Lens Resolution

[FlossyThePig]

The compact digital camera manufacturers are taking the megapixel game to greater extremes (10+ megapixel). Two questions spring to mind:

1. Has the quality of the lenses improved to match the sensors?
2. Can the lenses on the latest compacts resolve sufficient detail to actually take advantage of the sensor?

Sorry if this is a repost but searching revealed nothing on this topic

[Simpo Two]

You need to add - 'are the pixels so small the photons don't actually hit them?'

My compact is 3.2Mp and I refuse to change it because all the current ones have far too many pixels!

[VxDuncan]

Given it's rare a lens on a APS-C DSLR reaches the resolution limits of a DLSR sensor I'd say pretty unlikely...

[robinhood21]

There is an interesting comparison between the new Sigma DP1 (compact) Leica D-lux3 (compact) and the Canon 1D mark3 Here

Not scientific, but does give an idea as to how things are progressing in the compact market.

[FlossyThePig]

Simpo Two said:

You need to add - 'are the pixels so small the photons don't actually hit them?'
My compact is 3.2Mp and I refuse to change it because all the current ones have far too many pixels!

How big is a photon then? It's a difficult question to answer but probably sub-atomic.

robinhood21 said:

There is an interesting comparison between the new Sigma DP1 (compact) Leica D-lux3 (compact) and the Canon 1D mark3 Here

Interesting site but not really valid examples. Sigma DP1 has an effective pixel count of only 4.6 million, it is playing the megapixel game in a different way.

I would expect both compacts in the example to have lenses that are capable of resolving detail sufficient for the sensors as they both are:

• From manufacturers with a reputation for making lenses for the upper end of the market.
• Neither come into the cheap category (£100 - £150), which I failed to mention in the original posting. Sigma £550, Leica £390.

Edited by FlossyThePig on Friday 11th April 12:33

[GetCarter]

Amount of pixels is (almost) a complete red herring. Size of sensor combined with amount of pixels is what you need to consider (plus the glass and the electrics!) You can now get 5 mp Camera phones, but nobody in thier right mind would compare the results to a Nikon D1X (Top of the range 5mp digital SLR that cost £4.5k not so long ago)

Edited by GetCarter on Friday 11th April 13:21

[VxDuncan]

GetCarter said:

Amount of pixels is (almost) a complete red herring. Size of sensor combined with amount of pixels is what you need to consider (plus the glass and the electrics!) You can now get 5 mp Camera phones, but nobody in thier right mind would compare the results to a Nikon D1X (Top of the range 5mp digital SLR that cost £4.5k not so long ago)

Edited by GetCarter on Friday 11th April 13:21

+1

Basically you're talking about signal:noise ratios. You have a higher number of pixels for the same amount of light, the amount of photons landing in each "well" (in the case of a CCD) is reduced, therefore "signal" against background noise is reduced. Add in effects of heating, dead pixels etc it don't look good!

[FlossyThePig]

VxDuncan said:

GetCarter said:

Amount of pixels is (almost) a complete red herring. Size of sensor combined with amount of pixels is what you need to consider (plus the glass and the electrics!) You can now get 5 mp Camera phones, but nobody in thier right mind would compare the results to a Nikon D1X (Top of the range 5mp digital SLR that cost £4.5k not so long ago)

Basically you're talking about signal:noise ratios. You have a higher number of pixels for the same amount of light, the amount of photons landing in each "well" (in the case of a CCD) is reduced, therefore "signal" against background noise is reduced. Add in effects of heating, dead pixels etc it don't look good!

OK! I realise there are other factors in producing to final image. Assuming the the electronics has been improved, the sensor size has remained the same and ignoring signal:noise ratios.

Can the lens fitted to the cheaper compacts actually supply sufficient detail for the sensor?

If not what is the optimum number of pixels the lens can resolve?

[Simpo Two]

FlossyThePig said:

OK! I realise there are other factors in producing to final image. Assuming the the electronics has been improved, the sensor size has remained the same and ignoring signal:noise ratios.

Ratther too many 'ifs' and 'buts' there I feel.

My point, which I think missed its target, is that the quality from such tiny pixels will be so - er - ste - that the rest of the question is hypothetical. Smaller pixels are struck by fewer photons. Hence they are less sensitive to light. Hence the S/N ratio has to be cranked up, which produces noise, which is then mashed up by software into a blur. The lens I suspect will be the least of your problems. If quality is your goal, then you'll need to trade up.

