New Mandate: 46.8 Degrees; due Januray 17th, 2010
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From: Paul Furman on 13 Dec 2009 17:43 Bruce wrote: > Paul Furman wrote: >> I'm tempted to cheat this mandate by using a 50mm reversed on bellows >> for a macro shot <g> but I won't. > > As a *photographer* you ought to know that the bellows extension would > mean that the field of view was very much less than 46.8 degrees. Field of view becomes an abstract concept for extreme macros. All sorts of strange things happen. For one thing, reversing it might change the field of view, depending on the lens. If the entrance pupil looks like a different size from wither end. Or put a new aperture in the back and make it like a telecentric machine inspection lens which has a field of view that isn't measured with an angle, or if so it would be zero degrees and the entrance pupil moves to infinity behind the lens, so you'd have to call it an ∞mm lens :-) -- Paul Furman www.edgehill.net www.baynatives.com all google groups messages filtered due to spam
From: Troy Piggins on 13 Dec 2009 18:11 * Robert Coe wrote : > On Mon, 14 Dec 2009 07:28:43 +1000, Troy Piggins <usenet-0912(a)piggo.com> > wrote: >: * tony cooper wrote : >: > On Sun, 13 Dec 2009 11:44:50 -0500, Bowser <Canon(a)Nikon.Panny> wrote: >: > >: >>OK, here's the new mandate for the Shoot In, due January 17th, 2010. >: >>Let's simplify things this month. Drag out those 50mm primes and shoot >: >>a pic using nothing but that, or whatever lens you have that provides >: >>the equivilant angle of view of, yes, 46.8 degrees. Use a zoom if you >: >>like, but lock it at "50." Fire at will... >: >> >: >>http://www.pbase.com/shootin/468_degrees >: >> >: >>http://www.pbase.com/shootin/rulzpage >: > >: > I don't understand. I had prime lenses when I was shooting film, but >: > all I have now are zoom lenses including an 18/55. Does that mean I >: > shoot at 50? >: > >: > Does it mean no cropping? Just resizing? >: >: Yeah mate, challenge yourself. As Bowser said, lock the zoom at >: 50 (or crop equiv) and no cropping. :) > > I don't believe he said no cropping. Okay, but what's the point of shooting at "46.8 degrees" if you're then going to crop it to some other field of view? If you have a crop sensor, shoot with a wider lens so the equivalent field of view you end up with is 46.8 deg or thereabouts. Anyway, your interpretation is up to you. Sorry. -- Troy Piggins
From: Troy Piggins on 13 Dec 2009 19:34 * JimKramer wrote : > "Calvin Sambrook" <csambrook(a)bigfoot.com> wrote in message > news:hg3u0c$317$1(a)news.eternal-september.org... > [---=| Quote block shrinked by t-prot: 7 lines snipped |=---] >> shorter focal length will look different. Distances will be compressed >> for a start and foreground objects will appear relatively smaller. Not >> the same thing at all. I'm very surprised to hear that from you Alan, you >> seem to be a very "technical" photographer. >> > Calvin you are mistaken. Unless you use a lens that disproportionately > alters the field of view, i.e. fisheye or really bad barrel distortion, > there will be no difference as long as the same F stop is used. I encourage > you to try it with a zoom lens on a tripod. I kind of agree with Calvin. The perspectives are different. If you shoot a scene with a 100mm lens, then crop it down, and compare that with a shot taken with a 35mm lens, they will look different because you are taking the photo from a different location, so the perspectives are different. No? -- Troy Piggins
From: Michael Benveniste on 13 Dec 2009 19:44 On Sun, 13 Dec 2009 14:41:52 -0500, Bowser <Canon(a)Nikon.Panny> wrote: >Damn shame. According to Big Bob's angle of view calculator, they >should be 46.8: > >http://www.bobatkins.com/photography/technical/field_of_view.html And that's correct, _if_ most nominal 50mm lenses were actually 50mm. But they aren't for reasons dating back to the rangefinder era. >I strongly suggest you dump all the sub-standard gear, get a 5D II >along with a 50mm 1.4 Canon lens and then you can enter the >"competition." I doubt it would help. It's actually because of Canon (and indirectly Leica) that Nikon's 50mm lenses are designed to have a focal length of 51.6mm. Of course, had Nikon done it "right," their 50mm lenses would have had a focal length of 52.3mm to match that of Contax/Zeiss. >OK, how about 46.8 degrees plus or minus 5 degrees? 3 digit precision +/- 10 percent. Sounds about right. That may even cover the shift in focal length with focus distance found in most modern lenses... -- Mike Benveniste -- mhb(a)murkyether.com (Clarification Required) Don't succumb to the false authority of a tool or model. There is no substitute for thinking.
From: Russell D. on 13 Dec 2009 21:15
On 12/13/2009 02:24 PM, Robert Spanjaard wrote: > On Sun, 13 Dec 2009 11:44:50 -0500, Bowser wrote: > >> OK, here's the new mandate for the Shoot In, due January 17th, 2010. >> Let's simplify things this month. Drag out those 50mm primes and shoot a >> pic using nothing but that, or whatever lens you have that provides the >> equivilant angle of view of, yes, 46.8 degrees. Use a zoom if you like, >> but lock it at "50." Fire at will... >> >> http://www.pbase.com/shootin/468_degrees >> >> http://www.pbase.com/shootin/rulzpage > > Well... I'm not going to participate, because I probably won't shoot much > the next couple of weeks. But I did shoot at a fair last August, and for > that I only brought my Sigma 30mm F/1.4 (because of the neutral > perspective and the large aperture). > > BTW, number 4 and 5 are deliberately out of focus. :-) > > http://www.arumes.com/temp/kermis2009/ > Nice. I like those. It would be nice to see some EXIF data unless it's top secret. Russell |