83

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 ...


60

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 ...


58

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 ...


47

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 ...


39

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 ...


33

"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 ...


29

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 ...


28

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

The reasons to have difference in size can be (and most of them are related to image compression): Amount of details in the image. Save flat colour image and another with several colours and you will see the difference Number of colours. Related to above, but if you have more colours and lossy compression you may have bigger image (as size) Level of JPEG ...


26

As with many things, the end quality depends on the weakest link. Because most cameras are quite good, even cheap ones (even from mobile phones), the weakest link is mostly the person behind the camera. When learning some theory and practice, photographers can work around some pitfalls of cameras, but also knowing the shortcomings of a camera. When that ...


25

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.


25

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 ...


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

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

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 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 ...


21

For these two photos: as shown by ImageMagick's identify, the bird is JPEG quality 100 and the llamas are JPEG quality 92). This alone would be enough to explain the size difference (the other factor, chroma-subsampling, is the same in both pictures). To put things in perspective, a test picture, exported with various quality settings (all other settings, ...


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 ...


20

EDIT: This answer was posted before I knew that the files had increased in size by around 9 KiB (9055 bytes for the 256×256 image, 9612 KiB for the 512×512 image). In all likelihood, when you first rotated the image, Windows Picture Viewer did one (or both) of the following things: Added an EXIF tag that was not in the original JPEG image (perhaps the ...


19

DXOMark primary "scores" are utterly useless. IGNORE THEM. It is a futile effort to try and reduce a complex entity such as a DSLR to a single, scalar number that tells you everything about it. It's a fallacy. There are too many factors to consider, and which factors are most important for a given photographer differ. A single score entirely defeats the ...


19

Just because the image is mostly black doesn't mean the scene is dark. With a flash positioned on the left pointing at the subject (he's facing the flash) and a black backdrop you could possibly even pull this off in daylight. Start with a low ISO, a middle of the road aperture and the sync speed for shutter speed (probably 1/200th or 1/250th). The point ...


19

A great deal here depends on when you (generally) take pictures. In particular, with bright light, a smaller sensor makes little or no difference in quality. As the light level drops, however, a large sensor (generally) gains a greater advantage. So, if you're mostly taking pictures of the view from a mountain top in broad daylight, chances are that the ...


18

No. This is a wrong approach. File size in pixels, yes, has something to do with the final weight, but it is not the only factor. Make a test. Take a completely white file of the same 2400x600px, and save it as JPG. Now take a photo of a forest (same 2400x600px) with lots of details and save it. This file will be larger using the same compression settings....


17

Ironically, I just did the math for this in another thread. Image quality is a convolution of all imaging system factors. The resolution of the lens or the resolution of the sensor are not independent factors...they are factors that convolve to produce the final "system resolution". If we use your two cameras as examples, we can calculate the resolutions of ...


17

Going from JPG (which is a lossy format) to any lossless one (like PNG) does not. Going from any format to a lossy one, yes, including JPG to JPG. It could be too little to notice, and using the same compression ratio loses a lot less on the second saving than on the first one, but yes, it is cumulative. But beware... Some image formats store more ...


17

There is no absolute standard, nor is there any standard that is generally applicable or generally accepted. There are certainly certain situations where specific systems are used — your example list could be one. Or you could use this: Crucially — see the discussion in the comments below! — any one-dimensional scale can't possibly include every important ...


17

There are no standards as much of it is subjective. Even though I consider myself to be very rigorous, I find that there is a drift over time. This the intention of my rating system: The 3-star mark is what I reserve for a perfect photo: The subject is sharp and no major area is under or over-exposed. Framing is such that the subject is shown clearly ...


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