Quote:
Originally Posted by Atmos
The saturation point is all to do with well depth and at 40-60s it shouldn't even come close to saturation on anything but the brightest of objects even at ISO800.
What aperture were you using on the Zeiss 135mm?
At ISO800 the D850 likely has near a stop of dynamic range over the KAF8300 or ASI1600 variants.
Lagoon Nebula at ISO800 with 180s exposures at F/5.2. |
Hi Colin,
one example of an over-exposed image of Rho Ophiuchi (over saturated) with the 135mm lens at F2.8 is attached here, (apologies it was ISO 1600, not 800 as I claimed); so too, one of my images of the Galactic centre with the Zeiss Milvus 35mm at F2.8 30 secs and ISO 800 (and a feeble attempt at processing the image in LR). My camera was just sitting on my mount which was not polar aligned (no scope and it's hard to polar align with a camera alone; the polar scope was useless). Star trailing is obvious and I guess the white balance setting in the D850 was wrong (I forgot whether it was Auto or something else), hence the ghastly sepia tone of all 107 images I took. Not much to salvage here - but my point is if I were tracking accurately, how much better would any of these images look with 3 or 4 minute subs? Is it cooling the CMOS that is critical? As I have a full frame bsi sensor, would it be better to buy a CCD camera as I cannot imagine the Nikon in its unmodded state, delivering much more image detail, and certainly not the quality of your ASI094 image of Rho Ophiuchi....