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Traffic Trails Long exposures

X

x700_dave

Hi all,

Im using a Minolta X700 and id like to do some traffic trails, and also some shots on long exposures (of water etc). How do i calculate in order to get the correct exposure? My in-built light meter only goes up to 2 seconds i think.

Thanks

Dave
 
S

Scootsludes

It would be better if you used a handheld meter, but if you don't have one, and not willing to get one. then you need to figure out an exposure value. for ex&le if you're shooting at night, and you have your lens wide open at F2.8, and shutter 1/8. F4 would be 1/4, 5.6 would 1/2, and F8 would be 1sec and so on and so on. Bracket a lot, as film acts funny when you do long exposure, I forget what this term is called, bracket with different shutter speeds or aperture, not EV.

vince
 
X

x700_dave

Thanks Vince, ill give it a go. I wasnt sure how to work it out - i didnt realise calculating it was that simple!

Ill bracket a lot


Dave
 
D

ddai

Dave,

If that's the case, you need a little cheat on the camera. While the scene is not a complete darkness (with 1 or 2 EV luminance is OK), you can manipulate by increasing the film's ISO/ASA setting to let the camera do the metering. For instance, when you have ASA100 film in the cartridge, you can manually overwrite the ISO/ASA setting to 800 (3 stops) or 1600 (4 stops) to get the exposure then change back the ISO to the original and manual expose by 2 empowered by the stop value in exposure time (with same aperture of course), which means if you get 1 second in ASA 800 setting, you need 8 seconds, plus compensation, for your ASA100 film exposure.

For any shutter time longer than 1 second, I believe, you need exposure compensation due to the failure of reciprocity. Usually it differs from film to film and from b&w to color film. The general rule is: +1/2 stop for 1 second, +1 stop for 10 seconds, +1.5 stops for 100 seconds; and the compensation for b&w should be doubled. Pls refer to the Kodak website for a search of the subject.

Last but not least, for safety you need bracketing the exposures for important shots. I hope that can be of help.

Rgds, David
 
S

Siimt

Hei,

Just one question I had this morning.

My Maxxum 7 can only suggest exposures down to 30 seconds. If I don't have a manual meter can I somehow guess on longer exposures? For ex&le if I get 30 second on F2.8 then can I assume that @ F4 it's 60 seconds (plus then some for reciprocity failure)?

Of course then I would need a remote control to do this long exposure
Just wondering anyway.

Cheers,

Siim
 
X

x700_dave

Thanks for all the help guys, I'll not pretend I understand it just yet, but I'll read it all through again later on and try to make sence of it


Siim - i think the above posts answer your question?

Thanks again!

Dave
 
U

Uksnapper

see
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for some simple explinations. Reciprocity failure can result in crossed curves which simply put means that some layers of dyes in the film will be affected diferently resulting in the film having a colour cast.. I would suggest that night time exposures on subjects at infinity can be shot wide open as depth of fiels is not an issue this will lead to shorter exposures though . a 100asa film will need an exposure of about 1/30 sec @ f2.8 = 1 sec @ f16. Its worth bracketing to get longer streaks using 2,4, 8 sec etc exposures on neg film . I would simply shoot a roll of as a trial, get a minilab to print them up then go back , reshoot and refine the images.
 
X

x700_dave

Thanks guys, very very much. Ill try and have a crack at it over the weekend!

Ill post any good results on my website (
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) and on here if i get a chance!

Thanks again

Dave
 
G

gordon

New Member
Hi, I am new to the forum am trying to expand my shots to more than just family pics.I hope some of you can give me some advice on night time shots. I am currently in a hotel overlooking the Chrysler Building in New York which looks fantastic at night but am failing to get a good shot. I have an S414 and when everything is set to auto the lights on the building come out too bright and blurry. There is no camera shake so it must be down to the exposures. Any help is appreciated. Gordon
 
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