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Post by 3onthetree on Jun 6, 2006 8:14:56 GMT -4
Were the Astronauts able to adjust the exposure time on the camera? For some reason I thought they could only adjust focus. That may explain the plaque sequence on Apollo 17 from As17 134-20480 through to 134-20488. The astronaut is in Shadow and yet seems to get brighter and brighter. Could be a job for the Penguin.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Jun 6, 2006 8:18:51 GMT -4
The Hasselblad cameras were fully manual, the Astronauts had control of aperture, shutter speed and focus, although IIRC they largely left the aperture alone.
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Post by Jason Thompson on Jun 6, 2006 8:45:11 GMT -4
Were the Astronauts able to adjust the exposure time on the camera?
Absolutely. They adjusted it depending on whether they were photographing up-sun, down-sun, cross-sun, in full light or in shadow.
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Post by gwiz on Jun 6, 2006 8:58:45 GMT -4
They had a list of suggested exposure settings worked out in advance.
This was the way we all worked back in the old days if we didn't have an exposure meter, normally using the list of suggested exposures that came packed with the film.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Jun 6, 2006 10:43:28 GMT -4
...if we didn't have an exposure meter... Which Hasselblads don't
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MarkS
Earth
Why is it so?
Posts: 101
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Post by MarkS on Jun 6, 2006 10:44:46 GMT -4
Superman,
Welcome to the board; I hope reading the posts here is as educational for you as they have been for me.
In case you're new to HB posting, the standard routine at this point is to say that "light, cameras and optics behave differently in an atmosphere than in a vacuum, so your shots prove nothing." That will consume a half-dozen posts, then hit 'em with the "Hey, the astronauts* were wearing gloves; how could they adjust the camera apertures?" Finish up with the classic "but it's 250 degrees and the film would melt" and you're guaranteed a spot in HB Valhalla.
*Get it - astronauts?
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Post by JayUtah on Jun 6, 2006 12:55:25 GMT -4
Were the Astronauts able to adjust the exposure time on the camera? For some reason I thought they could only adjust focus.Nope, fully manual exposure and focus. Here's the lens on a real, no-foolin' Apollo-modified Hasselblad camera I got to play with. Sorry the picture is so fuzzy but the conditions were pretty poor when I took the picture. This camera was used by Pete Conrad during training for Apollo 12. (a) Shutter speed. There is a pretty full range, but the astronauts generally kept it at 1/250. (b) F-stop. The range is f/22 through f/5.6. I don't have the picture of the exposure chart online, but basically it recommends leaving the shutter speed set at 1/250 and then adjusting the f-stop from f/5.6 through f/11 depending on the lighting angle and distance. (c) Depth-of-field gauge. This is a handy little feature of good lenses. I doubt the Apollo astronauts made much use of it, but I use them all the time. As you adjust the f-stop, the depth of field changes. And that's indicated on this gauge, which you read in conjunction with the focus distance scale just behind it. (d) Focus. The Biogon lens was set up to use zone focusing. Although you could focus at any distance you wanted, there were detents on the ring for certain overlapping distances. The first detent is 1 meter, which corresponds to the length of the astronaut's sampling tool handle. To focus properly, the astronaut clicks to the first detent and then uses the sample tool to measure the distance to the subject. After about 30 seconds of messing around I was familiar enough with where the paddle had to be for each of the distance settings. You can see one of the paddles on the right. You just push that with your finger -- which you can do pretty easily in a space glove -- and the rings move. The astronaut is in Shadow and yet seems to get brighter and brighter.This is a sequence for which we have some actual exposure information. Armstrong -- who had photographic expertise -- said that he eventually worked up to f/5.6 at 1/60, not knowing for sure what the exposure should be. Could be a job for the Penguin.Ssh, don't give away his secret identity.
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Post by dwight on Jun 6, 2006 13:28:29 GMT -4
It should also be pointed out that the lux readings for the moon are easily relatable to earth based tests, as the moon (for illumination purposes) is the same distance from the sun as the earth is. ie an exposure setting of an earth mountain range would pretty much work for exposure of a maintain range on the moon.
Of course, aperture settings (f-stop), shutter speed and film speed all play a part in determining what exposure settings are used.
I have taken many a photo guessing what I should use based on experience. The astronauts did as well. Still, you sometimes come across multiple attempts at a photo with aperture variation just to cover all bases.
There is also "pushing" of the film development/processing which allows basic correction of photos that may be slightly over or under exposed.
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Post by JayUtah on Jun 6, 2006 14:09:42 GMT -4
My understanding is that the E-3 (Ektachrome) process/emulsion offered the most latitude to darkroom workers for correcting errors that occurred in the field. But according to Michael Light, there were some experimental procedures done at the time on some rolls that have compromised the longevity of the images.
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Post by 3onthetree on Jun 6, 2006 17:11:53 GMT -4
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Post by PhantomWolf on Jun 6, 2006 17:21:30 GMT -4
When you listen to the the radio chatter you often hear the ground controllers telliong them what exposures and focual lengths to use as well. Especially in the J-Missions where they had the LRV TV camera to see the conditions.
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Post by dwight on Jun 6, 2006 21:15:04 GMT -4
Well that is what Buzz Aldrin clearly asks prior to Neil Armstong stepping onto the lunar surface. Bruce McCandless responds with appropriate f-stop settings for shadow photography for the 16mm DAC, but the same values nonetheless. For some reason the likes of Margamatix could not believe that such settings would work.
Dwight
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Post by PhantomWolf on Jun 6, 2006 21:57:11 GMT -4
For those that can't find it in the ALSJ ---------------------------------- 109:22:06 McCandless: And we're getting a picture on the TV.
109:22:09 Aldrin: You got a good picture, huh?
109:22:11 McCandless: There's a great deal of contrast in it; and currently it's upside-down on our monitor, but we can make out a fair amount of detail.
109:22:28 Aldrin: Okay. Will you verify the position - the opening - I ought to have on the (16 mm movie) camera?
109:22:34 McCandless: Stand by. (Long Pause)
109:22:48 McCandless: Okay. Neil, we can see you (on the TV) coming down the ladder now. (Pause)
109:22:59 Armstrong: Okay. I just checked getting back up to that first step, Buzz. It's...The strut isn't collapsed too far, but it's adequate to get back up.
109:23:10 McCandless: Roger. We copy.
109:23:11 Armstrong: Takes a pretty good little jump (to get back up to the first rung). (Pause)
109:23:25 McCandless: Buzz, this is Houston. F/2 (and)...
109:23:28 Armstrong: Okay, I'm at the...(Listens)
109:23:29 McCandless: ...1/160th second for shadow photography on the sequence camera.
109:23:35 Aldrin: Okay.
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Post by dwight on Jun 6, 2006 23:32:31 GMT -4
Thanks Phantom Wolf! You are the man!
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Post by dwight on Jun 6, 2006 23:36:37 GMT -4
In response to the OP of this thread:
My oh my what will they think of next? Moving pictures over telegraph? Manual aperture control...phewie. Never heard of that newfangled technology...
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