Archived posting to the Leica Users Group, 2015/01/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Yes, and the first thing the picture editor did when he got that uncropped print was to mark it for cropping and send it to be made into a cut. On Mon, Jan 5, 2015 at 8:06 PM, Mark Rabiner <mark at rabinergroup.com> wrote: > People always spoke of the sanctity of never cropping their pictures. > People > in Magnum even did that. But I suspect it was all about the precious thin > black borders. A print in the stack with no black border stood out as weak. > > > On 1/5/15 8:46 PM, "Ken Iisaka" <ken at iisaka.com> wrote: > > > Yes, Mark, been there done that. > > > > Also, when using shorter lenses, such as Zeiss Hologon, the actual > exposed > > area on the film was slightly larger than the actual aperture of the > > shutter, since the rectangular aperture was a millimeter or two in front > of > > the film surface itself. > > > > On Mon, Jan 5, 2015 at 5:23 PM, Mark Rabiner <mark at rabinergroup.com> > wrote: > > > >> Most people I knew in the 90's and before filed out their negative > carriers > >> of their enlargers so they'd both get black borders from the clear > edges of > >> the film before the sprocket holes; and also insure the people looking > at > >> it > >> that not cropping had been done. We did this with our medium format > negs as > >> well. And our 4x5 sheet film. Full frame black borders. Soon at least > the > >> Omega company started making the neg carriers already wide enough so > we'd > >> not have to file them. > >> On the paper we'd leave ample white borders. Minor White said if you > don't > >> leave am inch border you're print was not archival. > >> So no your image size or magnification was not determined so much by > paper > >> shape. We printed the entire neg. if we were shooting with a Nikon F and > >> other flagship cameras which gave us 100% viewing then we were seeing > >> exactly what we'd be getting at the edge. > >> > >> > >> On 1/5/15 6:06 PM, "Ken Iisaka" <ken at iisaka.com> wrote: > >> > >>> When comparing sensors with different aspect ratios, the use of the > >>> diagonal to calculate the factor is overly simplified. > >>> > >>> With the diagonal measurement of roughly 21.6mm, the FourThirds sensor > is > >>> often said to have a crop factor of 2.0, compared to a "full frame" > 35mm, > >>> which has a diagonal measurement of 43mm. This implies that a 25mm lens > >> on > >>> FourThirds is thought to work like a 50mm lens on a "full frame" 35mm. > >>> > >>> But it's not quite that way. > >>> > >>> What you should be comparing is NOT the diagonal measurement of the > >>> sensors, but the dimensions of the actual area of the sensor that will > be > >>> used for the final image. > >>> > >>> So, if you are creating an image with an aspect ratio of 4x5, you are > not > >>> using the full area of the sensor, but only a smaller area of 24x30mm, > >> and > >>> 13x16.25mm. When doing so, the "crop factor" is not 2.0, but is merely > >>> 1.846. The different is not all that big, but is not insignificant > >> either. > >>> A 25mm lens on FourThirds works more like a 46mm lens, not 50mm. There > >> are > >>> some of us, who split hair between smaller than that. > >>> > >>> If you're creating an image with an aspect ratio of 5x7, the situation > >>> changes. You'd be using an area of 24x33.6mm from a 35mm sensor, but > >>> 12.38x17.33mm. Here, the effective "crop factor" is 1.9386. > >>> > >>> Want to make it more complicated? Sure, I can do that. > >>> > >>> We didn't really use the full 24x36mm area of the 35mm camera. The > slide > >>> mount or enlarger negative carrier usually cropped the image to 23x35mm > >> or > >>> so. So, if you are creating an aspect 4x5 image, the effective crop > >> factor > >>> was only about 23/13 = 1.77, since you only used an area that measures > >>> 23x28.75 to create your image. > >>> > >>> So, a 12mm lens on FourThirds behaves more like a 21mm lens instead of > a > >>> 24mm on a 35mm film camera (12*1.77 = 21.24) > >>> > >>> With hidden complexities such as this, I find all the discussions about > >> the > >>> crop factor, etc. to be absolutely absurd. Sorry, Mark. > >>> > >> > >> > >> > >> > >> -- > >> Mark William Rabiner > >> Photographer > >> http://gallery.leica-users.org/v/lugalrabs/ > >> > >> > >> > >> _______________________________________________ > >> Leica Users Group. > >> See http://leica-users.org/mailman/listinfo/lug for more information > >> > > > > > > > > > -- > Mark William Rabiner > Photographer > http://gallery.leica-users.org/v/lugalrabs/ > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > -- Regards, Sonny http://sonc.com/look/ Natchitoches, Louisiana 1714 Oldest Permanent Settlement in the Louisiana Purchase USA