Alley in Pisa, Italy

by Lars Kotthoff

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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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3answers
203 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 ...
2
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1answer
361 views

Why do some lenses focus past infinity?

On the kit 18-55 lens that came with my Nikon D5100 I have noticed that when trying to focus on infinity for shots in dark conditions (star-trails, etc) the lense tends to move past infinity out of ...
5
votes
3answers
623 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 ...
2
votes
2answers
761 views

What is the difference between depth of field and focal plane?

I would like to know how to address the difference between them and how relates to each other.
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vote
1answer
98 views

Correct aperture to manage precisely blur and focus zones

There is something that bugs me about aperture... I understood that aperture will influence my picture on both light and focus zone. Now when taking a picture, I find it difficult to know precisely ...
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2answers
151 views

How do I get the entire landscape in focus? [duplicate]

According to this calculator at 16mm, my hyperfocal distance is at 0.7m at f/11. So on the safe side, if I wanted to make sure the scenic background is tack sharp I would focus at 1m or so. But now ...
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votes
3answers
489 views

Canon 70-200mm F4 L USM IS Focus Issues Photo All Soft?

Focus Issues Bought myself a used Canon 70-200mm F4 L USM IS Lens but as yet I've not achieved a single Sharp image list of various settings tried attempts so far and still no joy very frustrating. I ...
0
votes
1answer
62 views

Can I remove the tiny amount of wiggle in the focus ring of my brand new lens?

I just purchased a Samyang 24mm T1.5 lens and the focus ring is not 100% solid and smooth, there is a tiny amount of give in the vertical direction (perpindicular to the horizontal direction the ring ...
3
votes
5answers
251 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 ...
4
votes
5answers
714 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 ...
4
votes
3answers
162 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 ...
2
votes
3answers
285 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 ...
4
votes
3answers
369 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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3answers
5k views

What does infinity focus mean and when should I use it?

All my lens have focus ring where at the end there's an infinity symbol. What does that mean? If I'm taking landscape shot and what everything from near to far to be in focus, do I use infinity? Or am ...
5
votes
2answers
526 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 ...
6
votes
1answer
346 views

When focusing at max zoom, focus is lost after zooming out. Is that normal?

On my Canon kit lens, I could completely zoom in, focus on the object and then zoom out to take the picture with the object still in focus. Now I have a Sigma 18-200mm (with a Canon 600D) and that ...
3
votes
1answer
1k 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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4answers
20k 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
4
votes
1answer
530 views

Do all telephoto zoom lenses backfocus on the wide angle end?

I’ve just gone through a round of testing with two telephoto zooms, on two different cameras, and both appear to have significant back focus issues at the 70mm end. I just had the Nikon 70-200 f/2.8 ...
4
votes
2answers
2k views

What is the effect of the number of cross-type focus points on sharp focus?

Canon claims that EOS 6D has special capability to focus in low light, but it has only one cross-type sensor and overall only 11 focus points. Does only one cross-type focus point in the Canon EOS 6D ...
1
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2answers
333 views

What does it mean for a telecentric lens to be focused to infinity?

I have a question about a telecentric lens Ive been studying (for physics research!) and was wondering if you guys could help clear some cobwebs in my head. For starters, I am simplifying the TC lens ...
6
votes
1answer
615 views

What do orange AF points mean on a Canon DSLR?

I recently bought a Canon 7D and Ive noticed that occasionally the AF points are orange. What conditions cause this? It seems like it is a warning of some sort. Usually when the camera focuses on a ...
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2answers
136 views

What happens when you turn the objective

What happens when a photographer with an old photograph machine turns the objective clockwise or counter-clockwise? Is the lens turned too? Or does it change lens? I'm studying optics right now and ...
2
votes
2answers
228 views

Canon 50mm f/1.2 focus shift not seen yet

I know that this lens is known to exhibits focus shift if the object is less than 4 feet away within the range f/2-f/4. However, I've done quite a lot of close-up photography (mostly flowers), ...
3
votes
2answers
3k 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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0answers
30 views

How do smartphone cameras focus? [duplicate]

I'm curious, when I focus my DSLR or my pocket camera the lens moves back and forth changing the distance from the sensor. Does this really happen inside my smartphone?
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votes
2answers
1k views

How can I get better results when manually focusing with my Nikon D7000?

