Panasonic LX-3 Review

First of all, thanks to Steve Fines and ColorChange for providing test files.

I have to say, I am quite impressed with the LX3 sensor; I couldn't believe the efficiency number when I first got it. Here are the sensor properties at base ISO, ISO 80:

Black RAW level: 16 (but blacks are clipped)
Saturation RAW level: 4095
photosite efficiency: 2.20 e-/raw level
Full well capacity (e- at raw saturation): 9000 e-
Read noise: 2.55 raw levels = 5.6 e-
Photosite dynamic range: 10.6 stops

The photosite efficiency is superior. I have compiled results for a number of DSLR's at
http://theory.uchicago.edu/~ejm/pix/20d ... #pixelsize
see Table 1 a bit further down the page. Translating the LX3 photosite efficiency to ISO 400 by dividing by 5=400/80, and dividing also by the pixel area (2µ)^2, gives an efficiency figure of merit of .106 electrons per raw level per square micron. Naively this is better than the 1D3/1Ds3, and just a bit short of the D3. However, the relative normalization of the ISO needs to be measured to correctly compare.

Here is the photosite S/N ratio (vertical axis, in stops) as a function of raw level (horizontal axis, in stops):


The LX3 is the blue curve, the G10 the red curve. The LX3 plot is not far from the 1D3 at ISO 800 (!); see
http://theory.uchicago.edu/~ejm/pix/20d ... tml#SNR-DR
Please note also that these are pixel S/N ratios; image S/N involves the S/N at a fixed spatial scale relative to frame height, which involves scaling the pixel S/N ratio by the square root of the MP count. Translated into stops, the G10 curve should be raised by about .25, bringing it closer (but still short of) the LX3 curve.

Emil, those results are pretty interesting. I was expecting around the same as the G10, at best, or more likely not quite as good. Mainly due to Panasonic's past history of under-performing sensors and bad noise. Instead, it looks like Panasonic has indeed taken a solid step forward; this kind of sensor noise performance plus a good lens makes for a nice combination for a digicam. Good for Panasonic...

I thought it would turn out well. I thought most of the huge improvement was the fast lens (f2.0) but it looks like the sensor is doing a good job as well. Add in less heavy handed noise processing and the LX-3 really turns out great shots for a P&S.

Great work Emil.

My credit card is tingling.

I am also very tempted by this camera, as well as the G10. The speed and wide angle of the panasonic is very tempting, but I kind of like the reach of the G10 better...........guess I will have to try them out and decide then!

One issue left hanging in my previous analysis was the relative normalization of ISO between the LX3 and other cameras. Thanks again to Steve Fines and ColorChange for providing some data. Here there will be differences due to both the ISO normalization of the DSLR compared to, as well as the transmissivity of the lens put on the DSLR. For the 1D3 tested with 24-70/f2.8, the LX3 was 0.51 stop more sensitive, for the 1Ds3 tested with 24-105/f4, the LX3 was 0.86 stop more sensitive. So relative to the DSLR at ISO 100 (assuming the DSLR normalized properly; otherwise, consider these ratios of sensitivities), the LX3 would be at somewhere around ISO 150 to 186 in the RAW data. However the cameras appear to be metering the same, so this means that the LX3 is overexposing the RAW by about .5-.86 stop relative to the DSLR.

EDIT: Initially I got the sign wrong and said the LX3 was less sensitive than the two DSLR's tested; I must need more sleep, because the actual result is the other way around! Sorry for the egregious goof.

That is interesting. I wonder if the Leica equivalent does the same thing. Leica claims that the firmware is different...

Emil, great stuff. Did you have a chance to run the LX2 results I sent. I would love to see how these look and just get a handle on how big the leap Pany has made really was? I seriously like the LX3.

I hope panasonic puts the same sensor in their next ultra-zoom camera.

DP Review just added the G10 and it shows the LX3 doing quite a bit better job, even when they compared the relatively poor jpg output of the LX3. Pretty resounding win for the LX3.

http://www.dpreview.com/reviews/canong10/

Unless I totally missed it, they did not compare RAW which makes it a worthless review in my mind.

EJ, I partially agree but that was sort of my point by comparing pany's weak jpg processing (and it still wins handily) to what you would see if you compared raws ... although I can't be 100% sure as I haven't done it or seen it done.

ColorChange wrote:DP Review just added the G10 and it shows the LX3 doing quite a bit better job, even when they compared the relatively poor jpg output of the LX3. Pretty resounding win for the LX3.

Yes, but in the native ISO settings the G10 outperforms Panasonic "The LX3 seems to be resolving less detail than the G10"...
I think this is clearly one of those situations were one has to decide it it prefers a batter performance at low or high ISO? At least in theory, the best image the G10 can make is better than the best image the LX-3 can...

William, I disagree. I question the low ISO results due to the poor jpg processing on the LX3, but even if it does exist, that benefit is small compared to the much longer low ISO capability of the LX3 (due to the fast lens) and vastly superior upper ISO performance.

Alexandre Vaz wrote:Yes, but in the native ISO settings the G10 outperforms Panasonic "The LX3 seems to be resolving less detail than the G10"...
I think this is clearly one of those situations were one has to decide it it prefers a batter performance at low or high ISO? At least in theory, the best image the G10 can make is better than the best image the LX-3 can...

Agin, no conclusions about ultimate image quality can be drawn from the DPREVIEW "quasi" review since it did not test either camera's RAW capabilities.

E.J. Peiker wrote:Agin, no conclusions about ultimate image quality can be drawn from the DPREVIEW "quasi" review since it did not test either camera's RAW capabilities.

Hummm... not sure if I agree here, since probably most of the LX3 buyers will be shooting in JPG anyway...

Alexandre Vaz wrote:

E.J. Peiker wrote:Agin, no conclusions about ultimate image quality can be drawn from the DPREVIEW "quasi" review since it did not test either camera's RAW capabilities.

Hummm... not sure if I agree here, since probably most of the LX3 buyers will be shooting in JPG anyway...

Alexandre - That's true. It's a useful review for a lot of people. However, you can't say that the G10 has more resolving power, or that the LX3 has lower noise, or anything like that without comparing RAW. And on these forums, that's what most people care about. At the very least you need qualifiers like the G10 resolves better in JPG mode.

dbostedo wrote:Alexandre - That's true. It's a useful review for a lot of people. However, you can't say that the G10 has more resolving power, or that the LX3 has lower noise, or anything like that without comparing RAW. And on these forums, that's what most people care about. At the very least you need qualifiers like the G10 resolves better in JPG mode.

I can agree with the following correction, G10 jpgs resolve better at low ISO.

Emil has proven that the LX3 has dramatically lower noise than the G10, and that testing was done in RAW.

Alexandre, you said that the LX3 appears to have less resolving power, I am simply stating that you can not know that from the DPREVIEW article because the max resolving power will be in RAW format not the JPEG format they tested.

One should go have a look at what DXO found regarding the LX3 and the G10. It appears that the LX3's setting of ISO 400 is actually closer to ISO 200! The new DXO site may be revolutionary in evaluating cameras from a rational and scientific basis. See: http://www.dxomark.com/

One can compare two cameras on the site in terms of ISO Sensitivity, SNR 18%, Dynamic Range, Tonal Range, and Color Sensitivity.

A comparison of the LX3 and the G10 can be done quite easily. The findings are enlightening.