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Large format astrophotography

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61 replies to this topic

#51 Uwe Pilz

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Posted 04 October 2018 - 11:15 AM

I never used a vacuum holder (and never made shots of the night sky larger than 6x6). But it is quite clear that the vacuum pump has to work during the exposition. Such exposition may last an hour or longer. WIth such long exposition times a lot of problems occur. One of them is the movement of the film due to its exposition to falling temperature and moisture.

 

I recommend starting with 6x6 or even with 35 mm for looking what happens and what fails. I further recommend to use a high speed film such as Ilford 3200 (which is an 800 ASA film in fact). The you may get decent results after 10 ... 30 mins of exposition, depending on the sky quality of your site. You fill find a lot of problems even then. Some are problems with guiding and optical aberration of a rather wide open lens.

 

If you start with all problems at once (large format = small stop = extra long exposition time, medium speed film = even longer exposition time, heavy equipment = more problems with the mount) it may be that you give up too early.



#52 Michal1

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Posted 05 October 2018 - 06:59 AM

Acros 100 can be still purchased at Ebay.

 

Nightfly has made some photos using a large format and medium format cameras, so you might ask him about the difference. Some examples are available here:

http://nightflyphoto...hotography.html

I think that very high resolution photographs can be obtained also using the medium format cameras which is less demanding, for example, the camera is less heavy, the lens are cheaper and faster or the film flatness is less problematic.

 

Occasionally, Danilo Pivato, also from Italy, contributes to our forum with his images taken using a Mamiya medium format camera. You can look for his posts in this forum or you can find his web page here

http://www.danilopiv...oto_&_maps.html

 

BTW, even the medium format cameras are not free of the problems with film flatness. Their severity depends on the construction of the particular camera. Maybe this is the reason why only a few MF camera types are used for astrophotography.  Danilo's photos prove that his Mamyia keeps the film flatness very well. Many users of Pentax 6x7/67 don't have problems with film flatness. I sometimes had, so I constructed a vacuum back for my Pentax 6x7and it helped substantially. You can judge the resolution of my photos here

https://www.astro.cz...ntax 6x7/HiRes/

especially on the newer photos at the bottom of the page. It seems that the photos taken this year will be a little sharper as I am getting more experience and improving the equipment.


Edited by Michal1, 05 October 2018 - 07:08 AM.


#53 Euphonia

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Posted 28 April 2019 - 08:43 PM

There is something very special with film. Film for scientific purposes is probably no longer valid, but film as an artistic medium feels more relevant than ever



#54 Alen K

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Posted 28 April 2019 - 09:30 PM

There is something very special with film. Film for scientific purposes is probably no longer valid, but film as an artistic medium feels more relevant than ever

Indeed, the do say an artist must suffer to make great art. Film astrophotography qualifies! (Did 35mm for six years in the 2000's.). laugh.gif

#55 mcolbert

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Posted 14 May 2019 - 02:58 AM

late to the party with this thread, but now following.



#56 Todd N

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Posted 14 May 2019 - 03:50 PM

Indeed, the do say an artist must suffer to make great art. Film astrophotography qualifies! (Did 35mm for six years in the 2000's.). laugh.gif

Once one thinks about it, isn't film astrophotography more or less easier?

 

Todd



#57 mcolbert

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Posted 14 May 2019 - 04:00 PM

Once one thinks about it, isn't film astrophotography more or less easier?

 

Todd

Todd I get the impression that those using imaging techniques and equipment look 'down' / across at us and see that we need 'perfection' in mounts, that we need to take time to see what has gone right and not so right -  whereas they can stack and remove unsuitable images, see what is happening 'live' so to speak and so on.  I'm reminded of the comments between the 35mm film users of years ago when talking with LF photographers, about how they could take so many more images, have 250 backs, motor winders etc.  Maybe it is a reflection in part of the person creating the photograph / image?  To paraphrase Sturgeon, why can't we all be imagers? :)



#58 Todd N

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Posted 14 May 2019 - 04:35 PM

Todd I get the impression that those using imaging techniques and equipment look 'down' / across at us and see that we need 'perfection' in mounts, that we need to take time to see what has gone right and not so right -  whereas they can stack and remove unsuitable images, see what is happening 'live' so to speak and so on.  I'm reminded of the comments between the 35mm film users of years ago when talking with LF photographers, about how they could take so many more images, have 250 backs, motor winders etc.  Maybe it is a reflection in part of the person creating the photograph / image?  To paraphrase Sturgeon, why can't we all be imagers? smile.gif

There is hardly any of us left to look down upon.lol.gif  Film has a lot of relevance and the case should be made that it should have potential interest from small CCD/CMOS imagers as a complimentary and specialized choice for at least wide-field imaging.

 

Todd



#59 mcolbert

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Posted 14 May 2019 - 04:39 PM

There is hardly any of us left to look down upon.lol.gif  Film has a lot of relevance and the case should be made that it should have potential interest from small CCD/CMOS imagers as a complimentary and specialized choice for at least wide-field imaging.

 

Todd

Todd you shan't get any argument from me, I'm one of the faithful.;)


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#60 Achernar

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Posted 25 May 2019 - 09:18 AM

I have learned how to use a 4X5 view camera and how to develop and print sheet film. I have actually tried star trails with an old style 4X5-inch press camera, and found that the film shifted in the holder, blurring the central region of the negatives. I was disappointed that hours of effort were lost.

 

Taras



#61 TxStars

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Posted 25 May 2019 - 11:12 PM

@Taras

Some of the 4x5 film holders had a single leaf spring in them to hold the film in place, but this does not work well if the camera is moving.

This issue along with the film not always remaining flat is why some have made/purchased the vacuum holders for formats larger than 35mm.


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#62 mcolbert

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Posted 26 May 2019 - 01:48 AM

@Taras is spot on, if you do a search of some of the major astronomy fora there are the odd threads about 5x4 astrophotography.  I also thought that I could find a reference in some of my astrophotography texts, but no luck.  

 

This may be the type of thing that you are after, BUT it is for 220 film!

 

https://www.ebay.co....yAAAOSwN3lc1RqN

 

Maybe a wanted ad in CN, SGL, ABS etc?




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