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35mm film and widefield AP - worth the hassle for a newbie?


c3po
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hi all,

i'e been itching to get into AP for sometime now, but the lack of a DSLR, and the only digital camera i own being a (not so great) bridge camera with extremely limited 'bulb' mode (30 seconds MAX) has meant i've been discouraged by my results.

however, i DO have a good few 35mm SLRs from my photography A-level course from way back before DSLRs became more reasonably priced devices. Among the cameras is a Pentax MZ-50 with 35-80mm & 80-200mm lenses, and a Canon 1000FN with 70-210mm lens.

now, i understand that film is expensive, but given what i've got and how much i want a DSLR but can't afford one as yet - are there any pointers or suggestions for the seasoned AP members here with regards to the difficulties and so on involved with Film based AP?

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I found my old starter shots on film the other day while unpacking.

Film is great for widefield. If you plan to scan then process you can remove some light pollution but only some. Otherwise you will require either a dark sky or tolerance of light pollution or a light pollution reduction filter.

I found that f5.6 was about as slow as I could go before reciprocosity failure started to intervene badly. I used 15 minute to 1 hour shots.

I used fuji and got some success, todays films should be better still so have a go (Edit: Film is more sensitive than unmodded DSLR to Ha). If you have processing at home great, otherwise you'll need to find someone who processes on site as you'll need to make sure your pics do not go through a machine on 'auto' as it will bleach them all out, you need the human touch. You want to ask for a dark grey background.

Derek

Edited by rfdesigner
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I agree that widefield film shots look great, paritcularly as projected slides. (I have a dark site so I can't comment on LP.) You might find this intersting from my friend and guest Maurice Toet, MFT on here.

FILM astrophotography | www.dutchdeepsky.com | Maurice F. Toet

and his article

Why Medium Format Astrophotography? | www.dutchdeepsky.com | Maurice F. Toet

Olly

Edited by ollypenrice
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Wow, such great and informative replies...I was expecting much more of the "don't bother with film, dslr is much better" talk...

Out of interest, purely wide field only, no tracking, what's the longest exposure I could take without start trails?

Edited by c3po
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Out of interest, purely wide field only, no tracking, what's the longest exposure I could take without start trails?

Divide your widest focal length by 600 :blob10:

eg 600 divide by 20mm = 30s longest exposure

Edited by Mike73
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excellent thanks guys...regards the developing & printing of the negatives, i've dealt with a company before who do manual developing and only print on request - perfect for me as i can then scan and edit the negatives digitally before printing.

just one more question (or actually a couple related to the same thing), obviously the above exposure timings are for a static camera, i.e. on a tripod with no tracking.

I have a Celestron 130EQ with an optional RA motor, and i'm led to believe that i am able to attach my camera to the scope 'piggy-back' style, my questions are:

  1. 1st and foremost, how do i do it?
  2. how accurately do i need to polar align?
  3. what would be the maximum exposure (assuming there is such a thing) on "bulb" mode when tracking RA?

p.s. apologies for the simplicity of these questions, but i'd like to get this right the first time around - as you all know, film ain't cheap!

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I can't speak for 130EQ

Alignment wise, my advice is get it as good as you can. With a wide field if you get it slighlty wrong then you will see field rotation. Personally I'd "drift align", which is a pain but about the only really time consuming bit at short focal lengths (other than the imaging)

Do you have a remote camera release?.. they're very cheap and stop vibrations or other movement.

To give you an idea of resolution:

film star sizes will be about 20um

at 50mm fl that mean you will get star sizes of 80 arc seconds.

assuming your mounts periodic error is +/-20 arc seconds (not great) you could image at 100mm fl unguided and still get excellent results, just so long as you are really well aligned.

With an alignemnet error of 0.5 degrees you can expect a 78 arc second drift after 10 minutes. I'd want to be at 0.1 degrees alignment error. or better so that I could go out to 20 to 30 minutes.

One thing you could do is take 5, 10, 20, 40 minute shots, scan them into a PC then stack them to get better dynamic range (see fred espinaks eclipse images for an idea http://www.suite101.com/view_image.cfm/346883)

Derek

Edited by rfdesigner
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Wow, thanks Derek. That's great info! Unfortunately, my film camera doesn't accept a remote release :-( but I assume I could use the 2 second self timer to help with vibration.

....just need to learn how to drift align now.

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Just check around the shutter button area...you may find that the ol' screw in release cable will fit.

definitely nothing like that on my Canon 1000FN, and according to details i found online, it was one of the last in the EOS camera series NOT to feature a remote shutter attachment, screw in or otherwise....guess i'll have to make do with the 2second timer :blob10:

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Oooh!.. no remote shutter release, not good. Even my old Practica has that!

If the shutter is electronic then you could open her up, put in two wires and feed them off to a toggle switch.

Derek

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I've got an old Eos 500 body and shutter release, your welcome to it if you'd like to give it a try.

I'm never likely to use it again and I don't think it's worth anything.

RobL, that would be great, thanks!! I'll PM you my details....

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I couldn't reply to your PM Simon (have you got PM's blocked?).

I'll post it tomorrow.

my apologies rob, yes i had them blocked (oops! :() that's rectified now...if you wanted to try again.

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Wow, thanks Derek. That's great info! Unfortunately, my film camera doesn't accept a remote release :-( but I assume I could use the 2 second self timer to help with vibration.

Or hold a sheet of black card in front of the camera when you hit the button, wait a second or two and remove it.

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Or hold a sheet of black card in front of the camera when you hit the button, wait a second or two and remove it.

Yes that works, but he's still limited to 30 or so second images.. no good for film unless he's imaging the moon or planets.

unless of course I've missed something and the camera is capable of holding the shutter open indefinitely in bulb mode without leaving your finger on the button.

Derek

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Thanks guys, appreciate the help...however I may now have alleviated the shutter remote issue with the kind offer of an EOS500 film with the remote shutter from Rob L.

hopefully the bulb mode on it will allow unlimited timed exposures, only when I get it will I know.

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