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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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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 ...
2
votes
2answers
377 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 ...
2
votes
2answers
773 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.
2
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2answers
228 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, ...
2
votes
1answer
395 views

Why is my Canon Powershot A1100 focusing only on the bottom part of scenes?

I've been using a Canon PowerShot A1100 IS camera for the past year and it had been working just fine until I decided to change its settings. After I had serious trouble with it, I reset the settings ...
2
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1answer
71 views

Compensating for 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 ...
2
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2answers
214 views

What factors determine the size of focus step done with remote shooting?

When a DSLR camera is used for remote shooting, corresponding software usually provides very simple way to change focus position: small, medium and large steps forward or backward. This is how it ...
2
votes
1answer
2k views

How do I select a focus point on the Nikon D5000?

My Nikon D5000 has 11 selectable focus points but shamefully I don't know how to choose another point other than the center point. How can I do this? Am I misunderstanding concepts?
2
votes
2answers
908 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 ...
2
votes
1answer
489 views

Wide angle + macro converter

I just bought an "0.43x Super Wide Angle" converter. The converter consist of two separate parts, a wide angle (W) part and a macro (M) part. The full converter screws on the filter thread of my Sigma ...
2
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
1answer
179 views

What types of rangefinders are there and what are the differences between them?

I have watched videos on YouTube showing the view through the M9 viewfinder, and it appears that only a small window in the middle allows you to focus. However, I once tried out an old Voigtländer ...
2
votes
1answer
81 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 ...
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vote
4answers
279 views

Why can't my DSLR with kit lens focus on objects close to the lens?

I have a Nikon D5200 with the 18-105 kit lens. I cannot focus the objects which are 15-20 cm away from the lens. Can anyone tell me how to manipulate the settings so that i can focus those objects? ...
1
vote
2answers
341 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 ...
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vote
4answers
448 views

Autofocus performance of different brands at night

Are there huge differences in the ability to focus in low light between different brands and models? I have a Pentax Kx with a Sigma 30mm 1.4. My problem is, that the camera's autofocus does not work ...
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2answers
97 views

What determines the sharp parts in an image: the DoF or the focus point?

I am a little bit confused between depth of field (DoF) and focus points. Which of them is responsible for making part of the image sharp?
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vote
3answers
151 views

Why can't I get a sharp macro image when shooting handheld, even with IS?

These days I shoot macro handheld, using the focus and recompose technique. I used AF-one shot. I used a Canon 100mm 2.8 on my Canon 550D. My shutter speed was 1/100s, but it was quite frustrating ...
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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 ...
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vote
2answers
105 views

How to focus manually with a Nikkor AF-S DX VR 50-200mm f/4-5.6G zoom lens?

I have a Nikon D3100, for which I just bought a Nikkor AF-S DX VR 50-200mm f/4-5.6G zoom lens. This is a CPU lens and works very nicely in auto-mode, i.e. when you let the camera set the focus. ...
1
vote
2answers
240 views

Help me understand effective f-number

If I set a lens to, say, f/2 but my focus is set to its closest point, my effective f-number won't be f/2 any more but it will be higher by a factor that depends on focal length, image magnification ...
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vote
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 ...
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3answers
442 views

What techniques are there to get focus and/or lock exposure other than center, half-press, and recompose?

The way I shoot is this: turn the camera so that the subject is in the middle of the viewfinder, where my center point is, press the shutter half way, the camera now focuses the lens on the subject ...
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2answers
827 views

Why does focusing feel less accurate to me on the Canon 600D than the 60D?

Is there a substantial (or minor) difference in the focusing in 60D and 600D. I tried both in a showroom and felt (I may be wrong) that there was a difference. The focusing I felt was very quick and ...
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3answers
89 views

Precise focus information in metadata

I am trying to get the precise focal length used for a stack of photographs taken with various focal length. See the following link. My problem is that even if the photographs are obviously focusing ...
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1answer
124 views

Nikon D3000 Blurry Pictures. Focus Issue?

