Severe artifacts or noise problem with Phase IQ180

[Ztacir]

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

 

[tjv]

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

 

[Ztacir]

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 .

 

[tjv]

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

 

[goesbang]

"Severe noise"? Have you cropped into any images from any other cameras/backs at 400% lately?

 

[gazwas]

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?

 

[torger]

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.

 

[etrump]

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

 

[Ztacir]

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.

 

[jlm]

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?

 

[stngoldberg]

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

 

[gazwas]

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.

 

[dougpeterson]

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.

 

[stngoldberg]

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

 

[Shashin]

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?

 

[stngoldberg]

80 second exposure-H4D50 Kodak sensor-no white pixels


original and 400% crop

Stanley

 

[Jack]

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.

 

[gazwas]

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.

 

[GrahamWelland]

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.

 

[pophoto]

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!