81

There are many characteristics which make better lenses better. The basic goal of a lens is to render an ideal replica of the framed scene, but because of the limitations of the real world, that's physically difficult. Lenses inevitably introduce optical artifacts not present in the scene itself. So, an important aspect is minimization of artifacts. Good ...


59

Rarity. There were only approximately 20 of these now out of production lenses ever made. When they were in production they sold for about $90,000 (US). Due to the time needed to grow the large fluorite crystal used in the 3rd element of the lens, once ordered they took about 18 months to produce. Autofocus Capability. These lenses include auto focus ...


57

Moiré is a form of aliasing whereby false patterns can be observed in an image. Imagine a lighthouse which sends a pulse of light every 5 seconds, and a camera (or other observer) which sees the lighthouse for three seconds and is then blocked from seeing it for three seconds: lighthouse: *....*....*....*....*....*....*....*... observer: ***...


55

This is based on a misunderstanding. Loss of quality happens only during the compression that is done when an image is saved as JPEG. But it doesn't matter whether it was edited or not. So: you will (with some very specific exceptions, see comments) lose quality if you open an image in an image editor and re-save it, even if you didn't make any edits. But ...


46

Does downloading an image off a website when WiFi is strong result in a higher quality image on your device? Signal quality does not usually affect the transmission of data that is sent, though it might result in incomplete transmission. However... Websites often send different data to mobile vs desktop. Some sites do use scripting to send different data ...


41

From a purely theoretical point of view: more megapixels good. People often talk about how high megapixel sensors were now outresolving most lenses, thus there was no point going higher unless using the very best glass. This is not always true. System resolution is the product of lens resolution and sensor resolution. Thus if you improve one, your system ...


36

This is most likely caused by entropy coding, which is the final lossless stage of JPEG compression, after the image data has been quantized to reduce its size. When a JPEG image is losslessly rotated, this final lossless encoding layer must be undone, the unpacked DCT coefficients shuffled around, and then the shuffled coefficients need to be entropy coded ...


35

The answer you found on Yahoo is mostly wrong. The basic statement (same as dpollitt's answer here) is correct — theoretically, image quality shouldn't degrade but a number of factors might make it worse. And the list of things that might go wrong is sound enough. But the mapping of symptoms to problems is very inaccurate. Point by point: One would be ...


32

In digital photography, the moiré effect stems from interference between fine detail in the scene, and the grid of sensels in the sensor. You can also get a moiré pattern when scaling a picture down for display -- in this case, the interference happens between the fine detail in the picture, and the grid of pixels in the display. Either way, you can get ...


32

"Better image quality." You use that phrase. When we say image quality in reference to comparing two lenses, we rarely are talking about anything with regard to which one is "... less dark and gives more vivid colors."¹ Those things are more a function of the light in the scene, the photographer's skill at seeing that light and capturing it while also ...


30

The size of files compressed with JPEG vary depending on the complexity of the image. Trying the control the file sizes the way you describe will result in highly variable perceived image quality. Consider the following options instead: The good-enough approach. Use a quality setting that you find acceptable, like 75. Compare the size of the result with ...


28

More than testing you should learn about your new lens. Although it is good to get some sanity checking first: Set up a flat target with sharp details that can cover the field-of-view of your lens. Set up your camera on a tripod pointing strait at the target. Repeatedly autofocus on your target and see if you can improve accuracy by manual focusing. If it ...


27

No. If you shoot in RAW, there is nothing lost. In fact, in RAW, the white balance you set in-camera is nothing but advisory information to the post-processing software. A different multiplier is applied differently to the red, green, and blue channels during RAW conversion depending on the setting, and if you're doing that conversion from a RAW file, you ...


27

The look you are going for is known as low key lighting. It is not necessary for the room to be dark. You just need to put enough light on your subject that there is a large enough difference between the shadows and the highlights. I took this self portrait by shooting into a mirror in a fully lit room. By using a good amount of flash power I could use a ...


