5d mark II strange black dots?

[hawkman]

<p>Kevin,<br>

Can you upload the RAW file please?</p>

[jack_graham1]

<p>Still waiting on official word back. In the meantime check the example linked to by HarryLally in this thread at DPR.<br>

Clearly visible at 100% and absolutely terrible looking!</p>

<p>http://forums.dpreview.com/forums/readflat.asp?forum=1032&message=30298089</p>

<p>There's definitely a serious issue here.</p>

[kevin2i]

<p>Well the 200% crops do get a little rough looking, the actual image is breaking down on magnification.<br /> A 100% crop comparison <img src="http://6887.com/5dII/blackspots-iso50-200.jpg" alt="" /> <img src="http://6887.com/5dII/blackspots-iso50-200.jpg" alt="" /> <br /> I'll put up 2 raw files - ISO 200 and ISO 50. The 50 has less black dots.<br /> In camera JPGS are included.<br /> <a href="http://6887.com/5dII/_MG_9715.CR2">http://6887.com/5dII/_MG_9715.CR2</a> <br /> <a href="http://6887.com/5dII/_MG_9716.CR2">http://6887.com/5dII/_MG_9716.CR2</a> <br /> JPGS of same files (in camera)<br /> <a href="http://6887.com/5dII/_MG_9715.JPG">http://6887.com/5dII/_MG_9715.JPG</a> <br /> <a href="http://6887.com/5dII/_MG_9716.JPG">http://6887.com/5dII/_MG_9716.JPG</a> <br /> Gird (multiple specular highlights) crop. This could have been a disaster, but is reasonable (looks better than a 5d shot)<br /> <a href="http://www6887.com/5dII/blackdotsgrid2.jpg">http://6887.com/5dII/blackdots-grid2.jpg</a></p>

[kevin2i]

<p>grid link incorrect<br>

<a href="http://6887.com/5dII/blackdots-grid2.jpg">http://6887.com/5dII/blackdots-grid2.jpg</a></p>

[rishij]

<p>Whoa whoa whoa.</p>

<p>The ISO 50 shot has less black dots. That sort of goes against <a href="http://www.appliedcolorscience.com/black_sun.htm">this</a> explanation for the black dots, doesn't it? Because if ISO 50 is just an implementation where an ISO 100 shot is taken overexposed by 1 EV, then there should be *more* of a chance for 'photon bucket spill' into the reference region, right? Which should then make this more of a problem at <em>lower</em> ISO.</p>

<p>Does anyone see a flaw in that argument?</p>

<p>What this might point to, then, is a problem with the noise reduction circuitry and/or algorithm, since that would be hiked up at higher ISOs... and perhaps hardly implemented at ISO 50. Just a guess.</p>

<p>Rishi</p>

[hawkman]

<p>Kevin,<br>

Your RAW files demonstrate this phenomenon plus some strange artifacts, do I have permission to print these and show them to some people?</p>

<p> </p>

[kevin2i]

<p>Arash,<br>

No problem.<br>

K.</p>

[afshin_qashqai]

<p>Kevin did you check (Black dots problem ) sRaw mode with different iso in the same situation?</p>

[kevin2i]

<p>Afshin - I'll try some sraw tonight. <br>

Still debating whether to keep or return the camera - that's why I'm working on the 'black dots' rather than enjoying it.<br>

The 5dII is a step up in terms of usability. The lcd, live view, remote shooting with live view, c1-3 user registers, quick menu, higher usable iso put this in a different class than the 5d. Feels more like a d300 for build quality. The resolution doesn't 'blow away' the 5d, but the improvement is there. With MF lenses, it is a huge improvement over the 5d (liveview focusing). Using the 5d vs 5dII back to back, the mkII makes the 5d feel antiquated (like jumping from a win xp computer to 98, or mac X to XP). <br>

The mkII does video too . . . . but I do prefer the rounded style of the 5d :)</p>

<p> </p>

[images_in_light_north_west]

