mtomalty Posted March 7, 2007 Share #1 Posted March 7, 2007 Advertisement (gone after registration) Has anyone experienced 'center split' with M8 files. This is a flaw where a processed file exhibits a difference of exposure from one side to the other on a horizontal capture and is distinguished by a hard line In reviewing some M8 raws I shot last week to familiarize myself with the camera I ran into this problem tonight. It has been a well documented issue with certain digital backs but I haven't seen it referenced with a 35mm camera I'll try to attach a reference but bear with me if I screw up a few times before getting it right Mark 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/18053-center-split-on-m8-sensor/?do=findComment&comment=192482'>More sharing options...
Advertisement Posted March 7, 2007 Posted March 7, 2007 Hi mtomalty, Take a look here Center split on M8 sensor. I'm sure you'll find what you were looking for!
mtomalty Posted March 7, 2007 Author Share #2 Posted March 7, 2007 Just wanted to add a note for further clarification. Despite my poor centering of this crop the split occurs symetrically in the frame from top to,I assume,bottom on a horizontal orientation. The original is a Raw capture processed in Adobe Lightroom and converted to black and white in Photoshop. Visible in both color and B+W. I'll go run the file through Capture One to see if things change Link to post Share on other sites More sharing options...
Jamie Roberts Posted March 7, 2007 Share #3 Posted March 7, 2007 Mark-- I've seen this; it's been noticed here a couple of times. Haven't seen it though, yet, with the fixed M8 and newest firmware. Link to post Share on other sites More sharing options...
mtomalty Posted March 7, 2007 Author Share #4 Posted March 7, 2007 FWIW,the center split is equally evident using Capture One Mark Link to post Share on other sites More sharing options...
mgcd Posted March 7, 2007 Share #5 Posted March 7, 2007 Hi Marc, that's a pretty scary thing although from what is outlined here, it appears to be a rare occurence. Hope you're well. Cheers, Link to post Share on other sites More sharing options...
erl Posted March 7, 2007 Share #6 Posted March 7, 2007 My M8 did it constantly at iso's above 160 BEFORE it went to Solms for upgrade. It has returned with upgrade and Ver 1.09 and no apperent split. It does, however, exhibit a green sripe with liht source right on the edge of the frame. Is your camera from the early batch and has it been upgraded? This may be the clue. Link to post Share on other sites More sharing options...
marknorton Posted March 7, 2007 Share #7 Posted March 7, 2007 Advertisement (gone after registration) This is the "Centrefold" problem; rows of pixels are read out of the sensor, left and right, half in one direction, half in the other and the data converted to digital. If that process is not exactly matched for both sides, you will be able to see the join. It's not the sort of thing which can be just set at the factory and left because it will change over time as the sensor ages and with things like temperature. TBH, I haven't figured out exactly how they do it, there must be some sort of automatic calibration process using a dark reference and since the last pixels read out from each side are either side of the join, they may also do some other calibration making the assumption that these pixels should be the same on each side. Hasn't been much of an issue so far, but I have seen discussions on one of the MF back forums where it is clearly a major problem. Was this one of a series of similar shots? Do they all exhibit the problem? Link to post Share on other sites More sharing options...
mtomalty Posted March 7, 2007 Author Share #8 Posted March 7, 2007 The camera was not mine and,in fact,belongs to one of the Canadian Leica reps. As such,I'm not aware of what firmware is installed but I will find out tomorrow and check back. The camera was only used for only about an hour so I did not shoot more than one or two frames of each situation and,therefore do not have any sequences where the same composition could be compared for the centerfold Mark Link to post Share on other sites More sharing options...
andit Posted March 7, 2007 Share #9 Posted March 7, 2007 Hi Mark, I seem to recall reading somewhere on the forum that the M8 sensor is actually made up of two smaller sensors (don't know if it's 4/3 sensors) that have been "Daisy Chained" together. If one of them went out of sync, this would account for the different exposure values resulting in this distinctive line. Andreas Link to post Share on other sites More sharing options...
barjohn Posted March 7, 2007 Share #10 Posted March 7, 2007 Why can't I see it in this image? I have looked all over it and I don't see it. Am I missing something? Link to post Share on other sites More sharing options...
