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Medium format 'deepsky' possible?

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#1 berkanxj

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Posted 12 January 2021 - 10:23 AM

Hey everyone, some questions as I’m a bit lost with all this information floating around.

 

I enjoy digital astrophotography on my star tracker, but I recently sold it as I’m planning on buying a Heq5 pro goto mount and a 6 inch reflector like the Skywatcher 150pds with a coma corrector. I use a Canon eos 800D/ rebel t7i. Will add guiding in the future. So this concludes my plans for digital astrophotography.
Now for film..

 

I own a Mamiya 645 1000s with 80mm f2.8 lens. I’d love to use a medium format, in this case my Mamiya I already own to do film astro. I can’t attach it to the reflector because it would be way too front heavy. Seems like I would need some sort of refractor to do this?

I’ve read the forum and it looks like the Olympus OM-1 is popular. Could I attach this to the 6 inch reflector with an adapter or is this not possible? It’s a 35mm and I love medium format but it looks like “deepsky” isn’t possible with the Mamiya 645 body, right?

 

I know it isn’t recommended to get into film astrophotography now. But film has gotten popular again, that’s why I bought this camera in the first place. Also plenty of places in my area the develop, scan, push/pull film. That’s why I’m focusing on my digital setup. But I would still like to use film (preferably my medium format camera I already own for some deepsky shots) Is this possible or am I being dumb haha. It looks like I can only use my Mamiya for a widefield shot with the Mamiya lenses, like this one I took https://i.imgur.com/mqGuzPn.jpg . Please let me know what the possibilities are! Thanks


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#2 ngc7319_20

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Posted 12 January 2021 - 10:31 AM

You should google Akira Fujii to see what is possible with medium format film.  Yes it is possible.

 

https://www.davidmal...ujii_index.html


Edited by ngc7319_20, 12 January 2021 - 10:38 AM.


#3 AnakChan

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Posted 12 January 2021 - 10:37 AM

If the focuser of your scope can handle the weight/load of the Mamiya 645, and if your scope has an imaging circle to make full use of a 6x4.5, don’t see why you can’t? I haven’t done film astrophotography in a -long- time but as long as you can retain film flatness with the 645 (old days astro film cameras used to have a vacuum back), and a focusing screen that’s helps focusing (split doesn’t help if I recall correctly), then you can give it a shot. Mirror lock also helps but if not, you can always use the “hat in front of the scope” trick.
 

I don’t know if hypersynthesizing film kits are still easily available but look out for them. Also keep your film dry frozen.



#4 ngc7319_20

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Posted 12 January 2021 - 10:55 AM

If the focuser of your scope can handle the weight/load of the Mamiya 645, and if your scope has an imaging circle to make full use of a 6x4.5, don’t see why you can’t? I haven’t done film astrophotography in a -long- time but as long as you can retain film flatness with the 645 (old days astro film cameras used to have a vacuum back), and a focusing screen that’s helps focusing (split doesn’t help if I recall correctly), then you can give it a shot. Mirror lock also helps but if not, you can always use the “hat in front of the scope” trick.
 

I don’t know if hypersynthesizing film kits are still easily available but look out for them. Also keep your film dry frozen.

Yes film flatness is an issue.  People were using vacuum backs and such to keep the film flat for hour long exposures, and stuff like that.  Was also necessary to keep the film dry during the exposure.  Film would tend to absorb water from the air and move / curl during the exposure.  I recall bagging up the camera with oven dried rice during the exposure to keep it all dry.  Others would run dry nitrogen into the camera.

 

Indeed there was gas hypering also, to increase the sensitivity to dim light.  I've still got a hyper outfit somewhere with vacuum pumps, heaters, gas tanks, etc.  Digital is so much easier.



#5 Delta608

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Posted 12 January 2021 - 01:32 PM

Hey everyone, some questions as I’m a bit lost with all this information floating around.

 

I enjoy digital astrophotography on my star tracker, but I recently sold it as I’m planning on buying a Heq5 pro goto mount and a 6 inch reflector like the Skywatcher 150pds with a coma corrector. I use a Canon eos 800D/ rebel t7i. Will add guiding in the future. So this concludes my plans for digital astrophotography.
Now for film..

 

I own a Mamiya 645 1000s with 80mm f2.8 lens. I’d love to use a medium format, in this case my Mamiya I already own to do film astro. I can’t attach it to the reflector because it would be way too front heavy. Seems like I would need some sort of refractor to do this?

I’ve read the forum and it looks like the Olympus OM-1 is popular. Could I attach this to the 6 inch reflector with an adapter or is this not possible? It’s a 35mm and I love medium format but it looks like “deepsky” isn’t possible with the Mamiya 645 body, right?

