Wide angle lens for Sony A7 system – another option

In the search for a high quality wide angle lens for my Sony A7 system, a friend of mine recommended that I look at the Nikon AFS 20 f1.8 G lens. It is well known that so far, there are no options below 25mm (Zeiss Batis) for the system. The Sony 28 f2 lens accepts a converter that gives 21mm, and of course there is the Sony Zeiss 16-35 f4 zoom. None of these fit my requirements of a high quality, fast wide angle lens below 24mm, to shoot landscapes and night skies. So far, as illustrated in my previous post, I have been using a Nikkor AIS 24 f2.8 lens, which is a very good option. But I need something a bit wider and faster for some of my photography.

Thus, I started to investigate about the above mentioned Nikon lens, which is a recent introduction into the f1.8 Nikon lens line for FX (Nikon’s name for full frame 35mm format). Reading some reviews, it quickly became apparent that the lens is arguably Nikon’s best 20mm so far, which is saying a lot. Then the chance presented itself to use the lens for testing in one of my preferred areas, southwest Portugal coast; and with a new moon night sky, some star trail and Milky Way photography would provide a good testing ground.

Now, it needs to be said that using a Nikon G lens (no aperture ring) on a Sony A7 means that setting the aperture is done via a ring on the adapter (I have a Novoflex). At first, this a bit awkward, but after a while, there is no problem, as one can count stops easily by noting the changes in shutter speed, while using said ring. Another thing is, the manual focus ring is not as smooth as a true manual focus ring (no surprise there), the focus throw is not large (short turn of the ring between close focus and infinity), and the depth-of-field scale is, shall we say, not very useful (f16 marks only). Oh yes, and there are no hard stops at close focus and infinity.

Regardless of the above (normal) limitations, the lens delivers very good results. Below are some initial test shots: a general photo to illustrate the location where I set up the night sky shots (taken at about 9.30 pm), plus a star trail and Milky Way panorama. I had a bit of concern about being able to achieve precise infinity focus, but using magnification in the LCD, I was able to quickly and easily focus on a bright star.

I will keep testing the lens in similar situations, but so far, it is looking like a winner. In terms of handling and ergonomics, the lens is not heavy, it has the common 77mm filter diameter, and comes with a lens hood. If Zeiss ever comes out with a wide angle Loxia (say 21mm or there about), it needs to be pretty good optically to outperform this Nikon.

View of shooting location


Star trail of around 120 minutes total


Milky Way panorama – 8 photos




Startrails and night skies

This is a type of photography that I like very much to do. It is not easy, as it requires the photographer to be out in the field at ungodly hours, but… why not make the most of today’s camera technology to capture the beauty in our sky? The other difficulty for most people seems to be to actually find a dark enough place to see the stars and constellations!

But, if you happen to be in a such a place at or near new moon (when the sky is darker), then it is not difficult obtain good results. You will need a good tripod, a wide angle lens, and a cable release.

For star trails, I typically I set my camera in Manual mode, ISO 1600, aperture around f2 or f2.8 (depending on the lens), and shutter speed around 30 seconds. Then I just shoot in Continuous drive with the cable release in lock mode. In this way, most cameras will keep on shooting for as long as you wish, or for as long as the batteries last.

It also advantageous to shoot a couple of dark frames, before and after the sequence, so you can use them in programmes like Starstax (highly recommended) to process for dark frame/noise subtraction.

Another option is simply shoot isolated frames of the Milky Way, say ISO 1600 or 3200, f2.8 and around 20 – 30 seconds. Exposure times will depend on the focal length; the longer the focal length, the shorter the exposure time must be to avoid trailing in the stars.  It is also possible to shoot multiple images and later on align and process them in programmes like DeepSky Stacker; these will align the images and produce a single one, the advantage being that with several images, one can boost the S/N ratio. There are some excellent guides available on the WWW, one of my favourites is http://starcircleacademy.com/quick-tips/

Below are some examples I took in Southwest Portugal.

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