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Any advantages shooting astrophotgraphy with film over digital?

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#1 Shakedown St.

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Posted 03 July 2017 - 01:36 PM

This keeps coming back to my mind, I am shocked and happy to see such a large film community out there. Digital senors produce digital noise from the sensor's heat called thermal nosie and bad pixels called readout noise.

I had someone tell me that average DSLR's detect around 40-45% of the photons that hit the sensor. For film they told me it's in the 2-5% range, and to avoid film at all costs.

Right now I own a Nikon F5 and a Nikon D300, I will be capturing deep sky objects without a cooling mechanism. Advice is much appreciated!

Edited by Shakedown St., 03 July 2017 - 01:38 PM.


#2 Michal1

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Posted 03 July 2017 - 04:03 PM

You have to feel the advantages of film astrophotography over digital by your heart. If there are some objective measures that are better for film than for the digital sensors, then I can't recall them. If you are doing astrophotography for your own enjoynmet, you have the choice. If you are doing science, you don't have the choice. If you can't resist the social pressure, you don't have the choice either.

 

People have various reasons for shooting on film. For me, the main reasons are these: 1) Film produces nicer images of bright targets for my eye. Here you can find many examples of film images:

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

You can compare them for example to the images you can find in the digital forums of CloudyNights.

2) I see little sense in producing images that is the internet full of. I want to be original. Digital can produce deeper and sharper images than film using the same telescope/lens. But why should I strive to take deep and sharp images when someone with better sky and equipment can take them even deeper and sharper? This would have no contribution.

 

I used to use both film and CCD for several years. I eventually sold the CCD because using it made me more unhappy than happy. With film, it was the other way around.


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#3 Shakedown St.

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Posted 03 July 2017 - 07:35 PM

I was real interested to find out if film would be better for me since I cannot cool the sensor I have, since film has no digital noise. That would be interesting to test out.


Edited by Shakedown St., 04 July 2017 - 12:51 AM.


#4 Michael Covington

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Posted 03 July 2017 - 07:39 PM

Film is worse than even an uncooled digital sensor.  Film certainly has noise (fog), it just isn't digital.

 

The one area in which film *might* have a technical advantage is meteor photography -- meteors are less affected by reciprocity failure than the sky background, so you can expose longer without hitting the sky fog limit.



#5 bobzeq25

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Posted 04 July 2017 - 08:01 PM

Look at my posts in your other thread re cooling and stacking.  There are a lot of forms of noise in astrophotography.  The worst is neither the thermal noise nor the read noise.  It's the sky noise.  Why they built the Hubble.

 

Digital cameras and computerized processing are far, far better than film for dealing with that.  This is what has turned astrophotography from a fringe activity to something a lot of people now do.


Edited by bobzeq25, 04 July 2017 - 08:02 PM.


#6 Uwe Pilz

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Posted 04 July 2017 - 11:37 PM

You have to feel the advantages of film astrophotography over digital by your heart.

The same is valid for me. I started photography in general and astronomical photography in particular in the 70th. Most photography was B/W at this time, and many people printed for their self, as I did and still do.

 

For me, a real photograph comes from a b/w negative and becomes manifest at a sheet of printing paper.

 

I don't perform astronomical photographing very much. But If I do I use b/w film.  I have no intention competing with other photographer, but take rather some kind of souvenir pictures.

 

To give an example: The transit of Mercury last year:

150509Merkurtransit5.jpg


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#7 Alen K

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Posted 10 July 2017 - 10:03 AM

A increased feeling of oneness with the universe? I'm only partly jesting. My feeling is that because film is a mechanical medium and the workflow to take astrophotos is intrinsically less electronic in nature, it's easier to retain more of that certain feeling I get under the night-time canopy (hard to put it into words). For me, electronics always intrudes on that. But that's just me. Other people seem perfectly content surrounded by equipment that looks like the bridge of the starship Enterprise.