<p>have not seen this on mine and I have done high iso night city shots<br>

Ross</p>

[kevin2i]

<p>sRaw2 does not eliminate the dots. Shooting L-Jpg + sRaw2 this compares iso 50 to 3200, and sRaw/jpg.<br /> The sRaws were converted in dpp to photoshop, then I doubled them in size and put them next to the camera jpg. I shot these with a zoom, slightly different angle of view.<br /> Iso 3200: Full size here: <a href="http://6887.com/5dII/blackdots-sraw3200.jpg">http://6887.com/5dII/blackdots-sraw3200.jpg</a> <br /> <img src="http://6887.com/5dII/blackdots-sraw3200.jpg" alt="" /> <br /> Iso 50 - full size here <a href="http://6887.com/5dII/blackdots-sraw50.jpg">http://6887.com/5dII/blackdots-sraw50.jpg</a> <br /> <img src="http://6887.com/5dII/blackdots-sraw50.jpg" alt="" /></p>

[afshin_qashqai]

<p>Thanks Kevin for taking the time :)</p>

 

[rishij]

<p>PLEASE SOMEONE COMMENT ON THIS:</p>

<p>The 'pixel buckets being overfilled' theory no longer makes any sense if ISO 50 doesn't show this black dot problem! Because ISO 50 is actually ISO 100 +1 stop... so the image taken at ISO 50 should run the risk of being overexposed much more than ISO 3200 (hence why ISO 50 has a limited dynamic range -- highlights blow out much more easily... if anyone wants an example of this, I can post it). Hence the ISO 50 should show more black dots if <a href="http://www.appliedcolorscience.com/black_sun.htm">this</a> theory were to be true.</p>

<p>Which then says to me this has something to do with noise reduction (higher ISOs). Which then says to me perhaps there's a firmware/RAW converter fix? Or maybe that's just wishful thinking?</p>

<p>Rishi</p>

[scott_ferris]

<p>Blah blah blah blah. Just write to Arash and Berg, better yet have a conference call, if you can get Bob's input then that is the one I'd listen to, the majority of people here are opinionated part time photographers with a healthy (mostly) interest in the gear, once you get down to the finer points of sensor physics you are way past most peoples knowledge and interest. You are building guesses on speculation, you can't work it out without testing only read about what other people think. </p><p><br></p><p>The 5D MkII is a great camera, it has an issue that affects some specific types of lighting, not an uncommon thing for a v1 but frustrating for owners and interesting to prospective owners. It is a camera, take some pictures and enjoy it, or choose not to buy it because it is crippled by its horrendous image quality, your choice, but endless untested speculation, even for those with an academic interest, is pointless.</p><p><br></p><p>Seasons greetings all, Scott.<br></p>

[yiannis_dedoussis]

<p>I noticed this report from the first day it was posted, but hesitated to reply. Being an amateur astronomer for many years and also an electronics engineer by profession I may be useful on this issue. It is not something new in cameras and is found on most cameras used on demanding applications with ultra high contrast as star fields on an almost dark background. Oversaturated pixels might lead to neighbour pixels with abnormal values in the direction that pixels are sampled. The first time I faced this issue was on a special monochrome camera made for astronomical photos back in 1998. Trying to use DSLRs for astro imaging I have noticed this behaviour even at the time of D10. <br>

It is a normal behaviour for a ccd or cmos camera that has to overcome saturated pixels while sampling sequential pixels. Above all emotional thoughts and expectations, these marvels of technology cannot escape basic troubles of electronics. I will try to be as simple as I can but not too much as not to miss the meaning. The photons captured by a single pixel (any kind of photo sensitive device used) result to a charge stored on this insulated device. This charge is proportional to the amount of photons that have struck the sensitive area until the limit of storage (known as ‘well capacity’ normally measured in electrons), where voltage has the max value and result in a saturated pixel reading. Today's pixels are insulated to preserve the charge until the processing circuitry is able to read the value. Older versions of image sensors had leakage of charge to their neighbour pixels when oversaturated, usually in the row that they were wired and created streaks on the image with saturated pixels, an effect known as blooming.<br>

