Pushing film to capture the Leonids Meteor Showergreenspun.com : LUSENET : Large format photography : One Thread
With the Leonid Meteor Shower due on 18-19 of November, I'm currently preparing for a small trip to capture the event on film. Astronomical web sites suggest 400ISO film, but this can't be found in LF sizes. Has anyone tried pushing Provia (or any other colour film) when shooting star trails (or better still, meteor showers)? What were the results and recommendations? I will be taking the 35mm gear, but I would love to get the spectacle on the 5x4 format film.
Regards, Graeme Hird
-- Graeme Hird (firstname.lastname@example.org), October 06, 2001
I would suggest color negative film rather than transparencies. More latitude, and I've had good luck with exposures of up to 20-30 minutes.
-- Chad Jarvis (email@example.com), October 06, 2001.
Unfortunately negative film will only get me to 160 ISO, and it can't be pushed the rest of the way. The exposure times are in the laps of the gods, since the meteors only last a couple of seconds at most. Therefore, 400 ISO is the minimum film speed. Latitude is not the problem - lack of usable light is.
-- Graeme Hird (firstname.lastname@example.org), October 06, 2001.
There is (to my knowledge) only one color negative 400 ISO available in 4x5", the Kodak Portra 400NC. I have used it for star trails photos and it works pretty well (really a lot of stars...). You may also want to try black and white negative films (TMAX 400,...), as they have relatively fine grains. Be careful with reciprocity failure though.
Slide film lacks dynamical range, and this _does_ matter, as most of the meteors are faint and will be underexposed on the film. The best the film can handle underexposure (i.e. has a wide dynamical range), the best it will show meteors
-- Pierre Kervella (email@example.com), October 07, 2001.
The star trails that I got on slide film were always disappointing compared to what I got with negative film. I think the slide do not capture enough dynamic range. Since pushing increases contrast, this might make things even worse. I expect photographing a meteor shower to be a rather similar application.
-- Q.-Tuan Luong (firstname.lastname@example.org), October 08, 2001.
Your main problem is just going to be getting enough light onto the film. I'd try the Portra 400NC, it's worked great for me in portrait situations before.
One other thing... assuming that you want to take pictures or stars or any other unresolved (shows up as just a point on the film) source of light, you need to use a lens with the largest possible front element. Don't think that a 90mm/4.5 lens will give you sharper images than a 210/5.6. The 210 has a larger element and can capture more photons thus giving you brighter star images. For extended objects (like the moon), this is exactly backwards and the 4.5 lens will give you a brighter moon picture since it is a stop faster. Most modern telescopes (for research) have huge light collectings areas but small focal ratios.. perhaps f18 or slower.
-- Nathaniel Paust (email@example.com), October 08, 2001.
huh, nathaniel, that's really interesting!
-- edward kang (firstname.lastname@example.org), November 16, 2001.