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

[rgacpa at gmail.com (Bob Adler)]

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
> 
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