For some reason I seem to have problems getting consistently well focused photographs. They are not always crystal sharp and this frustrates me. I know if I set the camera to auto, they are always ...
2
votes
5answers
201 views

Aperture priority mode in high speed lens while photographing more than one person

I use 50mm f/1.8 lens(with Canon T3i) for portraiture. It's quite easy when only one subject is involved :Open the aperture wide, focus on the eyes(most of the times) and you get a nice portrait. How ...
3
votes
1answer
129 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 ...
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votes
4answers
2k views

How does a camera without hardware autofocus focus?

For e.g. an Apple external Firewire iSight does not have hardware autofocus. So how does it focus? Related questions: Does it focus to infinity? Does that mean it needs a "longer" minimum distance ...
8
votes
5answers
1k views

Should both eyes be focused in a portrait?

I'm a hobby photographer, and I've just picked up "rules of thumb" and "tips&tricks" here and there. I have a 50mm f1.4, and I love it. But due to the extreme shallow depth of field (at f1.4), I ...
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2answers
180 views

How can I take better pictures in theatre fog?

I am taking still and video photography for a film production. It is set inside a theatre that is filled with light fog. I somehow can't get sharp focus and because of the low light I can't up the ...
5
votes
2answers
183 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 ...
2
votes
2answers
226 views

Automatic vs Manual Focus [duplicate]

Possible Duplicate: When is manual focus better than autofocus? Perhaps this question has been asked before. I understand that in some cases, automatic focus cannot be used, for example, ...
8
votes
2answers
653 views

How can I “focus peak” a photograph?

Does an application exist where I can input an image and then the application indicates what parts of the image are in focus? I imagine it as a sort of post-process focus peaking.
13
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1answer
11k 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 ...
6
votes
2answers
3k 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
553 views

Is it possible to get bokeh in cellphone photos?

I have wondered how to get some parts of the image out of focus when using smartphone cameras (or if it can even be done). Recently found out about the concept of bokeh, and am interested in ...
2
votes
2answers
902 views

How to calculate the size of the image circle at infinity focus?

How can I determine the diameter of the image circle (i.e. the diagonal size of CCD required to fully utilise a telescope's optics) at near-infinity focus? I have looked around online and found this ...
3
votes
2answers
2k 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?
11
votes
4answers
2k views

In food photography (using a nifty fifty lens) how can I make my food shot more in focus and not blurry?

I've recently purchased a "nifty fifty" lens for my food photography. I've noticed that when I'm taking photos of my food, I just can't seem to get the focus down. For example, when I get my shot ...
8
votes
5answers
491 views

Heavy colour saturation on night photos with new lens? Is this normal

I have a Canon 550D and bought a Sigma 17-70mm lens to upgrade from the 18-55mm lens kit. I decided to go out and try the new lens with some night shots. To be honest, the results were bad. I used a ...
4
votes
1answer
157 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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vote
0answers
85 views

Tips to manually focus sharply with viewfinder? [duplicate]

Possible Duplicate: How does one get manual focus right with a fast-aperture lens? I feel difficult to manually focus via the view finder because of its small size.Its seems to be in good ...
2
votes
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
votes
2answers
374 views

Why is my lens focusing sound lounder than before?

I'm new to DSLR camera. I didn't mount a lens properly. The camera still allowed me to take photos, so I didn't notice the error. After I had been using it for 10 minutes I noticed my error and ...
3
votes
1answer
379 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 ...
8
votes
4answers
4k views

What is the best auto-focus mode to use for bird photography?

Consider the image below: How would the shot be focused here? Using Auto-focus or manual? If there was a cluttered background, will auto focus detect the small bird and sharply focus on it?If manual ...
8
votes
3answers
1k views

Easier ways to pre focus a distance on a lens without manual focusing meter?

In applying zone focus(focusing at particular distance in advance, before the subject comes in) to shoot a bike that will come into frame, how do I correctly focus at a particular distance with a lens ...
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vote
2answers
339 views

Is there a way to use phase detection AF with live view on a Canon EOS camera?

On any of the EOS xx(x)D model that has the live view function, can the camera make focus using the AF collimators (instead of using contrast detection), as it's possible on the old Nikon D300 ? If ...