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Thread: IQ3 100MP long exposure issue - shadow filled with red color cast

  1. #151
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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by Iliah Borg View Post
    What you are showing looks like black level going up with exposure going up. You can try editing black level in RawDigger manually to confirm the issue. With correct black level there should be no magenta cast and normal contrast.
    That is also what I thought. There is perhaps a drift of the red channel. Manually specifying a higher black level of the red channel DOES remove the red cast in shadow. However this value is not fixed among my test shots. The positive side is that this could potentially be fixed with a firmware update or a Capture One update.

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by kimyeesan View Post
    anyone question the ND filters????? I mean ND filters are known to create this kind of red hue/IR polution to the image.... no????
    I don't think it has anything to do with the ND filters. It was explained at #83 of this thread. Another test shot without any ND filter at #129 of this thread also confirmed this.

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by voidshatter View Post
    That is also what I thought. There is perhaps a drift of the red channel. Manually specifying a higher black level of the red channel DOES remove the red cast in shadow. However this value is not fixed among my test shots. The positive side is that this could potentially be fixed with a firmware update or a Capture One update.

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    It looks like overall black level, not just red channel. Here is how it works. Raw data in not white-balanced. When white balance is applied, red and blue channels are multiplied by some number, while green stays as it is. Suppose the black level in raw is incorrect, and the "true" black (pitch black on a shot after black level subtraction) is something like 500 in all channels instead of 0. Now we multiply those 500 by WB coeffs, say, they are 1.5 for both red and blue. Result is (R, G, B) = (750, 500, 750); that is green is in "deficit". "Minus Green" filter = Magenta, that is we are getting magenta tint on the image.

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Have you started a support case and submitted your files to Phase One yet?
    Doug Peterson , Digital Transitions | Email
    Dealer for: Phase One, Mamiya Leaf, Arca-Swiss, Cambo, Eizo, Profoto
    Office: 877.367.8537. Cell: 740.707.2183
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  5. #155
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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by dougpeterson View Post
    Have you started a support case and submitted your files to Phase One yet?
    I've sent back the demo unit and raw files to my dealer yesterday and my dealer is currently running these tests on another demo unit. I think they are going to create a support case soon.

    Meanwhile, you are very welcome to do some tests with your demo unit (either to disprove or to confirm this issue).

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by dougpeterson View Post
    Have you started a support case and submitted your files to Phase One yet?
    My friend's dealer has responded:

    A support case has been created with case number 223.782 and was escalated to DK support.

    He did the following tests: 100MP + Alpa + 23mm lens, 30 minutes, cover the lens - no lights.
    First one is with Normal Mode + Normal Latency. Second one is with Normal Mode + Zero Latency
    Both images were captured in CF card mode.
    To ensure no drop issue, the battery was changed on each shot.

    The one with Normal latency is OK.
    The one with Zero latency is reddish color.

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by voidshatter View Post
    My friend's dealer has responded:

    A support case has been created with case number 223.782 and was escalated to DK support.

    He did the following tests: 100MP + Alpa + 23mm lens, 30 minutes, cover the lens - no lights.
    First one is with Normal Mode + Normal Latency. Second one is with Normal Mode + Zero Latency
    Both images were captured in CF card mode.
    To ensure no drop issue, the battery was changed on each shot.

    The one with Normal latency is OK.
    The one with Zero latency is reddish color.

    Click image for larger version. 

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    I've seen this happen when the back is used in zero latency but the sync signal is messed up (e.g. you give it a wakeup signal when it wasn't expecting it, but with such timing that it doesn't generate the sync error message on the back, or when the sync cable is defective). Often the issue doesn't manifest until the frame AFTER such a triggering error, making it a bit harder to track down.

    I'm not saying that is the case here; I'd have to be there to know all that is going on.

