What should I look for besides pixel density/count when choosing a smartphone with a good camera? [closed]

Question

I have read in many places online that a good smartphone camera doesn't solely depend on the amount of pixels. So, what else should I look in order to choose a good camera in a smartphone?

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Sorry, to the community at the outset for not being clear to the specifications of my requirements; I was taking a photo of two rainbow(a very rare thing) at the time prior to twilight. I had Nokia 6700c(5 MP) & took the photo but unfortunately all but the rainbows were in the photo. I then took the photo using my laptop's front camera(HP 2000) & though it was only 2 MP, it could take the image of the rainbow but only a single one with fine grains around it(which after googling, I saw it as noise; thanks to @feetwet). So, 2MP performed better than 5MP! But still the photo was not clear enough to catch the image of second rainbow. Also, I never could take the image of a distant plane neither by the phone nor by my laptop; no matter at what proximity the plane was, it always appeared as dot in the photo but the laptop still performed well w.r.t. the phone. I like to take the images of clouds, sky, halos of moon, planes, birds hovering etc... I only wanted to know why my laptop performed better than my phone despite my phone being superior w.r.t. pixels. Also, I do want to know what to use in order to remove those grains or noise & take the image of rainbow at twilight or prior to that; for all that, is pixel important or something else?

Answer 1

The general list of features you should consider has been pretty well covered by others, I will tackle this from a slightly different angle:

Just how important is the camera to you?

Is it more or less important than the phone features, or the phone OS for example? There are options that prioritize the camera over the phone, like the Samsung Galaxy S4 Zoom. It is more of a camera that happens to be a phone than a phone that comes with a camera. The zoom gives you 10x optical zoom and a friend of mine that attended conferences a lot and blogged absolutely loved it. Personally, I found it a little too bulky and I would prioritize other things.

If budget is no concern, but you don't want a dedicated camera, you can have your normal phone camera for most things, and then get a QX100 or similar (QX Series) from Sony that gives you a Carl Zeiss lens and separate sensor independent from your phone.

Then you get clever attempts to make digital zoom not suck, like the Lumia 1020, which gives you a 2.7x zoom equivalent at 5 megapixels. For that though, you have to be OK with Windows OS versus Android or iOS.

Finally, I am loathe to point you at something that is not available at the time of writing (but it is expected within the next month or so), but the Asus Zenfone Zoom seems like it may hit a sweetspot - 3x optical zoom, still slim, Image Stabilisation support, Android OS, and more.

Answer 2

General guidance for buying cameras alone can be applied here. There are several important aspects:

• Pixels
  This is the resolution that the image sensor is capable of capturing. The greater the number, the more detail you'll get in your image. This does, however, combine with the next point:
• Sensor size
  The bigger the sensor, the bigger the pixels can be. And the bigger the pixels, the better your image quality. 'Nuff said.
• Zoom type
  Only one part of zoom, this. Look at optical vs. digital zoom - in short, optical zoom uses lenses to make the image look closer to the sensor, whereas digital simply scales up the image. Optical results in better quality because the image size stays the same, but it's generally bulky because of the need for a moving lens. Digital on the other hand scales everything up, losing detail and resolution and also making noise more apparent. Most phones use digital simply because they don't have room to include a zoom lens in their cameras.
• Zoom range
  This is the number like that comes in the format "8x digital zoom" or "32x optical zoom". The bigger the number, the further away you can sense things from. Take care, though - big digital zooms often result in pixelated images. With a phone, you can often simply get closer to your subject - an 8x is often adequate.

Answer 3

Given your description of the shortcomings of your current camera, you want a camera with a large sensor (improved low-light performance and less "noise"), a very large optical zoom range, and a very wide wide-angle view.

Measured in degrees, you need an 84˚ field of view (or larger) for a rainbow, and a 5˚ field of view (or smaller) for a distant airplane.

Measured in "35mm equivalent focal length", you need a focal length of 19mm (or shorter) for a rainbow, and 500mm focal length (or longer) for a distant airplane.

Zoom factor (numbers like "10x" or "4x") is meaningless without knowing the focal length/field of view of one end of the zoom range. You need at least a 25x optical zoom range; given that manufacturers usually bias their zoom range towards the telephoto end rather than the wide end, you may need to go much higher -- this will get expensive, and image quality at the extreme ends of the zoom range will be poor.

Pixel count is generally one of the least important criteria when selecting a camera. One of these two images was created with a 6 MP camera, while the other was created with a 10 MP camera and scaled down. Which do you think is which?