If the limit is passed then you must be blurring.Yes that is more up to date than "cambridge in colour". Thank you.
C
Landscape comparison pics between cropped and FF sensors?
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Yes that is more up to date than "cambridge in colour". Thank you.
C
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This was definately the sort of answer I was after- Please do carry on your debate - It's going totally over my head
Glad to have helped
I thought for a minute that me and Donna had hijacked your thread. Silly me 
I think what I was trying to describe was the harvesting of photons - the more you have, the more you can do with an image. It's no surprise that professional landscapers use the biggest format they can get hold of, often big film cameras.
www.luminous-landscape.com is a good site for this kind of thing, and I think Micheal Reichmann (site owner, who runs a fine art studio selling huge and glorious landscape prints) uses a digital Hasselblad as weapon of choice, although he currently has a Canon 7D on test which will be interesting.
Just to throw the cat amongst, here's a link to a comparison he did with a 39mp Hasselblad and Canon G10, where people were asked to say which prints were from which camera - and they couldn't tell. http://www.luminous-landscape.com/reviews/kidding.shtml For kit lovers everywhere, this is very disturbing
Les McLean
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Yes, the 16-35mm (MKII) is generally accepted as the lens of choice for serious landscape photographers (on a Canon FF body), although the canon 17-40mm F4L is a close second (IMO)
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If your table is correct DonnaM, I can't use my zoom lenses on a 7d, and barely on a 40d
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I think I see what you're driving at, which is what I touched on earlier, to which I would say it is not diffraction per se, but an alleged effect of diffraction. Which I don't believe has much significance. If it did, it would mean that increasing the number of pixels reduced sharpness as a matter of course at most commonly used apertures, and that is evidently not the case.
The chart refers to pixel size and spacing, not to number of pixels, or to pixel density, which are quite different measurements. What about the gaps between the pixels, and their shape? Both would have a big impact if this data was relevant in practice (or was thoroughly researched).
Charts and calculations are all very well, but what does the real thing look like? You are very well placed with various high resolution cameras to hand, with different formats. The kind of differences you are suggesting, and their extent, would be clearly visible in side by side comparison of 100% crops.
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Actually, what is the unit on the Aperture column? f/mm? or mm?
As diffraction effects are effectively angle based, the total effect and spacing would be dependant on the distance from the diffraction source and the plane which the image is being sensed on.
As diffraction effects are effectively angle based, the total effect and spacing would be dependant on the distance from the diffraction source and the plane which the image is being sensed on.
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It's not that you can't use, they will just be softer than on a FF sensor camera.
Pixel size & spacing and pixel density are mathematically related. I have assumed that the gaps between pixels are small compared to the pixel itself otherwise it would be a pretty crap sensor. I would wholeheartedly agree on what it looks like in the real world. My chart describes when a point source of light gets spread into a disc the size of one pixel by diffraction. That is cold science but how that relates to picture degradation will be camera dependent as each manufacturer will interpret their raw images differently. What I am trying to say and what I thought this thread was about is that we all know as we reduce the aperture images go soft, in the digital age where we use pixels rather than film grain we can predict when this process starts mathematically and it starts sooner in cameras using sensors with smaller closer spaced pixels.
The aperture unit is f/ and yes you are correct though that does not appear in the commonly uses Airy disc formula see Wiki for details.
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Thanks for that Donna. But putting it all to one side for a moment and looking at what happens in practise, this is what I'm understanding from you.
If I take a two identical images, one with my 350D which has 6mp and one with my 40D with 10mp, with the same lens set at say f/11 when diffraction should be very clearly visible, you seem to be saying that the 40D image will be considerably less sharp. And if I had a 50D 15mp, it would be less sharp again.
Have I got that right? Because it is obviously not true.
What is the real, visible effect of what you are saying? I'm struggling with the practical significance of this concept.
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It would be right if all other things are equal which they are not (necessarily). All cameras using Bayer type sensors need anti aliasing and other software to interpret a full colour image from the red green and blue pixel signals and very often some sharpening is applied that further confuses things. How any camera performs in real life is very much down to its software and that, like sensors has been constantly improving. My chart relates to the physics of light being detected by a single photosensitive pixel - end of story. Very clever software engineers can mask that effect as they translate the information from Bayer RGB matrix signals into a full colour image but the underlying physics still remains. The real world upshot of all this may well be as you say, your 40D is "better" than your 350D and I could not deny your findings but I suspect that the improvement is in the software not the sensor.
At the end of the day we have chosen our cameras for other reasons than Airy disc performance, the sun is out here in Cumbria (a rarity this summer) so I will now go out to enjoy using mine. Many thanks for the opportunity to discuss this Hoppy but I think we may well as call it quits eh?
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It is a little strange these calculations. By the un-united column being f/mm, then this means a 400mm prime would not be showing diffraction until f/66 on a 40d. I am sure that is not the case.
However, a 17mm at f/2.8 would already be showing diffraction problems on a 7d
The 7d of course having micro-lenses which remove any spacing between pixels.
Think I am going to get my old Halliday Resnik and Walker out on this
However, a 17mm at f/2.8 would already be showing diffraction problems on a 7d
The 7d of course having micro-lenses which remove any spacing between pixels.
Think I am going to get my old Halliday Resnik and Walker out on this
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