[FlossyThePig]

Simpo Two said:

FlossyThePig said:

OK! I realise there are other factors in producing to final image. Assuming the the electronics has been improved, the sensor size has remained the same and ignoring signal:noise ratios.

Ratther too many 'ifs' and 'buts' there I feel.

My point, which I think missed its target, is that the quality from such tiny pixels will be so - er - ste - that the rest of the question is hypothetical. Smaller pixels are struck by fewer photons. Hence they are less sensitive to light. Hence the S/N ratio has to be cranked up, which produces noise, which is then mashed up by software into a blur. The lens I suspect will be the least of your problems. If quality is your goal, then you'll need to trade up.

I was not asking questions about the relative quality of the sensor or electronics and the problems that can arise from too many pixels in a small space. All I wanted to know was whether the lens could actually resolve the detail in the first place.

If the lens can only resolve say detail suitable for a 5 megapixel sensor the manufacturer should either improve the lens or improve the performance of their 5 megapixel sensor. I know I would prefer the latter but it would take a brave manufacturer to do that. In the words of an old tv comedy show "never mind the quality, feel the width".

[Ordinary Bloke]

Maybe this answers your question a little (or maybe not, who knows/cares?)

If you look at the most expensive lenses, used by the pro's, they never (or rarely?) have a zoom range of x3 or more.

Modern compacts often do. So why not the pro lenses? Because a non-zoom can be optimized to be sharp from centre to edge, at every aperture and focussing distance, Make it a zoom and you have to compromise.

Modern compacts tend to have i) a tiny sensor, a bit like ISO 64 slide film (ie Sh|t unless you're in bright sunshine) and ii) a x5 or x10 zoom which is compromised at every focal length.

There's a reason why the glass on my Canon Lenses is so big, and expensive. If Canon/Nikon/Sigma/Tamron could make high performance lenses that fit in your pocket for peanuts, I'm sure they would...

[Simpo Two]

FlossyThePig said:

I was not asking questions about the relative quality of the sensor or electronics and the problems that can arise from too many pixels in a small space. All I wanted to know was whether the lens could actually resolve the detail in the first place.

Why?

I fail to see the point in knowing, as the information is useless for all practical purposes.

FlossyThePig said:

If the lens can only resolve say detail suitable for a 5 megapixel sensor the manufacturer should either improve the lens or improve the performance of their 5 megapixel sensor.

Manufacturers who cram 10Mp onto the head of a pin are not interested in quality, resolving power or lens quality. They do it because the mass market think that more Mp means 'better quality, innit'. They have a PR story, a new product, and witless punters buy it. They will simply end up with files the size of Bolivia.

[Fordo]

I read a very interesting article on the net, that explained how 6 megapixels is about optimum for the size of ccd's compact cameras use.

My gf has just purchased a 8 mp compact, and while its terrific compared to a lot of compacts, use in low light was sooooo noisey.

She was proud to have a camera with more pixels than my dslr- then i compared photos in identical situations. she now wants my camera!

I think compacts and camera phones ccd are getting higher resolution than the glass. I cant see glass optics being improved that much- at the end of the day, you need more light to make a crisper, more resolved image.

But, where i can see it improving, is the software in the compact camera- advanced noise reduction, CA removal etc, will continue to improve, meaning compacts will produce better pictures as they progress.


In fact, I've read something about lens mapping at a recent broadcast show. the flaws in the lens are mapped in factory, and these results programmed into the camera, so the camera can compensate. This also means less expensive coatings would need to be put on the lens, making lenses slightly cheaper. I have no idea when this stuff will be on the market, or if it is already

Edited by Fordo on Saturday 12th April 10:17

Edited by Fordo on Saturday 12th April 10:20

[Simpo Two]

Fordo said:

In fact, I've read something about lens mapping at a recent broadcast show. the flaws in the lens are mapped in factory, and these results programmed into the camera, so the camera can compensate.

Like the Hubble telescope in fact. However could it work for a zoom lens? But again, this exposes the untenable starting position. If you're concerned about optical quality, don't buy a compact. If you want to race in F1, don't buy a Micra.