon 550D with the 18-135mm kit lens. I was out on a small trip in a nearby town to take some good snaps with my DSLR. I know the lens ...
4
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3answers
177 views

How can I defocus part of an image in-camera separate from depth of field effects?

What physical tools (lenses/filters/etc) can be used to blur a part of an image whilst taking the photo. (I don't mean software filters in post-processing, and I want to blur selective areas ...
4
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4answers
603 views

How can I make close-by objects appear as if they were much bigger?

We all know the popular Tilt Shift technique that gives objects a "miniature" look, making them appear much smaller than they actually are. I'm wondering whether it's possible to achieve the opposite ...
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2answers
126 views

Light-field shots entirely in focus?

A light field camera can be used to make shots which can be truly refocused after the shot, however if I understand the technology correctly it would be just as easy to process the "image data" in ...
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1answer
167 views

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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1answer
133 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 ...
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3answers
517 views

How Does Focus Differ Above and Below Water?

While I am trying to figure out what I need for split-underwater photography, an interesting fact came to light: A lens focuses at different distances in air than underwater. How is the focus ...
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4answers
1k views

How to avoid soft image at longest focal length with telephoto zoom lens?

I have a Tamron 70 - 300mm lens. I have noticed that the best focus I can achieve at the 300mm setting is not as sharp as the focus I usually get at a lower setting. Is this a common problem? Is there ...
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5answers
329 views

How do I get more in focus when aperture is already quite small?

When doing a product shot like this, how do I get more in focus when the aperture is already so small. I don't want to get any smaller for the risk of introducing significant diffraction. Note the ...
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2answers
4k views

Do the issues with sharpness I am seeing require AF fine-tuning?

I own a nikon D7000 with 18-105 lens. I am not happy with sharpness I get with autofocus in portraits. I read about front/back focusing, but I am not sure whether my gear has this issue. Is this issue ...
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3answers
3k views

How do I take forced perspective photographs with a point & shoot camera?

My teenage son needs to take some forced perspective shots this weekend as part of a camping/hiking trip. He has a Panasonic DMC-FX01 point and shoot camera. He wants to be able to hold up something ...
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2answers
637 views

What might make focus points blurred/gone from viewfinder on Canon T2i after cleaning?

The red lights are all but lost in my T2i now....barely a haze of a blur. The focus points work fine, and I get the audible beep, but I have to check my focus point on the back before shooting and I'm ...
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4answers
33k views

How can I fix an out-of-focus blurred photo in Photoshop?

How can I fix this picture? Somebody else took this picture and well he wasn't able to do it very well, and it's blurred. I have photoshop
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1answer
107 views

Why is it harder to focus using LiveView?

I have a Canon EOS 650D with 18-135 f/3.5-5.6 IS STM. When shooting in LiveView, I find it harder to achieve focus when it's in the dark, and sometimes it can not lock focus despite my touching the ...
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1answer
2k views

Nikon D5100 Focusing Issue

The issue I have had is where the camera tries to focus and cannot focus. It just zooms in and out constantly and no matter what I do it will not focus and fire. The only way I have found around this ...
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2answers
725 views

All my photos were blurry

I recently did a shoot of a baby and my 6 year old son, and I got some fantastic shots that were super sharp. I then did another shoot of a 6 year old and toddler and every single photo was slightly ...
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3answers
2k views

Is there a webcam that can focus to infinity, for time-lapse landscapes?

Does anyone here know of a webcam (at least 720p) that has the ability to focus to infinity? At least one webcam I know of (Logitech C910) doesn't allow that. I would like to use it for time lapse ...
3
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1answer
102 views

Do lenses have focal planes or focal spheres/ellipsoids?

The title says it pretty much all. I'm asking this because I find myself always using the focus point in the center, and after I focused, I rotate my camera to make the framing right. However, if ...
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3answers
253 views

Do focus area modes matter if shooting in manual focus?

It seems my camera lets me change the focus area modes (e.g wide, center or spot) even when I am shooting in manual focus so I am trying to understand if area modes matter even if the camera is in ...
3
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1answer
978 views

Taking pictures with fixed/full focus camera

I have got a fixed focus, 5 MP camera with 3.3mm focal length (not sure what it means) on my phone. I want to know what's the best way to take pictures with since it's missing auto-focus feature. Is ...
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2answers
469 views

How To Fix Badly Functioning Shutter Release-Button?

I have a compact Pentax OptionM10 which I bought in 2006 and sometimes shutter-release button works only when pressing it on edge and under specific angle, but mostly as I apply little pressure which ...
3
votes
1answer
2k views

What settings affect how the focus points are displayed for my 7D?

My Canon 7d is about 2 months old. I used it for a shoot in DC, and it just isn't behaving as expected. When I try to focus, I get little black boxes in the focus frame. They used to be black, with ...
3
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1answer
132 views

Does lens focus affect the appearance of sensor dust?

I know that aperture affects the appearance of dust on a camera's sensor (or, technically, the filter in front of the sensor), but does focus matter at all? Since the dust is behind the lens, I ...
3
votes
1answer
464 views

Why does my Canon 1000D focus only on the bottom part of an image?

I had it checked in case it needed repair, but they said they could not find a problem with it. I really need help on this one. [the process] I turn the camera on, select M mode, select the top ...
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0answers
68 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 ...
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4answers
2k views

How do Canon 600D and 650D compare with respect to focus points types?

My photographic style is action, and according to a website that I read I need at least 9 focus points to get better photos. I'm considering getting a Canon EOS 650D, but it turns out that it has ...
2
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2answers
223 views

Why doesn't pixel peeping with magnified Live View give the sharpest possible image?

I've seen this comment (most recently in this question), or similar, in several answers here on photo.SE: "Pixel peeped images aren't likely to look sharp". Why is that? It would seem to me that if ...
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3answers
357 views

How to correctly focus on the background person in a shot?

I tried to take some portraits of my sister-in and her fiance earlier in a sunny, green park. I took a few pictures where the fiance is closest to me but turning to look at his wife-to-be who is ...
2
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2answers
367 views

How can I find which lenses have “Continuous manual focus”?

Canon lenses with USM auto focus can be called "continuous manual focus" (at least some). By this I mean that you can override the AF without switching it off. I've found this very handy, and I often ...
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2answers
524 views

What is the difference Focus mode and AF-Area mode?

I am using Nikon D5100. To shoot a subject which is: Stationary: we can set AF-area mode to Single Point AF we can set Focus mode to AF-S Moving: we can set AF-area mode to Dynamic-Area AF we can ...
2
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2answers
154 views

What would appear on polaroid film exposed without a lens?

I am trying to get a better understanding how lenses & focusing works. Let's say that I am standing in a completely dark room holding a unexposed polaroid film, and turn on a TV in the other ...
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2answers
2k views

How can I see photos on my PC as I shoot them?

I am trying to find out how to use manual zoom. Can I connect the camera to my laptop and see the images on PC as I shoot them? I have a Canon 550D Rebel 2Ti. Do I need any special cables for this?