 

I know it isn’t recommended to get into film astrophotography now. But film has gotten popular again, that’s why I bought this camera in the first place. Also plenty of places in my area the develop, scan, push/pull film. That’s why I’m focusing on my digital setup. But I would still like to use film (preferably my medium format camera I already own for some deepsky shots) Is this possible or am I being dumb haha. It looks like I can only use my Mamiya for a widefield shot with the Mamiya lenses, like this one I took https://i.imgur.com/mqGuzPn.jpg . Please let me know what the possibilities are! Thanks

  Keep us posted on your progress if ya move forward...As an old film addict I find it interesting..



#6 Michal1

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Posted 12 January 2021 - 05:00 PM

Sure that medium format AP is possible. You can find many examples in this thread:

https://www.cloudyni...aphy-galleries/

You can certainly get a photo like from you link easily. Orion is a bright target. It should be easy to take a photo like this from your HEQ5 mount in one minute. Most likely, you won't even need guiding for that.

 

There are not many telescopes that can cover the large area of a medium format by sharp and unvignetted image. Those which can are very expensive. This is why most of us use photographic lenses. The situation is a bit better with the 35mm format. Today's commercial telescopes are typically intended for smaller digital sensors. Look for one with a sufficient image circle and when you have a candidate that you want to buy, you can ask us for more details.

 

As for a suitable film, this situation is a bit difficult now. There are not many active members in this forum to try new films and share their results. I personally use a discontinued excellent brand of film that I conserved in the refrigerator. I heard that people recently had good results with the new Kodak Ektachrome 100 film. You can find some examples in this forum. I can't say how it compares to other available films. The Portra film from your example should still be available too.



#7 Todd N

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Posted 12 January 2021 - 05:22 PM

Hey everyone, some questions as I’m a bit lost with all this information floating around.

 

I enjoy digital astrophotography on my star tracker, but I recently sold it as I’m planning on buying a Heq5 pro goto mount and a 6 inch reflector like the Skywatcher 150pds with a coma corrector. I use a Canon eos 800D/ rebel t7i. Will add guiding in the future. So this concludes my plans for digital astrophotography.
Now for film..

 

I own a Mamiya 645 1000s with 80mm f2.8 lens. I’d love to use a medium format, in this case my Mamiya I already own to do film astro. I can’t attach it to the reflector because it would be way too front heavy. Seems like I would need some sort of refractor to do this?

I’ve read the forum and it looks like the Olympus OM-1 is popular. Could I attach this to the 6 inch reflector with an adapter or is this not possible? It’s a 35mm and I love medium format but it looks like “deepsky” isn’t possible with the Mamiya 645 body, right?

 

I know it isn’t recommended to get into film astrophotography now. But film has gotten popular again, that’s why I bought this camera in the first place. Also plenty of places in my area the develop, scan, push/pull film. That’s why I’m focusing on my digital setup. But I would still like to use film (preferably my medium format camera I already own for some deepsky shots) Is this possible or am I being dumb haha. It looks like I can only use my Mamiya for a widefield shot with the Mamiya lenses, like this one I took https://i.imgur.com/mqGuzPn.jpg . Please let me know what the possibilities are! Thanks

You are not going to be able to use a medium format camera with standard scopes; Forget about theoretical possibilities. You could get an adapter custom made but all consideration involved this would not be worth it. Very view telescopes out their have corrected fields to use larger format. The few that do are super expensive. Think about buying a telephoto lens for the MF camera. https://www.keh.com/

 

You probably could attach a 35mm cam to this reflector from what I could find out; It's astrophotography compatible. You will need a T-ring attachment and coma corrector or much of the frame will have distorted comatic stars.

 

There is no reason not to at least try film and/or shoot both analog an digital. I feel film can produce better widefield shots than digital: See "Nightfly" James Cormeir's work: http://nightflyphoto...y.blogspot.com/

 

Forget about suggestions like hydrogen hypersesitization or other chemical methods to enhance film performance. Most films these days will not respond to it. Pursuing these ideas in the beginning would be a distraction.
 



#8 SMigol

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Posted 13 January 2021 - 01:06 PM

I have found that focal lengths of 300 to 400mm are a sweet spot for film astro.  When well-guided, the stars end up being just above film grain and I can do a deep scan at 5600 dpi to about 5-10 microns.  The star images hold up well and compare nicely with digital at this scale.

 

Any higher magnification usually requires very sturdy mounting, very precise guiding, and very good polar alignment,

 

Expect exposures of 45 minutes to 1 hour at F5.6.

 

The new E100 works well.

Portra 400 also works well.

Acros is the only black and white film worth using.


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#9 berkanxj

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Posted 16 January 2021 - 09:32 AM

Thanks for the replies everyone!! I will update in the future as a lot of things are on backorder at the moment. Thanks for the help and suggestions, will keep it in mind!




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