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#8 Oldironsides

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Posted 29 August 2017 - 10:27 AM

Hello, everyone,

 

I am no longer into film astrophotography having boxed up my Honeywell Pentax Spotmatic many years ago but I raised an interesting subject over in the DSLR group and someone suggested I post it here.

 

Has anyone ever compared the mechanics of a 35mm film camera lens iris and shutter design to those of a DSLR? Until a few days ago I never considered this until I began comparing some photos I took of the 1970 total eclipse in Virginia where I captured a striking image of the diamond ring effect to what DSLR cameras being used today have tried to do.

 

Looking at everyone's eclipse photos I just realized how bland and flattened the diamond ring affect appears when photographed with modern DSLR cameras. I was so excited in planning to venture 400 miles south to shoot the August 21st eclipse with a whole array of high tech equipment that I rented but last minute problems caused my plans to unravel and I had to stay home. I was very fortunate to witness the 1970 total eclipse in Virginia and photograph it with my trusted Spotmatic 35mm camera with roll film, although with only a 200mm prime telephoto lens. And the striking appearance of the diamond ring effect that I captured must have been because of the design of the shutter and iris in the camera which modern cameras don't have.

 

I am far from being an expert on the subject but I would be interested in reading some comments.

 

Regards,

Nelson

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#9 CQDDEMGY

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Posted 29 August 2017 - 12:56 PM

That picture is stunning. Thank you for sharing.

#10 Michael Covington

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Posted 29 August 2017 - 03:19 PM

The iris and shutter on a DSLR work the same as on a film SLR, unless you happen to be using electronic first curtain shutter, a relatively uncommon feature.  In that case, the mirror goes up, the shutter opens, and then the beginning of the exposure is initiated electronically, to eliminate vibration.



#11 Oldironsides

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Posted 29 August 2017 - 07:36 PM

The iris and shutter on a DSLR work the same as on a film SLR, unless you happen to be using electronic first curtain shutter, a relatively uncommon feature.  In that case, the mirror goes up, the shutter opens, and then the beginning of the exposure is initiated electronically, to eliminate vibration.

Like I mentioned, I'm not an expert, but why do all the eclipse diamond rings photographed with DSLR cameras lack the flare that my 35mm Spotmatic captured? In fact, the DSLR images of the diamond ring appear to be just a flat blob of sunlight.

 

I captured two images of the diamond ring in 1970 and both have the dramatic flare.

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Edited by Oldironsides, 29 August 2017 - 07:40 PM.

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#12 Cajundaddy

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Posted 29 August 2017 - 08:20 PM

Lovely diamond ring Oldironsides. Sadly I don't think that was a result of film imaging but more a product of a highly active sun during the eclipse of 1970 and also 1979. Both were at or near solar maximum resulting in very vivid prominences. This combined with a rough lunar surface at the point of diamond ring results in the kind of striking images we have seen. In 2017 we are at or near solar minimum with historically low solar activity. Few prominences were visible during the eclipse with a very smooth solar limb and if the topography of the moon was also smooth at that point we get a much less striking diamond ring image.

To the TS,

I did film AP imaging for about 10 years back in the 90s. It was very analog and I understood it well. The drawbacks are the wait time between image gathering and seeing your results, reciprocity failure, and film fog. I am no longer actively involved in AP and have fallen far behind in digital post processing techniques that were just being explored 20 years ago. Film can still be done and if it pleases you, go for it. I still have a lightweight Taurus Astro Camera and off axis guider for film. If you have any interest, drop me a PM. I do not plan to use it again.

Edited by Cajundaddy, 29 August 2017 - 08:32 PM.

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#13 Oldironsides

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Posted 29 August 2017 - 08:32 PM

Cajundaddy, Thank you clearing that up. All these years I wanted to replicate that diamond ring effect with better equipment to get a larger, sharper image. I would have been sorely disappointed if I tried again with the stuff I rented for the August 21st eclipse. I'm sorta glad now that circumstances beyond my control prevented me from making the trip. Also glad Lens Rentals gave me most of my money back.

