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CFV bad pixels, phocus and aperture

R

rikkles

New Member
Hi I'm new here so sorry if this has been posted already (I did do a cursory search).
I just bought a CFV for my old 500C, and while I'm exceedingly happy with the color quality, I noticed that when using Aperture I see a large number (over 50) of bad pixels (pure blue or red for example). When using Phocus, it seems the app extrapolates the correct info on those pixels and removes them.

So my questions are:
- is it normal to have that many bad pixels in the sensor?
- how to make Aperture automatically fix them the way Phocus does?

Also I've got an issue of blurriness in the picts when looked at closely unless I'm at 1/250 or faster. Seems the camera is very sensitive.

Thanks in advance.
 
I presume you are using a standard lens or one with similar focal length like maybe a 100 mm Planar.
Even under less than optimum conditions you should be able to use at least
1/125 s shutterspeed.
Maybe your camera needs a CLA with new foams for the mirror.
It could be a case of mirror action due to bad condition of the foam.

50 dead pixels seem like too much.
I am sorry but I can not say what is the accepted max number of those for a CFV back.
You can contact Hasselblad service department yourself:
www.hasselblad.se

First register with your CFV back.
That will give you acces to downloads and information about digital products.


Paul
 
I'm using one of the old 80mm, but I'll figure out the blurriness. The real issue is with the dead pixels. I'm going to try to clean the whole thing with compressed air and see what happens. Otherwise I'll contact Hasselblad if I can, considering how pathetically buggy their site is. Has no one told them that 80% of the time, login fails? (actually I tried, but the comment form failed as well, so I gave up)
 
The Hasselblad site could use an update more frequently but I did not have a problem login in just now.
I never had any problem like that before. May be something else is causing the problem at your end.
 
rikkles

I can not use PHOCUS at the moment , because my graphic card is too slow .
Also , PHOCUS is still a beta version . Therefore , have you tried
FLEXCOLOR 4.8.5 ? ? ? The download is free , and I suggest you try to use FC and compare the results . Just to make shure it is the CFV BACK or PHOCUS which causes the issue .
In my opinion , 50 bad pixels is a bad result , even if it can be corrected by PHOCUS . I have no bad pixels on my CFV BACK .

As a figure of comparison , my MAC CINEMA 20"" screen is accepted as beeing bad , if there are more than 5 dead pixels . I have none .

Please try to use FLEXCOLOR and come back with your results .

Regards Jürgen
 
I am using Aperture and it's pretty problematic. The bad pixels are the same from photo to photo, whatever the lighting.
Here are examples of what I'm talking about (in a dark bad picture, but it shows the bad pixels clearly):
2513251615_0918ec1979_o.jpg


and:

2514076606_6bea75111e_o.jpg


I'm hoping I'm doing something wrong and it's a matter of calibrating or cleaning something... I don't know.

PS: I've got Flexicolor and I'll be trying it later with new pictures.
 
rikkles

That in fact does not look very good .
Have you deinstalled and reinstalled PHOCUS ? ? ? Are your batteries fully loaded ? ? ? As I understand , you have cleaned the sensor , carfully , and there are no spots on the sensor surface causing this ? ? ?
If you get the same results with FLEXCOLOR , having bad pixels and pixel groups , always at the same positions , you should show this to your dealer .

Jürgen
 
I'm using Aperture as well, but have had no problem with pixels. YET!
Do you have the newest update for Aperture 2, as well as current firmware for you CFV?
 
Have no idea if its related, but when I view images say in light room, the images have lots of bad pixels when viewed up close, yet after a few seconds when fully loaded they disappear. Also I find I need to shot at 250, to make sure of sharp pics.

Have you tried viewing the image in other software?
 
rikkles said:
Hi I'm new here so sorry if this has been posted already (I did do a cursory search).
I just bought a CFV for my old 500C, and while I'm exceedingly happy with the color quality, I noticed that when using Aperture I see a large number (over 50) of bad pixels (pure blue or red for example). When using Phocus, it seems the app extrapolates the correct info on those pixels and removes them.

So my questions are:
- is it normal to have that many bad pixels in the sensor?
- how to make Aperture automatically fix them the way Phocus does?

Also I've got an issue of blurriness in the picts when looked at closely unless I'm at 1/250 or faster. Seems the camera is very sensitive.

Thanks in advance.
Click to expand...

I see the same "problem" with PHOCUS, don't know about Aperature but no problem with Flexcolor. My guess, the "bad pixels" are a RAW converter problem.

Steve
 
All sensors have bad/dead pixels. I have no idea what the limit is (as in the analogy with a cinema screen). The reason you see them first then they disappear is that you are first seeing a lores preview. When the full image is loaded a factory created calibration file is applied which maps out those pixels. Every sensor has it's own unique calibration file which maps out dead pixels and accounts for any variations in the signal being pulled of the chip from well site to well site. From your experience it seems that aperture is not applying the calibration file to your files.
Nick-T
 
nickt said:
All sensors have bad/dead pixels. I have no idea what the limit is (as in the analogy with a cinema screen). The reason you see them first then they disappear is that you are first seeing a lores preview. When the full image is loaded a factory created calibration file is applied which maps out those pixels. Every sensor has it's own unique calibration file which maps out dead pixels and accounts for any variations in the signal being pulled of the chip from well site to well site. From your experience it seems that aperture is not applying the calibration file to your files.
Nick-T
Click to expand...

That's probably it. Now why it's not happening, I don't know. I'm going to try a couple of things: first, plug the camera into the computer for a while (not only with the battery in) so the internal clock battery is filled up. second, clean again the sensor, and third load up flexcolor to apply any firmware updates to the back.

Thanks everyone for the good suggestions, this is a great board!
 
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