Canon 40D vs 20D high ISO test

As requested, I have made some 100% crops at ISO1600 and ISO3200 from both the 40D and 20D. All were shot in RAW and converted with DPP and then cropped and slightly sharpened with Photoshop CS3. the lens used was Sigma 30mm f1.4 DC. Shutter speed and aperture were matched exactly the same on both cameras.

The first shot is from 40D at ISO 1600


The next shot is from 20D at ISO 1600


The following shot is from 40D at ISO 3200


The next one is from 20D at ISO3200


You can see the Canon EOS 40D full review article here.

16 thoughts on “Canon 40D vs 20D high ISO test

  1. Pingback: Canon EOS 40D initial impressions « The World According to Roland

  2. Hmmm, looks pretty much a dead heat between the two. 40D appears more saturated but perhaps that’s just because it seems darker? The sensors must have slightly different ISO calibration.

    what we really need is a subject with more texture / detail to assess how much sharpness is preserved.

  3. I agree looks like a dead heat, BUT the 40D looks about 1/2 stop underexposed as compared to the 20D at the same camera settings. This will affect the noise as well.


  4. You are absolutely correct that there is no difference between the two. However since the 40D is 10 MP camera you have a larger file size which requires less interpolation to the same size print, therefore 40D will show less noise than the 20D on the same print size.

  5. 40D’s ISO results seem to be worse than from 20D. maybe it’s just me,but I checked a few online pictures,thaat were posted and they are all pretty bad. OBVIOUSLY Canon didn’t fix the issue. I was hoping they would,with the Digic III and all.
    How’s picture quality though. Any difference?

  6. hi, just looking at the two pictures together you can see their is more grain in the 40d and yes i think its stoped down 1 stop or you have deepened the colour in cs3 i was thinking for buying it as i already have the 10d but i not sure now….

  7. Hi Brigitte,

    As I have said, I only resized and slightly sharpened the images in Photoshop CS3. I did not do any other post-processing. So the deepening of the colors could not be due to post-processing. I used exactly the same routine to process the photos from 40D and 20D. Therefore, even if there was any step in my post-processing routine that might have affected the colors would have equally affected both sets from 40D and 20D.

  8. 40D’s high ISO should not be better than 30D’s, and 30D’s should not be better than 20D’s. The CMOS chip size did not change from 20D towards 40D. But the effective pixel increased aroud 67%, which means Canon has to find out ways reducing the noise due to the fact they are not willing to change the CMOS chip size, actually they should have to. It is like to put 10 peaple on top of a table which can unfortunately support 6. Why? Do not forget their EF-S lens. They are for 1.6x sensor. So Canon has to make it 1.6x, not 1.5x, not 1.2x.

    Anyone played with 300D would find the beauty of dynamic range, though it is only 6M. 20D reached 1.6x chip’s sweatest point. 40D improved a bit than XTi (400D) by structual re-design, which tried to squeeze for more space for the sensory portion. So I would expect better noise control than XTi.

  9. I think the 20D has much LESS noise than the 40D. Check out the grain in the apple – appears much larger even correcting for saturation effect.

    Why did Canon use a cheap-o sensor that’s found in the Rebel XTi? they must be planning a 5D upgrade soon.

  10. Noise is definitely better on the 20D, with much better shadow detail as well. I’ll definitely pass on this mediocre upgrade although I really do appreciate your review of both the camera and the grip. Canon better get their act together because Nikon is fixing to whip their a@@ with both the D300 and the D3. If I didn’t have a bunch of Canon glass I’d already have an order in for the D300. I’ll keep my 20D until the Spring when I hope that Canon stops screwing around and starts making quality cameras again…no 45-pt focus in the 40D, no 12MP sensor and no substantial noise reduction like the D300, no dual-CF, no UDMA, no 920K LCD, D300 has 50% greater shutter life, D300 uses every lense that Nikon has made, not true with the 40D, and on and on. And the sad fact is that I’m a Canon guy. You better wake up Canon.

  11. From my observations from the images, the 20D definately has less noise than the 40D image in both ISO1600 and 3200 comparisons.

    I also agree with the others that the 40D image is slightly underexposed maybe by 1/3 stop. If exposure compensation was used on the 40D to bring it up to the same luminance as the 20D image, the noise would increase further again.

    I would give the 20D here advantage for noise control, but on the other hand the 40D is revealing a bit more detail and shadow information on the apple stem. I really had to look hard to see this improvement, whereas the higher noise from the 40D was easily picked on first glance.

    Based on your excellent work Roland, I can see 20D and 30D owners satisfied that their 8MP sensors indeed can produce images with lower noise that the latest 40D.


  12. Hmm. Well, I disagree with all these posts.

    The 40D has rich, natural color that has been compared (by Luminous Landscape) to the 5D.

    The 20/30D models have the wimpy, washed-out color you see in the shots, above – resulting in the NECESSITY of post-editing every single shot, in order to make a decent image. I know because I had them both (20D and 30D).

    View, if you will, the yellow thing (whatever it may be) in the lower right corner. If what you are seeing is under-exposure, why is it not uniform, throughout the image?

    Examine the color – CLOSELY. The difference in color IS uniform, throughout the image.

    Though I have had my 40D only long enough to take 18 shots with it (it rained like he77 yesterday… and this morning) I can say, for sure, that the difference between the 20/30D and the 40D is the rich, vibrant color AND the far better representation of the subject by the sensor.

    still needing help? go here:

  13. Hello, Monte. You have raised some good points here with regards to 40D having a more rich colours. What we must then ask is which picture was closer to what we see with our eyes. Roland, mabe you can elaborate on this. These perceived rich colours may indeed be an advantage, but may not have been like that in reality.

    Personally I do not mind applying my own “colour richness” to an image, as it allows me to select what I want it or prefer a more natural look. Natural look sometimes can be useful for skin tones, etc.

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