One of the reasons the D5 supposedly was chosen was because of its high dynamic and good low light performance. It can go up to ISO 3,280,000:
* https://en.wikipedia.org/wiki/Nikon_D5
The D5 has been used on the ISS, including EVAs, since 2017, so is a known quantity:
* https://en.wikipedia.org/wiki/List_of_cameras_on_the_Interna...
EDIT: sorry, it seems I'm wrong. I just checked https://www.photonstophotos.net/Charts/PDR.htm and while the Z9 has the clear edge with 2 more stops of dynamic range at low ISO, the D5 actually pulls ahead at high ISO. Perhaps the technological improvements haven't been that much for the shot-noise dominated regime.
Video alleges people think ISO makes the sensor "more sensitive or less sensitive". (I … don't think this is common? But IDK, maybe this is my feldspar.)
(The video also quibbles that it is "ISO setting" not "ISO" … while showing shots of cameras which call it "ISO", seemingly believing that some of us believe ISO is film speed, in a digital camera?)
Anyways, the video wants you to know that it is sensor gain. And, importantly, according to the video, analog gain, not digital gain.¹ I don't know that the video does a great job of saying it, but basically, I think their argument is that you want to maximize usage of the bits once the signal is digitized. Simplistically, if the image is dark & all values are [0, 127], you're just wasting a bit.
You would want to avoid clipping the signal, so not too bright, either. Turn your zebras on. (I don't think the video ever mentions zebras, and clipping only indirectly.)
The video does say "do ISO last" which I think is a good guideline. Easier said than done while shooting, though.
… also while fact checking this comment, I stumbled across Canon's KB stating to use as low an ISO as possible, which the video rails against. They should talk to Canon, I guess?
¹with the caveat that sometimes there is digital gain too; the video notes this a bit towards the end.
This is because the ADC (analog to digital converter) right after can only handle so many bits of data (like 12-16ish in consumer cameras). You want to “center” the data “spread” so when the “ends” get cut off, it’s not so bad. Adjusting the ISO moves this spread around. In addition, even if you had an infinite bitrate ADC, noise gets added between the gain circuit and the ADC so you want to raise the base signal above the “noise floor” before it gets to the ADC.
Gain is not great — it amplifies noise too. You want as low ISO as possible (lowest gain), but the goal is not actually to lower gain; your goal is to change the environment so you can use a lower gain. If you have the choice between keeping the lights off and using higher ISO versus turning on the lights and using a lower ISO, the latter will always have less noise.
Most photo cameras have one gain circuit that has to cover both dark and light scenes. Some cameras like a Sony FX line actually have two gain circuits connected to each photosite and you can choose, with one gain circuit optimized for darker scenes and the other optimized for brighter scenes. ARRI digital cinema line cameras have both and both are actually running at the same time (!).
...or integration time.
> … also while fact checking this comment, I stumbled across Canon's KB stating to use as low an ISO as possible, which the video rails against. They should talk to Canon, I guess?
Isn't ISO last the same as setting it as low as possible? Obviously it's always set to something, so I thought 'doing it last' means start with it low, set exposure & shutter, increase as necessary?
(Shutter speed being dictated by subject and availability of tripod, essentially it's just exposure & ISO which becomes about how much light there is and how it's distributed, I suppose.)
I'm not really into photography though, so perhaps that's all nonsense/misunderstanding.
Peak sharpness is about f/8. They should have had the D5 on aperture priority auto iso, pushed the exposure comp either way and then just fired at f/8 and let the camera make the decisions.
But they are astronauts not photographers :)
The modern Z lenses are far better and sharper open but much larger generally.
The only real relevant thing for the photograph is rotation though as long as the camera doesn’t float in front of the window frame, and airflow is probably much more relevant for both points than gravity.
To fully answer the question, the moon's gravitational gradient does pull on the Earth, the ocean closest to the moon, and the ocean furthest from the moon differently. But those are objects separated by thousands of kilometers, having hours of gravitational influence acting upon them.
d5 has an actual shutter yeah? not mirrorless? I think the shutter moving will spin the camera.
In this special situation you get as many as you can a few dozen at least. Then only publish the one that looks the best. If it's f4 then f4 worked best.