Originally posted by Simmo25 If Astrotracer functions fine in Bulb Mode, and I have done this, what then is the Astrophoto mode (contained in User Mode 3) used for?
Thanks in advance for some help.
You mustn't make the mistake of interchanging "Astrophoto" and "Astrotracer", they are two separate functions, each of which can enhance the other.
Astrophoto is a combination of exposure settings, saved as a "User Mode", designed to emphasise the "blackness" of the sky and retain the original colour of the individual stars. As a stand-alone feature it works very well within the limitations imposed by subject movement, so best used with shorter exposures and 'stacking,' unless you want star trails, of course, at which it excels!
Astrotracer is the mechanical shifting of the image sensor to combat star trails, allowing much longer exposures and often eliminating the need for stacking. When used in conjunction with
Astrophoto the colours of the final image are enhanced.
So, in a basic scenario with no O-GPS1, put the K-70 into
Astrophoto mode, (U3 on the Mode Dial if the defaults haven't been overwritten), focus, frame and fire as usual at whatever aperture and shutter settings have been deemed adequate for the lens in use, repeat until as many frames as are required for a "stack", take the results to your computer and process as required.
However, with an O-GPS1 fitted, the prior calibration is necessary, as is ensuring that
Astrotracer is enabled from the Control Panel or within the menus. Then proceed as before, but with the benefit of much longer exposures, so fewer exposures are required. Indeed, for some subjects, especially in a wider-angle shot, a single exposure may be all that is necessary
Enjoy