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Thread: Severe artifacts or noise problem with Phase IQ180

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    Severe artifacts or noise problem with Phase IQ180

    Dear friends,

    I have been using Phase One IQ180 back with Cambo W-RS AE and Rodenstock 23mm,40mm and 70 mm lenses over a year now.Attached image is a small crop from a 400% zoomed image.This shot was taken using ISO35 at f/11 for 1 second.
    As you see,there are tons of unwanted white pixels and some black pixels which seems like an outpıut of a very high iso image from a poor camera .Is it only me who is asking too much of a 40,000$ back or other IQ users experiencing the same problems?
    I always print extreme sizes as 60"x80" being my standart size or I sometimes go to 78"x90" print and those pixels cause problems unless I spend my whole day trying to clean one by one.

    Ziya
    Ziya Tacir

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    Re: Severe artifacts or noise problem with Phase IQ180

    Are these hot pixels, do you think? Looks strange to me.

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    Re: Severe artifacts or noise problem with Phase IQ180

    I have no idea what they are but I have these pixels in all my of pictures when zoomed in 400% no matter how good the lighting is .

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    Re: Severe artifacts or noise problem with Phase IQ180

    Are you using Capture One to process? Does the back do a dark frame subtraction at 1 second speed?

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    Re: Severe artifacts or noise problem with Phase IQ180

    "Severe noise"? Have you cropped into any images from any other cameras/backs at 400% lately?
    Siebel
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    Re: Severe artifacts or noise problem with Phase IQ180

    Looks pretty normal for a 400% view. When printed, do they actually show up noticably in the image? Have you tried applying single pixel noise reduction?

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    Re: Severe artifacts or noise problem with Phase IQ180

    Although CCDs have lots of hot pixels compared to any recent CMOS and the number increases with shutter speed, even my old Aptus 75 does not show that amount at 1 second. At 15 seconds or so it starts looking like that. So maybe there's some problem. I'm not sure how an IQ180 is supposed to look though.

    The solution is hot pixel cleanup in the raw converter, it reduces the problem to ~0 since the hot pixels are usually isolated single-pixel islands and can be interpolated from neighboring pixels. A fairly large amount of hot pixels is something one have to live with in the MF world, so standard workflow should include hot pixel cleanup.

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    Re: Severe artifacts or noise problem with Phase IQ180

    Is this an unprocessed, unsharpened view of the raw image from capture 1?

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    Re: Severe artifacts or noise problem with Phase IQ180

    I am using Capture One for raw processing.
    The image was unprocessed,unsharpened raw image only LCC applied.
    I have never printed my images without cleaning them manually.
    If I use pixel noise reduction extensively,my image loses its crispiness which is the last thing I want.
    I have not compared any other image from another camera or digital back but I assume this is the king of the digital world ,
    I should expect a better quality.
    I think image files from Phase backs require incredible amount of post-processing work which makes me wish I convert to film days.

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    Re: Severe artifacts or noise problem with Phase IQ180

    I have always wondered what is the best zoom % for a reasonable analysis of the image. seems like a lot of variables come into play, like size and res of your monitor, final print size, etc. but there ought to be some sort of rule of thumb

    any advice?

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    Re: Severe artifacts or noise problem with Phase IQ180

    Attached is a 400% crop from my Hasselblad. Appears NOT to have the white pixels
    Stanley

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    Re: Severe artifacts or noise problem with Phase IQ180

    Quote Originally Posted by stngoldberg View Post
    Attached is a 400% crop from my Hasselblad. Appears NOT to have the white pixels
    Stanley
    Kodak or Dalsa sensor?
    Above 1 second exposure?
    Tech camera with LCC?

    I've got plenty of shots without the white speckles like your example above but under the right conditions i do see these using a P65 which shared the same sensor.

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    Re: Severe artifacts or noise problem with Phase IQ180

    Anytime a camera is used on a not-short exposure (1 sec being a "not short" exposure) there will be hot pixels. The amount (in the underlying raw data) will increase with time.

    Most modern raw processor have a behind-the-scenes algorithm to reduce or eliminate them. So most users of most cameras with most software simply do not see them except on very long exposures. They also do not have any control to adjust how aggressive this algorithm is; it is either entirely automatic or, in the case of Lightroom, tied directly to the general noise reduction slider which also applies the smoothing luminance noise reduction effect as well as more aggressive single-pixel noise reduction.

    Capture One provides a slider to access this algorithm, providing the user control over how much it is applied. Often you need to tweak the defaults which often are a bit conservative, especially in the 1 second exposure range. These conservative defaults can lead users to see these pixels and be concerned about them (when there is nothing to be concerned with, just up the slider a bit).

    Set the Single Pixel Noise Reduction slider to around 30 and you'll be using about the same strength of this algorithm as LightRoom uses at default*. Anything less and you'll tend to notice more than in LR (or Aperture, Phocus etc). Any more and you'll notice less.

