[Darley]

The smoothing on the Canon 5D was very easy to see (I shot that body for a few years). Even the Pentax 20D sensor had better high ISO performance (but not as good at low ISO). Of course, all the 16 mp sensors in the Pentax cameras outperform the Canon 5D in every respect - especially dynamic range, and especially so from 400 ISO upwards. Full frame on the older cameras were not as good as the newer crop sensors, but it takes field shooting to know that - as opposed to the standard bench tests that get reported.

I was only going by Ken Rockwell's comparison of the 5D with APS sensors and the images from the 5D were clearly sharper and more detailed. Surely RAW files are not 'smoothed' in any way?

[ScooterMaxi Jim]

Thank you, that goes a long way to answering my question! So would a modern 6MP sensor be better than a 12MP sensor and if so why don't they make them?!

The 12 mp sensors in the KX and KR series were very good in low light - much ahead of the previous sensors, and better than the 14 mp Samsung sensors in the high-end K20D an K7 (which was particularly bad due to the highlight clipping issue). This was a frustrating time for Pentax because the sensor in the flagship K7 was not as good as the K20D before it, and quite inferior to the KX mid-line unit that had a great sensor but was stripped down on features.

[Joojoo2010]

With my k100d super i did use iso 800 as a standard iso with flash photos. I did notnotice any noise that was bothering my eye.

With k5 i not want to go as high as iso 800 cos i feel noise is bothering my eye.

Yes i know k5 have less noise than k100d...but i would say that noise is diffrent and k5 noise is more easely bothering my eye. Maybe this is explanation, i do not know...but Strange.

[ScooterMaxi Jim]

I was only going by Ken Rockwell's comparison of the 5D with APS sensors and the images from the 5D were clearly sharper and more detailed. Surely RAW files are not 'smoothed' in any way?

No one takes Rockwell as gospel, and I doubt he ever compared the 5D to a Pentax. Again, the 5D is a good sensor at low ISOs, even with the limited 12 mp sensor you can get great sharpness. I shot the 5D a lot in low light, and it simply wasn't as good as the K20D in high ISO situations. Yes, the Pentax was a bit noisier - but the detail was much, much sharper. How DXOmark can tag Pentax with smoothing when Canon had done so excessively (at least with the 5D it was clearly so), you have to take the claims with a grain of salt.

Yes, RAW images get smoothed (DXOmark is testing RAW only). I would even venture to say that more of the progress made in low light on the dSLR sensors has been done via engineering in camera as opposed to what is captured at the sensor surface. The technology hasn't changed for big sensors (although the small ones really have improved with the advent of backside illumination).

[twitch]

More megapixels does not mean more noise, all else being equal (including output size, QE, sensor size). This is a myth that has been refuted many times yet it still seems to be common wisdom to many.

[Stone G.]

Thank you, that goes a long way to answering my question! So would a modern 6MP sensor be better than a 12MP sensor and if so why don't they make them?!

Not necessarily better - because you loose resolution. But perhaps better for your purposes? You can find CCD cameras for astrophotography with modern sensors in that range - but they are costly!

For what it is worth, I just took a night scene under nominally identical conditions: ISO200, 10 seconds, Pentax DA* 200mm f/2.8 lens stopped down to f/5.6 (I say 'nominally' because no one really knows what digital ISO really is). Here is first a reduced image of the entire scene taken with my 6 MP Pentax *ist DL:


Un-cropped Pentax *ist DL image; click to see larger (1280 px wide) version.

And then for comparison 100% crops of the same scene taken with the 6MP *ist DL; 10MP K200D and 16 MP K-5:


100% crops of Pentax *ist DL, K200D and K-5 images. Click to see non-resized version (approx 1600 px wide).

These are manual focus images. All sorts of in-camera noise reduction have been disabled and there is no post-processing, just JPEG straight out of the camera.

Conclusions???

[Darley]

No one takes Rockwell as gospel, and I doubt he ever compared the 5D to a Pentax. Again, the 5D is a good sensor at low ISOs, even with the limited 12 mp sensor you can get great sharpness. I shot the 5D a lot in low light, and it simply wasn't as good as the K20D in high ISO situations. Yes, the Pentax was a bit noisier - but the detail was much, much sharper. How DXOmark can tag Pentax with smoothing when Canon had done so excessively (at least with the 5D it was clearly so), you have to take the claims with a grain of salt.

Yes, RAW images get smoothed (DXOmark is testing RAW only). I would even venture to say that more of the progress made in low light on the dSLR sensors has been done via engineering in camera as opposed to what is captured at the sensor surface. The technology hasn't changed for big sensors (although the small ones really have improved with the advent of backside illumination).

No I don't take it as Gospel but the pictures were clearly better from the 5D - though I can't recall what he was comparing it to! Well my question is pretty much answered - modern image processing is superior and gets more out of the sensor yes?

