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+--- Thread: What about this Sigma cameras... (/showthread.php?tid=1208)
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What about this Sigma cameras... - Brightcolours - 03-24-2015
Quote:"fake sharpness/false detail" is really one of the most stupid judgements I heard about those Sigma camera output.Well, you call it stupid. But it is just plain fact. The real world is not made out of a grid of sharply edged pixels. So, what you get is aliasing, which makes for fake sharpness (edges where there are none at that exact location) and false detail (detail which is not there in real). One needs to use a low pass filter (ie: anti aliasing filter) to prevent the fake sharpness and false detail to appear. If you want to appear less "stupid", read up on sampling theory.At least, it's a unique and original one and you don't have to share that opinion with many others. :lol:
I could understand the term "overly sharp", but what makes you say fake and false - and what is in you definition then "true and righr"? Foveon is a different type of light perception. Anyway, it's just one of BC's statements when everything he doesn't use himself can't be good, so I'd be a fool to take it seriously.It would be so easy to find tons of disadvantages of the Sigma concept, but the one thing they have a clear advantage is what you're critizising. Just poor. It doens't add more sharpness than there is. But hey, even camera dealers who are unfamiliar with Sigma, mumble something about "in camera sharpening", yeah, sure, there must be some trick when it takes 5...10 seconds to save this 50MB RAW.
You're of course the big specialist in true sharpness with your Canons. B)
http://en.wikipedia.org/wiki/Nyquist–Shannon_sampling_theorem
https://www.youtube.com/watch?v=PlVnW2kv4tE
http://www.cs.tau.ac.il/~dcor/Graphics/adv-slides/sampling05.pdf
http://redwood.berkeley.edu/bruno/npb261/aliasing.pdf
What about this Sigma cameras... - JJ_SO - 03-24-2015
Well, in "real world" there are not such things as pixels at all, those are as artificial as AA or lowpassfilters. I know what you mean with aliasing, but this concerns each sensor with a regular squarish pattern of receptors. I prefer one which I can smoothen afterwards to a degree I like, because regeneration of lost sharpness by using unsharp masking is as false and fake and artificial as all those digital (meaning: picture consisting out of 1 and 0) pictures.
We're used to this techniques in music reproduction and in graphic reproduction and we rely on the smudging caused by printers, screens, loudspeakers - none of them could reproduce a squarish pixel / tone, all of them add something to it. I don't see much aliasing in the Sigma pictures and I doubt you do. If there would be more smoothness, more natural behavior in a Bayer sensor made picture - great, tell me which one. So far I only saw Bayer pictures when comparing with Foveon as less powerful in contrast and less clear in color. So, each one who adds more contrast, micro contrast, more saturation, more clarity actually adds more artificial parts to a picture which already IS artificial.
I think each photographer has to decide how far he wants to use digital reproduction techniques - or go to film (and I purposely avoid the word "back" in this sentence) or paint on canvas. I wonder how people would decide when two samples are in an exhibition on display.
Short version - the Foveon samples are different from he Bayer samples, but using fake or false doesn't make sense as no digital way is working without breaking reality into little bits and bytes.
What about this Sigma cameras... - Brightcolours - 03-24-2015
Contrast differences are about the tonal curve chosen. Sigma/foveon often has exaggerated saturation and at times wrong colours.
Short version: AA-less makes for fake sharpness and false detail (you just have not realized that), something you seem to find impressive, and I find not so desirable.
What about this Sigma cameras... - JJ_SO - 03-24-2015
I knew it would be pointless to discuss with a concrete-head <_<
What about this Sigma cameras... - Brightcolours - 03-24-2015
Your screen is reflecting?
What about this Sigma cameras... - borisbg - 03-24-2015
Quote:I see it the same way, sometimes it appears overly sharp. And when it comes to fine texture, I'm always amazed about seeing a kind of "relief" (I just wanted to avoid the "3D" phrase, but I know what you mean). The prints of those pictures have a special quality. I try not to get used to it too much.
Joju, do you have a file (hi-res) on your smugmug that you can share for printing. I am ready to give it a try.
What about this Sigma cameras... - JJ_SO - 03-24-2015
You got PM.
What about this Sigma cameras... - borisbg - 03-27-2015
JoJu, the print quality is excellent;
Here is what I noticed:
Shadow detail - very good;
Texture - excellent;
Transitions from light green to dark green - excellent. The same goes for all colors.
Nothing looked over processed in terms of sharpening and color saturation.
Thank you for sharing.
What about this Sigma cameras... - JJ_SO - 03-27-2015
You're welcome
Of course I like what you wrote. I just wanted to add, the little Merills are at first a cheap way to collect experiences with Foveon and the strength of the sensor is not a huge dynamic range
One really needs to be very careful on both sides of the histogram. A simple panorama can become really challenging.What about this Sigma cameras... - borisbg - 03-27-2015
Dynamic range-that why I decided to print that specifics picture where light is evenly spread and big part of the picture is on the left side of the histogram. Again shadows are rendered very well.