Archived posting to the Leica Users Group, 2014/03/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I think maybe Howard is suggesting doubling the pixel count at the same image size, e.g., an 18" wide print at 720ppi? As I recall, Jeff Schewe suggests changing the resolution from 360 to 720ppi for printing. I tried that but didn't see any benefit. As far as up-sizing for a larger print, my guess is that one would need two files - one 9" print at 360 and one 18" print at 360. I think I have just exceed my pay grade. Ken On 3/22/2014 6:45 PM, Bob Adler wrote: > Hmmm. Lemme check again. Could have been a cropped image I used. > But my question still stands: if I double the pixels to get smothered, > more realistic details as Howard stated, how do I then downsize the > dimensions to retain that effect? > Thanks, > Bob > > Sent from my iPad > >> On Mar 22, 2014, at 4:38 PM, Ken Carney <kcarney1 at cox.net> wrote: >> >> Bob, >> >> There must be a wrong setting somewhere. I don't have a Leica M but I >> imagine the file size is larger than 3352 px. My 5D II files are 5616 >> px. Jeff Schewe says that upsizing to 200% is usually no problem and >> that has been my experience with "preserve details" in Photoshop. The >> 5616 px files are 18.7" at 300 ppi, so I could have some cropping room >> with modest upsizing in PS. Lord only knows what we are talking about >> with your MF gear :) or whatever the emoticon is for envious. >> >> Ken >> >>> On 3/22/2014 4:59 PM, Bob Adler wrote: >>> Hi Howard, >>> Trying to wrap my layman's brain around this. >>> When I bring an M240 file into CC from LR with no resolution change, it >>> is 2,682 x 3352 px at 360dpi. It is 7.45 x 9.311 inches in size. >>> So if I use bicubic smoother and upsize the number of pixels to 2x(2,682 >>> x 3,352) or 5,364 x 6,704 at 360dpi I should get the effects you are >>> predicting: sharper looking images with smoother gradients BUT is now a >>> 14.9 x 18.622 inch size. >>> What needs to be done then if I want my print size to be at the original >>> dimensions: 7.45 x 9.311 inches? Or a larger size than the now 14.9 x >>> 18.622 inches? >>> Thanks, >>> Bob >>> >>> Sent from my iPad >>> >>>> On Mar 21, 2014, at 7:40 PM, Howard Ritter <hlritter at bex.net> wrote: >>>> >>>> Poking around with huge degrees of enlargement and up-sampling (but >>>> perhaps not irrelevantly so for making large prints of landscapes, etc) >>>> in PS with files from M9, M240, NEX-7,and D800 (not E), I found: >>>> >>>> 1. The D800?s 36MP FF sensor with the current Nikkor 35/1.4 at f/5.6 >>>> produces conspicuously better detail near the limit than the M240?s >>>> 24MP FF sensor with the Summilux 35 ASPH at 5.6 does, and the NEX?s >>>> 24MP APS-C sensor (same pixel size as a 54MP FF sensor) with the kit >>>> 18-55 zoom set to produce the equivalent of FF 35mm FL produces about >>>> the same image resolution as the M. This is not the end-all of >>>> important sensor characteristics, but it can be an important one under >>>> some circumstances. What this tells me is not only that a 24MP FF >>>> sensor does not put modern premium prime glass to the test, but also >>>> that even inexpensive modern kit-zoom glass would not be outclassed by >>>> a 54MP FF sensor with regard to resolution. This would seem exactly >>>> analogous to the role of fine-grain film back in the day (anyone >>>> remember that stuff?). One wonders what Leica AG (and every other >>>> manufacturer?s) engineers make of this fact, and whether there is a >>>> 54MP camera (M540?) or beyond in their minds. Of course, as with >>>> Microfile film, the part of the "need spectrum? such capability >>>> occupies would be very small. Still, Microfile had its enthusiasts >>>> beyond microfilming documents for efficient filing. I?d like to know >>>> what pixel count (disregarding tradeoffs in noise etc) corresponds to >>>> the innate resolving power of the best modern glass at center and >>>> optimum aperture. Given the improvement produced by the ~25% linear >>>> increase from 24MP to 36MP and the 50% increase to (an effective) 54MP, >>>> it?s clearly at least 1.5 times, and maybe twice, the linear count of a >>>> 24MP sensor (i.e., ~50 to 100MP). And what pixel count corresponds to >>>> the best general-use emulsions from the Age of Film (K64, Plus-X, etc) >>>> in terms of lp/mm? Anyone have a reference? These results also make me >>>> wonder about the actual utility of the new superpremium normal lenses, >>>> the 50mm Summicron ASPH and Nikon?s 58mm 1.4, with current sensors. >>>> Maybe they extend the envelope in which they are not outmatched by the >>>> sensor further from the center and from the optimal aperture beyond >>>> what lesser lenses do. >>>> >>>> 2. Doubling the linear number of pixels H and W in PS produces a >>>> clearly smoother image, with what appears to be better resolution, near >>>> the limit. I know that in theory this is illusory, as creating new >>>> pixels from the averages of their parent and neighboring pixels cannot >>>> add new information. But the appearance of doing so is strong, and I >>>> think this is a result of the fact that for the most part, natural >>>> subjects are not wholly random but have fractal dimensions and high >>>> degrees of internal correlation: for example, linear or continuous >>>> features are common, such as areas, edges and boundaries, and so on. >>>> Such features are not likely to be confined to a few pixels but to >>>> extend over many. Multiplying pixels as is done in PS can create a >>>> powerful illusion of making a linear feature seem better defined and >>>> sharper. If you took a picture of a wall of tiny square, randomly >>>> colored tiles such that the image of 4 tiles in a square exactly >>>> occupied an entire pixel, the original file would make the 4 look like >>>> 1, with a color representing their average (this is a thought >>>> experiment, ignoring the fact that we deal, Foveon aside, with >>>> single-color pixels and Bayer patterns). Pixel-doubling would then >>>> produce not a faithful depiction of the actual 4 tiles making up the >>>> square, but an illusion of 4 tiles and an artificial average color for >>>> each of the virtual tiles. But this is a very unnatural situation, and >>>> in real life, with natural subjects, what appears at any given point in >>>> an image is likely to closely resemble what appears at the points that >>>> correspond to the adjacent pixels, so that pixel-doubling does, in at >>>> least a semi-real sense, have the effect of increasing the visual >>>> resolution of the image. I think of up-sampling the original file to >>>> increase the pixel count as ?unmasking? information that was implicitly >>>> there as a result of the innate characteristics of the physical world. >>>> >>>> ?howard >>>> >>>> _______________________________________________ >>>> 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 >> >> >> _______________________________________________ >> 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