27

No, your camera sensor is not bigger than your smartphone sensor, they are both about 1/2,5". The difference is that your Canon camera uses ancient sensor technology (more noise), smaller aperture (less light) and no sophisticated image processing, so no wonder it will produce inferior images in nearly all conditions, except when zooming in, thanks to its ...


25

one of my Facebook accounts seem to have lost a significant amount of resolution Facebook (and other social media sites) compress photos while storing/displaying. Considering the amount of data that gets uploaded in these sites, its difficult to argue against it. This link talks about how you can minimize that to a small extent (but that article is old and ...


24

Anytime you add something in the optical path you will lose quality. The quality you will lose depends on the filter quality, filter type and lighting conditions. Most filters are extremely susceptible to flare because they add a flat reflective surface and can take a great image and make it completely unusable. That does not mean you should never use a ...


24

What you're seeing is colors produced by the multiple layers of plastic you're looking through along with polarized light from either the plastic itself, the sky, or both. According to this page, the colors arise from constructive and destructive interference between the polarized sunlight passed through bifringent (double refracting) plastic windows.


24

I went ahead and repeated the experiment to see if I could figure out what's going on. Procedure I generated a random 256-by-256 pixel RGB image using the "Solid Noise" filter in GIMP (Filters > Render > Clouds > Solid Noise...) using the default settings (shown below): And the result: Then I saved the image as a JPEG using the default settings: Then I ...


24

you don't have to reproduce the algorithms that the camera is running to render your photo on the small display on the camera. This all depends on how much you value what is shown on the camera's LCD - it isn't any more "right" than any other algorithm. If you personally happen to like Sony's algorithm, then you may find it advantageous, although you can ...


23

I think you're going about this the wrong way. If you have 2GB of images at 4-5MB each, that's somewhere between 400 and 500 images. That's way too many. Even your close friends probably don't want to wade through all of that. Instead, go through and pick out the very best 10%. Or 5% or even 1%. Take some care and write a meaningful caption for each one. An ...


23

Absolutely not. You need to edit the file and re-save it as a JPEG in order to compound the effects of image compression. Just viewing it has no effect at all — if it did, all of the JPEGs on the web would "wear out" completely in a day or two at most.


23

No. Aliasing is result of sampling, taking discrete samples or readings of a signal, at a low enough frequency that the frequencies in the input signal are confused for other frequencies, such that they cannot be distinguished from each other. If film grain were aligned with regularity, their spatial frequency would create opportunities for aliasing, just ...


22

The type of lighting, the way the subject reflects light, presence of haze, the lens design and coatings and the dyes used in the sensor all have an influence on the vividness of colours in an image. But the major factor, which outweighs all of these by a significant margin, is how the image is processed. Either in camera or on a PC the saturation settings ...


22

The primary reasons for the differences in image quality between the two cameras are the settings and technique used to capture the image, not sensor technology. To get sharper images, increase ISO, increase shutter speed, and use shorter focal length. Choose appropriate aperture and exposure compensation. Use shutter half-press, and hold steady while ...


20

Regarding composition, it's important to judge all the things that are in the frame. Everything in the frame either hurts or adds to the picture. In this sample picture, the flower pot and glass pane give a clear hint that the photo is made on a window sill. While people do like to eat in a table near window, only few would consider window sill as a ...


20

There are so many variables here, it would be impossible to give you a precise answer. It depends entirely what you are wanting to do... The kit lens can, in many cases, give a satisfactory photograph, however there are two main areas in which the kit lens suffers in competition against a pro lens: Aperture. Kit lenses are slow. They are usually about ...


20

How viable are "photography templates" where a professional gives the exact settings to use in a specific set up...to allow noobs to produce high quality photos? That sounds a lot like the "scene" modes built into most cameras. The camera evaluates the scene and chooses settings using an algorithm designed to produce a nice photo. Having the camera do ...


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