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IQ180 80MP Stitched ?

G

Googaliser

Guest
I've just finished my first serious job with the 180 and was a bit surprised by the results. My beautiful Bali skies have banding in them. Its very uniform too - 3 feint vertical bands - the first right down the middle, the other two equidistant from the middle and the sides. It is about a column wide with slight shadow a few columns wide.
I checked the sensor and see that it actually appears to be a grid of 6 sensors - divided in exactly the same way as my sky....

The banding is very noticeable in Lightroom. Its is quite hard to spot though in C1 - as though there is an algorithm to conceal it - although it is still noticeable on 100% crop whilst moving the image (before it appears to be dithered).
I'm on a laptop so I'm struggling a bit to visualise/assess whether this would be visible in large prints when processed via C1 (my usual workflow). Lightroom clearly isn't viable.
Have others seen this effect ?

PS: Aside from this, the 180 is phenomenal - so this isn't a bashing thread - just trying to figure out what this banding thing is and how to work around it.

M
 

Jack

Sr. Administrator
Staff member
Seriously, this has been discussed before --- USE C1 FOR CONVERTING PHASE FILES as LR is lacking some of the more advanced correction algorithms! The big Dalsa MF sensors are made up of a grid of smaller sensors -- IIRC, the IQ180 is a 4x4 matrix. Each back has a dedicated "calibration" algorithm to compensate and level the minor differences in those sectors on the array. You see the bands on the image move because it is redrawing and needs to reapply all algorithms before final display. The fact there is a visible lag, tells you how much math is going on behind the scenes to correct the many anomalies off high-res digital sensors.
 

Guy Mancuso

Administrator, Instructor
Also you should be in a color space like Adobe RGB or Prophoto color space. If working this in srgb you can certainly get banding as it compresses the color space.

I would NEVER use LR for any Phase files , it is actually not even on my system.
 
G

Googaliser

Guest
Really appreciate the rapid response. Apologies for missing the previous discussion(s) on this. LR is what we use to review a days still shots - always from several different cameras. Its a good melting pot - but not something we PP in. The 180 files attracted a pixel peeping client - will make sure they only get viewed C1 in future... Just glad to be able to rule-out a real-problem, of which we have had a number of this week leaving very little redundancy.
 

anGy

Member
This problem is not Lightroom specific. It's also showing when using Capture 1. I've seen it during a test when using the IQ180 on a Cambo WRS + 35mm Schneider. File developed in C1, 16b, prophoto.
The sensor is composed of 8 pieces and it looks like they are not reacting the same way to light/color cast? creating thin visible lines in the sky for instance:
Full image:


100% cropped (top right):


This is an issue. Back is serial# 1038
 

Jack

Sr. Administrator
Staff member
This problem is not Lightroom specific. It's also showing when using Capture 1. I've seen it during a test when using the IQ180 on a Cambo WRS + 35mm Schneider. File developed in C1, 16b, prophoto.
The sensor is composed of 8 pieces and it looks like they are not reacting the same way to light/color cast? creating thin visible lines in the sky for instance:

snip

This is an issue. Back is serial# 1038
Angy,

Did you use the LCC correction using the "Analyze technical wideangle" method? Those fine screen lines are a known issue for tech cameras using lenses under 50mm, and why it was added to C1 when the IQ180 was released.
 

Wayne Fox

Workshop Member
Angy,

Did you use the LCC correction using the "Analyze technical wideangle" method? Those fine screen lines are a known issue for tech cameras using lenses under 50mm, and why it was added to C1 when the IQ180 was released.
Image is awfully clean ... can't imagine getting that image without the LCC. Not sure if perhaps running the normal LLC instead of the technical wide one may cause the issue.

Is there a possibility the back needs to be recalibrated?

Also, getting these bands out of LR are hit and miss. My current IQ180 is excellent out of the most recent version of LR shooting with the DF. I've done a couple of conversions that needed some serious local adjustments (graduated filters) that were just too much work with C1, and they turned out terrific.
 

Jack

Sr. Administrator
Staff member
Image is awfully clean ... can't imagine getting that image without the LCC. Not sure if perhaps running the normal LLC instead of the technical wide one may cause the issue.