    In any case, sounds like your dealer is on it!
    Doug Peterson , Digital Transitions | Email
    Dealer for: Phase One, Mamiya Leaf, Arca-Swiss, Cambo, Eizo, Profoto
    Office: 877.367.8537. Cell: 740.707.2183

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by dougpeterson View Post
    I've seen this happen when the back is used in zero latency but the sync signal is messed up (e.g. you give it a wakeup signal when it wasn't expecting it, but with such timing that it doesn't generate the sync error message on the back, or when the sync cable is defective). Often the issue doesn't manifest until the frame AFTER such a triggering error, making it a bit harder to track down.

    I'm not saying that is the case here; I'd have to be there to know all that is going on.

    In any case, sounds like your dealer is on it!
    Hi Doug, thanks for replying. You don't have to be there to know what's going on. All you need to do is to spend a day and test it with your own demo units. You could even test it with sync cables of different brands (e.g. Cambo, Arca etc) since you are most resourceful in this forum.

    Our current observations are:

    a) There is a red cast in the shadow with increased long exposure time;

    b) In descending order of severity: aerial mode (1/60s preliminary darkframe) + either zero latency or normal latency > normal mode + zero latency > normal mode + normal latency.

    c) The issue is not profound if the image is shot with appropriate darkframe NR (either normal mode or a preliminary darkframe of appropriate exposure time in aerial mode) along with normal latency.

    My dealer has been very helpful with this "issue" and also contacted Phase One and they have my thanks. Unfortunately Phase One does not care about anything shot other than "normal mode + normal latency" because they claim that "normal mode + normal latency" is the way in which the IQ3 100MP is designed to work.

    To me, it looks like a firmware update or a Capture One update can fix this for aerial mode (1/60s preliminary darkframe) + zero latency and make it work as the IQ250 does. However my dealer doesn't think Phase One will implement this kind of "feature development".

    I don't like the idea of normal latency with dedicated sync cables because I always mess up by forgetting to cock the shutter. It's also fragile as I once broke one of those more complicated sync releases in the field while I was in a hurry to catch the sunset. I like zero latency with the very basic soft touch release button, in accordance with Alpa's quote "Things are Simple at the Top". This is not about money but about the ease of use and reliability.

    To me and to many of the seasoned long exposure photographers, not having to rely on any in-the-field darkframe countdown is essential. Having to shoot in normal mode with a darkframe NR countdown after each frame is not acceptable. Shooting a preliminary darkframe of appropriate exposure time in aerial mode is not practical in many situations either.

    Almost all current 35mm format cameras (e.g. Nikon D810, Canon 5DSR etc) can shoot long exposure without darkframe NR. The IQ250 also works great in aerial mode (1/60s preliminary darkframe) + zero latency, which essentially doesn't need to rely on any darkframe NR countdown in the field.

    As Phase One doesn't regard this being an "issue" for the IQ3 100MP, there should be no worries that this thread would affect the sales of the IQ3 100MP by any means. As long as everyone knows the limitations and workarounds and is happy with the gear choice it's fine to put this to rest unless there's more valuable information for an update.
    Last edited by voidshatter; 21st July 2016 at 20:57.
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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by voidshatter View Post
    Unfortunately Phase One does not care about anything shot other than "normal mode + normal latency" because they claim that "normal mode + normal latency" is the way in which the IQ3 100MP is designed to work.

    To me, it looks like a firmware update or a Capture One update can fix this for aerial mode (1/60s preliminary darkframe) + zero latency and make it work as the IQ250 does. However my dealer doesn't think Phase One will implement this kind of "feature development".

    I don't like the idea of normal latency with dedicated sync cables because I always mess up by forgetting to cock the shutter. It's also fragile as I once broke one of those more complicated sync releases in the field while I was in a hurry to catch the sunset. I like zero latency with the very basic soft touch release button, in accordance with Alpa's quote "Things are Simple at the Top". This is not about money but about the ease of use and reliability.
    Whilst I can understand Phase One not wanting to under take support of Aerial Mode + zero latency and long exposure, I don't understand why they wouldn't recognize that there are many technical camera shooters who do use Zero Latency + Dark frame NR for extended exposure shooting. Heck, that's me and I'm sure plenty of other folks here.

