1Dx, rumoured D800 and the diffraction question

Started Oct 19, 2011 | Discussions thread
Severian The Lame
Contributing MemberPosts: 523Gear list
Like?
Re: 1Dx, rumoured D800 and the diffraction question
In reply to buellom, Nov 16, 2011

buellom wrote:

Hi all,

just wondering where the limits of the „returns on investments“ are when a camera has more pixels. Beside noise there has diffraction to be considered.

At the-digital-picture.com you find a table where the Diffraction Limited Aperture (DLA, see last column) is calculated for several Canon cameras:

http://www.the-digital-picture.com/Reviews/Canon-EOS-5D-Mark-II-DSLR-Digital-Camera-Review.aspx

I understand that “higher resolution sensors generally continue to deliver more detail well beyond the DLA than lower resolution sensors”, but nevertheless I would like to know where diffraction kicks in with the

Canon 1Dx (FF, 18 MP), Sony A77 (APS-C, 24 MP) and the rumoured Nikon D800 (FF, 36 MP).

Thanks in advance for your replies.

Best, Buellom

-- hide signature --

********************
http://www.freude-am-licht.de
********************

Diffraction doesn't suddenly "kick in". It is always present. And sensor resolution has nothing to do with diffraction per se. The limits referred to in the "DLA" mentioned in your quote are very soft limits, not a hard limit where some scary bad diffraction stuff kicks in! Moreover, the DLA is mostly only relevant to pixel peeping at 100%. You shouldn't sweat about these things. On the other hand, it's a rare occasion when I would go over f/13 on APS-C, no matter the resolution of the camera.

Nonetheless, I present for your delectation the following chart (the vertical bars are the Nyquist limits of the respective sensors):

The graphs below show the influence of diffraction on a reasonably sharp lens. The MTFs were generated using slanted edge analysis of 7D raws (converted in LR 3 with default settings except for custom white balance) of an ISO 12233 test chart. Note that while lens MTF can never be better than the diffraction limit (the black curves below), the total system frequency response can.

http://www.imagescienceassociates.com/mm5/merchant.mvc?Screen=SOFTWAREsfredge&Store_Code=ISA001
http://www.graphics.cornell.edu/~westin/misc/res-chart.html

 Severian The Lame's gear list:Severian The Lame's gear list
Canon EOS 7D Canon EOS 5D Mark III Canon EOS M Canon EF 100mm f/2.8L Macro IS USM Sigma 50mm F1.4 EX DG HSM +10 more
Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow