Archived posting to the Leica Users Group, 2010/03/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]It's interesting to study the differences in these (pondering the exact coordinates of "about the same distance"). (I realize this is really basic stuff to most of you so -- skip. I'm just trying to figure it out in a way I can internalize and never have to think about again, as with, say, making a left turn in a 5-speed manual transmission car as I do every day) -- but the main difference appears to be in the angle of the lines leading to Dr. Man's Vanishing Point (a drive-in theater B-film Roger Corman title if ever there was one). With the ones on the 20 starting somewhere behind us and *much*farther apart then they would with a 40mm on a 35mm frame. The ones in the M9 50mm seem almost straight and parallel though the whole image and a 40mm on the M9 would only be a little less parallel than that. To my extremely amateur and unpracticed eye the image of Geoff looks roughly like what I'd get with my 28mm f/2.8 AIs on my old Nikon FE if I held the camera about a foot-and-a-half or a foot closer to Geoff than Howard likely did here. Or a 35mm held a bit further back than that, maybe eight inches or twelve. So for me, I'm starting to picture the crop not as snipping the edges away from a two-dimensional photographic print (and then possibly blowing it up a little or a lot -- this is how many publications and people basically describe it); NOR is it a doubling of the size of everything in the len's view (absolutely not that, in fact; even though this is implied quite often); but I'm picturing the 20mm image on the 2X sensor as a three-dimensional rectilinear cone -- a four-cornered dunce cap pointed toward the center/rear of the image -- with the some of the wider end of it sawed off so it "begins" closer to the focal point than it would as a regular 20mm full frame image; the same effect roughly achieved with a 20mm full frame held a little closer to the image (but not half the distance closer: no, less than that). Sorry. But thanks for those images Geoff. Vince On Fri, Mar 26, 2010 at 9:16 AM, Geoff Hopkinson <hopsternew at gmail.com>wrote: > Howard grabbed this shot over dinner recently, no doubt intent on showing > me > consuming dessert. > The next shot is with my 50 on the M9 (pointing across the table the other > way but about the same distance). > http://gallery.leica-users.org/v/hoppyman/1/P1010223.jpg.html > > > > Cheers > Geoff > http://www.pbase.com/hoppyman > > > On 26 March 2010 18:22, Richard Man <richard at imagecraft.com> wrote: > > > DoF I meant as Depth of Field (Death of Field?), i.e. the amount of > > "in-focus" zone, which is related to the focal length, distance to > subject, > > distance of viewing, and size of print, and of course, the circle of > > massive > > confusion. > > > > On Fri, Mar 26, 2010 at 1:13 AM, Vince Passaro <passaro.vince at > > gmail.com > > >wrote: > > > > > That's what I thought you meant. But ain't that DofF? > > > > > > I'm going to make a pronouncement now: nobody really understands this > > crop > > > factor thing in a rational way: some of us (not I, but others, among > you > > > guys) know from practice how a 35mm lens will look on a full frame M9 > > > versus > > > a 1.3 M8 versus a 1.5 Nikon versus a 2X G series, but no one can > explain > > > it. The fabulous and popular new 20/1.7 for all you G-sters is a good > > > starting point. I look up and see new postings from the lens every day. > > And > > > the images don't look like 20mm images and they don't look like 40mm > > images > > > either, except when they've been cropped even further on PS or LR. > > > > > > On Fri, Mar 26, 2010 at 3:55 AM, Richard Man <richard at > > > imagecraft.com> > > > wrote: > > > > > > > Perspective as in .... the vanishing point!! > > > > > > > > e.g. if you take a photo of a person with a building way behind them. > > On > > > a > > > > 40mm perspective, the building will appear one size, but a 20mm > > > perspective > > > > will (I'm pretty sure) make the building look smaller. > > > > > > > > > > > > On Fri, Mar 26, 2010 at 12:30 AM, Vince Passaro < > > passaro.vince at gmail.com > > > > >wrote: > > > > > > > > > Richard: I understand "closeness" and "frame" and DofF here, but I > > > don't > > > > > know what you mean by "perspective" in this case. Can you explain > the > > > > > perspective part? > > > > > > > > > > On Fri, Mar 26, 2010 at 1:04 AM, Richard Man < > richard at imagecraft.com > > > > > > > > wrote: > > > > > > > > > > > Vince, try this: > > > > > > > > > > > > You are getting a ~40mm closeness, e.g. if you want to frame a > > > > headshot, > > > > > > you > > > > > > will end up ~where you would be if you are using a 40mm lens on a > > > 35mm > > > > > > camera, but the perspective (and DoF) would still be 20mm. Hence > > the > > > > look > > > > > > is > > > > > > not quite like straight 40mm on a 35mm camera. > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > Leica Users Group. > > > > > See http://leica-users.org/mailman/listinfo/lug for more > information > > > > > > > > > > > > > > > > > > > > > -- > > > > // richard <http://www.imagecraft.com/> blog: < > > > > http://imagecraft.wordpress.com> > > > > // portfolio: <http://www.imagecraft.com/pub/PICS/AnotherCalifornia2 > > > > > > // mailing lists: <http://www.imagecraft.com/contact.html> > > > > [ For technical support on ImageCraft products, please include all > > > previous > > > > replies in your msgs. ] > > > > > > > > _______________________________________________ > > > > Leica Users Group. > > > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > > > > > > > _______________________________________________ > > > Leica Users Group. > > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > > > > > > > > -- > > // richard <http://www.imagecraft.com/> blog: < > > http://imagecraft.wordpress.com> > > // portfolio: <http://www.imagecraft.com/pub/PICS/AnotherCalifornia2> > > // mailing lists: <http://www.imagecraft.com/contact.html> > > [ For technical support on ImageCraft products, please include all > previous > > replies in your msgs. ] > > > > _______________________________________________ > > Leica Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >