star trails on medium format - any ideas?

[adrastea]

Due to my lack of "real" equipment I tried to take some star trails over the city (Edinburgh, I live across the river in Fife) on my medium format yashica TLR. The film I used was Ilford Delta 100 because I figured (maybe this was a mistake) that a slow film would stop the star trails being flooded out by lights from the city and the reflections on the water. I figured I'd take an experimental roll, get them developed and maybe come back a different time if it went well. Using the cable release I had exposures of 5mins, 10mins, 30 mins and 60 mins (it was a long night!). The focusing did look pin-sharp through the viewfinder but when I got the roll back (I don't have my a darkroom unfortunately and since everything is digital now there seems no point), EVERYTHING was blank. Every single photo. She (Jessops girl) accused me of handing in an unexposed film... which is pretty impossible with 120 anyway. I definitely didn't have the lens caps on because I had to put the torch on to find where I'd put them, thus ruining my night vision. The negatives weren't burnt out or anything, they were just... blank. I can't understand it - actually it's been about three weeks since I got the films back and I'm still scratching my head. I'm thinking either I should have used a faster film (but an exposure of an hour pointing towards a capital city...? surely that wouldn't have made any major difference) OR there's something wrong with the camera. I know it's a bit random, but I wondered if anyone had any ideas? I'm not holding my breath, but it's worth a shot...

[barkis]

I don't know the camera, but it seems to me that the the images have not registered on the film because of the Low ASA. 100 is pretty slow for stars. 1600 ASA would have probably given you something, including light pollution too unfortunately.

The camera lens possibly contributed to the poor result also. What size lens, and focal length please.?

If you could get hold of an Olympus OM camera cheap on ebay, and a couple of lenses for it. Load it with 400 ASA + Film, and I guarantee you will get some star trails. And, if you go on to make yourself a barn door mount, you can get some wonderful results of the Milky Way star fields. It is a very rewarding pastime, and not everyone is hooked on digital, lots of people still operat Film format cameras.

I still have my old SLR stuff.

Ron.

[jcm]

I agree with what Ron said.

When I used to use film for star fields it was 800 or so ISO. Also I used the lens at nearly full open ( ie one stop lower than wide open).You would certainly get something in 20 or 30 secs. With a 200mm lens working at F4 and 800 ISO film I would expose for about 2 mins. With a shorter focal length lens you would need less time. I mainly used slide film because the development was always done the same way and they would return the film unmounted and uncut. I then used an enlarger and processed the slides on the photographic paper.

John

[Kaptain Klevtsov]

What was the aperture set to? From memory they didn't do very fast lenses for TLRs, so you might find that you'll do better with a non-electric SLR. The Zenit ones are dirt cheap and the lenses are surprisingly good.

Kaptain Klevtsov

[adrastea]

actually I just had a thorough look at the camera and there seems to be a mechanical fault with the shutter, which answers my question. probably should have checked before posting :? :? :? but hey, at least I know more about suitable film speeds.

one question - how can I get some decent (long) star trails over Edinburgh without the film getting swamped by light from the city? from where I generally take photos, the light pollution really isn't that bad, and some parts of the city can actually look quite dark. but I know it will still be a problem. The only thing I can think of is putting a black card over the bottom of the lens to screen out the city for most of the exposure, then remove it for the last few minutes. would that work, or would the background still be flooded with light?

[Andrew*]

you're going to get light pollution whether the actual city's in the shot or not. You might get an improvement if you used a 2" CLS filter in front of the lens. The black card idea sounds okay, but you're going to get a harsh line across the shot like that...

I wouldn't go too high on the ISO or you will get nasty grainy images. I would stick to ISO 400 or even 200. You will still get decent exposure for star trails, and limit the LP too. When you're imaging DSOs tracked, then you need as much light as you can get and using a higher ISO is preferable.

Hope you sort out your dodgy shutter.

Andrew