Digital sensor quality problems

[Riggaberto]

I was talking to a guy at my local camera shop that says he is waiting to switch over to digital until sensor quality rises. He says that despite 10-12 megapixels being close to 35mm in quality image-wise, they're having problems with the sensors declining in quality after a few years and requiring more and more light for the same exposure.

Is this accurate? I wanted to get some second opinions on it. Just for cost practicality and ease of use I was planning on getting a nice canon sometime in the next few years, but if the thing is only going last around 70-100k exposures, it's really not going to be cost effective at all.

 

[Digital Matt]

I have had a Canon 20D for several years now, and I can tell you that it still exposes faithfully. Different people have different opinions on quality. There are lots of opinions on the internet that 10mp is already better than scanned 35mm film.

As for permanence, digital SLRs probably won't last as long as their film equivalents, unfortunatly. The technology is changing so rapidly everyday. If you use your excuse, you'll never get into digital. You'll always be waiting on the sideline. You've really got nothing to lose.

 

[Alex_B]

When you buy a film camera, you might be happy with its quality for decades as there is no degradation, and you always buy fresh film .. OK, someday the shutter will die, but that can be replaced.

However, digital sensors (as all electronic materials) are not made for eternity, so there certainly is degradation, and from my point of view as a former semiconductor physicist, always will be. I am not sure, how fast degradation will become noticeable. My guess would be, that today's sensors easily outlive the shutter-lifetime of a camera. I do not know of a single case among my friends where you could actually see sensor degradation in the final image after years of using their cameras. Anytime someone claims that the camera does not produce any good pictures anymore, then that always was inspired by seeing newer cameras with better sensors. So if you then compared images taken recently with that respective camera with images taken 4 years ago, then they would be equally poor

My guess is that sensor lifetimes are, as with most other semiconductor electronics, diffusion-limited. If that is the case (I am not an expert on sensors though), then sensors would have rather long lifetimes since they do not get that hot, at least not compared to the semiconducting material in CPUs (which are not that short-lived either).

12 MP are hard to beat by 35mm fine grain pro-film, even with a pro scanner. In some cases quality is equal, but most times digital wins in terms of resolution. If you print directly from film, without going via a scanner, then things look slightly brighter for film.

The thing where I would hope and expect future sensors to be better than today's sensors, is dynamical range and basic sharpness (BAYER pattern sensors are certainly not the best in that respect, and also Foveon hasn't reached its potential yet).

 

[fmw]

+1. I remember this argument from when I was in the computer business. There was always a new chip on the horizon. Apparently you did buy a computer.

My own opinion is that 10mp is better than 35mm film, scanned or otherwise - at least in terms of resolution. Some can argue the superior gradation of film but the difference is pretty trivial. I still get better results from medium format film but I view 35mm film as dead forever. And I used 35mm film for over 1/2 a century. The only 35mm camera I still own was a gift. I don't use it. I just keep it for sentimantal reasons.

My oldest digital is a fancy p&s Nikon that I bought in 1999 for web photography. It still works the same as it did back then. It may fade over the years but we don't know that yet because digital hasn't been around long enough for them to fade. What the camera store fellow said is plain guesswork.

 

[darich]

first time i've ever heard of a sensor "fading". i could understand if pixels started to die or some other electrical component failed but the sensor to reduce in effectiveness?? Strange one. I always thought that electronics either worked or didn't.
Like Matt said if you're always waiting because there will be a newer better version on the market soon then you'll wait forever.

Another thing, does the shop have a surplus of film cameras that they can't shift? special deals on them?
it may be that he's looking to get rid of film cameras and is using this as a ploy to get people to buy them. If so then you have to ask, what will he replace the film cameras with. The answer is almost definitely digital!

 

[Big Mike]

I still walk to work and back (20 miles, up-hill both ways), I'm waiting to buy a car...I hear that cars wear out and that flying cars are just around the corner.

 

[fmw]

I still walk to work and back (20 miles, up-hill both ways), I'm waiting to buy a car...I hear that cars wear out and that flying cars are just around the corner.

Mike a bicycle will shorten that trip and the technology bicycles use today is about 100 years old. I think it's a safe bet. Tell me about the flying cars.

 

[Riggaberto]

Mike a bicycle will shorten that trip and the technology bicycles use today is about 100 years old. I think it's a safe bet. Tell me about the flying cars.

Ownt.

Thanks for the advice though. I'm not even going to bother looking at digitals until I get a job though. I know I'm not gonna screw around though, I'd get something at least 12 megapixels.

 

[DSLR noob]

Mega pixels aren't everything.

 

[Don Simon]

Exactly. There's compact models with 12mp now but they still won't be able to touch the sensors on digital SLRs with less megapixels, especially at high ISOs.

 

[Riggaberto]

Exactly. There's compact models with 12mp now but they still won't be able to touch the sensors on digital SLRs with less megapixels, especially at high ISOs.

How do high ISO film and high iso digital results compare? I dont really even understand how ISO speed is changed with digital (in technical terms, I know you can just change it when you feel like)

 

[Alex_B]

How do high ISO film and high iso digital results compare? I dont really even understand how ISO speed is changed with digital (in technical terms, I know you can just change it when you feel like)

basically when the camera is set to low iso, then the signal coming from the sensor's pixels is rather strong (as that signal only depends on the light reaching it during the exposure time), at high iso, the signal is rather weak, as aperture and shutter speed are set such that less light reaches the sensor.

Now, when this then translated into image information, the signal is amplified such that the high and the low iso image should look the same... the high iso signal is amplified more then of course.

Now the problem is something you call signal-to-noise ratio (S/R)
. Noise always has about the same "strength", so for an originally weak signal, the S/R is small, giving a very noisy image, for an originally strong signal S/R is larger.

Or in other words, the original noise is always the same, just at high iso it is amplified more with the rest of the signal. And there is some extra noise generated by the amplifier, not sure if this is negligible with modern digitals.

In practice (in the final image), to me it looks very similar to the effects created by larger film grain.

 

[Don Simon]

I think that high ISO digital images (from a 6mp dSLR at least) pick up more detail than high ISO 35mm film. On the other hand, to my mind digital noise looks horrible, while film grain can be very pleasing when it suits the image, so to my mind noise is not the same as grain. Having said that, sensors and software are getting much better at dealing with higher ISOs; my 6mp sensor is hardly state-of-the-art but I regularly shoot at 1600, and even 3200 is very useable with some application of NeatImage or other software.