8
votes
What is this bright squarish pattern that I'm getting in long exposure images?
It is a hot pixel.
The reason it makes that little checkerboard shaped mark is because of the way digital cameras use single luminance values for each pixel to create color information by filtering ...
- 175k
6
votes
Accepted
Does taking pictures with my iPhone 8's camera meet the required specifications for designing a book cover?
All versions of the iPhone 8 have a 12 MP rearward facing camera with a 4:3 aspect ratio. That figures to about 3000 pixels x 4000 pixels in vertical (portrait) orientation. That's more than enough to ...
- 175k
6
votes
Does having larger pixel pitch (more microns) makes camera brighter at night?
ISO should mean the amount of light that must be received by the sensor to provide a proper exposure. As such, it is independent of pixel size. The 6 micron pitch sensels will receive 36/16 times ...
- 1,904
5
votes
What is this bright squarish pattern that I'm getting in long exposure images?
That is a hot pixel, not something different. See Are hot pixels just one pixel? for some explanation, or What could cause this white speck in a blue sky? for an example where the pixel shows up as a ...
- 143k
5
votes
Number of pixels on longest side of email attachment?
There is no right answer. It's up to you how you compromise, considering the following:
3840x2160 is the highest resolution for consumer displays. This is known as 4K Ultra-HD and is not widely ...
- 103k
5
votes
Since larger pixels increase depth of field and sensitivity, why don't we have large sensors with a low number of pixels?
... why don't we just have big pixels (and thus large sensor surfaces, because we keep the number of pixels fixed)?
There are camera models with lower resolution sensors, but the reason they are made ...
- 26.9k
5
votes
What is the meaning of pixel size for sensors
The pixel size which is mentioned in the size is the size an actual physical pixel has on the sensor itself. So it gives the size the pixel takes in silicon on the sensor.
What you are talking is the ...
- 699
5
votes
Accepted
Image File Size Question
Your naive computation works on naive image formats (early BMP, TGA).
However, most popular image formats use some form of compression, which can be lossless or lossy, and in both cases, the achieved ...
- 20.6k
4
votes
Does higher resolution in an image imply more bits per pixel?
A pixel can be understood as a 3-dimensional thing.
A pixel holds information. How "deep" this information can be is the trick.
Pixel Depth
Here is a representation of one pixel. On the left,...
- 23.8k
4
votes
Accepted
Does higher resolution in an image imply more bits per pixel?
Image resolution (amount of pixels) and bit depth (bits per pixel) can be changed independently. Any combination of high/low resolution and more/less bits per pixel is possible.
Sometimes, however, ...
- 5,045
4
votes
Sensor pixel size "pixel area" any important?
That's just the nature of fractions. 5/4 (1.25) is the reciprocal of 4/5 (0.80).
1.25 - 1 = 0.25 = 25%
1 - 0.80 = 0.20 = 20%
5.95µ is 25% greater than 4.76µ
4.76µ is 20% smaller than 5.95µ
So whether ...
- 175k
4
votes
Image File Size Question
The reason is simple. The images are in PNG format, which implies lossless compression (like zip) of the data. Your calculations will be true if you store the image ...
- 11.4k
3
votes
Accepted
Large difference between number of image sensor pixels and pixels in the image from my iPhone
My iPhone 5S takes 8 megapixel images, specifically, 3264x2448 pixels. This is native size. This is speaking of still images, not the movie images which of course are 1920x1080 or 2 megapixels.
...
- 12.9k
3
votes
What are these purple pixels on my Canon 60D and how do I get rid of them?
It's near impossible to tell exactly what the spots in your picture are. It is fairly easy to look at them and eliminate what they are not: hot or dead pixels.
Due to the sharp outlines and well ...
- 175k
3
votes
Podcast Cover Art Help!
885x1024 sounds like your contact emailed the image to you and his email software/system has resized the image.
Ask them to zip the image file and send it again, or use an online service like dropbox ...