    For shooting in normal mode the only trigger that I found anywhere near reliable was the Alpa sync and then only the very latest version II and cables. Of course, that's a very expensive solution (well, it's Alpa so that goes without saying), especially if you want one on each lens. Swapping the trigger in the field is fraught with peril IMHO. I avoid screwing devices on & off the Copal shutter where possible and so shoot zero latency exclusively and actually fit all of my technical camera lenses with Gepe Pro release cable extentions so that even the shutter release is screwed in & out of an easily replaceable part vs the shutter itself.
    Ylem ...

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    A senior moment? Of course you recall that "Gepe Pro release cable extensions" are referred to as "Libby adapters."

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by GrahamWelland View Post
    I avoid screwing devices on & off the Copal shutter where possible and so shoot zero latency exclusively and actually fit all of my technical camera lenses with Gepe Pro release cable extentions so that even the shutter release is screwed in & out of an easily replaceable part vs the shutter itself.
    I use that same Gepe extension on all of my lenses. I was flabbergasted at the price increase from $29.95 (which I thought was already expensive) to $44.95!! They must be going out to breakfast with Alpa......

    Victor
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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    I apologize in advance for the long post. For those who don’t want to go through the whole thing here is the Executive Summary: My back does not apply dark frames in a way that makes any sense so I am going to talk to my dealer about submitting a case. For example, when in normal camera mode and zero latency I see hot pixels even though it takes a dark frame in that mode. I suspect this problem is lurking in the background of all these results and this whole thread, so I doubt it is just my back.

    The Rest of the Story
    I haven’t posted recently because of a combination of 1) travel, 2) fear this thread would go exactly where it went for a while, and 3) the effort it takes for me to do something that should be simple! I got pulled into this early with the mistaken idea I could help with something, but alas, not so much. I’m in a real conundrum because I am far in the camp of this application being not just out in left field, but beyond BFE. It’s like Yunli is complaining that the air conditioner in his 911-R goes out if it is in Track Mode for over 4 hours. On the other hand, he has done a good job demonstrating that for him, this is a very important application. I certainly understand laying out $four-figures$ and then finding out the product might not perform the way you wanted it to in an application that is important to you.

    Yunli, there are a couple things you might consider when approaching these issues: When you post images in these situations, also report what you are doing in C1 to highlight the problems you see (in this case shadow and exposure settings). This would do a few things:
    • It would make it clear how others could reproduce what you are seeing
    • It would diffuse some of the aggressive responses because it would be clear how far you are pushing things when seeing these results. Many of us in this community are tired of the constant bashing, and it is too easy to dump this into that category. Perhaps not justified, but for a community to work we all have to be considerate of each other.

    (sorry for the lecture).

    As for my testing, I am not going to post too many photos because there is really nothing new to see. Last week I sent Yunli some of my raw files, which he agrees looked fine. However, as I’ve posted previously, taking a very short initial exposure is a big part of the issue here because it forces the back to use an irrelevant dark frame. Yunli and I disagree about how cumbersome it is in the field to take an initial exposure on the order of minutes, but I bow to his experience in these types of shots, which I really never do.

    I can duplicate the red cast by taking short initial exposures then a long exposure and pushing the exposure and shadows. I moved to the basement to get controlled lighting conditions and because the temperature is a consistent 67-68d F down there. Two weeks ago I did a first test and got weird results that included images shot in normal camera mode and normal latency that looked like there was no dark frame applied. I sent those images to Doug just to let him know. I tried to convince myself I screwed up my notes!

    So I focused my testing on different modes and situations to see if and when it applies a dark frame. Again, my results are not at all what I expected. Because of the results in my first test, I was suspicious of what Doug mentioned above regarding sync errors, so I used the following sequence:
    • 277 Normal Mode – Normal Latency
    • 278 Aerial Mode – Zero Latency (no dark frame)
    • 279 Normal – Zero
    • Turn off the back
    • 280 Aerial Mode – Zero Latency (forces a dark frame)
    • 281 Short exposure
    • 282 Normal – Normal


    Please note as I mentioned in previous posts, it is not switching to Aerial mode that forces an initial dark frame – it is instead powering down and back up. Here are the SOOC images, purposefully underexposed.