The stored signal (el. charge) has to be read by an analogue to digital converter but at first has to be buffered and amplified. These circuits take care of the conversion of the stored charge to a signal at levels usable as the input of A/D converters, but also take care of the required amplification as advised by user's ISO setting. Canon sensors are advertised to have amplifiers on each pixel (perhaps buffering for low noise operation) but also final row amplifiers acting as conditioners of the sampled signal. Sampling subsequent pixels connects these amplifiers to each pixel. Saturated pixels will lead these amplifiers to their physical limits and moving from a saturated (overcharged) pixel to a contrasty dark pixel (with very low charge) does not mean that the amplifier will be able to respond linearly as a perfect follower. It will overshoot, meaning it might read smaller values than the real ones, depending on the speed that we try to sample the pixels. There is always a trade-off between speed and accuracy of an amplifier, something decided at design time of the circuit. When seeking high accuracy and linear operation this amplifier must have the time to return to normal operating range and respond, and also feedback is chosen accordingly. Perhaps the "need for speed" is today’s must but it does not come without sacrifice.<br>

This is the problem with these black pixels, and if sampling and timing values are incorporated in the firmware files, something can be done through a new firmware that distinguishes movie sampling mode and high quality photo sampling settings. <strong>Until then, a user in demanding photos should use as low amplification as can be used (low ISO setting). This will also lead to high dynamic range and smoother tones. Higher amplification (higher ISO) will create more pronounced black pixels.</strong><br>

Noise reduction is the technique of subtracting a dark (unexposed) image of the same duration from the light (exposed) frame. In this case the black pixel effect could be even worse because of errors in mathematics of an exposed pixel being darker than the corresponding dark frame's pixel. <strong>Avoid noise reduction when shooting ultra high contrast shots and really want to avoid black pixels.</strong><br>

I did try to explain it as simple as i could. Hope this helped.<br>

Yiannis</p>

 

[www.danahoff.com]

<p>The truth is, CANON needs to wake up! They are pissing off a lot of people, (me included) professionals and prosumers with their lame product releases. The only thing more offensive is the response Canon provides, by attempting to put the responsibility on the camera owner, or pass posted images as having "no way to verify the image is from a Canon 5D II". What a crock of crap. <br>

I have an EIGHT THOUSAND DOLLAR six month old Canon 1Ds Mark III, (a replacement to the two month old original who's sensor failed). My camera just took a five week tour of the NJ, NY and CA service centers in hopes of a repair for a white ghost pixel issue. I was getting a dozen or so blank white pixels on my images. Canon' resolution is to basically say that they can't find the problem or re-create it.<br>

There's three things that need to happen here.<br>

1. If you have not laid out $3,000 for the 5D Mark II, DO NOT GIVE CANON YOUR MONEY in hopes that you might get a "good one" until THEIR problem is solved.<br>

2. If you did buy a bad camera, phone your retail place of purchase and DEMAND your money back.<br>

3. If you can not return your camera, bombard Canon until you get a solid answer on a solution.<br>

The only thing Canon is going to listen to ultimately is $$$$ Cash being swiped out of their hand. So be it.<br>

I had my name on the 5D Mark II waiting list and just requested my deposit refunded. This is B.S. and typical Canon as of lately, sad to say. I might consider the 5D IF AND WHEN the issue is corrected in a well documented fashion.<br>

If anyone is awake at Canon, Bad, Bad, BAD.</p>

[bobatkins]

<p>No, only two thing needs to happen:</p>

<p>Wait a week (or less) to hear what Canon have to say.</p>

<p>Have reasonable expectations and a sense of proportion.</p>

<p>If their response doesn't make you happy, then you can start to complain. If you haven't bought a camera, then you have nothing to complain about of course, except being disappointed.</p>

[dennis_knoxville]

