Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: jeff_singer on August 21, 2007, 02:12:55 pm

Title: Phase One Image Corruption When Backlighting
Post by: jeff_singer on August 21, 2007, 02:12:55 pm
Any time I shoot into the sun as in the following shot, there is a "line" through the image that is clearly a problem with the sensor in this situation.  I've attached two image.  One is a 100% crop of the problem and the other is a low res version of the entire image for frame a of reference.

I saw this on my P25 and now again on my P25+.  Anyone else having this issue?

Jeff

jeff singer | photoBLOG (http://jeffsingerphotography.com/blog)
Title: Phase One Image Corruption When Backlighting
Post by: vgogolak on August 21, 2007, 05:44:05 pm
It's called the photo-electric effect.
Those electrons have to go SOME where
:-)
in a CCD they go down the channel used for reading
Title: Phase One Image Corruption When Backlighting
Post by: Caracalla on August 21, 2007, 06:23:05 pm
Quote
It's called the photo-electric effect.
Those electrons have to go SOME where
:-)
in a CCD they go down the channel used for reading
[a href=\"index.php?act=findpost&pid=134647\"][{POST_SNAPBACK}][/a]

[span style=\'font-size:14pt;line-height:100%\']What ever it is called, it should be fixed period!!![/span]
Title: Phase One Image Corruption When Backlighting
Post by: eronald on August 21, 2007, 06:35:21 pm
Quote
It's called the photo-electric effect.
:-)
[a href=\"index.php?act=findpost&pid=134647\"][{POST_SNAPBACK}][/a]

It's all the fault of a guy in some swiss patent office with too much time on his hands

Edmund
Title: Phase One Image Corruption When Backlighting
Post by: vgogolak on August 22, 2007, 01:05:17 pm
Quote
[span style=\'font-size:14pt;line-height:100%\']What ever it is called, it should be fixed period!!![/span]
[a href=\"index.php?act=findpost&pid=134657\"][{POST_SNAPBACK}][/a]

(No need to yell)

unless you want them to change the laws of physics. If you put 10 oz of water in an 8 oz glass, it will spill over.

Here, the electrons just happen to march out in a line  :-)

The only way to fix is by lowering sensitivity, or, aiming away from the sun. Yes, some other sensors behave differently, but I saw the same phenomena when I accidentaly had a mirror in the frame of a flash; it 'spilled' up the row of pixels.

It rarely happens, and may be mitigated with software, but then other factors may suffer; for example speed of readout, or bit depth.

All designs are trades. In general I find backs do pretty well.
Title: Phase One Image Corruption When Backlighting
Post by: Richowens on August 22, 2007, 02:21:47 pm
It is also called sensor bloom. It will happen no matter what format you are using. I have seen it on my lowly D70.

 It is more prevalent with longer lenses and wider apertures. The only way I have found to mitigate is to shoot at f16 and smaller. You might also try a ND filter if you need to shoot wider than that.

 Whenever I am in this situation, I use film, usually 35mm but occasionally medium format. I don't shoot for a living, just my own pleasure, so the time scanning is irrelevant .

 Vgogolak is right on, it is all a tradeoff.

 Rich