06-06-2010, 06:29 PM
Diffraction is "caused" inside the lens, and is related to just how small the hole is the light passes through, and the distance from the hole to the sensor or film.
ALL APS-C cameras will have the same softening from diffraction at the same settings and the same lens, no matter how high the resolving power of the sensor is.
So... a 6mp EOS 300D will have the exact same diffraction "hit" on the image as an 18mp EOS 7D.
So.. it can NEVER occur that you will have an image from the 300D that you are happy with in terms of sharpness (or rather, lack of softness) printed at a certain size, where you are not happy with the sharpness of a same image taken with a 7D.
The only thing that happens when you have a higher resolution image is that you get more detail, including more detail in the softness from diffraction. It is only when you have an image from a 300D that you print at a size where the (lack of) resolution starts to show, where you then would start to also notice that the 7D shows a softness due to diffraction. With lower resolution sensors, it is the lower resolution masking the diffraction. It is not that with higher resolution sensors you get more diffraction.
So, this means that a sensor NEVER can get too high a resolution, in respect to diffraction. Diffraction always will remain the same for the image. You only gain with higher resolution (possible detail), but you never lose anything compared to lower res. sensors.
Switching to full frame also will not be a solution to limit diffraction, because with full frame you will have to close the aperture down (by a factor of 1.6, compared to a 7D) to get the same depth of field, and the smaller aperture then will give more softening due to diffraction.
Remember that it is about the image, not about individual pixels.
[quote name='PuxaVida' date='06 June 2010 - 12:41 PM' timestamp='1275824497' post='265']
Wim, thanks for the very "brief" info![[Image: smile.gif]](http://forum.photozone.de/public/style_emoticons/default/smile.gif)
... I understand that the high quality lenses produce way better resolutions than the sensor can.
But when it comes to the IQ produced, do you think the 120 lp/mm resolution of the sensor is prone to diffraction (even with high quality APO lenses), or do we still have a room for it in there? This question is asked ignoring the fact that 7D is not the best body for wide angle & closed aperture shots, but better for tele& bird shots. I'm playing my "theoretical discussion" card and try to get from you what I can![[Image: rolleyes.gif]](http://forum.photozone.de/public/style_emoticons/default/rolleyes.gif)
...
Regards,
PS: I'm not sure how I could manage not to post this message as a reply to Wim... but it was... anyway, long live the new edit mode !...
Serkan
[/quote]
ALL APS-C cameras will have the same softening from diffraction at the same settings and the same lens, no matter how high the resolving power of the sensor is.
So... a 6mp EOS 300D will have the exact same diffraction "hit" on the image as an 18mp EOS 7D.
So.. it can NEVER occur that you will have an image from the 300D that you are happy with in terms of sharpness (or rather, lack of softness) printed at a certain size, where you are not happy with the sharpness of a same image taken with a 7D.
The only thing that happens when you have a higher resolution image is that you get more detail, including more detail in the softness from diffraction. It is only when you have an image from a 300D that you print at a size where the (lack of) resolution starts to show, where you then would start to also notice that the 7D shows a softness due to diffraction. With lower resolution sensors, it is the lower resolution masking the diffraction. It is not that with higher resolution sensors you get more diffraction.
So, this means that a sensor NEVER can get too high a resolution, in respect to diffraction. Diffraction always will remain the same for the image. You only gain with higher resolution (possible detail), but you never lose anything compared to lower res. sensors.
Switching to full frame also will not be a solution to limit diffraction, because with full frame you will have to close the aperture down (by a factor of 1.6, compared to a 7D) to get the same depth of field, and the smaller aperture then will give more softening due to diffraction.
Remember that it is about the image, not about individual pixels.
[quote name='PuxaVida' date='06 June 2010 - 12:41 PM' timestamp='1275824497' post='265']
Wim, thanks for the very "brief" info
... I understand that the high quality lenses produce way better resolutions than the sensor can.But when it comes to the IQ produced, do you think the 120 lp/mm resolution of the sensor is prone to diffraction (even with high quality APO lenses), or do we still have a room for it in there? This question is asked ignoring the fact that 7D is not the best body for wide angle & closed aperture shots, but better for tele& bird shots. I'm playing my "theoretical discussion" card and try to get from you what I can
...Regards,
PS: I'm not sure how I could manage not to post this message as a reply to Wim... but it was... anyway, long live the new edit mode !...
Serkan
[/quote]