Is there a possibility the back needs to be recalibrated?
I suspect a regular LCC was done. If it was the TechWide LCC, then I'd agree the back needs to go back to Phase for a re-calibration.
 

anGy

Member
I suspect a regular LCC was done. If it was the TechWide LCC, then I'd agree the back needs to go back to Phase for a re-calibration.
'Analyze technical wide angle' has been used - just redid it to be 100% sure, same result.
 

anGy

Member
It's a demo back from my dealer that I'll return next week. Maybe an early production sample. Glad to ear that this is no standard behavior of the IQ180 !
 

etrump

Well-known member
Actually, recalibration of a back can be done from a raw LCC exposure without returning it to phase.
 
M

madmanchan

Guest
The current IQ180 support in LR is preliminary (i.e., still a work in progress, not finalized). You can expect improvements going forward.

Cheers,
Eric

Camera Raw Engineer, Adobe
 
G

Googaliser

Guest
Eric -
I am *really* glad to see Adobe represented here... the C1 mob is getting bigger and I'm not sure how much longer I can hold out ;-)
M
 

Guy Mancuso

Administrator, Instructor
The current IQ180 support in LR is preliminary (i.e., still a work in progress, not finalized). You can expect improvements going forward.

Cheers,
Eric

Camera Raw Engineer, Adobe
That is awesome news and something us Phase shooters been wanting for a long time.
 

dougpeterson

Workshop Member
The current IQ180 support in LR is preliminary (i.e., still a work in progress, not finalized). You can expect improvements going forward.

Cheers,
Eric

Camera Raw Engineer, Adobe
Welcome to the forum Eric! It's great to have a diversity of opinion on the board, especially when it is from someone with direct/extensive knowledge!

I hope you'll stick around and contribute as the community always benefits from such presence.

Perhaps you could tell us a bit about yourself, and the team you're on (or run). It's always great to know a bit beyond a screen name. Maybe you could start a thread for comments/questions/concerns on LR for medium format use!

And don't worry even though I'm very pro Capture One I play nice :). Both softwares have some great advantages and disadvantages. For instance the super-high ISO (e.g. ISO 12,800 on a 5DII) processing in LR3 is spectacular whereas the skintone gradations at middle-high ISOs (e.g. ISO3200 on a 5DII) in C16 can't be beat! Import-to-final-rendered-images in LR is much faster than C1 but applying a style to 1000 images (to final rendered images) is much faster in C1 than LR. Plus there are a lot of features that are ONLY available in one or the other. We could go on and on :).

The point is - stick around! We can have some lively conversations that everyone would benefit from.

Doug Peterson (e-mail Me)
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Last edited:

Thierry

New member
Welcome too, Eric.
Same for me, I hope we can all "take advantage" of your knowledge and information here.

Best regards
Thierry
 
M

madmanchan

Guest
Hi folks, I'm glad to be here. I must admit I don't post often (4th post -- woohoo!) though I do read and learn a lot.

I'm relatively new to photography. I got hooked while in grad school in 2003, and I still remember being bowled over in 2004 when seeing Charles Cramer's 24x30 prints at the Ordover Gallery in San Diego. I've since developed a strong interest in printing. And keeping my prints away from my cats.

I joined the Camera Raw engineering team at Adobe in early 2008. The main focus of my work is raw image processing (noise, color, optics, sharpening, etc.) and camera support. So the main products I'm involved with are Camera Raw and Lightroom. New cameras regularly cross my desk: everything from compacts to MFDBs, just as long as it supports raw! It's my responsibility to test these cameras, measure them, and characterize them. And keep them away from my cats.

While I enjoy brainstorming about new image processing techniques and hacking code, I also enjoy engaging directly with photographers and consider user education a top priority. This is why I like to go to the forums and (when possible) meet face-to-face with photographers ... I get a much better sense of what works and what doesn't. It helps me to understand the wish lists and pain points of photographers. And it gives me an opportunity to explain (more in depth) how certain features of Camera Raw and Lightroom work. As long as the cats aren't sitting on my keyboard.

:)

Eric
 

Guy Mancuso

Administrator, Instructor
Nice to have you here Eric. Let your friends know about us at Adobe. The more we interact the better we become in this industry as a whole.
 
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