[Darley]

Not necessarily better - because you loose resolution. But perhaps better for your purposes? You can find CCD cameras for astrophotography with modern sensors in that range - but they are costly!

For what it is worth, I just took a night scene under nominally identical conditions: ISO200, 10 seconds, Pentax DA* 200mm f/2.8 lens stopped down to f/5.6 (I say 'nominally' because no one really knows what digital ISO really is). Here is first a reduced image of the entire scene taken with my 6 MP Pentax *ist DL:


Un-cropped Pentax *ist DL image; click to see larger (1280 px wide) version.

And then for comparison 100% crops of the same scene taken with the 6MP *ist DL; 10MP K200D and 16 MP K-5:


100% crops of Pentax *ist DL, K200D and K-5 images. Click to see non-resized version (approx 1600 px wide).

These are manual focus images. All sorts of in-camera noise reduction have been disabled and there is no post-processing, just JPEG straight out of the camera.

Conclusions???

Hmm well they are different sizes! I think I see more detail in the last shot but hard to say if it's just the size ... ?

On the down side the K200D (my camera) looks poor in comparison!

[Stone G.]

More megapixels does not mean more noise, all else being equal (including output size, QE, sensor size). This is a myth that has been refuted many times yet it still seems to be common wisdom to many.

Well the laws of physics and statistcs do mean more photon-count statistcal noise. But as I have said, there are many other factors. One problem is that we do not really have "more megapixels" and "fewer megapixels" to compare with "all else being equal"

Clarkvision: Does Pixel Size Matter

[Darley]

One thing i can confirm is more MP does not mean more noise. My Canon 18MP 600D (Rebel T3i) produced fine images at ISO 6400 (whatever that actually means) but to make a comaprison with compacts and small sensors, my 16MP Canon SX160IS is useless beyond ISO 200.

[Stone G.]

Hmm well they are different sizes! I think I see more detail in the last shot but hard to say if it's just the size ... ?

Images formed on the sensor have of course the same linear size because I have used the same lens. But what I show is crops that are all the same number of pixels high and wide. And since the 6 MP pixel is about 1.63 times larger than the 16 MP pixel in linear dimension, the church also occupies fewer pixels on the 6 MP sensor than on the 16 MP sensor. What you see is the increased sensor ('spatial') resolution as pixel size decreases.

[ScooterMaxi Jim]

With my k100d super i did use iso 800 as a standard iso with flash photos. I did notnotice any noise that was bothering my eye.

With k5 i not want to go as high as iso 800 cos i feel noise is bothering my eye.

Yes i know k5 have less noise than k100d...but i would say that noise is diffrent and k5 noise is more easely bothering my eye. Maybe this is explanation, i do not know...but Strange.

A few things are going on here. First, a well exposed ISO 800 shot (such as what flash will yield) will look pretty good (I still would never recommend it - as you still lose a lot of dynamic range). Even on the Q, by mistake, I shot at ISO 1000 in good light - and the noise was not a big problem. Good light overcomes a lot of evils!

The 6 mp CCD sensor can really look great, as the noise looks more natural (film like) than the noise from newer sensors. I think Pentax does a better job with the mix of chroma and luminance noise reduction, even on the CMOS sensors. Bottom line, though, the K5 does ISO 800 a lot better than the old 6 mp sensors. But, the look can trick you into thinking the old camera is as good or better.

[wombat2go]

It mostly comes down to reduced sensor noise in the newer cameras I think.
Pixel count helps when the image is heavily cropped.
Also provided images are reasonably exposed, there is not much benefit from having a 16 bit sample depth in the camera while we still use 8 bit video hardware on the monitor.
And I wonder if the eye could resolve any better that 8 bit anyway?

The ist ds and K-01 both have 12 bits per sample so maximum brightness is Hex &H0FFF
I took a raw photo in the dark room with each camera grossly undereexposed so that the levels peaked at about &H003F
That is about 7 stops underexposed and means the resolution is limited to only 1 part in 127.
Also it is well down among the sensor noise. The raw images were completely black when opened in a viewer with 0EV of exp comp
Then used ImageMagick >convert -auto-level to automatically map the images up to normal brightness as 16 bit tiff, full brightness is &HFFFF
Then GIMP converted 16 bit tiff to 8 bit jpg for the video driver and monitors

The upper image is the istds and the lower is the K-01. The ist ds artifacts are mostly noise I think

[carrrlangas]

Here´s a very good read about sensors, lenses and low light photography. "étendue" concept exaplained throughly... Clarkvision.com home

[Darley]

Here´s a very good read about sensors, lenses and low light photography. "étendue" concept exaplained throughly... Clarkvision.com home

Interesting site