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I'd have probably shot it wide open at f/2.8 rather than cranking the ISO up to 51200. Incredibly impressed at the steady hands for a sharp image at 1/4 s shutt
by porphyra 7mo ago
I'd have probably shot it wide open at f/2.8 rather than cranking the ISO up to 51200. Incredibly impressed at the steady hands for a sharp image at 1/4 s shutter speed though! Maybe they just let the camera float in space with the mirror up, triggering it remotely.
- treis 7mo agoThey're in space so they only sort of need to hold the camera.
- sdenton4 7mo agoOr maybe press the timer and let it float...
- plaguuuuuu 7mo agoor sticky-tape it to the window. d5 has an actual shutter yeah? not mirrorless? I think the shutter moving will spin the camera.
- hackerdood 7mo agoI haven’t looked at the manual but it likely has the ability to flip and keep the mirror up for direct capture on the sensor without the mirror flipping up and down between exposures.
- cloudfudge 7mo agoI would love to see the effect of the mirror's effect on the motion of the camera in a weightless environment. I bet it's enough to measurably affect the picture, especially on a long exposure. Net torque of it opening and then closing should be near (but probably not exactly) zero, but while it's open the camera should spin a tiny amount.
- embedding-shape 7mo agoBad idea, shutter speed was 1/4 apparently (https://news.ycombinator.com/item?id=47632457 https://news.ycombinator.com/item?id=47632457), even the small rotational inertia everything in zero gravity gets from a human "dropping" it would probably be enough to be annoying, you'd get a better shot holding it.
- narmiouh 7mo agoI would imagine since they are not circling the earth, that there will be pull of gravity and the camera would start to move relative to the spacecraft. But may not fast enough for a short exposure
- dotancohen 7mo agoThe gravity of the Earth (and moon, and everything else) is uniform (i.e. no gradient) on the scale of things the size of that capsule at the distance that capsule is from them, on the order of time of the exposure of that photograph. So the gravity (from any source) will pull on the spacecraft and on the camera in the same fashion. 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.
- gus_massa 7mo agoOnce you are out of the atmosphere and turn off your thrusters, you are on "fee fall" and the gravity on the camera, you and the spaceship produce the same acceleration and they cancel and it looks exactly like "zero gravity". It doesn't matter if you are in orbit around the Earth, going to the Moon.
- echoangle 7mo agoActually not quite correct. The camera and spaceship will generally have different starting positions of their center of gravity but the same starting velocity, leading them to drift apart. 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.
- gus_massa 7mo ago> will generally have different starting positions of their center of gravity but the same starting velocity That are the tidal forces, they are quite small for a system of the size of Orion.
- throw0101d 7mo ago> I'd have probably shot it wide open at f/2.8 rather than cranking the ISO up to 51200. 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 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_International_Space_Station https://en.wikipedia.org/wiki/List_of_cameras_on_the_Interna...
- porphyra 7mo agoThe good low light performance was amazing for its time (10 years ago), and it still holds up decently today. But let's not kid ourselves -- it has been clearly surpassed by modern backside illuminated CMOS sensors like the one on the Z9. EDIT: sorry, it seems I'm wrong. I just checked https://www.photonstophotos.net/Charts/PDR.htm 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.
- nelox 7mo agoWas hoping to hear from the person at NASA who made the choice and why.
- throw0101c 7mo agoSure, but D5s were also doing EVAs for many years and much more of a know quantity in space.
- ourmandave 7mo agoYou can get a D5 on amazon.com. It would be amazing if one of the astronauts did a review explaining how it performs in space.
- jen729w 7mo agoYou might misunderstand how ISO works on digital cameras. (I did.) https://www.youtube.com/watch?v=ZWSvHBG7X0w https://www.youtube.com/watch?v=ZWSvHBG7X0w
- deathanatos 7mo agoGood grief, that video suffers the YouTube-ism of "ramble on about how you don't understand X" for way too long. 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.
- js2 7mo agoWide open generally sacrifices lens sharpness.
- porphyra 7mo agoSure, but less grain is often worth it. There's a reason why fast lenses exist. The high quality lens being used here can probably still resolve 20 MP adequately even wide open.
- dgxyz 7mo agoI had that lens. It’s soft as fuck around the edges open. 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.
- throwaway290 7mo agoIf you think they only took one shot, you're not a digital photographer) 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.
- chrisbarr 7mo agoIt was shot at f/4, so opening up 1 stop to f/2.8 would only reduce the ISO to 25600
- kccqzy 7mo ago> Incredibly impressed at the steady hands I’m an amateur photographer and I’m actually incredibly impressed at how good the optical image stabilization tech is these days even in entry-level cameras. I wouldn’t hesitate to use 1/4 s shutter speed when necessary (such as in many indoor environments) and I’m quite amazed at the sharpness.