Superb images considering such short exposures and high ISOs!
It seems the A7S is as good in low light as Nikon D3S was or it's even a little better.
Alan, I have a few questions regarding your experience in field with A7S:
1) how bad is Amp Glow and at what ISOs and/or long exposures becomes noticeable? Under the same conditions, does the Amp Glow dissapear in APS-C mode?
2) does the camera allow you to use MultiFrame noise reduction with very long exposures? How many shots does it take to create a single image with MultiFrame noise reduction?
3) what is the maximum distance (without obstacles) at which the A7S can be controlled via WiFi with a PC/Android phone/etc.? (With Android you can use this app https://play.google....nycamera&... )
4) how do you program/control the A7S to take 30 shots automatically? Have you found an intervalometer for this camera?
5) how sensitive is A7S in Ha compared to your Canon 60D?
6) is the 921.000 dots resolution of the LCD screen enough for precise focusing on a star for astrophotography?
7) does in-camera dark frame subtraction remove Amp Glow?
8) how do you find the 12Mpx resolution for astrophotography and day time shots?
You are a slave-driver!
1) Amp Glow is noticeable at about ISO 51200 and above and really doesn't seem to get worse with exposure; not like the Amp Glow I've seen off other cameras where Amp Glow can consume almost half the image.
1a) No noticeable Amp Glow in APS-C crop mode
2) MultiFrame noise reduction takes four(4) images and stacks them. Doesn't make any difference what the exposure is up to 30 sec; not applicable in Bulb mode. There are also two different implementations of high dynamic range (HDR) on the A7 series cameras and dynamic range optimization. The HDR employs three images.
3) I don't normally use WiFi with the camera; however, my iPad will control it from about 20 feet away. Have no idea what the max. distance is?
4) I'm using a wired remote time. JJC TM-F2 Remote Timer for SONY A58 NEX-3NL A7 A6000 HX300 HX50V RX10 RX100III
from Buy-Market on eBay. $20 each. I bought two; they work fine.
4a) I also use the Time-Lapse App on both the A7R and A7S. It works up to 30 sec exposures but not with MultiFrame or Long Exposure noise reduction or in silent shutter mode. The silent shutter also does NOT work in Bulb mode; real bummer!!
5) WRT Ha, the A7S has better Ha sensitivity but is definitely not as good as the full spectrum A7R. Still debating whether to mod the A7S?
6) I've used the electronic viewfinder and liveview screen for focusing by themselves, with Focus Peaking and with a Bahtinov mask. With Focus Magnification you get 1:1 display so more than adequate for accurate focusing. I've found Focus Peaking is just as accurate as using a Bahtinov mask. You can also use the electronic zoom feature to give you a 4x larger image.
6a) I used the liveview screen and a Bahtinov mask last night to focus through an Ha filter with no problem.
7) In-camera dark frame subtraction (Long Exposure Noise Reduction) does remove Amp Glow.
8) I've sort of concluded I'll use the 36 MPixel A7R for wide-field where I really need higher resolution and sensitivity isn't as important (f/1.0->f/6) and use the A7S on longer lenses/scopes where resolution isn't as important but sensitivity is (f/8-f/15+). For astrophotography I try to "design" for about 1-2 arcsec/pixel, i.e.: the A7R on lenses/scopes less than 500-750mm focal length and the A7S on longer scopes, although I used the A7S on a 450mm scope (AT65EDQ) last night and the results look good... But the A7R on the AT65EDQ is a combo made in heaven!
8a) I really like the A7S for daytime usage; one of reasons I'm dragging my heels getting it modded. With the 28-70mm zoom (A7 kit lens) it is a great general purpose daytime and low light camera, and it autofocuses literally in the dark. Handheld at 11:00pm; only light was the Moon
is a case in point (you can see a few other nightscape shots in this album). As for inside shooting, I haven't run into a situation where I would even consider the need for a flash! If I can see a hint of my target, I can take a reasonable picture of it. I'm still amazed by this having started photography when 50-100 ASA film was the norm.
9) Although not asked. To this point I've been shooting primarily Ultra Fine JPG's. On the A7R there is considerable difference in image quality between RAW's and JPG's, even the best JPG's. I shot both RAW's and JPG's when I was shooting astrophotography in New Mexico with the A7R. I processed all the wide-field shots from JPG's and a few weeks later went back and tried extracting some of the smaller targets; didn't work well. So I reprocessed all the smaller extracts from the RAW's, worked MUCH better, per: Extracts from RAW's
. One of reasons I like the A7R for wide-field! I'm sure the results would NOT have been as good off the A7S. I will be shooting RAW subs off the A7S when I go after serious targets.