Rongnongno wrote:
The importance of the D/P/S-PI matter. Many here and elsewhere consider it a myth but if the same folks would even consider taking the time to think they may remember some of the following...
The D, P ans S represent a pixel. That alone should kill the 'myth' argument.
A pixel is the lowest form of a digital image regardless of media used to create, modify or see it.
The smallest pixel in a display is on the screen of some smart phones and the largest on large screen TVs.
The size influences the light quality and the resolution.
72DPI
Many folks are at war with the 72DPI... Where do you find it? Who use that crappy older standard? Well, every WEB site that converts or resize an image to display it on their page (like UHH - not to name one) use JPG 72DPI. Just saying. Problem? The larger the image you upload and then reduced byt the host server the softer it appears, simple at that. Create an image that corresponds to UHH display size (600x800) with 72 DPI and it will be sharp. I have posted two images for comparison long (few months) ago.
Display
If you have the right drivers for your OS and display you should have no issue unless you use a ruler to check for printing size. Note that many imaging software ask for your screen native DPI. Ever wonder why? Simply because more often than not high pixel displays use virtual resolution. But then again this also a myth.
Printing
Interestingly enough, many of those high end camera produce so-so prints when other using less capable produce incredible prints... Ever wondered why?
Here again very few use the tools at their disposal to print correctly. To have the optimal printing rendition you must set your image to the ratio you want then set the DPI then resize the image in inches (or centimeters) it will be printed at and then make corrections due to the re-sampling modification. Once again this is not a joke for any serious photographer who prints. For the other it is a myth. In short, the larger the image the more prone to errors when resized by the printer - EVEN if you use a calibrated monitor and an ICC that is for the printer and the paper selected.
Camera
The larger the pixel the better the light quality but the lower the resolution. One can successfully argue* the light quality is not all that much even if in a lab it is. High end cameras like the Canon 50mb, the current D810 offer the smallest pixel in the DSLR market but....
A smaller pixel means it is more prone to record minute motion than a larger pixel. Here again the pixel is important in more ways than one.
Then you have the use of the image... High pixel does not mean 'crop' to correct poor skills or poor choice of lens. It means you can print larger (MUCH larger) and better prepare for the end product.
So... DPI, PPI, SCI and whatever per inch just does not count for anything. I read it some where, it is true, it simplifies everything. Only stupid peoples who think they are photographers use this old legend.
-----
* Health, taste and environment when viewing are constant factors.
The importance of the D/P/S-PI matter. Many here ... (
show quote)
I mostly agree with everything you've written, but on the topic of pixel count, it's not about making large prints. Billboards have been made from 8 mp images, or 3264x2448 px. I'm sure you've seen the Apple billboards advertising the image quality of their iPhone 6. In similar fashion, graphic wraps for semi-trucks have been made from medium resolution digital cameras.
http://lifeinlofi.com/more/iphone-photo-sizes-2007-2013/Museums and galleries routinely display giant prints - 40x60 and larger - made from 6-18 mp cameras.
The whole thing has to do with the eye's ability to perceive fine detail and image flaws. If you were to look at a newspaper's fine print, and assuming you have perfect vision, you'd have no problem reading it at 12-15 in away. But paste that newspaper on the wall and move away, to say 10 feet, and you wouldn't be able to read anything but the headlines. Pictures printed in newspapers look pretty low quality due to the 85 LPI (lines per inch) halftone screen. Again, up close images look pretty bad, but when you move away, your eyes can no longer see the dots, and the images appear much smoother.
So, high MP cameras are not about making giant prints, as much as they are about cropping. And cropping is something that can be used to focus the eye on an element in the picture, or remove extraneous elements that do not contribute to the main focus, and in the case of wildlife and sports, to create emphasis. Ideally I would love to shoot my birds in flight with a 1200mm or longer lens and not have to crop (much), but the mechanics and logistics of using a lens that large (it would have to be fast to be able to use faster shutter speeds and reasonable ISOs, it would most certainly be tripod mounted, and it would be next to impossible to track something moving in the viewfinder.
I often down-sample an image in order to average the noise in adjacent pixels, resulting in less overall noise and slight improvement in image detail. DXO Labs has written on the subject of down sampling and after reading their position it makes a lot of sense.
On the other hand, when I do landscape, I rarely crop provided I can position myself exactly where I want to be and there are no obstructions in the way or distracting elements in the scene. I do find I crop more with a prime lens than a zoom. Sometimes you just can't get into the perfect position, like when I am hanging off wet slippery rocks trying to get a good shot of a waterfall, or hiding behind a tree trying to get a shot of a black bear without becoming bear chow.
If I use a very wide angle lens I will crop the edges to minimize the volume distortion that can be ugly a the sides and corners. Also, if I end up tilting the camera upwards, cropping is necessary when you perform the correction for converging verticals.
Sometimes when I shoot macro I am really close to the ground, and it is not always practical to lie in the mud on my belly to get a great composition. So I back off a bit, shoot a wider view, and crop later.
I just wanted to lend some clarity to the notion that cropping is to make up for wrong lens and shooting distance choices, which it most certainly does, but there are other perfectly valid reasons to crop.
Most small cameras have pixel sizes that are far below those found in the D810, 5DS and others.
Here is a list of some popular cameras and pixel sizes ranging from high quality point and shoot to high mp full frame cameras:
Nikon D810 - 23.72 µm²
Canon 5DS - 17.06 µm²
D7200 - 15.13 µm²
Canon 80D - 13.91 µm²
Olympus OM-D E-M1 Mark II - 11.02 µm²
Sony RX 10 III - 5.76 µm²
Canon G 16 - 3.50 µm²
You can find a pretty exhaustive list at:
https://www.digicamdb.com/specs/canon_eos-80d/