If even more reach is required, a teleconverter might be a choice. However, the usage of inexpensive teleconverters often implies a significant loss in terms of quality and light transmission (2+ EV stops).
- the situation does not require frequent refocusing, or
- the scenery does not presume hectic movements, and
- enough light is available.
Macros & Portraits
Finding your targets
Focusing at night
Taking the picture
We are all perfectionists
Contrast & Sharpness
Working on a Tripod
- a stable tripod,
- a gimbal system,
- activated mirror lock-up settings, and
- a remote release.
- Set the exposure time to 1/2000 s or faster. Depending on the situation, you might want to set the ISO at very high levels though. ISO 4500 works fine for me in most cases. A low noise camera body is always a good investment. Shoot in RAW format.
- Put your camera on something solid, i.e. on a beanbag, a window frame, a branch, or a rock. Alternatively, you can lean against a tree or a wall.
- Hold the lens with both hands. Focus as good as you can. Do not invest more than 5 seconds on focusing.
- Hold your camera tight. Now, hold your breath and take 3 photos of the subject.
- Examine quickly how they came out. Adjust the ISO. Refocus as good as you can and take 3 photos again!
- Repeat the above steps several times.
Usage as a Spotting Scope
Here too, atmospheric turbulence interfering the view may be an issue depending on the weather and the acclimatization grade of the lens.
“How often would you use an 800 mm lens?”
Photo Gallery: http://dark.astrodigital.net/samyang800