What really makes big sensors produce more appealing images? *Serious*

Started Mar 13, 2014 | Discussions thread
bobn2 Forum Pro • Posts: 59,122
Re: What really makes big sensors produce more appealing images? *Serious*

dikipix wrote:

Lots of close attention to the sensor here, but the other two key elements are less well considered. Cameras or more correctly imaging, comprises three main elements, lens, sensor and digital processing (in camera)

To me, it seems the lens accounts for a large amount of the image quality in the finished image. For instance, put a high quality lens on an ordinary camera, you can get remarkable results. Put an ordinary lens on a high end camera, the results are less likely to be impressive.

One of the severe limitations of smaller cameras, is smaller lenses. It is difficult to make a small lens perform like a larger lens, the real estate is just not there to enable that to happen. Add to that cost, it will cost a lot more to manufacture a small lens that performs at a similar level to a larger lens, because the tolerances will have to be much finer. But, no one wants to spend more money, on a smaller item. Yes, manufacturing has improved immensely in recent times, but the improvements are applied to small and large alike.

I don't quite agree with that. I had a long argument with regular poster Anders W, who claims the exact opposite of you, that smaller lenses are intrinsically better than big ones. I think where you're wrong and he is also, is the assumption that small lenses and big ones would be built the same way. The quality of a lens is ultimately decided by how much you're willing to spend manufacturing it (and the trade off like most things goes towards getting more for less outlay as progress is made) - but manufacturing trade-offs really are size dependent - at different sizes different manufacturing techniques become feasible and relative prices for different ways of building things change. So, in th end, I don't think its a given that small lenses would be build or designed like big lenses.

Similarly, large sensors, with more real estate available, can capture far more information than a smaller sensor, it's a question of available real estate.

Again, that's not intrinsic. A small sensor can be made to collect just as much information as a big sensor, but it does mean letting it accept a higher exposure.

The result, you get much better headroom, meaning you can apply more post processing to the image, and still have good information remaining in the image to support that processing.

As I suggested above, that's only because designers don't grade 'base ISO' according to sensor size. If they did, sensor size is less important. What becomes the absolute limit is the f/0.5 lower limit on f-number.

Then there is the final arbiter, the chipset, the digital processor that each manufacturer includes with the camera. Each chipset is a finely honed set of compromises, able to apply a series of mathematical algorithms to give the camera the best imaging possible, for a given set of lens-sensor-camera settings that have been applied.

Actually, I don't think it os. Each chipset is an off the shelf applications processor. cameras ride on the back of mobile phone volumes here. The engineers design their firmware into the application envelope, not vice versa, and the designers select on price performance from what the chip vendors have available.

Digital processing has to evaluate the captured information from the sensor, apply the algorithms and turn it into an image in the smallest amount of time, for the smallest amount of power consumed. Manufacturer algorithms also account for much of imaging quality, and the variations between different cameras.

Most camera processors are not even close to what could be done in terms of 'smallest amount of time' - they are the most suitable of what is available. They are typically running at clock speeds of 1GHz or less, with single or dual core processors and JPEG hardware pipelines designed originally for phone use. That's why when Canon and Nikon produce 'small raw' formats they are just halfway processed JPEGs - they don't have the freedom to produce a sensible format, the best they can do is use the JPEG hardware and take a feed halfway through.

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