small aperture test
in [Digital Cameras]
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From: John Navas on 5 Nov 2009 13:19 On Thu, 05 Nov 2009 23:39:40 +1000, Bob Larter <bobbylarter(a)gmail.com> wrote in <4af2c78c$1(a)dnews.tpgi.com.au>: >The 50mm/F1.8II is a surprisingly good lens for the money. I've taken a >lot of excellent shots with mine, so please don't sell it short! >I've since 'upgraded' to a 50mm/F1.4, but it's not as much of an >improvement as you might expect from the price difference. What you get for the money with the f/1.4 over the f/1.8 is speed, not IQ. -- Best regards, John Buying a dSLR doesn't make you a photographer, it makes you a dSLR owner. "The single most important component of a camera is the twelve inches behind it." -Ansel Adams
From: Bob Larter is Lionel Lauer - Look it up. on 5 Nov 2009 18:14 On Thu, 05 Nov 2009 23:40:44 +1000, Bob Larter <bobbylarter(a)gmail.com> wrote: >Better Info wrote: >> On 4 Nov 2009 17:49:36 GMT, Chris Malcolm <cam(a)holyrood.ed.ac.uk> wrote: >> >>> Dudley Hanks <dhanks(a)blind-apertures.ca> wrote: >>> >>>> "David J Taylor" >>>> <david-taylor(a)blueyonder.not-this-bit.nor-this.co.uk.invalid> wrote in >>>> message news:t6aIm.1501$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. >>> The diffraction limit of aperture is usually taken to be the last >>> aperture in a decreasing series of sharper apertures, i.e., stopping >>> down further makes the image softer because of diffraction. But that's >>> not a fixed aperture, it depends on such things as the exact sensor >>> pixel size (or crop factor) not just the nominal "1.5", on the >>> resolution of the lens, and whether you're looking at the centre of >>> the image or the edges or some compromise between the two. Why >>> should it depend on those? Because the point at which an extra stop's >>> worth of diffraction softening becomes larger than how much other >>> kinds of lens aberration are being improved by stopping down obviously >>> will depend on the size of those other errors. In other words better >>> lenses will have larger sharpest apertures. >>> >>> I find for example on my Sony A350 that my general purpose zoom is >>> usually sharpest at f8, but at its soft extremes that becomes f11, and >>> my 50mm prime is sharpest at f5.6. >>> >>> This can only be established for your camera and each of your lenses >>> by taking a comparative series of shots while varying the aperture. On >>> zooms it may change with focal length. >> >> Your test won't work. > >Please, get back to us when you grow a clue. Bye! Bob Larter's legal name: Lionel Lauer Home news-group, an actual group in the "troll-tracker" hierarchy: alt.kook.lionel-lauer (established on, or before, 2004) Registered Description: "the 'owner of several troll domains' needs a group where he'll stay on topic." <http://groups.google.com/groups/search?hl=en&num=10&as_ugroup=alt.kook.lionel-lauer> "Results 1 - 10 of about 2,170 for group:alt.kook.lionel-lauer."
From: Bob Larter on 5 Nov 2009 20:56 John Navas wrote: > On Thu, 05 Nov 2009 23:39:40 +1000, Bob Larter <bobbylarter(a)gmail.com> > wrote in <4af2c78c$1(a)dnews.tpgi.com.au>: > >> The 50mm/F1.8II is a surprisingly good lens for the money. I've taken a >> lot of excellent shots with mine, so please don't sell it short! >> I've since 'upgraded' to a 50mm/F1.4, but it's not as much of an >> improvement as you might expect from the price difference. > > What you get for the money with the f/1.4 over the f/1.8 is speed, > not IQ. The f1.4 also has more aperture blades, so the bokeh is a bit nicer as well. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^---------------------------------------------------------------
From: Outing Trolls is FUN! on 5 Nov 2009 20:14 On Fri, 06 Nov 2009 11:56:53 +1000, Bob Larter <bobbylarter(a)gmail.com> wrote: >John Navas wrote: >> On Thu, 05 Nov 2009 23:39:40 +1000, Bob Larter <bobbylarter(a)gmail.com> >> wrote in <4af2c78c$1(a)dnews.tpgi.com.au>: >> >>> The 50mm/F1.8II is a surprisingly good lens for the money. I've taken a >>> lot of excellent shots with mine, so please don't sell it short! >>> I've since 'upgraded' to a 50mm/F1.4, but it's not as much of an >>> improvement as you might expect from the price difference. >> >> What you get for the money with the f/1.4 over the f/1.8 is speed, >> not IQ. > >The f1.4 also has more aperture blades, so the bokeh is a bit nicer as well. Post-processing plugins with depth-map masks afford an infinite number of aperture blades for bokeh, as well as even emulating catadioptric lens systems no matter what camera took the image, and more. Catch up, know-nothing snapshooter DSLR-Troll!
From: Dudley Hanks on 5 Nov 2009 22:40
"Bob Larter" <bobbylarter(a)gmail.com> wrote in message news:4af37455$1(a)dnews.tpgi.com.au... > John Navas wrote: >> On Thu, 05 Nov 2009 23:39:40 +1000, Bob Larter <bobbylarter(a)gmail.com> >> wrote in <4af2c78c$1(a)dnews.tpgi.com.au>: >> >>> The 50mm/F1.8II is a surprisingly good lens for the money. I've taken a >>> lot of excellent shots with mine, so please don't sell it short! >>> I've since 'upgraded' to a 50mm/F1.4, but it's not as much of an >>> improvement as you might expect from the price difference. >> >> What you get for the money with the f/1.4 over the f/1.8 is speed, not >> IQ. > > The f1.4 also has more aperture blades, so the bokeh is a bit nicer as > well. > > -- > W > . | ,. w , "Some people are alive only because > \|/ \|/ it is illegal to kill them." Perna condita delenda est > ---^----^--------------------------------------------------------------- Any difference in number / quality of elements? Take Care, Dudley |