PDA

View Full Version here: : Sony Nex 6 for astrophotography


gregbradley
04-05-2013, 01:34 PM
I have been working with a Sony Nex 6 ($815 body only on Ebay, 5R which is similar is about $200 less) for a little while now. I am now familiar enough with it to give it a bit of a review. There's more to familiarise myself with it but I've got enough of a feel for it to give detailed impressions.

Firstly this little camera is very high tech and cutting edge. Tilt screen Sony Exmor 16.3mp sensor with the PDAF AF pixels on sensor. Low noise at high ISO (not quite as good as Fuji XE1 which has a unique colour matrix over the lens but still very good).

Noise levels are not as low as my Nikon D800E and I would presume Canon 6D and 5D3 but probably a better than a 5D2 to get an idea of where it sits. So ISO 6400 seems fairly useable with some cleanup.

This camera is very small and very light which makes it easy on the Polarie to mount. I put it on a Polarie and a carbon fibre tripod and its very manageable.

Focus peaking makes manual focus very easy. So does magnification of live view. Focus peaking is where the image can be made to show a white, or yellow or red (you chose) colour fringe when it is max focus. This gives a very easy to see visual guide to when manual focus is achieved.

The camera has an EVF (electronic viewfinder) or can be viewed in live view. The EVF is good and well implemented and even though its the same unit as the Fuji XE1's EVF it is implemented better and easier on the eye. It can be a tad dazzling at night but its easy to see. You can turn it down I am pretty sure.

One feature I bought the camera for was Sony sells a series of apps like for iphones. One of these is called Time Lapse. I finally got it working. Its not that user friendly so it may take a bit to master it but when its setup right it works very nicely. I've taken a few now and its very handy. You can save individual images in RAW or JPEG as a sequence or have it do a time lapse and output it as an avi file. The time lapse sequence is buried in another folder in the SD card and it took me a while to find out where it saves it, so again not user friendly like on my Nikon D800E (which is self evident and the movie is saved as the next image - obvious).

Anyway, the weak point of the Sony is the poorly designed menu structure. Its not well done at all so it takes some getting used to. Once you get used to it you almost forgive it for being so poorly done but not quite.

You can turn off the LCD display during the time lapse something I know Alex said you can't do on Nex 5n (latest model is Nex 5r).

There is a dedicated Samyang 8mm Fisheye F2.8 for Sony A mount and this is a nice lens. $269 so its reasonable for a good lens.

The Sony with its focus peaking is particularly suited for old good quality lenses so you can get some nice glass for low prices making it a cheaper but high quality system.

I'd give the Fuji XE1 a 7/10 and the Sony Nex 6 an 8/10 due to the app, the tilt screen, the LCD display turn off and the focus peaking.

Its a real alternative to Canon, Nikon and other brands DSLRs.
Some of these makers are moving away from APSc sensors (Canon and Nikon, Sony) so mirrorless APSc have quite a future.

The advantages over DSLR APSc cameras are;

1. Small and lightweight more suitable for Polarie's payload. Portable for daylight imaging, pocketable with the standard 16-50 zoom lens which is not too bad for a kit lens.
2. Better sensor that is cutting edge which is sensitive, low noise at high ISO and high dynamic range. Its mostly about this incredible sensor and they are only going to get better here.
3. Time Lapse app (unless you are using Nikon DSLR and it has time lapse function).
4. Focus peaking (some Nikons have this but not as well implemented, not sure about Canons - some may).
5. for video - stabilised, power zoom, digital zoom, fantastic stereo sound, proper AF that is quite, face recognition AF that tracks the subject - very nice for video.
6. A lot of 3rd party support for this system. Its being developed still with a decent future ahead of it whereas APSc main camera makers are moving out of APSc into full frame.
7. Auto white balance seems to work very well in nightscapes as opposed to my Nikon D800E which really needs it to be manually set. Same with Fuji XE1.
8. You can playback images on either EVF or LCD. Focus with either EVF or LCD, with focus peaking or with magnified view. So easy to focus manually. EVF is great on a sunny day to review your image.
9. Overall I find it quite snappy and responsive and accurate. It does everything you can imagine and there are several interesting apps with the choice improving over time.

disadvantages:
1. No grip available so battery life for a long time lapse is in question. (there may be a grip so not 100% sure on this point).
2. for terrestial work moving subjects do not AF as well as most DSLRs and most DSLRs in general are more responsive, faster.
3. Most Sony lenses for it are not so great. 50mm F1.8 gets good reviews, so does 18-200 but in general nowhere near as good as Fuji lenses which are up there with the very very best. Legacy lenses seem the way to go or spring $1050 for the Zeiss 24mm F1.8 that everyone seems to love. 2nd hand Contax g Zeiss lenses 2nd hand are to die for and "reasonable" at $265 to $450 each), they need a $70 Fotodiox adapter and are manual only (there is a new Taiwanese $300 AF adapter though if you are really keen). These Contax g lenses are the best I have used. They are also full frame so if Sony puts out a full frame Nex camera (expected end of this year early next year) then you are all set.


Greg.

Hans Tucker
04-05-2013, 02:02 PM
The Sony Nex cameras are an interesting breed. I was interested in the Nex7

I love the Saturn image Roland took with his AP175 using a Sony Nex7.

http://www.astro-physics.com/index.htm?products/telescopes/175edf/175edf

gregbradley
04-05-2013, 05:02 PM
That is impressive. Nex 7 has an engineering flaw though where ultrawide lenses cause the light rays to hit the sensor along the sides at too steep an angle and causes a magenta colour cast on the sides.

A Nex 7n is expected to be released soon no doubt this aspect is being corrected.

Greg.