    As a nerd and detail oriented person I greatly prefer this approach as it allows me as the user to control how much of this specific algorithm to apply rather than having it applied in the background or be tied to other kinds of noise reduction I may not want to apply to a given image.

    But in the marketing sense it is maybe not the best.

    As a historical note this was not available as a separate slider in previous versions of capture one. So if you used a P45+ in Capture One 4 for instance the algorithm was being applied behind the scenes.

    *this amount is obviously rough and is based on my own experiments mostly with Canon and Phase One.
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    Re: Severe artifacts or noise problem with Phase IQ180

    Hi Gareth,
    H4D50-Kodak sensor-exposure was 1/60 sec, f11, iso 100-Arca Swiss Tech camera with LCC
    Stanley

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    Re: Severe artifacts or noise problem with Phase IQ180

    I don't shoot with Phase IQ backs, but the number of hot pixels you are getting is far from the performance I would expect from a second exposure at ISO 32. What were the ambient temperatures like when you shot this?

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    Re: Severe artifacts or noise problem with Phase IQ180

    80 second exposure-H4D50 Kodak sensor-no white pixels


    original and 400% crop

    Stanley

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    Re: Severe artifacts or noise problem with Phase IQ180

    Stanley,

    If the image of the house on the left is original size, no way the image on the right is a 400% crop, it's more like a 25% crop! When we say 400%, we mean a crop out of a 400% actual pixel view in Photoshop, or IOW each pixel is represented by 4 pixels on your monitor.
    Jack
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    Re: Severe artifacts or noise problem with Phase IQ180

    Quote Originally Posted by Jack View Post
    Stanley,

    If the image of the house on the left is original size, no way the image on the right is a 400% crop, it's more like a 25% crop! When we say 400%, we mean a crop out of a 400% actual pixel view in Photoshop, or IOW each pixel is represented by 4 pixels on your monitor.
    And with the contrast jacked so high you'll never see them showing up in an image processed/exposed like that.

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    Re: Severe artifacts or noise problem with Phase IQ180

    Something else to consider is using the Photoshop Dust & Scratches filter in addition to C1's processing.

    I regularly shoot 1 min+ with my IQ160 and as you would expect I get noise/hot pixels much stronger than you are seeing at 1 sec. C1 Pro automatically adjusts default noise reduction slider settings and I can use the hot pixel slider there too but it still leaves some number of hot pixels in the processed TIFFs whatever I do. PS D&S filter set to 1 pixel pretty much completely removes any stragglers without smearing the image.
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    Re: Severe artifacts or noise problem with Phase IQ180

    Quote Originally Posted by Ztacir View Post
    I am using Capture One for raw processing.
    The image was unprocessed,unsharpened raw image only LCC applied.
    I have never printed my images without cleaning them manually.
    If I use pixel noise reduction extensively,my image loses its crispiness which is the last thing I want.
    I have not compared any other image from another camera or digital back but I assume this is the king of the digital world ,
    I should expect a better quality.
    I think image files from Phase backs require incredible amount of post-processing work which makes me wish I convert to film days.
    The original picture you posted is very difficult to distinguish what it is. It would be better to methodically troubleshoot issues like this instead of guessing, ideally shoot against a flat color background, say a middle grey, with uniform lighting conditions. Shoot again with by changing to say a blue background and see if the exact spots repeat themselves or still showing up but in different area! You could also try to do this at different exposure times, including very short and say 1s, 10s, 30s, just to see if a pattern is forming!

    Well something I would do to check my own sanity

    If I were guessing it was some sort of granite or marble, embedding inside and along the cut surface are usually very spec like surface that are highly reflective or metallic like because of the minerals, and that could be catching the whites (highlight), but I shouldn't/wouldn't have to guess that!
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    Re: Severe artifacts or noise problem with Phase IQ180

    Also if you're using zero latency the back could simply be hot. Switching to normal latency or turning the back off every once in a while (e.g. when moving to a new shot) would solve that issue. Usually doesn't matter for ISO35 and 1 second exposures, but we don't know the ambient temperature or how long the back had been on so I'm offering it as a variable to look into.
    Doug Peterson , Digital Transitions | Email
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    Re: Severe artifacts or noise problem with Phase IQ180

    I thought about the reflections off the wall but apparently it is not the issue because it was a painted wall .However,I will perform the test "Popfoto" suggested.
    I think what Doug is suggesting might solve my problem.This shot was taken some time ago but I have taken at least 100 shots and I have never turned off my back and it was August around 90's .
    I will do some more tests and let you know the results .

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    Re: Severe artifacts or noise problem with Phase IQ180

    Make sure your IQ firmware is up to date. They made big improvements to power/heat management after the early firmware.

    90's with the back on constantly in zero latency, or shooting many frames in a row without pause, would cause higher than usual noise in 1 sec exposures.

    I notice this with people who bracket long expsoures. If you do a 30 second, then 15 second, then 8, then 4 seconds, then 2 second exposure, and you don't have any break between the images, then the last image will have noise similar to a 1 minute exposure since at the end of the 2 seconds the sensor will have been on and heating up for 59 seconds worth of exposure.

