GMB Posted March 6, 2007 Share #1 Posted March 6, 2007 Advertisement (gone after registration) I got my M8 last weekend and I am generally VERY happy. Shot some really nice portraits. However, in some shots I noted artefacts. Attached is a 100% crop from a shot over water with light from the front/side. The sky was pretty grey and the shot is not great, to say the least. I did it more to test the camera. However, the artefacts in this and another shot are pretty disturbing for my taste. Anyone similar experiences. Shot was taken with a 35/2. Straigt JPEG. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/18034-m8-artefact-on-wather/?do=findComment&comment=192235'>More sharing options...
Advertisement Posted March 6, 2007 Posted March 6, 2007 Hi GMB, Take a look here M8 Artefact on wather. I'm sure you'll find what you were looking for!
jaapv Posted March 6, 2007 Share #2 Posted March 6, 2007 Ir cut filter? I think it may be IR projecting an unsharp halo around highlights. Otherwise ; banal sensor blooming. Link to post Share on other sites More sharing options...
GMB Posted March 6, 2007 Author Share #3 Posted March 6, 2007 Ir cut filter? I think it may be IR projecting an unsharp halo around highlights. Otherwise ; banal sensor blooming. No IR cut filter but a UV filter. What doe you mean by banal sensor blooming? Looks pretty ugly to me. I had a similar effect when photographing a street at night. Link to post Share on other sites More sharing options...
jaapv Posted March 6, 2007 Share #4 Posted March 6, 2007 All sensors exhibit blooming sometimes, a digital fact of life But in this case my diagnosis is IR. It focusses differently from visible light, so it may cast a magenta halo around highlights. Try similar shots with an IR cut filter. Link to post Share on other sites More sharing options...
bsmith Posted March 6, 2007 Share #5 Posted March 6, 2007 It's because jpgs are terrible on the M8 Link to post Share on other sites More sharing options...
jaapv Posted March 6, 2007 Share #6 Posted March 6, 2007 I wouldn't know about Jpeg's. I haven't used one as a "negative" since 2003..... Link to post Share on other sites More sharing options...
carstenw Posted March 7, 2007 Share #7 Posted March 7, 2007 Advertisement (gone after registration) I don't see anything I would consider unreasonable in that image, apart from the awful sharpening. If you turn the sharpening down, the dark haloes around the branches ought to diminish in strength. I would recommend sharpening in post if you feel you need to add some occasionally. Link to post Share on other sites More sharing options...
jaapv Posted March 7, 2007 Share #8 Posted March 7, 2007 It is sharpened so much because it is backfocussed. The small splattery thing in the background is in focus, the trees are out of focus. But oversharpening does not produce magenta haloes around highlights. Infrared does. Link to post Share on other sites More sharing options...
carstenw Posted March 7, 2007 Share #9 Posted March 7, 2007 I only see the red fringe in a couple of isolated places, but the top edge of many branches look oversharpened to me. Actually, before discussing any further, it would be helpful to know which artifact the OP is talking about. Link to post Share on other sites More sharing options...
GMB Posted March 7, 2007 Author Share #10 Posted March 7, 2007 I only see the red fringe in a couple of isolated places, but the top edge of many branches look oversharpened to me. Actually, before discussing any further, it would be helpful to know which artifact the OP is talking about. I was talking about the spots on the water, not the edges of the branches. As mentioned, this is a 100% crop. The developed unsharpened DNG file shows exactly the same spots. I shall post it tonight: The tree lying in the water was about 15 m away from where I took the shot and was in focus. There are a few out of focus branches in the foreground though, but one hardly sees them. Link to post Share on other sites More sharing options...
adan Posted March 7, 2007 Share #11 Posted March 7, 2007 Two points: 1. There are several sources for "glows" around bright highlights. It can be "blooming", as mentioned, (spillover of voltage from an overloaded pixel to the surrounding pixels - usually blue to magenta because blue is the most energetic wavelength). It can be chromatic aberration in the lens, or induced by the micro-lenses. Which would include infrared since it is just another wavelength on the EM spectrum. With the M8, there can also be aliasing effects that create colored edges to things, although I don't think that's the prime effect seen here. 2. Oversharpening (and this shot looks significantly oversharpened) can emphasize the color effects, by hardening the edges of the "glows". With the M8 jpegs, any sharpening setting other than "off" is too high for clean results at 100% views or big enlargments (it may be fine for crisp minilab prints). IMHO the artifacts shown here could be either CA or blooming - or both - made even more obvious by excessive sharpening. I only see this effect this obviously in my shots when shooting jpegs with the sharpening turned on (to any level) - which is why I only shoot .dng. Link to post Share on other sites More sharing options...
sandymc Posted March 7, 2007 Share #12 Posted March 7, 2007 Difficult to tell from a JPEG, but is very unlikely to be blooming - firstly, the Kodak sensor has anti-blooming protection (as, btw, do almost all modern CCDs used in cameras) - see the KAF-10500 data sheet. Secondly, blooming tends to produce artifacts with vertical or horizontal "tails" e.g., see Blooming vs. Anti-Blooming. My guess is moire amplified by the JPEG processing, given that is it around sharp transitions in luminance. But could be CA. Sandy Link to post Share on other sites More sharing options...
marknorton Posted March 7, 2007 Share #13 Posted March 7, 2007 These "smarties" or "spangles" are a JPEG artefact and a clear case for falling back to DNG... Link to post Share on other sites More sharing options...
carstenw Posted March 7, 2007 Share #14 Posted March 7, 2007 Which raw developer did you use? Older versions of Lightroom and ACR are known for being bad at handling this kind of thing. Try C1 as a comparison. Link to post Share on other sites More sharing options...
Jamie Roberts Posted March 7, 2007 Share #15 Posted March 7, 2007 It is sharpened so much because it is backfocussed. The small splattery thing in the background is in focus, the trees are out of focus. But oversharpening does not produce magenta haloes around highlights. Infrared does. Jaap--Andy's right, I think, there's a host of digital artifacts that produce magenta haloes and fringing (purple fringing). The Canon stuff does this too; it's not IR, it's specular highlights and the sensor (not bloom, either). I was told by a Canon tech this was birefringence. Most folks just call is CA. You need to do as Carsten says and turn off sharpening in JPEG. Oh, I don't know the aperture on this shot but this tends to happen more wide open than stopped down, but that just might be the problem. As for focus, well it might be backfocussed, or it might not be Hard to tell from the shot. Link to post Share on other sites More sharing options...
jaapv Posted March 7, 2007 Share #16 Posted March 7, 2007 Jamie, I'll gladly bow to superior knowledge Anyway, judging by the host of responses the final conclusion is clear. We can only tell the OP :welcome to the digital world. Link to post Share on other sites More sharing options...
thpeters Posted March 7, 2007 Share #17 Posted March 7, 2007 Georg, Seeing your picture in my humble opinion it is out of focus. Theo Link to post Share on other sites More sharing options...
gogopix Posted March 7, 2007 Share #18 Posted March 7, 2007 What means "OP"? Link to post Share on other sites More sharing options...
GMB Posted March 7, 2007 Author Share #19 Posted March 7, 2007 Jamie, ... We can only tell the OP :welcome to the digital world. Thanks ! As indicated earlier, I shall post tonight the developed raw file with exposure infos. I use C1 Le ... and Jamies protocolls. Link to post Share on other sites More sharing options...
cmb_ Posted March 7, 2007 Share #20 Posted March 7, 2007 What means "OP"? Victor, "OP" means original poster. Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.