 

Now if I live long enough to try again in 2024, that next total eclipse will be only a 30-minute drive away.


Edited by Oldironsides, 29 August 2017 - 08:34 PM.


#14 Alen K

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Posted 29 August 2017 - 09:47 PM

Well done, Oldironsides! Your diamond ring photos indeed look worthy of the name.



#15 KLWalsh

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Posted 02 September 2017 - 06:33 PM

I shot the eclipse with a D810a on a 6" f/5. 

I was just a fraction of a second quicker than I'd intended catching the Diamond Ring, but I'm still happy with my shot.

I think it shows that DSLRs can do pretty well.

And just btw, I still have my old Minolta SLR and some B&W film.

I do think that film B&W photography has an appeal and a look that DSLRs have trouble matching.

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#16 TxStars

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Posted 03 September 2017 - 01:41 AM

Prom 2   Copy

Most optics produce some unique images due to their design

This is an unprocessed image from 8-21-2017

Taken with my Takahashi FC-100 @ F/5.9 and my Cannon T3i

 

 

 

 

 

 

 

 

                                                                         

tn_gallery_12231_8163_36990.jpg


Edited by TxStars, 03 September 2017 - 01:54 AM.


#17 Oldironsides

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Posted 03 September 2017 - 12:31 PM

 

 

Most optics produce some unique images due to their design

This is an unprocessed image from 8-21-2017

Taken with my Takahashi FC-100 @ F/5.9 and my Cannon T3i

 

 

 

 

I have been told that the defined flare in the diamond ring in my 1970 eclipse photos was due to the light reflecting off some internal parts of the lens or camera. I have looked at many eclipse photos and haven't seen any like mine so maybe something about the Honeywell Pentax Spotmatic and or the 200mm Takumar lens had some affect.

 

Another person who commented, Cajundaddy, said it might have been the solar maximum during the 1970s that did this but if that were so then there would be other photos of that eclipse that showed this.

 

 

 

 

 

                                                                         

tn_gallery_12231_8163_36990.jpg

 

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Edited by Oldironsides, 03 September 2017 - 12:31 PM.

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#18 Achernar

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Posted 03 September 2017 - 11:43 PM

Film is more forgiving of optical imperfections than CCD and other digital cameras, as users of some lenses that were mainstays of film based photography found out when they tried them with digital and CCD cameras. Unless you have a full frame or larger chip in the camera, a 35mm SLR camera will get a wider field of view than a CCD or digital camera will with the same telescope. And it's simple to shoot photos of the Sun and Moon, at least whole disk images of them. Having the negatives or transparencies in hand means you can always scan them or print them as often as you like. That said, film in a number of ways sucks compared to digital cameras. Where I am, milky skies and light pollution make long exposures with film an exercise in futility. Add to that that at best, film responds to one or two percent of the light that reaches it. I've seen how a digital camera can record more in 30 seconds than film will record in 30 minutes or even an hour of exposure time. It also loses sensitivity at very low light levels, and you have no idea if you got anything or not until you develop it. That is not to say it's useless, but in many, but not all respects, it's not able to compete with digital imaging.

 

Taras


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#19 Michael Covington

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Posted 03 September 2017 - 11:48 PM

Yes, film is more forgiving of optical imperfections, and also guiding imperfections.  You can't "pixel peep" film to see 5-micron details; the effective resolution is more like 25 microns.  

But you can also simply downsample your digital images to have the resolution of film.



#20 donlism

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Posted 09 September 2017 - 08:44 AM

25 microns?  That number surprises me -- it's 1/40mm or 20 line pairs per millimeter.  I notice the specs for Acros 100, for example, are 40 lpm (12.5 microns) at a contrast of 1.6:1, and 200 lpm (2.5 microns) at a contrast of 1000:1.  Where does the discrepancy come from?