<p> Interesting - The Pop Photo review is now on the web</p>

<blockquote>

<p>"But this low-light performance isn't glitch-free. As have commenters on the web, we noticed tiny black blotches next to areas of blown-out highlights, such as the streetlights in our image of the skater. We found it hard to predict what images these spots would turn up in -- sometimes we'd find them, sometimes we wouldn't. Canon is aware of the problem, and our bet is that the issue soon will be resolved with a firmware upgrade. In any case, the blotches are easily removed in postproduction." - Pop Photo in tehir review<br>

<a href="http://www.popphoto.com/cameras/5677/canon-eos-5d-mark-ii-test.html">http://www.popphoto.com/cameras/5677/canon-eos-5d-mark-ii-test.html</a></p>

</blockquote>

 

[steve_may1]

<p>If these black dots are visible to me at 100% in Photoshop, then they will be visible to the Photo Editors and Picture Libraries who routinely search for artefacts at 100%. If they find one of these the whole batch will fail. It is enough hassle removing dust spots without needing to remove these as well. Is it possible that photos from this this camera will become 'marked' by the Editors and Libraries for a more thorough screening than other cameras?<br>

The consumer has ultimate power in the buying market, despite the manufacturers desire to maintain a cashflow. Surely the consumer must be in a stronger position with the money still in his pocket. No, I don't own a 5D Mark 2, nor will I buy one just to see how real the problem is....then feel the donkey's ears growing faster than the number of black dots. As with Dana, above, I will reconsider my buying position as and when a comprehensive solution has been documented by a reputable source, comprehensively. If Nikon produce a high quality D700x at a reasonable price, that may be another option I consider.</p>

[jeffevans]

<p>Just got mine in the mail today. I don't have a lens with me at work to try it out yet, so I'm stuck here pretending to take photos.<br /> This will be of interest to you all:<br /> <a href="http://www.photographybay.com/2008/12/08/canon-5d-mark-ii-black-dots-fixed/">Canon 5D Mark II Black Dots Fixed</a><br>

Since i haven't used the camera yet, I have no idea if this works. Check it out.<br>

jeff</p>

[phule]

<p>Could some moderator please fix the FTP call being made in one of these replies?</p>

<p>The offending code is here:</p>

<p>ftp://6887.com/5dII/blackspots-iso50-200.jpg<br /> <br /> <br /></p>

[scott_ferris]

<p>Thanks for finding that Rob, it was bugging the hell out of me!</p>

[bobatkins]

<p>Regarding the "black dots fixed" comment, the offending pixels appear to be present even when looking at uninterpolated intensity data in the RAW file, so things like noise reduction and auto lighting optimization aren't the cause (since they are both done during RAW file processing). HTP can affect RAW file data, but does not appear to be the cause of the dots.</p>

[rishij]

<p>Yiannis,</p>

<p>So then you're basically saying that as the pixels are being read, for a saturated pixel the amplifier applies less gain than for a darker pixel (for which it applies a higher gain)? In which case, if virtually no gain is applied for a completely saturated pixel, and the next pixel (to the right) happens to be very dark, then the amplifier can't respond quickly enough to increase its gain for that dark pixel to the right of the saturated pixel? Hence that dark pixel ends up appearing darker than it otherwise would?</p>

<p>Also, for the rest of you with the camera who have reproduced the black dots -- what is their RGB value? Are they just low, or are they 0,0,0?<br /> <br /> Rishi</p>

[bobatkins]

<p>Some of the pixels in the "black dots" are often 0,0,0 after RAW conversion to JPEG. At least one channel (R, G or B) aways seems to be zero. In the RAW file, they often show a level below that of the black point (i.e. the signal from a pixel that gets no light at all, which is always >0)</p>

<p>Amplifier gain is (or should be) fixed. It's what sets the ISO. I think the suggestion made above is that when the output of the amplifier clips (at the high limit), it might then have some sort of "dead time" before it fully recovers, so low level inputs result in a zero output (or at least an output below the black level)</p>

<p>Why some bright white overexposed pixel groups have a black dot next to them, yet others in the same image don't remains somewhat difficult to explain.</p>