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For some reasons when I look at my first pictures from my camera (DSLR), they look stunning. I know it could be just psychological. Another friend told me that her camera was really good when she bought it fours years ago (10 MP), but now it is just ok. I see her P&S very blurry in indoors (almost like phone quality pictures).

A quick search yielded this yahoo answer, which is actually not bad. That answer can be summarized as: not really, but some things make image quality worse. Listed factors include:

  • Dust accumulation on the sensor (blamed for "resolution loss, pixels of false colors, noise, spots")
  • Worn-out moving parts leaving the sensor out of alignment ("focus images, blurry and distorted images")
  • Improper maintenance leading to "blown-out receptors on the sensor" (which lead to "blank spots on the image, false-color pixels and resolution loss")
  • Dust in the lens ("noisy, blurry and distorted images")
  • Scratched or destroyed lens coating ("distortion or false colors due to ultraviolet and infrared radiation reaching the sensor")

Is there any truth to it? What should I be careful for proper maintenance?

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See also Do sensors wear out? –  mattdm Nov 30 '11 at 13:47
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4 Answers

up vote 6 down vote accepted

Practically speaking, digital cameras do not lose quality over time.

Some factors can come into play such as:

  • Equipment can wear causing it to be out of spec
  • Environmental factors such as dirt, sand, dust, moisture can degrade quality
  • Heat or excessive use(causing heat) can cause all electronic devices to experience wear
  • Other regular use issues from dropping, lack of cleaning, etc

But overall, these things should hardly turn a great looking 10MP point and shoot camera into a 640X480 resolution cell phone.

Maintenance, is an entirely new question if you would like to ask or search for that.

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I'd add degrading electronics, leading eventually to dead pixels in the sensor, to that list. It's not just heat and excessive use doing that, it can happen even if the device is idle and in storage, though the process will take much longer in that case. –  jwenting Nov 30 '11 at 6:53
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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 dust accumulation on the sensor which leads to resolution loss, pixels of false colors, noise, spots.

This can definitely lead to distinctive dust spots. However, for there to be overall resolution loss, there'd have to be an even coating of dust, which seems unlikely. False colors and noise are unrelated.

Worn-out moving parts can lead to the sensor moving off its original position, which can lead to out of focus images, blurry and distorted images.

Mostly true, although the relevant parts should be pretty sturdy unless you smash the camera. But distorted isn't very likely. A loss of alignment could lead to uneven focus, where half the frame is in focus but the rest isn't, as with a tilt/shift lens (except without any control).

Improper maintenance can lead to blown-out receptors on the sensor, which can lead to blank spots on the image, false-color pixels and resolution loss.

This is just wrong. Stuck ("false-color") pixels are common, and can increase as a camera ages, but they're not generally due to improper maintenance — unless you're taking long-exposure pictures of the sun, and that case the damage is likely to be distinctive. "Resolution loss" isn't an issue here: if you have a 10 megapixel camera with an insanely-high 1000 dead pixels, that's only 0.01% of the resolution!

If you camera is a compact camera (lens not interchangeable) then dust might have accumulated inside the built-in lens, which can lead to noisy, blurry and distorted images.

This is more likely to lead to the lens getting jammed than to the problems described. In general, dust in the lens is undetectable, although if it's on the rear element you might see some light shadowing under certain conditions. If it's a huge amount of dust, you'll have a small loss of resolution and contrast. (Not "noisy, blurry and distorted images".)

Also the lens coating might be scratched or gone altogether which makes your images more susceptible to distortion or false colors due to ultraviolet and infrared radiation reaching the sensor. Ultraviolet radiation is known to produce wash-out colors.

It's possible that the lens coating could be damaged, but it's very unlikely that it's gone. And it's true that unfiltered UV can be problematic, but digital cameras almost universally have a built-in UV filter right over the sensor — this is not the function of the lens coating.

A missing lens coating would make your lens more susceptible to flare and to veiling glare, which could reduce overall contrast. A partially-damaged lens coating would probably be a visible scratch, and that basically falls under the same category as dust in the lens.

So: a digital camera is a precision device, and there are parts that can go out of alignment. Extreme factors (or abuse) can make this happen. Generally, you shouldn't need to do an regular maintenance, or send the camera in, although if you have a nice camera you keep for several years a checkup now and again won't hurt — especially if you suspect a problem.

But the main reason it seems worse, I think, is the same one that makes my once-fast desktop computer now unbearably slow — expectations have changed.

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Loved expectations have changed that sums it up. –  photo101 Nov 30 '11 at 3:22
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Tilt-shift photography (especially hands-on experience with a view camera) should give you a good idea what uneven focus due to misalignment might look like. –  Jefromi Nov 30 '11 at 5:32
    
@Jefromi — yep. –  mattdm Nov 30 '11 at 18:34
    
If anyone has the "level" required to vote down an incorrect answer down on Yahoo's site, the referred-to answer seems like a good use of your vote. –  mattdm Dec 7 '11 at 3:15
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As an aside rather than an answer with much practical importance...


The solid state detectors in the focal plane can be damaged by ionizing radiation. So--in principle--a pixel here or there could have it's efficiency reduced by cosmic rays.

That said, in particle physics we see this effect in cameras and other detectors that are exposed to "kill you in hours" levels of radiation day after day for months. The odds of a camera you don't leave in the experimental hall being affected are miniscule.

See also Cosmic Rays: what is the probability they will affect a program? or seach the web with terms like "radiation damage" and "gain monitoring".

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Oh! This reminds me of photo.stackexchange.com/questions/15127/do-sensors-wear-out. Thanks. :) –  mattdm Nov 30 '11 at 13:47
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There's another source of potential image quality 'loss' - changing the settings of the camera. We all do it as we go along and we also all generally forget to set it back to 'factory'. If you think your camera is off try resetting it.

That said I did once have my Nikon D100 go out of focus along one side. Strenuous use or a bump had misaligned the sensor by a minute fraction. Took it to Nikon UK and they fixed it up on the spot and for free.

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Very true! Well said (did you camera had setting problems?) –  photo101 Nov 30 '11 at 16:03
    
well said, I just realized a few days ago that my backfocus issues were caused by my adventures inside the debug menu years ago... :) –  Mihaly Borbely Dec 1 '11 at 3:05
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