- 9,539
3
votes
Full well capacity
Both approaches are correct. At least as I understand what I think you are trying to say. I'm not sure, though, what you mean by, "(4 time bigger)".
Raw luminance values are monochromatic in the ...
- 175k
3
votes
Accepted
Is using image found on google (without watermark) and turning it into pixel art with some filter would be illegal?
DISCLAIMER: THIS IS NOT LEGAL ADVICE.
Not having a watermark does not put the image in the public domain and so you are using those images without permission to create another artwork.
This is called ...
- 103k
2
votes
What megapixel value is equivalent to which ISO film?
Depending a lot on the developer used as well.
35 mm Adox CMS 20II dev. in Adotech IV gives you a resolution of about 500 MPix!
http://www.adox.de/Photo/adox-films-2/cms-20-ii-adotech-ii/
With 510-...
2
votes
What are these purple pixels on my Canon 60D and how do I get rid of them?
These are irregular shapes and my guess is that they are not pixels, but drops of some purple liquid. If you set your camera to the cleaning mode, remove the lens and inspect your sensor with loupe ...
- 5,215
2
votes
is it possible to retrace back to the values of intensities that have been captured by the digital camera from the image's RGB values?
Only if you still have the original data from the raw file. You cannot normally derive the original monochromatic luminance values from each sensel (pixel well) on the sensor from the demosaiced data ...
- 175k
2
votes
What happens when pixels cover almost all the area of the sensor?
With conventional CMOS sensors the issue isn't so much the spacing between photosites (pixels). It's all of the circuitry on top of them (usually on the edges of each photosite) that blocks light from ...
- 175k
2
votes
poor image quality
it looks like a weird design on my bare skin that is green and my bf swears its a tattoo and it's not how can I prove its not a tattoo
Simple. Show him the area of skin. If it's not tatted or ...
- 20.5k
2
votes
Does higher resolution in an image imply more bits per pixel?
Not in common digital imaging terminology. Instead, we call bits-per-pixel bit depth.
Once unpacked from whatever compression format they were stored in, digital images are usually represented as ...
- 143k
2
votes
Accepted
Pixels and photodiodes
The pixels you get in a finished, camera-independent image file - a JPEG, TIFF, BMP, ...) file you get either from your camera or from your RAW processor software - are usually the results of multiple ...
- 7,182
2
votes
Since larger pixels increase depth of field and sensitivity, why don't we have large sensors with a low number of pixels?
The drawback is that if the sensor area is fixed, you have less pixels with increasing pixel size. Thus, the image resolution suffers. That's hardly what photographers want. Also, DoF depends on the ...
- 6,588
2
votes
Since larger pixels increase depth of field and sensitivity, why don't we have large sensors with a low number of pixels?
The DOF does not change based upon pixel size (surface area). It changes with the sensor size. This is due to a larger physical sensor area requiring less magnification for an equivalent output size. ...
- 14.7k
2
votes
What is a better pixel size for a scanner to use for showing photos only on screen 25um or 30um?
I assume your intent is to scan physical media, perhaps film X-rays, and display the results on a monitor?
The issue boils down to resolution :
Resolution of the physical media
Resolution of the ...
- 2,231
2
votes
What is the formula to upscale a photo?
I’ve been told to upscale my photo before getting it printed
It is a recommendation. You do not have to if you do not want to. The point, in reality, is if you actually know how a 100PPI image looks ...
- 23.8k
2
votes
Does having larger pixel pitch (more microns) makes camera brighter at night?
Sensors with large pixels are one possible way to make a camera usable at higher ISO settings without suffering from too much noise (this is the way eg the Sony A7s series and Nikon D3s/D4 do it). ...
- 7,182
2
votes
Does having larger pixel pitch (more microns) makes camera brighter at night?
The lens' aperture diameter (entrance pupil) determines how much light passes through the lens, and the lens' magnification (focal length) determines how spread out that light is; those two factors ...
- 14.7k
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