DIGISCOPING CONTINUED–EXPOSURE

WOW, we made it through another week and we are now ready to kickoff the weekend. It’s been a rough week with some pretty harsh weather: rain, high wind, tornado watches, etc. But, we’ve emerged victorious and we hope you’ve all done the same.

Each Friday we have a shoot-the-shit topic where we discuss everything and anything under the sun, be it gear related or not. As a reader you may, and we encourage you to, participate. That participation is completely unstructured and readers are free to make any unsupported comment, insult anyone you wish, use profanity or change the subject to something else.  This is your moment for mental hygiene, or as we call it, a cerebral laxative. Our approach eliminates the need for you to compensate a group of individuals who’s sole reason for studying the behavioral sciences, in the first place, was to understand themselves; as such, they are living proof that free market economies produce sufficient surpluses to absorb what is otherwise useless.

This Friday, we were going to shoot-the-shit about the GEICO Tarzan commercial. This is the one where Jane asks the monkey if it knows how to get to the waterfall. What’s timely and extraordinary about this commercial is its direct applicability to how Americans are seeing their government, be they Democrat or Republican. Fortunately, we were rescued by a couple of reader questions requesting examples of exposure related issues. So, rather than answering these questions directly we slid our way out of Tarzan to discuss exposure.

I have five pictures below that illustrate the issues you’ll encounter when digiscoping. The photos were taken through a 15x to 45x fixed eyepiece spotting scope with a 65mm objective. The camera is a Nikon DSLR attached to the spotting scope with a camera adapter and T2 nut for a Nikon F-Mount. Recall that in last week’s topic we said that to control exposure when digiscoping with a DSLR we use ASA(ISO) and shutter speed. Why? Because the spotting scope replaces the camera lens; as such there is no aperture adjustment. All of the picture metadata is shown alongside the photo.

Proper exposure is that combination of ASA (ISO) and shutter speed that delivers the most detailed image. By detail I mean color rendition and observable detail in both light and dark parts of the image.

If you look at the three power plant pictures, the image at the bottom is an example of overexposure. It was shot using an ISO of 200 and shutter speed of 1/200th of a second. The image is washed out with poor contrast and total loss of color. The next photo is shoot using an ISO of 200 and a shutter speed of 1/400th of a second. Note that contrast has improved, we see greater detail along the tree line and we begin to see beach details. In the next picture we use a faster shutter speed still at 1/1000th of a second. This photo is slightly underexposed  so it’s a little darker but retains most of the detail. Ergo, the proper exposure for this subject is somewhere between 1/1000th and 1/400th and in my camera that value is 1/500th of a second shutter speed with an ASA (ISO) of 200.

In the power plant set, the other thing that you’ll notice is the effect of haze on image clarity. The spotting scope does not discriminate, it magnifies everything including atmospheric artifacts. Therefore, subjects at great distances will be less sharp than subjects closer to the observation point. Mirage and haze will distort your image significantly.

The last two pictures compare the image of a subject taken at 15X and another at 45x. Your take away from this comparison is that the 15x image is much sharper and brighter with good balance and contrast. Why? True with all variable power spotting scopes, the higher the magnification the lower the light transmission. What differentiates a $3,200 spotting scope from a $400 unit is the quality of its glass and how well it transmits distortion-free light.

This should shed some light on the exposure issue.

The best way for you to approach digiscoping is discovery. Get out there with your friends or family and have a great time. It will be quality time I guarantee you. Have a safe and enjoyable weekend.

                  (Distance from OP – 8.4 miles, Azimuth – 158)

DSC_0639

  • Exposure
    Aperture:    f/0
    Shutter Speed:    1/1000s
    Exposure Mode:    Manual
    Exposure Comp.:    0EV
    Exposure Tuning:
    Metering:    Center-Weighted
    ISO Sensitivity:    Auto (ISO 200)
  • Magnification  – 15X

 

DSC_0637

  • Exposure
    Aperture:    f/0
    Shutter Speed:    1/400s
    Exposure Mode:    Manual
    Exposure Comp.:    0EV
    Exposure Tuning:
    Metering:    Center-Weighted
    ISO Sensitivity:    Auto (ISO 200)
  • Magnification  – 15X

 

DSC_0635

  • Exposure
    Aperture:    f/0
    Shutter Speed:    1/200s
    Exposure Mode:    Manual

    Exposure Comp.:    0EV
    Exposure Tuning:
    Metering:    Center-Weighted
    ISO Sensitivity:    Auto (ISO 200)
  • Magnification  – 15X

 

              (Distance from OP  – 336 meters, Azimuth – 131)

DSC_0623

  • Exposure
    Aperture:    f/0
    Shutter Speed:    1/500s
    Exposure Mode:    Manual
    Exposure Comp.:    0EV
    Exposure Tuning:
    Metering:    Center-Weighted
    ISO Sensitivity:    Auto (ISO 400)
  • Magnification  – 15X

 

DSC_0626

  • Exposure
    Aperture:    f/0
    Shutter Speed:    1/500s
    Exposure Mode:    Manual
    Exposure Comp.:    0EV
    Exposure Tuning:
    Metering:    Center-Weighted
    ISO Sensitivity:    Auto (ISO 400)
  • Magnification – 45x

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