Gear Talk > Processing & Publication
The downsizing challenge - Part 1: The Problem
simsurace:
I have heard from a few people that they are experiencing suboptimal results when trying to downsize a high-res image -- say, from a D810 -- to a lower resolution (for web use). The downsized images are reported to have certain qualities which are not pleasant, but sometimes hard to describe.
It has been said that software has not kept up with this challenge and that it is hard to find the correct downsizing method for those images.
Another related problem is that high-res images are sometimes badly displayed by some software for previewing/culling. Since the software has to downsize the image to display it on a monitor with a much lower resolution than the image itself, the same downsizing challenge applies behind the scenes.
Of course, we have to realize that any digital image cannot properly represent detail which exceeds the Nyquist frequency, therefore we might have to reset our expectations accordingly. But we should not be getting worse results out of the high-res file compared to a lower-res file, e.g. the same scene shot with a D800 vs. a D700 should not look worse when downsized to web resolutions unless the downsizing was done in a suboptimal manner. What I understood from some people is that they are finding it hard to match the results obtained with lower-res cameras, and this is where this thread comes in.
I think it is important to thoroughly understand the problem first, for there might be several individual problems for which separate solutions have to be found. Personally, I have not experienced these problems (despite not having a 36mp cam, I have worked on panos that measure several hundreds of megapixels and I have downsized them quite successfully IMHO), so I might first need to be educated about the problems others are perceiving.
Here, my aim is to collect examples of downsizing to try and identify the problem and how it manifests itself. If you are experiencing problems when downsizing high-res files, please post an example. If possible, please make available the raw/full-res file (e.g. on dropbox or via some other hosting service) as well as your attempt at a downsized version (jpeg). If you can, please try to describe what you don't like about the downsized version.
When we have collected enough examples, we will try to find a workable solution to solve the problem. Other forum participants will be able to take your full-res file and come up with their downsize, and you will be able to judge whether an improvement has been made over your own attempt. The concept I have in mind is very similar to the RAW editing challenge, but more specifically geared towards downsizing.
Ron Scubadiver:
I think a lot of it has to do with how the image is sharpened.
Andrea B.:
I'm very interested in this. I'll get back with a couple of examples this weekend. I'm still getting caught up on the domestic front after being gone 2 weeks on the Scotland NG Meetup.
elsa hoffmann:
I am experiencing the same issue with downsizing. Images don't appear sharp. 99% of the time I dont have to sharpen my images at all - (when processing the high res) so for me it can't be an issue due to how I sharpened
the solitaire:
For my girlfriend (not able to post here herself due to lacking English skills, especially when it comes to technical explainations) the biggest problem is tha images that appear perfectly sharp on a pixel level on her computer, even when converted from NEF to JPG, appear completely out of focus when subsequently uploaded to facebook. Since she uses facebook as the main portal to portray her work we have been looking into a solution for this for quite some time.
It does not happen with all images, but a considerable amount.
To the tehcnical details, she uses a D800 to shoot lossless compressed 14 bit NEF files
I will make a file available later today. Need to upload it to dropbox which given my slow internet connection will take a while.
I will also post a link to the uploaded file on facebook.
I think this here will be a good example.
https://scontent-fra3-1.xx.fbcdn.net/t31.0-8/13115992_878889058903527_8707603759883841782_o.jpg
Any help in how to prepare the file for an upload on facebook and ending up with a representation of the file that appears sharp is greatly appreciated.
Here is the NEF to the picture
https://www.dropbox.com/s/ozr8i2zt04pwhy3/DSC_5551.NEF?dl=0
And the processed JPG
https://www.dropbox.com/s/04z2me0zyeng1yc/DSC_5551-Bearbeitet.jpg?dl=0
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