Here are two examples: Both pictures are in NEF format here. The pictures have not been modified in any way except except for being resized and converted to PNG. Just for kicks (and to prove I'm ...
1
vote
1answer
127 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, ...
1
vote
1answer
77 views

Is there a way to avoid focus searching? [duplicate]

While using my camera in a relatively low light scenario I noticed some shots I missed because my camera was struggling to focus. I use a Nikon D7100 and noticed that the AF assist light only came on ...
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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 ...
1
vote
2answers
336 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 ...
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vote
2answers
172 views

How can I increase the amount of 'keepers' from my Nikkor 50mm 1.8D

I have been using this lens for a while, mostly for portraits and have noticed that for some reason the outdoor pictures where I most likely had to quickly compose and take the shot have had something ...
1
vote
2answers
321 views

Why does my Samsung NX1000 zoom way in when manually focusing?

I bought a Samsung NX1000 this week, and I have the 20-50mm lens. However when I put it on manual focus, the picture keeps jumping from standard zoom to "mega zoom" — it zooms a lot further in then ...
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3answers
387 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 ...
1
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1answer
133 views

How can i get AF confirmation working with Samyang 500mm f/6.3 with dandelion chip?

I've put a dandelion chip (4th gen) on my Samyang 500mm f/6.3. I shoot a Canon 6D by the way. So, that's cool now I've set the chip to return f/6.3 and I can get a correctly exposed LiveView, EXIF ...
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2answers
72 views

Science Fair Project Relating focus to pinhole size

I am doing a science fair project in which i want to see how the size of a pinhole effects the light diameter, and i would like to also relate this to focus and focal point. How would i do this?
1
vote
2answers
152 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 ...
1
vote
1answer
76 views

Tricking compact's camera autofocus

I'm trying to get some bokeh using a compact (almost premium) camera, a Nikon Coolpix p300 (although the question is general). Since the camera hasn't got a manual focus option, I'm trying to use the ...
1
vote
1answer
241 views

Does autofocus work with the Pentax K10D and Tamron 18-250mm?

Hallo; does autofocus actually work with the Pentax K10D and Tamron 18-250mm? If so,how good/fast is it?
1
vote
1answer
244 views

Is it possible to improve focus with the Samsung Galaxy S?

Samsung Galaxy S video and photo quality is pretty good but only when fully focused. The focus is getting lost very easly and it become blurred. Are there any ways to increase focus quality and speed? ...
1
vote
1answer
159 views

Why do I see different focuspoint in my DSLR's viewfinder and screen with old lenses?

I've had an old completely analog Praktika SLR with a set of lenses for a few years now. The camera and lenses are still quite good but I wanted to go digital. Having recently acquired a Nikon D5200, ...
1
vote
1answer
192 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 ...
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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?
1
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 ...
1
vote
0answers
380 views

How do you focus in the dark? [duplicate]

Possible Duplicate: How to focus in complete darkness When I take a photo of landscape (or something beyond the range of the focus assistance lamp) at night, it's hard to see when the ...
0
votes
2answers
4k views

Best Focus Settings and Methods for DSLR Video?

Camera Body: Canon T2i Lens: Canon EF-S 18-55mm f/3.5-5.6 IS SD Card: Transcend 16GB, Class 10 Stabilization: Handheld/tripod (maybe) Question: I'm going on vacation this weekend and would like to ...
0
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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 ...
0
votes
2answers
87 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 ...
0
votes
1answer
143 views

Canon 50mm F1.4 focus problems

I've had this lens for a couple of years, but am really struggling to get sharp pictures now. I've tried it on a 400D and a 7D and both show the same results. I had the problem with it getting stuck ...
0
votes
1answer
130 views

What is the purpose of Quick Mode focusing in live view?

What is the purpose of Quick Mode (found on some Canon DSLRs) focusing in live view? To me it seems like a bad blend between live view and viewfinder mode that really doesn't cut it. Of course it's a ...
0
votes
2answers
160 views

how to select a proper aperture for 50mm portrait lens? [duplicate]

I am using 50 mm 1.8 potrait lens with my canon 600D. But when i take a portrait with f1.8 on Av mode using autofocus, only subjects eyes are sharp and rest of the other face is slightly blurry. How ...