Ugly blown highlights – a processing bug

Posted on April 30, 2009 by Carl Rytterfalk

As some of you have noticed, some shots, especially at ISO50 has cut highlights in a ugly way – This currently is a bug in the new SPP 3.3(mac) and SPP 3.5(PC) software (processing bug) and rumors says that they’re working on a fix (Foveon / Sigma). I’d recommend older versions of SPP for processing of SD14 / DP1 files as this bug can be quite nasty for some pictures – DP2 files still need the new SPP. You can have dual version on the same computer. Read the Sigma Dpreview forum for updates.

About Carl Rytterfalk

Welcome to my blog! I'm Carl Rytterfalk, a swedish photographer who loves everything that is interesting in the world of photography. In 2002 I fell in love with the three layered Foveon sensor and has since then been an addicted user of Sigma cameras. Though I use Canon and Nikon as well. :)
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9 Responses to Ugly blown highlights – a processing bug

  1. Lucas says:
    May 1, 2009 at 6:51 am

    Is ISO 50 a true iso 50? Or is it like other camera’s that are really just shooting an overexposed iso 100 pulled back to a proper exposure? If so, wouldn’t this explain the hard gradient of blown highlights? I know even my 5D does the same thing when shooting at iso 50. I think you’re better off just shooting iso 100 and exposing to the right in the histogram.

    Reply
  2. Graham says:
    May 1, 2009 at 7:13 pm

    Have there been examples of the bug occurring at faster speeds than ISO50? I have not seen any. ISO50′s tendency to overexpose areas may just make it more prone to this issue though.

    In any case, when Sigma fixes their software, be sure to repost this beautiful photo. I love the colors.

    Reply
  3. Lucas says:
    May 5, 2009 at 12:47 am

    Bjorn, I think what I am trying to say is that the there is no amplification to signal difference between ISO 50 and ISO 100. ISO 50 is just the camera shooting at ISO 100 with a +1 exposure compensation that is then pulled back one stop before spitting out a jpg or raw file with these ‘in camera’ adjustments unknown to the user. Obviously with this process highlights are surely to get clipped in scenes with wide dynamic range – as seen in the clothespin image where the shadows of the clothespin would be much darker than the reflective surfaces of the white painted windows of the barn. Carl’s other ISO 50 shots with mostly even lighting show no clipping of highlights. If he shot at ISO 100 and overexposed, he could surely pull back the image in the RAW editor to achieve the same results. If ISO 50 is an optional ISO expansion setting and not a standard ISO, then I believe that no software fix will improve this I’m sorry to say.

    Reply
  4. Sebastian says:
    May 8, 2009 at 10:49 am

    Lucas was correct. The ISO 50 of Sigma DP1, like all digital cameras up to this point, is not an actual ISO 50. The DP1′s actual lowest sensitivity of the sensor is ISO 100 equivalent.

    Reply
    • Carl Rytterfalk says:
      May 9, 2009 at 12:12 am

      I was about to say the same. At least from what I’ve understood so far this is the case. But if light in a scene allows it, you can even push an ISO50 file down to ISO25 in some cases. That’s really really cool. :P (For the DP2) – it mostly depends on what colors and what type of highlighted areas there is. Will try to make examples of this.

      Reply
  5. Echodyne says:
    May 15, 2009 at 4:55 pm

    Take a look at the linked DP2 image – the lower neon text “An der Hauptwache” shows blown highlights in a pretty ugly way and some pink/purple colors. However, it was shot in ISO200. Any idea what could have caused this result?

    http://www.bildercache.de/bild/20090515-163342-490.jpg

    Cheers,
    Echodyne

    Reply
  7. Carl Rytterfalk says:
    May 17, 2009 at 10:17 am

    Echodyne, I can’t load your image.

    Igor, yes. That’s the bug thing. Hopefully they’ll fix it soon.

    Reply

  8. Pingback: DP1x highlight issue.. Fixable! | Carl Rytterfalk Fotografi

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