    From now on, all images are pushed 100% shadow and +1 Exposure.



    I was going to continue testing and force a sync error, but my results at this point were strange enough that I stopped. Because I’m taking long dark frames (not 1/60 sec like Voidshatter), you can see the red cast when pushed but it is more subtle; you need to compare images to see it. The more interesting result is how dark frames are applied given the above sequence. If I see hot pixels I assume either a generic dark frame was applied or no dark frame was applied:
    • 277 Normal – Normal: No Hot Pixels
    • 278 Aerial – Zero: No Hot Pixels(!)
    • 279 Normal – Zero: Hot Pixels(!)
    • Turn off the back
    • 280 Aerial Mode – Zero Latency (forces a dark frame): Hot Pixels(!)
    • 281 Short exposure: No Hot Pixels
    • 282 Normal – Normal: No Hot Pixels



    Sorry, the hot pixels do not come across very well in the JPEGs, but you can see in the 100% crop the reddish shadows; those are the two with hot pixels.

    I cannot explain the use of a dark frame on images 278-280. 278 did not take a dark frame but there are no hot pixels. Both 279 and 280 took a dark frame but there are hot pixels. I know what you all are thinking: I again screwed up my notes. Of course I thought the same thing, so I repeated it again this morning – same result! Here are screen shots FF and at 100%.
    • 549 Normal – Normal: No Hot Pixels
    • 550 Aerial – Zero: No Hot Pixels(!)
    • 551 Normal – Zero: Hot Pixels(!)
    • Turn off the back
    • 552 Aerial Mode – Zero Latency (forces a dark frame): Hot Pixels(!)
    • Forced sync error
    • 553 Normal – Normal: No Hot Pixels





    It appears to me the back is not applying dark frames as it should, and it is more related to zero latency than it is Aerial mode. I do not normally use zero latency. For those of you who do, you may want to investigate.

    Dave
    Last edited by dchew; 23rd July 2016 at 07:24.
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  13. #163
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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    After thinking more about the scenarios, I found:

    In zero latency, if my back takes a dark frame it does not apply it. If it does not take a dark frame, it finds one to use and applies it.

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quick note that this issue has been improved in Feature Update 3. In some situations/combinations-of-variables an IQ3 100mp long exposure could have a very slight red bias in the shadows. As of the update this should no longer be the case.
    Doug Peterson , Digital Transitions | Email
    Dealer for: Phase One, Mamiya Leaf, Arca-Swiss, Cambo, Eizo, Profoto
    Office: 877.367.8537. Cell: 740.707.2183
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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quick note to Voidshatter.

    Thanks for taking the time post your initial results. You took a bit of un-necessary heat IMO when you first brought this issue up back in July.

    Glad to see it has been addressed.

    Paul C

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by dougpeterson View Post
    Quick note that this issue has been improved in Feature Update 3. In some situations/combinations-of-variables an IQ3 100mp long exposure could have a very slight red bias in the shadows. As of the update this should no longer be the case.
    Thanks for getting back to this Doug - it's good to see that Phase One is actually paying attention to this! I will test it myself when I have the chance. This is because it would be quite rare to see an IQ3 100MP user/seller to release test shots that reflect problems. To be specific, I have no interest in test shots with a preliminary darkframe of appropriate exposure time.

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    Re: IQ3 100MP long exposure issue - shadow filled with red color cast

    Quote Originally Posted by Paul2660 View Post
    Quick note to Voidshatter.

    Thanks for taking the time post your initial results. You took a bit of un-necessary heat IMO when you first brought this issue up back in July.

    Glad to see it has been addressed.

    Paul C
    Well I'd say it was necessary to take the heat, otherwise all that we would have got from Phase One would have been that "Neither aerial mode nor zero latency is supported by Phase One". The existing owners of the IQ3 100MP chose to hide the problematic raw files from me and from the public, trying to hide the problem or to justify that it wouldn't affect their usage. Well that's totally understandable!

    I'm looking forward to see whether this has been addressed or not!

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