small aperture test
in [Digital Cameras]
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From: Dudley Hanks on 4 Nov 2009 02:17 I've heard a lot about how the cropped sensor cameras are defraction limited to around f/8 - f/11, so I thought I'd see what kind of an image my XSi puts out at a small aperture. I snapped on my 50mm f/1.8 lens and set it up to take a picture at f/22, with a shutter speed of 1 sec. How did it turn out? http://www.snaps.blind-apertures.ca/images/SmallWinterPortrait.jpg (quick download) http://www.snaps.blind-apertures.ca/images/SelfPortraitWinter.jpg (full size) Take Care, Dudley
From: David J Taylor on 4 Nov 2009 02:32 "Dudley Hanks" <> wrote in message news:4U9Im.50459$Db2.29545(a)edtnps83... > > I've heard a lot about how the cropped sensor cameras are defraction > limited to around f/8 - f/11, so I thought I'd see what kind of an image > my XSi puts out at a small aperture. > > I snapped on my 50mm f/1.8 lens and set it up to take a picture at f/22, > with a shutter speed of 1 sec. > > How did it turn out? > > http://www.snaps.blind-apertures.ca/images/SmallWinterPortrait.jpg > (quick download) > > http://www.snaps.blind-apertures.ca/images/SelfPortraitWinter.jpg (full > size) > > Take Care, > Dudley Difficult to say, Dudley. Yes, the image isn't "tack sharp" (a term I loathe), so there could be some diffraction visible, but I'm also not convinced that the subject didn't move within the 1 second exposure! Cheers, David
From: Dudley Hanks on 4 Nov 2009 02:59 "David J Taylor" <david-taylor(a)blueyonder.not-this-bit.nor-this.co.uk.invalid> wrote in message news:t6aIm.1501$Ym4.551(a)text.news.virginmedia.com... > "Dudley Hanks" <> wrote in message news:4U9Im.50459$Db2.29545(a)edtnps83... >> >> I've heard a lot about how the cropped sensor cameras are defraction >> limited to around f/8 - f/11, so I thought I'd see what kind of an image >> my XSi puts out at a small aperture. >> >> I snapped on my 50mm f/1.8 lens and set it up to take a picture at f/22, >> with a shutter speed of 1 sec. >> >> How did it turn out? >> >> http://www.snaps.blind-apertures.ca/images/SmallWinterPortrait.jpg (quick >> download) >> >> http://www.snaps.blind-apertures.ca/images/SelfPortraitWinter.jpg (full >> size) >> >> Take Care, >> Dudley > > Difficult to say, Dudley. Yes, the image isn't "tack sharp" (a term I > loathe), so there could be some diffraction visible, but I'm also not > convinced that the subject didn't move within the 1 second exposure! > > Cheers, > David Thanks, David, I'll try it again with an inanimate object, or a faster shutter speed. I suppose, if the test is to be useful, I should also take an equivalent pic of the subject using a wider aperture so the two images can be compared. Take Care, Dudley
From: David J Taylor on 4 Nov 2009 03:10 "Dudley Hanks" <dhanks(a)blind-apertures.ca> wrote in message news:DvaIm.50463$Db2.1880(a)edtnps83... [] > Thanks, David, I'll try it again with an inanimate object, or a faster > shutter speed. > > I suppose, if the test is to be useful, I should also take an equivalent > pic of the subject using a wider aperture so the two images can be > compared. > > Take Care, > Dudley Indeed, yes. Tripod and very careful focussing come to mind. While the degradation due to diffraction at f/22 is noticeable with careful inspection, you probably wouldn't notice with normal use - just sharpen a little more. Diffraction on small sensor cameras is one reason why some of them are limited to f/8 or f/11 as the smallest aperture. Cheers, David
From: Ofnuts on 4 Nov 2009 05:49
David J Taylor wrote: > > "Dudley Hanks" <dhanks(a)blind-apertures.ca> wrote in message > news:DvaIm.50463$Db2.1880(a)edtnps83... > [] >> Thanks, David, I'll try it again with an inanimate object, or a faster >> shutter speed. >> >> I suppose, if the test is to be useful, I should also take an >> equivalent pic of the subject using a wider aperture so the two images >> can be compared. >> >> Take Care, >> Dudley > > Indeed, yes. Tripod and very careful focussing come to mind. While the > degradation due to diffraction at f/22 is noticeable with careful > inspection, you probably wouldn't notice with normal use - just sharpen > a little more. Diffraction on small sensor cameras is one reason why > some of them are limited to f/8 or f/11 as the smallest aperture. > Some of them haven't even got diaphragm and the "diaphragm" is simulated with a neutral filter. -- Bertrand |