• Documentation,  General,  Landscape

    Frame averaging

    Otto Flechtenmacher was a painter who lived in Austria, an uncle of Christa. I often did photography for documentary purposes, especially paintings.

    This morning I listened to a workshop of portrait photography. To some extend the audience received explanations of the PhaseOne camera, which I use quite frequently. The vast dynamic range and the frame averaging feature of a PhaseOne were mentioned.

    To reproduce these features I intentionally underexposed a photo of a painting of Otto. The original histogram can be seen on the left, the processed one on the right. The quality is quite surprising, when you are used to full frame sensors.

    Typical histogram of the RAW-files
    Typical histogram after processing in CaptureOne

    To compare the quality of a single shot image to frame average files, I did a sample of a single shot and two shots of 5 and 9 averages. Clearly, noise will be reduced. At the same time, structures come out more detailed, what might be seen from the following examples:

    I never thought of using this feature for landscape photography – but it makes sense. By applying frame averaging you can get a landscape photograph with preserved highlights and well structured dark parts.

    Roses - oil painting by Otto Flechtenmacher © Julian Köpke
  • Architecture,  Monochrome,  Travel

    Surprising light

    Looking for a photo opportunity I stumbled over a burial site which is not far from the part of Stuttgart I grew up for several years. I had the chance to test a back for my Phase One. So I visited the grave monument of Württemberg commissioned by Wilhelm I. for his beloved wife Queen Catharina Pavlovna.

    On a sunny day at noon each cam works nice. Hence, for a testing opportunity, the decision to photograph the vault or crypt was made quickly. And she paid off.

    Burial site of Catharina Pavlovna Stuttgart © Julian Köpke

    The central hall is covered by a dome roof, which makes a clear allusion to the Pantheon in Rome. The top of the dome in Rome is open. As a result, the influence of the weather is directly perceptible within the sacred space. In Swabia, with lot of rain and occasional snow, a glass dome was chosen as the end.

    My 35mm lens is on my Phase One equivalent to 22mm full frame sensor. The following image is a single shot without a tripod. No HDR technique was applied.

    Dome roof a the burial site of Catharina Pavlovna Stuttgart © Julian Köpke

    In the tomb one floor deeper, the main person of this burial site is presented with a bust on which a fresh flower had been draped laterally. The delicacy of the flower and its color was impressive. Who put the flower there ?

    Bust of Catharina I, Queen of Württemberg © Julian Köpke

    Bright electric light bulbs were placed in front of the sarcophage of Catharina and her husband so that a visitor could read the inscription. Dark corners are present as well as moderately bright spots.

    Sarkophage of Catharina and Wilhelm © Julian Köpke

    It was hard for me to leave the building, which had given me so many different and actually tricky light conditions, so close beneath together. Each image was obtained handheld, without tripod or flash, of course.

    Leaving the chapel on Württemberg © Julian Köpke
  • flowers

    A rose is a rose is a rose

    Just photograph a rose and show its beauty – how wonderful that would be. Is the light right ? Do false shadows emerge ? Is the structure correctly reproduced ?

    Again and again I have to go through our garden and look at the flowers. Yesterday was it again. The sun had just set and the full moon should have decreased a little later.

    I tried it with all f-stops the camera and lens gave to me. To my surprise the aperture 32 at ISO 50 with 45s exposure speed was my favorite. Only at the edge the picture had to be darkened and desaturated. Post-processing can be as simple as that.

    Rose during Golden Hour © Julian Köpke
  • General

    RAW conversion matters

    Every camera stores sensor image data in a file for further use. The sensor image data are just grey values of different intensities in every pixel. A single pixel doesn’t show color. Our sensor image data contain a black and white world. How sad.

    How do we get color images with a sensor that maps only grey values between white and black  ?

    All the colors we know can be derived from a combination of a specific value of Red,  a specific value of Green and a specific value of Blue. If we know the shares of Red, Green and Blue in a color we know the color.

    Our camera sensor measures the shares of Red, Green and Blue with small lenses in front of each pixel on the sensor that act as filters for Red, Green or Blue. The complete sample of these filter lenses is called a color filter array or „CFA“. The distribution of Red, Green and Blue filter lenses on the sensor is completely known only to the manufacturer.

    The file that contains the sensor image data is called a RAW file. Beside the sensor image data at the beginning of a RAW file are informations about the complete file content. I found a nice Wikipedia article pointing this out. A RAW files contains also exposure data and information about the camera lens.

    A software converting the sensor image data of a RAW file into pleasing colorful images is called a RAW converter. A well known and popular RAW converter is Adobe Camera RAW (ACR). A Phase One Raw file can be straight forward converted by ACR to a 16-bit TIFF. No further postproduction has been applied (see left image below).

    A RAW conversion of the same file with the Phase One manufacturer’s own RAW converter Capture One to a 16-bit TIFF shows different color and brightness (see right image below). There was no setting of temperature, hue and saturation to make the images identical.

    Still. Conversion ACR. Courtesy P. Kleiber
    Still. Conversion Capture One. Courtesy P. Kleiber

    One RAW file was converted to two different TIFF. The difference between the TIFF can easily be obtained in Photoshop with the difference layer mode. The difference is an image in itself. With a sensitive gradient applied the following image is obtained:

    Difference image of RAW conversions using Capture One and ACR © Julian Köpke

    The difference TIFF (Capture One) – TIFF (ACR) is derived pixel by pixel. The converted TIFF using Capture One contains more green, more magenta and more yellow in the darker values. The impact on the final result is unclear at the moment.