Forum Replies Created

Viewing 6 posts - 1 through 6 (of 6 total)
  • Author
    Posts
  • #11096
    Matt Croxton
    Participant

    I’m sorry! I realize this small piece of peacock ore is not a fossil. The reason I chose to use it is because I thought the highly-textured, iridescent surface would show off any focus errors clearly – and it does.

    Here is some technical information on the shot:

    Lens: 200mm macro, f/7.1, 1/4 s exposure for each frame. Once a correct exposure was determined, the camera was set to manual mode to insure that this exposure time and aperture remained constant through the dozen images. The shutter was released by timer for each shot, to minimize camera vibration.

    Lighting: Two color-matched spotlights were used to illuminate ore, one to the left of the camera, and one to the right.

    Staging: I didn’t have a pristine piece of neutral colored fabric available, so I just rested the ore on my leather wallet for the images.

    Processing:

    1. Images were imported into Adobe Lightroom. An initial color temperature and exposure adjustment was made to one image and then these settings were “synchronized” to all the others. Full size tiff files were exported from Lightroom.
    2. The tiff image files were imported into Zerene Stacker. A depth map method of stacking was chosen. This method requires the user to manually mask out areas which do not contain image detail using a slider for control. In the case of this image, much of the dark background was mapped out in the creation of the depth map.
    3. The stacked image that was output from Zerene Stacker was imported to Photoshop.
    4. In Photoshop, my first step was to tone down the brightness of highlight regions while also bringing up shadow areas ever so slightly. I used a method sometimes called the Picture Postcard Workflow (PPW). If you are serious about good color balance and realistic image enhancement, investing your time learning the resources and using the panel at http://www.moderncolorworkflow.com is worth the effort.
    5. My next step in Photoshop was to enhance the color separation in a natural way by using, and then backing off the Modern Man from Mars (MMM) technique. See the link above for explanation on how this approach works. There is also a book if you are interested in learning all the enhancements possible in the PPW. All require a fairly advanced level of comfort at working with layers in Photoshop, but none are gimmicks.
    6. In my final steps, I corrected a color cast in the shadow tones that was imparted during color enhancement, by using curves and measuring color values to assure that the wallet was the neutral black that I knew it to be. Lastly, I applied a black gradient across the left, right, and top side of the image to darken the background and better focus attention on the subject. A spot or two in the background was retouched.

    I am attaching a single image from Lightroom, as it appeared prior to import into Zerene Stacker. It can serve as a “before” image for comparison to the final result.

    Attachments:
    You must be logged in to view attached files.
    #11094
    Matt Croxton
    Participant

    Now, here’s the closeup showing blurriness where detail should have been pixel-perfect if I’d moved through the focus range in smaller increments.

    Attachments:
    You must be logged in to view attached files.
    #11092
    Matt Croxton
    Participant

    Hi All,

    Sorry for my delay in following through on a focus stacking forkflow. I moved and have just started school, so I’ve been very busy!

     

    First, I’ll start with an example image that is a stack made of 12 images. Each image was manually focused using high magnification live view, and I still made mistakes in focusing too far between frames. “Over focusing” results in the strange areas of blurriness that you see when zoomed in to the full resolution. Some are indicated using black arrows, but there are still other areas blurred in just this small crop. So, the lesson to take from this exercise is that you should try and remove human error at every point possible

    Attachments:
    You must be logged in to view attached files.
    #6884
    Matt Croxton
    Participant

    @rleder

    Hi Ronny,

    I use a Voigtländer 90mm f/3.5 SL II APO-LANTHAR lens, usually stopped down to f/8 or f/9. While this lens is out of production for Nikon and Pentax mounts, it is still available for Canon. Scroll to the bottom of this page for more information on the optic. Please be aware that this lens is manual focus only, and is adjusted for each specimen by confirming focus using the camera’s live-view function.

    For lighting, I use a floor lamp with a single PAR 20 Solux bulb and two collapsible white/silver reflectors to provide a little bit of shadow fill. This bulb has a consistent color temperature, full spectrum reproduction, and very good illumination. With this lighting, images are always made using a tripod. Fossils are placed on a black towel to minimize backscatter and an X-Rite ColorChecker Passport is used to indicate scale and provide a neutral color balance point in the image.

    #6397
    Matt Croxton
    Participant

    I’d enjoy making an illustrated tutorial. I’m evaluating grad studies in education and working out the details is consuming much of my spare time and creativity at the moment. I’m sure you can understand. When the pieces start to fall into place, then I’d like to continue participating by contributing!

    Cheers!

    #6370
    Matt Croxton
    Participant

    Here’s a coiled trilobite specimen captured using a focus stack of seven images.

     

    Attachments:
    You must be logged in to view attached files.
Viewing 6 posts - 1 through 6 (of 6 total)