I thought that tiling was an adverse effect related only to CCD sensors.Regarding tiling issue and vertical bandings, yes we confirm that when a wide angle technical camera lens is shifted along the shorter edge of the sensor to the extreme, all three digital backs can suffer from the tiling issue...
On the other hand, it is very easy to see that on the CCD sensors even unshifted, and that could be 3 vertical lines in addition. The 8 partitions are clearly visible on a fullframe CCD sensor by eye, but when you stare at the IQ3 100MP surface it looks like a whole (without any partitions at all).
IQ260+40HR unshifted but at ISO 200:
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If it is like it has historically been the suppression banding and tiling can be improved, but the loss of saturation clearly seen in the long exposure sky (crosstalk effects) is not.
It is interesting though that the bug caused a green cast, maybe it is because they're trying to do something with the saturation... it shall be interesting to see what the update can do.
In an extremely processed dark frame I can get one tile line on my 50MP Kodak (which has two readout channels) but I've never had any real world problems.
With the CMOS there's no problem with ADC channel matching (I think), but there can still be uniformity variation tiles from manufacturing.
Normally the tiles are 100% neutralized with the LCC shot, but if you have some crosstalk (which you have on the wides, especially when shifted) the tile lines appear with different strength depending on what actual light/color there is at the line which means that the LCC shot cannot cancel it out fully. To remove the tile line you then need to make some filtering after the LCC has been applied, which Capture One does with varying success.
If you actually get problems with tile lines depends a lot of what post-processing style you have. If you do low contrast stuff you rarely get any issues. If you do black and white high contrast processing you're almost guaranteed to get at least some issues. With the Dalsa CCDs that is... I don't know how many issues there are with the Sonys, I have seen tile lines at least one time but only at crazy crazy extreme processing just to test if I could get a line visible.
Here's an image showing Dalsa tile lines:
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> Unfortunately the IQ250 is still not fully supported
Sorry, but how do you mean it is not fully supported?
Please check back in about 2 hours time
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There are calibration data tags also for the CMOS backs. They're obviously less important to decode and apply than for CCD backs, but they're still there. I don't think all sensor calibration tags for the CMOS backs have been reverse engineered, at least it's not done in DCRaw. This is probably causing the difference for the IQ250 files.
It's messy to handle the calibration data for us third parties as the MF companies introduce new tags with new formats with new sensors (as new sensors have new needs). I've reverse engineered for some Dalsa sensors for IIQ, and I've done it for some Kodak sensors in the Hasselblad 3FR format. But I haven't done it for CMOS neither 3FR or IIQ, but I know there are tags, just make a exiftool -v listing and you see them.
As there's virtually noone using open source software or independent third parties when it comes to $40k backs there's a lot of work for little reward doing this. The reason I did it for the Kodaks was that I needed it myself for my own H4D-50 back, and for the Dalsa I thought about getting such a back and needed proper support for it, but in the end I didn't get one. Another reason that it's not that rewarding is that the files usually look perfectly okay without calibration data applied, the calibration data just adds a tiny bit extra quality on top. For the Dalsas it was very important though as tiling usually was quite visible if the calibration data was not applied. For the CMOS there's no obvious reason to apply the calibration data, at least for us that shoot an LCC for each shot, but I don't know for sure as I don't know what's in all those tags.
In any case it's most likely that the CMOS tags are quite simple though as the calibration need is much smaller for CMOS than a CCD with external ADC.
Sometimes if you decode the IIQ of the IQ250 or Credo 50 by Adobe Camera Raw / Lightroom directly, shadow SNR gets beaten by the Nikon D810. In this regard, the Canikon solutions are less dependent on the RAW decoding software.
> From what I can see there is no LCC applied. No Chromatic aberration removal or lens correction has been applied either.
Thank you. RawDigger displays raw data and statistics; DNG is pre-processed (for example, the black level is subtracted, and in non-uniform manner), and that is normal for raw conversion. But RawDigger is not a raw converter, it is more or less a tool to discover the true nature of the raw data, and the tweaks and "cheats" added by different raw converters. If one wants to see the raw starting point to evaluate the sensor and lens performance, that's what RawDigger is for.
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I know Adobe's DNG converter applies calibration data to Dalsa IIQs (so the DNG you get is "cooked"), but even then it was not exactly as Capture One. Some calibration data tags are things like polynomial curve handles so it can vary a few sample values depending on implementation. And at the time Capture One actually had a bug in their flat field calibration data application, so Adobe did it better at that particular point in time
With the IQ250 perhaps Adobe thought that calibration data made so little difference that it was not worth the effort implementing it even if they had documentation.
It should also be said that Capture One can in some cases make post-processing of the file, additional cooking, to improve quality. Removal of tile lines and micro lens ripple is one such post-processing thing that is not related to any calibration data. It's not unlikely they make additional minor tweaks, and indeed this is one thing Doug loves to speak about -- the advantage to be both manufacturer of camera hardware and raw converter in one. Using third party software you can miss out on some of the minor tweaks.
Which one could be better for tweaking and "cheating"? In-camera chip + firmware, or a sophisticated software like Capture One? I would imagine the latter in most cases.