Guest Bernd Banken Posted March 7, 2007 Share #11 Posted March 7, 2007 maybe your screne? It's approx. one finger width from the upper left corner of the building. Link to post Share on other sites More sharing options...
marknorton Posted March 7, 2007 Share #12 Posted March 7, 2007 maybe your screne?It's approx. one finger width from the upper left corner of the building. LOL - that depends on the size of your screen - and your fingers! Look for the faint vertical line in the image. The image has been cropped so it's not perfectly centred... Link to post Share on other sites More sharing options...
rob_x2004 Posted March 7, 2007 Share #13 Posted March 7, 2007 ............ 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/18053-center-split-on-m8-sensor/?do=findComment&comment=192535'>More sharing options...
marknorton Posted March 7, 2007 Share #14 Posted March 7, 2007 Hi Mark,I seem to recall reading somewhere on the forum that the M8 sensor is actually made up of two smaller sensors (don't know if it's 4/3 sensors) that have been "Daisy Chained" together. If one of them went out of sync, this would account for the different exposure values resulting in this distinctive line. Andreas Andreas - it's a single sensor but there are two output channels, one reading out the left hand side of the image and the other reading out the right hand side. This is done to reduce the time it takes to get the image samples out of the sensor to about 0.2 seconds. The DMR had only a single channel and was slower as a result. That is what is happening here - the two sides are going out of sync, or calibration, with each other. Since it's a rep's camera, it might well be back level and early hardware. I heard that the earliest cameras - such as were used at Photokina - were being distributed to retailers as long term demo cameras. Link to post Share on other sites More sharing options...
barjohn Posted March 7, 2007 Share #15 Posted March 7, 2007 Thanks, I can just barely see it now on my 23" MAC Cinema screen. I had to crank up the brightness a little. Link to post Share on other sites More sharing options...
adan Posted March 7, 2007 Share #16 Posted March 7, 2007 A data point: My early production M8, NOT upgraded physically, does this but only at ISO 2500. It becomes REALLY noticeable if ISO 2500 is underexposed and then the exposure cranked up in raw processing. It also shows with the edge-exposed Mark Norton green band - but that's really a separate issue of which the visible split is only a byproduct. No significant difference with firmware v. 1.092 - not better, not worse. One of the first things I checked after loading the new code. I would say if it is showing at any ISO below 2500, and especially at "daylight" ISOs (640 or below)......and you didn't underexpose and "overdevelop" in RAW......then it's a real problem that needs something fixed. Link to post Share on other sites More sharing options...
Guest guy_mancuso Posted March 7, 2007 Share #17 Posted March 7, 2007 From what I understand it is the processing engine that is off. It is a two channel processing engine for faster write times and one is slower than the other and reason for the split. It's been awhile since we seen this and it's possible the new firmware may correct it. Did this camera have the hardware update. Link to post Share on other sites More sharing options...
xerxes Posted March 7, 2007 Share #18 Posted March 7, 2007 I receieved my M8 in February, and have been using it for night photography. I immediately encountered the horizontal banding issue, and was constrained to exposures under 30 seconds. I loaded the new firmware this morning, and took a 180 second exposure at F16 to test the firmware. The banding issue is completely gone, but the split on my sensor is as apparent as ever. You can clearly see that the left side has a green cast to it compared to the right. Again, this does not appear in daylight shots. -Mark Flaming 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/18053-center-split-on-m8-sensor/?do=findComment&comment=192986'>More sharing options...
marknorton Posted March 7, 2007 Share #19 Posted March 7, 2007 I'm dumbstruck! Link to post Share on other sites More sharing options...
timwalker Posted March 7, 2007 Share #20 Posted March 7, 2007 I have a second generation M8, delivered in January with version 1.09 firmware, that exhibited a similar problem to this... only in low light situations and only sometimes. In my case, it appeared as if there was an overlap of sorts, causing it to appear like a vertical ghosted band just right of center. I put the lens cap on and made test shots at various ISO settings and shutter speeds and it appears consistently in those, but it doesn't appear in the vast majority of my shots made in normal shooting circumstances. I was told by Leica that the issue would be fixed with future firmware upgraded. I just upgraded to 1.092 yesterday but haven't tested this out yet. Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.