Quote:
Originally Posted by Atmos
My plan for this coming new moon has been to do a 36 panel mosaic of the Milky Way with my Nikon D7200 and a Sigma Art 85mm F/1.4. It's FOV will be kinda similar to that of my 14mm + D7200 but as a 3.5 gigapixel image.
The star shapes with the D7200 @ F/2.8 at the frame corners are reasonable, reasonable enough that I'd consider using it again although I may test dropping it a fraction slower to see how much things tighten up. I know that I would be able to get 2x300s images per panel per night so the end result would basically be the number of nights I spent out doing the imaging.
About an hour and a half ago I started thinking about the possibility of blowing the dust off of my D700, doing a 16 panel with an even larger FOV and running the Sigma @ F/1.4!
The D700 is a 12mp FX sensor with 8.445 micron pixels and an anti-aliasing filter. The D7200 is a 24mp APS-C sensor with 3.91 micron pixels and no anti-aliasing filter. In short, I think I could run the D700 @ F/1.4 and still have near perfect stars in the frame corners!
As much as I love the idea of the resolution that the D7200 achieves, there is a part of me that wants to see what the sky looks like with 30 minutes per panel (per night) @ F/1.4! There is another part of me that also knows that there is greater contrast to be achieved with higher resolution.
Thoughts? Comments? Suggestions?
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Hello Colin,
If you can get
"near perfect stars" in the corner of your full-frame option (D700 @ f/1.4), it (the corners) will only get better
with the same lens used at APS-C sensor size (referring to your 2nd paragraph,in which you say that the
D7200 @ F/2.8 is only "reasonable") .
The Sigma Art lens is a great choice of 85mm lens for low coma & astig. abberations.
In choosing beteween the D700 and D7200 for your task, I would also look at the difference in long exposure noise - Take dark frame images from both at your intended exposure and then even hype the sensitivity and exposure time further to see what differences can be revealed. Dark frame subtraction is not perfect (either in camera or post), so I'd opt for lowest noise out of camera as important, as evidenced by the amount of dark frame noise you see.
Whilst the D700 is a wonderful camera, with great big pixels, it comes from a while ago (2008) and the D7200 (circa 2015) has about 2 stops better dynamic range below 400-800 ISO and equal dynamic range above that. The D7200 also has much lower read noise, which is where I think its increased dynamic range advantage at lower ISO comes from. The D700 unfortunately also doesn't share the same 1 stop dynamic range advantage over other Nikon APS-C sensors across the board as the more recent Nikon FF DSLRs (D600, D610, D750, D800, D810, etc).
Best
JA