About making pictures   - Monitors  by  Waeshael

 

resolution

By the time the image is scrunched down to make it small enough to fit within a browser window, any resolution benefit, from the higher number of pixels, is lost.


I have examined pictures made by cameras from $50 to $15,000 and I have not been persuaded that one is better than the other when it comes to showing images on the WEB in a browser window. No matter what the initial resolution of the camera, the image must be reduced to somewhere between 2 and 4 megapixels. The bigger the reduction, and the more the scaling, the more potential for image degradation.


There is another issue with scaling that is never discussed, and that is the unequal scaling factor of large and small objects. Small objects below a certain size should become invisible during the scaling process. For example: a two pixel wide object that on scaling would normally become less than one pixel and invisible, is rebuilt by the software so that retains its visibility, but is larger than it should be. A rigging wire on a boat that is 1/4” in diameter and only 1 pixel wide, when scaled 4:1 for the web is still 1 pixel wide, and this looks out of proportion as it appears to be 1 inch in diameter. This uneven scaling creates problems with landscapes where fallen leaves look much bigger than they are, and this adds a coarseness to the picture, and the picture becomes a caricature  of the original. The most common scaling algorithms (like the Adobe bi-cubic and its variations) are like this.


A good scaling routine (like Lanczos 3, which is proprietary and Adobe doesn’t have it,)  first puts the image through a low pass filter to remove any object that upon scaling would become invisible. Then the scaling is done. Finally a sharpening is used to bring back the sharpness of the luminance channel. Pictures scaled with Lanczos are noticeable brighter and sharper.


None of this PP is necessary if you shoot the scene at a resolution that matches the viewing monitor between 2 and 4 MP for consumer devices. (2 MP for most laptops and 1080 monitors; 4MP for Chromebook Pixel, Nexus 10, iPad Air, and MacBook Pro with Retina display.



High resolution displays

At the moment (Oct 2016) a relatively inexpensive high resolution consumer display is the UHD Samsung Monitor which can display 3840 x 2160 pixels when connected by HDMI cable to my MacBook pro 13”. That is about 7MP of data on the screen. A capture choice of 8MP on the camera would allow for some cropping and the picture would fill the screen at 100%.


But, for posting at leicaimages the longest side should be less than 2000 pixels, so I would have to crop the 3840 longest dimension of the picture to 2000. I would then have a 2000 x 1520 pixel image which fits the display and is almost 4:3 aspect ratio.


The DMC-LC5 4MP camera produces a maximum image size is 2240 x 1680 which I would only have to crop slightly to match the browser window of waeshael.Leicaimages.com


So, you see that all you need is a camera that captures around 4MP with a 4:3 or 16:9 aspect ratio, to match a browser window. 

For ordinary 1080 monitors that are 1920 on the long side, even a 4 MP image is too big to display. And if you allow the software to scrunch it down to fit the monitor, you have no control over how it does the scaling - usually it will use something that is quick to do, definitely not the best - like Laczos which takes a second or two to do the scaling. The monitor display software also will use anti-aliasing to smooth out text and picture, because the scaling is an odd fraction of the original pixels. Some software lets you switch this function off, so you can see the picture at its highest resolution. But the default on Mac monitor display software is to leave anti-aliasing on.

Go here to see some of these cameras.

DMC-FZ1.html
AboutPictures.html
Physical_Limits.html