    Not much time is needed for the back to dissipate heat away from the sensor. The passive cooling of the chassis is really excellent (great heat sink design). A very short break in shooting is all that's needed (if in normal latency) or a very short time of the back being off (if in zero latency). And no concern/adjust-to-workflow is needed at all if you aren't combining warm/hot weather with long exposures or high ISO.
    Doug Peterson , Digital Transitions | Email
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    Re: Severe artifacts or noise problem with Phase IQ180

    Further to Doug's observation of the heat sink performance and zero latency, a friend of mine was shooting with his IQ & Credo backs recently under desert sun conditions (115f) and within 10-15 minutes or so the backs were HOT. Not hot, HHHOOOTTT to the degree that you could hardly touch them. I suppose that it's a testament to conducting heat away from the sensor and electronics passively but we were both surprised at just how blisteringly hot these backs can get.

    Note to Phase One/Leaf: how about a white or reflective paint version? These backs both absorb and dissipate a lot of heat.
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    Re: Severe artifacts or noise problem with Phase IQ180

    i also had a heat problem, running zero latency, apparently I had mis-set the auto-turn off time, (usually at 5 min) put the camera back in it's padded bag, and later found it HHOOOTTT

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    Re: Severe artifacts or noise problem with Phase IQ180

    While heat is a big culprit of hot pixels and 100 shots in hot conditions without a break is not great on a MF back, I also think a major part of it is to do with how much you pull the files about. By that I mean big LCC corrections for movements with tech lenses, pulling up exposure for badly exposed images or being too heavy handed lifting the shadows. A mixture of all three spells disaster and can really exaggerate this sort of problem and without knowing the original and your processing steps its tough to put it down to one reason.

    Images posted below are original full version, 400% crop and 400% crop with the shadows over lifted. All with no noise correction applied and default sharpening on a P65+. As you can see the white pixels are visible in the original 400% crop but of little significance. With a bit of contrast/pulling up of the black levels they would virtually disappear. Pull up the shadows too much and the white pixels really stand out.

    Shot at 0.5 sec at f11 with a SK43XL (no centre filter) and LCC correction in C1. Longer exposures just get worse.




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    Re: Severe artifacts or noise problem with Phase IQ180

    Looks a heat problem to me. Had the same experience when my release cable failed and I had to use zero latency in the summer heat of HK/Thailand. Turning the back off for a bit works, they cool down really quickly.

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    Re: Severe artifacts or noise problem with Phase IQ180

    Quote Originally Posted by GrahamWelland View Post
    Further to Doug's observation of the heat sink performance and zero latency, a friend of mine was shooting with his IQ & Credo backs recently under desert sun conditions (115f) and within 10-15 minutes or so the backs were HOT. Not hot, HHHOOOTTT to the degree that you could hardly touch them. I suppose that it's a testament to conducting heat away from the sensor and electronics passively but we were both surprised at just how blisteringly hot these backs can get.

    Note to Phase One/Leaf: how about a white or reflective paint version? These backs both absorb and dissipate a lot of heat.
    You did say 115f heat, under those conditions, I would surely have melted by then, surely the back getting hot is "normal," no?
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    Re: Severe artifacts or noise problem with Phase IQ180

    There's hot and then there's SCORCHING hot. Like John, he'd turned off the auto power off and it just got hotter and hotter.

    Dry 115f - no problem. 80f and 99% humidity and you can keep it!
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    Re: Severe artifacts or noise problem with Phase IQ180

    Quote Originally Posted by dougpeterson View Post

    90's with the back on constantly in zero latency, or shooting many frames in a row without pause, would cause higher than usual noise in 1 sec exposures.

    I notice this with people who bracket long expsoures. If you do a 30 second, then 15 second, then 8, then 4 seconds, then 2 second exposure, and you don't have any break between the images, then the last image will have noise similar to a 1 minute exposure since at the end of the 2 seconds the sensor will have been on and heating up for 59 seconds worth of exposure.
    In reference to the above from Doug Peterson.

    I am a Leaf user, but since the Phase IQ backs now use the Dalsa sensor that Leaf uses, a long exposure technique that Yair Shahar taught me to reduce hot pixel noise may be helpful and worth a try.

    Try a very short exposure following each long exposure. For example, shoot at 1/500th after a 4 second exposure. Somehow the quick exposure helps to flush out the buildup of hot pixels. It won't completely eliminate them, but it is much better than shooting 8 sec several times in a row, or a series of long exposures brackets.

    I live in the desert and over half the year we have temps in the 90's - 110's even at dusk. I do well with my Leaf Aptus, but the thought of upgrading to one of the new backs with the battery contained inside the back is a bit scary. I may be sticking with Aptus for now, as the new backs do get alarmingly hot!

    However, I think it's kind of silly to setup up in direct sun at such extreme temperatures as 115F. A simple umbrella to shade your camera and digital back is easy enough to carry and use while shooting or waiting for the light, etc. and also is handy as a wind break during long exposures.

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