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03-16-2022, 04:29 PM   #31
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QuoteOriginally posted by geehzer67 Quote
This will cost Ricoh plenty.
It's not Ricoh's satellite, Geehzer!

03-18-2022, 11:17 AM   #32
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QuoteOriginally posted by RobA_Oz Quote
By my calculation, the resolution requirement of 5m at 400km equates to 3.75 microns at the focal plane, whereas the Sony 36MP sensor in the K-1 has a reported sensel size of 4.88 microns. If that’s accurate, there’s no question of the sensor out-resolving that lens, but it leads me to wonder how it would go against a higher resolution sensor.

Anyway, good on them for choosing a Pentax lens, when there were other options available.
Hm, DA*300 gets sharper on stopping down on K1; so we would need f-stop and image height (and contrast) for the resolution statement. Btw, I would turn the wording around, the lens outresolves the sensor since it surpasses the sensor resolution.
The distance between pixel centers is 4.88 micron, the size of a pixel may be smaller.
03-18-2022, 06:07 PM   #33
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I've been reading all the comments on the dpreview site, where an article just appeared concerning this.
Aside from the usual Pentax bashing, which actually surprisingly there isn't that much of, there are some comments that I'd like to ask about.

Some have complained about it being F4 and it's DOF. My question is, in space, does one even have to worry about depth of field? Isn't focus length infinity anyways (?) I mean, isn't any aperture value going to be about the same usefulness, as things are such a long distance away, then F1.7 would deliver the same flat images as F16 (?). I'm certainly an amateur when it comes to this question concerning outer space, please explain to me someone.


One person said that the images sure would be "dark." What are users, here, comments/reply about this? I mean, I know that "star trails" show up with long exposures, but wouldn't short enough exposures, still be long enough, to avoid a dark image?

A curious question: Is this version of the lens, on the micro-satellite, is it K mount or the medium format variety?


Regards,

Michael

Last edited by Michael Piziak; 03-18-2022 at 06:18 PM.
03-19-2022, 01:26 AM   #34
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QuoteOriginally posted by Michael Piziak Quote
A curious question: Is this version of the lens, on the micro-satellite, is it K mount or the medium format variety?
It's a DA* 300mm f/4, with nonessential parts removed (rather, excluded/not assembled) - including the K-mount:
https://news.ricoh-imaging.co.jp/rim_info/da_300_custom.jpg

03-19-2022, 06:02 AM   #35
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QuoteOriginally posted by Michael Piziak Quote
I've been reading all the comments on the dpreview site, where an article just appeared concerning this.
Aside from the usual Pentax bashing, which actually surprisingly there isn't that much of, there are some comments that I'd like to ask about.

Some have complained about it being F4 and it's DOF. My question is, in space, does one even have to worry about depth of field? Isn't focus length infinity anyways (?) I mean, isn't any aperture value going to be about the same usefulness, as things are such a long distance away, then F1.7 would deliver the same flat images as F16 (?). I'm certainly an amateur when it comes to this question concerning outer space, please explain to me someone.


One person said that the images sure would be "dark." What are users, here, comments/reply about this? I mean, I know that "star trails" show up with long exposures, but wouldn't short enough exposures, still be long enough, to avoid a dark image?
The lens as I understand it will be imaging the earth not the stars. The earth is quite bright typically or very dark depending on the sunlight falling on it. As for depth of field… that is not going to be a factor.
03-19-2022, 08:21 AM - 1 Like   #36
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The DA*300 Goes to Space!

Saw this article pop up in my news feed this morning - Japan sends a modified Pentax 300mm F4 lens into space aboard its Kitsune 6 microsatellite: Digital Photography Review

As a DA*300 owner and certified data nerd, I find this pretty cool!
03-19-2022, 08:42 AM - 1 Like   #37
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"The Pentax 300mm F4 lens was selected due to its resolving performance, compact size and adaptability to use in space. Because it's a commercially-produced lens, it's also an affordable option. The lens has been placed inside a customized barrel for use in the satellite."

If I ever order a satellite I'll include one in the specs.

04-10-2022, 07:11 AM   #38
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QuoteOriginally posted by UncleVanya Quote
The lens as I understand it will be imaging the earth not the stars. The earth is quite bright typically or very dark depending on the sunlight falling on it. As for depth of field… that is not going to be a factor.
Depth of Field over 250 miles. Maybe the DiPReview guys thought it was 250 microns.
05-02-2022, 10:39 PM - 1 Like   #39
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Cool!!
Sorry if this is somewhat OT but I think new members of PF might be interested in this:
Pentax k10d in space - PentaxForums.com
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