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30
votes
5answers
15k views

Is there any practical difference between saving at 300ppi or 72ppi?

I often see statements in discussions about web displayed image quality that go something like this: "I only upload pictures at 72 dpi and 1200 pixels on the long edge, so if someone copies and prints ...
45
votes
5answers
48k views

What is the “Rule of 600” in astrophotography?

This question mentions the "Rule of 600" for avoiding star-trails in astrophotography. What is this rule? How was it derived? How should it be applied?
14
votes
5answers
4k views

Lots of noise in my hockey pictures. What am I doing wrong?

I often take pictures of hockey players but they have a lot of noise and look very bad. I guess my lens doesn't have a big enough aperture, but I'd like to know what I could do to take better shots. I ...
36
votes
5answers
147k views

How do I calculate the distance of an object in a photo?

If I took a picture of a windmill on the horizon — given that I know the sensor size and the focal length of the lens and other factors to do with the shot — could I calculate how far away an object ...
9
votes
4answers
6k views

What is the relationship between ISO, aperture, and shutter speed?

I know digital cameras have ISO options, and that ISO is the camera's sensitivity to light, but if you set higher ISO then you can get a noisy image. I also know there are two other camera options, ...
61
votes
3answers
4k views

What should I pay attention to when choosing a tripod?

I am a novice in photography and my current camera (Sony alpha 230 kit) which I recently have bought is the first DSLR of mine. Soon I'd like to buy a tripod for it. Please advise me what should I ...
41
votes
7answers
6k views

What is “Hyperfocal Distance”?

I'd like a clear & easy-to-understand (especially for non-physics-types) explanation of what Hyperfocal Distance is, how it affects photographs, and what determines its value.
34
votes
6answers
44k views

What is one “stop”?

I always hear this term, e.g., I had to go down one stop Increasing X by Y raises Z by one stop I turned down the flash/the light two stops This lens/sensor/strobe/Photoshop tweak raises X by around ...
25
votes
1answer
5k views

Is it really better to shoot at full-stop ISOs?

The second half of this answer says Notice that I only shot full-stop ISO which is important with Canon DSLRs because the gain to obtain the 1/3 stops in between is applied in software by the ...
35
votes
15answers
9k views

What is the best way to clean the sensor on a interchangeable lens camera (mirrorless or digital SLR)?

I've got a couple of spots of dust on the sensor of my Canon 20D. A rocket blower isn't shifting them, and I'm ridiculously scared of some of the more direct methods for cleaning sensors — what ...
33
votes
4answers
21k views

What is a macro lens?

I've read a few threads on here that mention some elementary descriptions of macro lenses and found some marketing fluff in the box for my Canon about them as well, but being a complete novice I was ...
35
votes
4answers
8k views

How can I know what speed card to get for my camera?

Cameras rarely specify exactly what speed cards you should be using in them - I just checked the manual for my DSLR, and all it says is to use an SDHD card, and a "high speed" card should be used for ...
11
votes
3answers
67k 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 appearance of depth that you can achieve. That is great in a lot of scenarios, but not in all. When ...
65
votes
4answers
147k views

What does f-stop mean?

What does f-stop mean? Is it the same thing when people say "2 stops" for example?
66
votes
7answers
18k views

How is ISO implemented in digital cameras?

If I change the ISO settings on my camera, obviously the gain of the system is increased, amplifying the signal from the sensor. What's not clear to me is where the amplification takes place. I see ...
8
votes
4answers
2k views

Why did manufacturers stop including DOF scales on lenses?

Seriously why? I hate it and I hate memorizing it or check my phone app for the depth of field of the current aperture. I find it so useful in old lenses. The DOF preview doesn't help that much ...
45
votes
3answers
9k views

What is the “Rule of Thirds”?

Please can someone explain the "Rule of Thirds"? What is it? What does it tell me? Why is it important? What can I do with it?
9
votes
4answers
2k views

What is the advantage of a lens with a curved focal plane?

