| The Minolta SRT100x With 28mm f2 lens fitted and original 35-75 f3.5 lens. |
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I am writing this document after the fact ! I have spent the last year doing all the things below to get to a stage in tripod astrophotography where i normally 20 frames out of a 24 exposure film are good enough to show friends and family with maybe 2 or 3 are good enough to show to everyone else (although i have yet to publish any). Here within lies my path from no experience to the standard mentioned above.
About a year ago i decided to start using my old Minolta SRT100x for tripod only astrophotography. This camera is on long term loan from my younger brother, i think he bought it from a car boot sale with a 35-70mm f3.5 zoom lens for £40. I thank you little brother for letting me use this camera for such a long time. My initial foray into the world of tripod astrophotography was to say the least un-successfull. Initially i used ISO 200 Kodak Gold film (i got a whole bunch of this stuff from another car boot sale, 50 24exp for £50 bargain). I picked a random roll and shot in daylight to check that the film was ok and it was. A few days later i was beset with a clear mid summer evening and i began.
A note i must add, this doc is more about astrophotography than the actual camera but for those of you seeking new avenues to use your manual SLR its a resource. For those of you seeking info about the actual camera you should try Minolta SRT SLR Cameras Dick Sullivan or Miniman.
Film Type: Kodak Gold ISO 200
Subjects: Constellations, Ursula Major/Minor, Cygnus, Perseus
Lens Setting: 35mm f3.5
Exposures: 25 returned
Exposure Times: 5, 10, 15 seconds per constellation
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Using nothing more than a standard tripod i pointed the camera at Ursula Major set the focus to infinity set the f rating to max
(3.5 with this lens) attached the shutter release cable then pressed the button down. 10 seconds later i let the release go,
i continued like this for an entire roll of film (25 pics in all) went to my supermarket to get the film developed on a next
day basis. I got the film back the next day and to my dismay all the pics where blurry, what ! Why where all the pictures
blurred ? After much thought and a few daylight pics taken in the same way i sussed it.... When i pressed the button on the
shutter release cable it made the camera wobble. Next time i will do somthing about that.
Film Type: Kodak Gold ISO 200
Subjects: Constellations, Ursula Major/Minor, Cygnus, Perseus
Lens Setting: 35mm f3.5
Exposures: 23 returned
Exposure Times: 5, 10, 15 seconds per constellation
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This time i thought i could damp out the vibrations by attaching a bucket of water to the bottom of the tripod. WRONG!
Still the pics where out of focus. By this time you guys probably know the answer but i didnt and was on the verge of giving up.
My dear old paa talked me out of it saying "we dont make mistakes, we learn lessons" so i now know that a damper of any
kind dosent work. I spent more time prognosticating about how to solve the problem then in a blinding flash it came to me.
Put my hand over the lens.
Film Type: Kodak Gold ISO 200
Subjects: Constellations, Ursula Major/Minor, Cygnus, Perseus
Lens Setting: 35mm f3.5
Exposures: 23 returned
Exposure Times: 5, 10, 15 seconds per constellation
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This time i tried the old hand over the lens trick and it seemed to work. No blurring of an images was present.
But it did seem to show a slight over exposure to the inner edges of the frame, i guess this is because of the breif
but minor amount of light reflection from my hand. This is still not good enough for me (i am very critical of
everything). I have an old black hat some where i will try that next time !
I have yet to produce an image of a quality that i feel confident to publish, but hey ive only been doing this for three rolls of film. Now i beleive that i have the basics sussed. Next time i will use the same film and a black hat as a hand held "shutter". I think using the same film to build basic experience on is a good way to learn the little tricks of your equipment and your site. Swapping films all the time means changing camera settings and such to suit. Once you have the basics and can get constant results for a given type and speed of film then you could try different films and speeds to achieve shorter or longer exposures.
Film Type: Kodak Gold ISO 200
Subjects: Star trails centered on Polaris and 0'DEC
Lens Setting: 35mm f3.5
Exposures: 14 returned 9 over exposed
Exposure Times: 5, 10, 15 minutes per subject
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Having composed pictures of constellations for nearly 2 months (see above) i decided a change was needed. Star trails!
Star trails are easy even for a complete muppet, open the apeture up wide, put your hat over the lens, press the shutter
release, take away your hat fro 15 mins or so then replace your hat and release the shutter release cable. You can try,
as i did closing the apeture down to f8 or more and leaving the shutter open for an hour or more or even longer. In a
dark site i have left a star trail picture running for over 4 hours with the apeture stopped down as far as the camera
will allow.
This roll of film was very successfull with all images being returned 14 good ones and 9 overexposed ones. Use this link to open a popup window with 3 of the good ones. These are not the best from this roll of film but they are pretty good.