[Leica] Random observations on resolution (long and irrelevant to the craft of being a good photographer)

[rgacpa at gmail.com (Robert Adler)]

Geoff is correct with pixel dimensions; I must have been looking at a
cropped image. Question still stands though...


On Sat, Mar 22, 2014 at 4:45 PM, Bob Adler <rgacpa at gmail.com> 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
>



-- 
Bob Adler