Upcoming Celestial Events

There's an annular eclipse coming up in May, and Venus will transit in front of the Sun in June.  The transit in particular is of some interest, since the planet will not make the transit again for over 100 years.  Hopefully I'll be dead when that happens.  While I didn't set out to do astrophotography when I bought my camera, I'm considering picking up a solar filter and a teleconverter (probably a TC-300 to mate to the 400mm—turning it into a 1200mm- f/11-equivalent lens on my d7000) to try to capture both events.  I'll probably do some tests on the Moon if I make the purchases.  I'm also considering extension tubes, which could have some interesting effects on the 400 as well, particularly in macro ranges.

On ND filters

For my birthday last year, I was gifted with an ND grad (.6, i.e., two stops) filter.  I haven't used it very much in regular shooting, but a recent trip out to a local tourist trap provided some opportunities to use it.  I've been trying to refine a raw workflow, but my hardware is limited and it has been a bit of a struggle to produce images in a timely fashion.

Neutral density filters are useful for a variety of scenes.  An ND filter reduces the light hitting the sensor by some amount.  This is helpful for scenes with a wide dynamic range (e.g., a sunset) or when additional motion blur is desired.  In the former case, the filters are usually graduated so that the horizon can be set properly:  above the grade, light is reduced; below the grade it is transmitted without change.  This is the sort of filter I have, but it serves in both capacities because it is large enough to fit over a 52mm lens without touching the grade.

Images with discussion following the jump.

More Moon Work

So I'm still getting started with the raw workflow.  The issues of noise and other artifacts come up pretty often when I'm working on the moon pictures, especially at 400mm.  The 70-300 seems like its not as sharp, but it also handles the noise a lot better.  I don't shoot with it anymore, so there's no definite side-by-side comparison.

I processed another photo today of the moon with RawTherapee, emphasizing better noise reduction (luminance, chrominance, and so on).  Here's the result:

400mm, 1/800s, f/11.0 @ ISO 200

For reference, here's the other processed image; it's a bit sharper, and the exposure compensation is obviously different:

The Moon, Again

With the full moon and a clear sky last night, I couldn't resist taking a few moments:

400mm @ f/11, 1/800s, ISO 200

In the raw processing, I added about 3.5 stops of exposure and did some denoising.  This lost a little definition, but the atmosphere was definitely getting in the way of a noiseless shot.  After the import, I applied very slight curves adjustment and an unsharp mask.

The 400 really is a swell lens.  I shot at f/11 to see if I could get a sharper image than I've gotten shooting at f/5.6, but it doesn't appear to have made much difference.  This isn't too surprising, since I'm shooting a crop sensor and holding pretty steady in the center of the imagine.

This was shot hand-held.