I just purchased a brand new 24-70mm f2.8 II for my upcoming trip. I've been testing out this lens for the past few days, and have noticed something that I'm a bit confused by.

It seems by my tests, the L lens produces more noise than my Canon 50mm f1.4 at the same ISO. Here are two awkward shots of the same subject in similar environments (100% zoom). I've highlighted the increase in noise levels.

enter image description here

Additionally...you can see that even at a low ISO 250, noise is very apparent...even in bright environments (100% zoom).

enter image description here

The ultimate question is...is this expected, or should L lens not exhibit an increase in noise level. I'm currently using the 6D, which I always thought dealt with additional noise well.

Thanks very much!

  • 9
    \$\begingroup\$ Noise is a function of the sensor chip in your camera, and should not be affected by the lens. In the examples above, the f/1.4 lens may just be letting in more light, producing a brighter image. Brighter images have less noise. My guess is if you took the same shot indoors with these two lenses at 50mm f/8, you would no longer see any noise difference. \$\endgroup\$ Commented May 12, 2015 at 21:07
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    \$\begingroup\$ Without exposure details, it's hard to say very much about the source of the noise. For a start, you're not really comparing similar images. Is it sensor noise, or is it noise that has been introduced / boosted in post processing? You could try shooting at 100 ISO if it's a bright as you say; there may be little reason not to have the ISO as low as possible. \$\endgroup\$
    – John
    Commented May 14, 2015 at 7:58
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    \$\begingroup\$ You deserve an upvote. You posted a question that can be understood and you posted example images, great job and welcome to the site! \$\endgroup\$
    – dpollitt
    Commented Dec 24, 2015 at 21:25
  • 1
    \$\begingroup\$ Looks like JPEG artifacts. Did you record RAW? \$\endgroup\$ Commented Apr 7, 2016 at 15:38
  • \$\begingroup\$ theJollySin is correct. It is merely a factor of more light = less noise. Noise is wholly a factor of sensor construction otherwise we would have had it in film cameras as well. \$\endgroup\$
    – bethanyP
    Commented Jul 11, 2016 at 4:29

2 Answers 2


To me it looks fine. You're looking at different areas of a picture. If you look at the blurred area of the photo taken by the 50mm, the graininess is the same.

The main performance difference between primes and zoom lenses (for me at least is the chromatic aberration) is that when opened to their max aperture, prime lenses seem to do much better. If you look at the lines in the picture... (off topic)

Try taking another picture with the two lenses at 100 ISO, and see if you still see the graininess.


Noise is caused by the sensor sensitivity, not by the lens. In your case, because the 24-70mm is an f/2.8 lens, and the 50mm is an f/1.4 lens, the 50mm is allowing 2 stops more light into the camera vs the 24-70mm, allowing the camera to use a lower ISO than when the 24-70mm is being used. A lower ISO means less noise, so obviously the 50mm is going to appear to have less noise, but that's just because it is letting in more light onto the sensor than the 24-70mm.


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