Calibration data usually fixes linearity, flat field (uniformity variations), tiling, mapping out dead (or half-dead) pixels. So if you evaluate those things your decoder must apply it of course. On the Hassy Kodak I looked at there was a strange type of calibration that moved some pixel data from the neighboring pixel, but it really was required to make the demosaicer work optimally (I guess it was some sort of readout crosstalk compensation). There's also tags like sensor temperature and such and I imagine that Capture One could be steering some pre-step noise reduction parameters based on those values.
So while evaluating raw data is valuable, one also needs to check the end result in the native raw converter too as software conversion is very much a part of the final image quality. Anyone who's used Capture One over a longer period of time knows that it happens now and then that they adjust tweaks, sometimes introducing bugs (like the LCC bug now).
Regarding tweaks I think the noise reduction part (the one that is always applied and can't be turned off) is probably what you gain most in using the native software, and indeed fine-tuned noise reduction has kept the "usable DR" of the medium format backs at a higher level than the sensors should actually be capable of. With third party software you can do good noise reduction too, but you generally need to tweak it manually and it's not always possible to make as fine tweaks as the native raw converts do. Noise reduction is not part of the calibration data, but some of the tags can be used as parameters into the noise reduction algorithm.
Round tower shots iso 1600 n 3200 is nosier than pentax iso 16000 if i recall...
If this new back only usable in iso 800 people will not upgrade from IQ180...
Maybe those 15 bits of base ISO DR couldn't be combined with great high ISO performance? It would be interesting if they've made a deliberate trade-off.
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I just made a quick visual inspection iso3200 compared to A7r2 on a per pixel basis. I couldn't see that IQ3100 was any worse, if anything it seemed a little cleaner. This in RawTherapee with no noise reduction tricks activated.
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How is it compare to Pentax ISO 3200? Same Sony Sensor.....
Even the older backs can be used to make amazing images.
Even Yunli (voidshatter) has created some stunning images made using the purportedly "useless" IQ260.
The fact is cameras and backs are tools to make photographs. They ALL have limits. Cool to see people finding those limits (which in most cases nowadays are VERY extreme!) but they do not exemplify the complete user experience.
Last edited by Ken_R; 9th January 2016 at 06:22.
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IQ180: Help - WB & Exposure when shifting
IQ180: Issue with IQ180
IQ180: IQ180 frustrations.
IQ160: Tiling - how to remove in post?
IQ160: IQ160 tiling issue
If we take the official sample image of the IQ260 (shot by Antony Spencer as advertisement for the IQ260) as an example we can see the below:
I have not bothered to investigated the conditions of occurrences. I only know that for the fullframe CCD sensors it's likely to happen for uniform/simple contents and is more likely to happen when a technical camera lens is shifted to the extreme.
Sometimes an LCC correction can fix it. Sometimes content-aware healing tool in Photoshop can fix it. Sometimes it's just annoying and it's difficult to fix it. I gave up and moved to a CMOS sensor.
It's a nice image btw. I just wanted to demonstrate the tiling issue. I know you would never ruin an image like this, and perhaps you have ways to work around it. (If you dislike this I will remove this post.)
Okey, I have removed it and you have my apologies.
OK Lets make something completely clear.
Images are owned by their creators unless made under a contract that says something different.
We assume though that folks that post images own them and thus control their usage.
We encourage the posting of images, after all it is not all about gear but about the images we make with it. Some images are intended as art, some to illustrate some aspect of gear, processing or technique.
It is perfectly fine to ask to use an image for a test or some other purpose such as variations on processing, but the key point here is that you MUST ask and get permission and furthermore your request MUST say what you intend to do with them.
Good, now carry on.
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Yunli are you ever happy or satisfied with anything?
I will something Doug posted in one of the threads you linked to:
Yunli, please consider the effect your posts have on people before posting. Put them in context since obviously not everyone can read between the lines and not everyone can put the comments in perspective or in balance with other aspects of the gear in question. You isolate a problem and pound on it. Relentlessly.
Yes, I'm being grouchy however this is how I make my living.
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I don't know whether there was a copyright violation or not, but don't you see how the "author" of the photo might object to someone appropriating and manipulating it?
Appropriate: to take something for one's own use, typically without the owner's permission.
Sure, I see that the author of the image might object (and, in fact, he did) but in this context I can't see that the usage was harmful: it was an attempt to show a certain technical problem in the context of a technical discussion to the readers of this section of getDPI. If this would have been my image, I wouldn't have objected.
But I don't think we should discuss this in more detail, I don't want to derail this threat.
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I remember going from P65+ to IQ180, and being confounded by the changes, like stronger lens cast, inability to use Schneider wide angles, worse battery life, etc. Now here we are, and many of us wonder if it's wise to leave our venerable IQ180's for the IQ3-100. Your information is invaluable in the light of this expensive upgrade question.
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Help - WB & Exposure when shifting and applied a filter to demonstrate how obvious the tiling issue is for the IQ180 (In a nice way of asking I think, then removed it).
Sorry that it affects your living.
PS: I thought this how it works at getdpi when you grab someone else's test shot and ask during discussion: CFV50c Images.
Last edited by voidshatter; 9th January 2016 at 19:15.