In this answer it is noted that: many lenses intended specifically for portraits or fisheye lenses, are designed to have a spherical field of focus What advantages does having a spherical (or ...
62
votes
10answers
22k views

Are there reasons to use colour filters with digital cameras?

Digital photos can have colour filters applied after the fact by software, so are there any good reasons to use colour filters with a digital camera? As I understand it, the main reason for them ...
18
votes
7answers
47k views

How can I recover photo files from a memory card with a corrupt filesystem?

I know this is not specifically a photography issue but since many of us with prosumer/professional-level DLSRs use Compact Flash cards, it is bound to happen to others as well. I have a Sandisk 16GB ...
22
votes
6answers
4k views

Does the dpi number reported by camera in JPG have any meaning?

I have two cameras, a 6mpix Panasonic FZ8, and 14mpix Canon A2200. When I compare shots from two cameras, one of differences I notice is dpi number that camera reports in JPG info: FZ8 reports dpi=...
118
votes
7answers
8k views

How and why do you use an image histogram?

I realize that an image histogram is a graphical display of an images tonal distribution (i.e. horizontal darks to lights, vertical pixel distribution), but how does one really use it and why? I mean, ...
86
votes
4answers
12k views

What historic reasons are there for common aspect ratios?

The most common width to height ratio rates in the "old good" paper photography seems to be 3:2, which was adopted by today's DSLRs. Early (non-professional) digital cameras adopted 4:3 aspect ratio, ...
105
votes
5answers
6k views

What is RAW, technically?

From a technical perspective, what exactly is RAW and how does it differ from JPG or bitmap images? I'm not asking about the pros/cons versus another format, but rather what constitutes RAW format, ...
69
votes
11answers
12k views

Are there any downsides to using a good-quality UV filter?

Are there any real downsides to using a UV filter? I know that a poor quality UV filter can effect image quality ... but, assuming I use a good quality UV filter, will that actually be an issue? Is ...
44
votes
14answers
8k views

What are the pros and cons when shooting in RAW vs JPEG?

In general shooting in RAW format uses a lot more file storage than JPEG. What am I gaining when shooting RAW? Besides file size are there any downsides to shooting RAW?
33
votes
13answers
26k views

Should I buy a camera with kit lens, or body plus lens separately?

I am planning to buy a DSLR soon. Before I zero in on the model, I want to know whether it is advisable to buy a kit (body + 18-55 lens) or not? OR should I go for the camera-body and the lens ...
24
votes
4answers
3k views

Do smaller apertures provide more depth of field past the diffraction limit, even if peak sharpness suffers?

In Understanding Exposure (3rd edition, on page 48), Bryan Peterson has what might be called a rant against modern on-line conventional wisdom about diffraction limits. Answers on this web site are ...
25
votes
5answers
4k views

What is the shape of the focal plane?

This is something I just realised I don't entirely know the answer to, so I'm going to ask it here as I think it's interesting. In most non-scientific writing on depth of field, diagrams generally ...
13
votes
3answers
3k views

What is sync speed? [duplicate]

When referring to flash exposure, what does "max sync speed" mean?
3
votes
1answer
937 views

Pictures of surfers start in focus then go out of focus?

I was recently shooting some surfers after a session with my 7D and Tamron 18-270mm F/3.5-6.3 Di II VC PZD. I started shooting while he was in focus, then as he got to the main part of the maneuver ...
121
votes
7answers
12k 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 ...
68
votes
9answers
67k views

What is the 'Golden Ratio' and why is it better than the 'Rule of Thirds?'

Somebody recently told me that I will be able to compose more pleasing pictures if I use the Golden Ratio instead of the Rule of Thirds, and that the Rule of Thirds was an inferior way to compose ...
81
votes
8answers
35k views

Do fluorescent lighting and shutter speed create a problem with color cast?

