Discussion Forum Leica S System S2 S2 CCD Dynamic Range
  • September 6, 2011 at 7:57 am #887
    Bobby Lee

    Hi all,
    I am new in this forum. I am from Hong Kong. I would like to ask if anyone has tested the practical dynamic range of the S2 system. We all know Leica says it is around 12 f stops, as reconfirmed from the factory via email last night, but almost all medium format digital back manufacturers mention the real life dynamic range of their system. In the real life, say if Mr. Ansel Adam still alive and using a digital camera, he as a serious photographer will ask the manufacturer where are the upper and lower clipping points related to the mid tone exposure setting.
    I have used Sekonic’s test chart and it’s own software to test the S2 and that was within six f stops. Sounds much less than expected but it is already way better than shooting film!
    Anyone has more information on this topic?
    Looking forward to learn more in this forum.
    Bobby

  • September 8, 2011 at 8:54 am #910
    Bobby Lee

    Hi all,

    I have used the Data Transfer Software from Sekonic and the Exposure Profile Target II Grey Chart to measure the S2’s exposure dynamic range at both ISO 160 and 320 using Broncolor studio flashes.
    Attached is the result. The image files for the measuring software are in jpeg format so the actual dynamic range when shooting in Raw should be larger.

    7.2EV is not bad at all in compare to positive film (slides) which limited to a little bit more than 4 f stops. (I have tested again using Camera Raw to convert the jpeg files, so the result is different from what I have mentioned in the last post).

    Please note the upper and lower clipping points. This is very useful when you are setting up your own lighting.

    Bobby

    Attached files

  • September 8, 2011 at 8:59 am #911
    Bobby Lee

  • September 8, 2011 at 12:28 pm #912
    David Farkas

    Bobby,

    Interesting test. I’m curious about your testing process. Assuming that the JPG for testing was generated from the DNG, how did you process the file?

    If using LR, I’d strongly suggest lowering the Black Point from the default of 5 to 2. This alone will give you back some DR in the shadows that the software is clipping. In fact for testing purposes, you may want to drop this to 0. Also, did you apply any Fill Light or Recovery as one would do in real-life processing?

    I’ve found that extra DR can be extracted pretty easily from the DNG. Would be interesting to see how the results change as a function of different LR settings.

    If you send me a DNG file, I’m happy to process it and send it back to you as a JPG if you want any assistance.

    David Farkas
    Red Dot Forum
    Leica Store Miami
  • September 8, 2011 at 12:38 pm #913
    Bobby Lee

    Hi David,

    Thanks for the info. The problem I encountered is the software from Sekonic. As you may find a demo video on YouTube, it only read jpeg files. I have tried full resolution tiff with no adjustment but the software generated un-usable curves. What I will do tomorrow when I am back to the studio is to down size the tiff and see if that will work. If not I will send you the three DNG files for the conversion (one normal exposure, one three stops under and one three stops over exposed).

    I have email to Leica asking the same question but they only told me the range is 12 f stops.

    I have also performed a simply test for the sensitive of the auto focusing sensor of the S2. May be we can share after the dynamic range topic!

    Thanks again and update with you later!

    Best,

    Bobby

  • September 9, 2011 at 2:31 am #921
    Bobby Lee

    Hi David,
    I have ran another test. All with the same DNG files, one normal exposure as an incident meter reading, one three stops under exposed and one three stops over exposed. The difference is I converted these DNG file in Camera Raw (pls see screen shot) into 8 bit. First without any adjustment; Recovery = 0, Fill light = 0, Black = 0, Brightness =+50, Contrast =+25, Clarity = 0, Vibrance = 0, Saturation = 0.
    The result is almost the same (pls see attachment) with what I have got with jpeg files. Only expended 0.1 in its range.
    I then adjust the Recovery to 40 and Fill Light to 20 and converted another set of 8 bit tiff files. The result is different, quite big a difference. The dynamic range is now 8.6EV (pls see attachment).
    It looks like we can extend the dynamic range by cheating a bit but I am not sure if this is the right approach to find out the usable data in practical photography.
    The result for ISO320 is about the same.
    I do hope these data can help fellow photographers to fully utilize the capability of the Kodak CCD and produce the best output from the S2 image files.
    Bobby

    Attached files

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