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#21 AstroBobo

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Posted 09 September 2017 - 07:16 PM

 

The iris and shutter on a DSLR work the same as on a film SLR, unless you happen to be using electronic first curtain shutter, a relatively uncommon feature.  In that case, the mirror goes up, the shutter opens, and then the beginning of the exposure is initiated electronically, to eliminate vibration.

Like I mentioned, I'm not an expert, but why do all the eclipse diamond rings photographed with DSLR cameras lack the flare that my 35mm Spotmatic captured? In fact, the DSLR images of the diamond ring appear to be just a flat blob of sunlight.

 

I captured two images of the diamond ring in 1970 and both have the dramatic flare.

 

The flare shape is the result of the iris of the lens.



#22 Alen K

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Posted 09 September 2017 - 08:20 PM

25 microns?  That number surprises me -- it's 1/40mm or 20 line pairs per millimeter.  I notice the specs for Acros 100, for example, are 40 lpm (12.5 microns) at a contrast of 1.6:1, and 200 lpm (2.5 microns) at a contrast of 1000:1.  Where does the discrepancy come from?

Comparing film and digital is apples and oranges of course, but see this: http://www.normankor...ials/MTF1A.html

and

http://www.normankor...rials/MTF7.html

 

Just as one datapoint I usually had my Elite Chrome 200 slides scanned at 4,032 x 2,688 (10.8 MP). That would be 9 microns per pixel in the scanned image or 56 lp/mm. At that resolution the grain was fully evident and I felt I was getting about as much information as practical from the slide. 

 

BTW, the contrast numbers above seem mixed up. Contrast should be lower at higher spatial frequencies.


Edited by Alen K, 09 September 2017 - 08:28 PM.

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#23 donlism

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Posted 09 September 2017 - 10:18 PM

Ah... I think one of the differences here is color versus black and white.  Color is obviously going to be a lot lower resolution because of the nature of the film, the development, how the color is formed, and all of that.  I would expect Kodachrome to have the best chance of competing with black and white, but still fall short due to the three layers and diffusion through them and the rest of that.

 

As to the contrast numbers, they are as stated by Fuji, and similar to other values given for Kodak films and such.  The contrast is that of the subject, not the resulting image, and that might be why they're backwards, as a hand-waving generality.


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#24 Alen K

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Posted 10 September 2017 - 12:09 AM

As to the contrast numbers, they are as stated by Fuji, and similar to other values given for Kodak films and such.  The contrast is that of the subject, not the resulting image, and that might be why they're backwards, as a hand-waving generality. 

MTF is a more common way to specify in my experience. I was looking at the Kodak Elite Chrome 200 data sheet just before I posted above. It specifies MTF curves for each emulsion layer but does not give target contrast numbers. I looked at other data sheets for Kodak films. Same thing. Fuji also specifies MTFs in addition to target contrast numbers for all of their current consumer films. (I also looked at some Ilford spec sheets. No resolution spec at all. Oh well.)



#25 ClownFish

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Posted 27 November 2017 - 04:16 AM

As a long-time film shooter, and just now learning digital astrophotography,  I can tell you that the technical procedure to get an image that looks good takes much less effort with film than with digital.  Digital can produce much sharper images, with more faint detail than film because of digital post processing of multiple exposures.  Film requires very long exposures to capture faint detail and that causes brighter parts to be blown out and stars that are bloated.  With film there are no darks, no bias, most do not use a flat.  In many cases it's just one exposure and then send off for processing.

 

 

Here's a few shots I took with color slide film on an 8" Schmidt Newt (F/4) - a wonderful imaging scope btw. 

These are all single 30 minute shots, except M45 which was a 45 minute exposure.

 

10399352_19631382857_1666_n.jpg

 

10399352_19632077857_37_n.jpg

 

10399352_19631392857_2351_n.jpg

 

10399352_19632897857_961_n.jpg

 

10399352_19631387857_2029_n.jpg

 

 

 


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