I took a bunch of photos at my son's martial arts club using a D90 with a 50mm F1.8. The club is lit with overhead fluorescent lighting, and I was getting some weird results where some shots are "...
27
votes
5answers
28k views

How can I determine the minimum shutter speed to avoid blur from camera shake?

How can I determine the minimum shutter speed at which I can effectively avoid camera shake while hand-holding the camera?
69
votes
17answers
9k views

Where can I find reviews of lenses?

I want to check reviews when deciding to buy a lens. There are so many factors beyond what is written in the name. Where can I find such reviews? What information does each site cover? Which reviews ...
27
votes
8answers
12k views

How can I recover deleted photos from an SD Card?

My technophobe mother returned from a European trip to discover she'd erased all but 15 images from a nearly full 2GB card. As I am the computer guy in the family, she posted the card to me and asked ...
6
votes
3answers
7k views

Why do my photos look different in Photoshop/Lightroom vs Canon EOS utility/in camera?

I've recently been shooting in raw with my new 100mm usm is macro but I'm getting strange results in out of focus areas with bright colours in. I've used Lightroom for ages and not had any issues with ...
54
votes
23answers
40k views

How can I backup my RAW photos while travelling without Internet access?

This question seems similar to this one, but my needs are different : I shoot in RAW exclusively I'm looking for a 100% offline solution: while traveling, Internet won't be accessible the "laptop" ...
4
votes
2answers
3k views

Does wide angle equivalent in crop sensor skew image?

I see many posts on both this forum and elsewhere the discuss the use of a wide angle on a crop sensor. For example, they discuss how at 14mm lens is 14mm on a 35mm film or full frame, but with a 1....
30
votes
8answers
21k views

Technically, why is the out of focus area blurred more when using a bigger aperture?

I'm wondering, technically, why and how does the out of focus areas blur more when using a bigger aperture. I think it'd help a lot if I presented a problem that's been driving me nuts for a long time:...
30
votes
3answers
4k views

What is the meaning of “white balance”?

I would like to understand the term white balance. My camera has settings for white balance with the following options: Auto white balance Daylight Cloudy Shade Flash Incandescent lights White set1 / ...
38
votes
8answers
10k views

Why do people recommend 50mm or other prime lenses as starting lenses for learning photography?

I've seen quite a few people recommend the 50mm prime lenses, in particular the sub-$100 50mm/f1.8, as a starting lens for photographers (especially because they're likely to be using cameras with ...
18
votes
3answers
3k views

What is HDR photography?

What is HDR photography, and when might it be useful?
30
votes
2answers
24k views

What is T-number / T-stop?

Usually, when discussing aperture of a lens, F-stop and F-number are used for quantifying. But some photographers, and especially videographers, also mention T-stop. The concept and numbering used (e....
37
votes
5answers
6k views

What is the difference between a linear and a circular polarizer?

When I bought my polarizer, a friend told me that I should get a circular one, because the linear ones can mess with the autofocus. Is this true? What should each be used for?
28
votes
7answers
5k views

Is high ISO useful for photography?

I started photography sometime back, and always wondered when is high ISO handy in photography? Also can it be used to get any special effect in pictures? My camera has Max ISO of 800 but I see some ...
26
votes
2answers
4k views

Why use a small aperture when trying to see sensor dust?

Here and there I read of people who set their lens to a small aperture while testing their sensor cleanness, supposedly to get the best image of dust speckles. However, the image of the on-sensor dust ...
18
votes
3answers
43k views

Can you photograph the milky way with a full moon out?

Is it possible to photograph the milky way (or just any stars or stellar objects) when a full moon is out?
11
votes
4answers
16k views

How do zoom, magnification, and focal length relate?

Zoom lenses and cameras with superzooms are often sold with a times ("×") zoom number — like a 12x zoom or 30x zoom. The question How do I convert lens focal length (mm) to x-times optical zoom? ...

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