Novice question

[Thompsonr]

I'm new to large format photography. I'm interested in long exposures but not sure where to start.
I saw the f4 rule (1/ISOx day) posted in this forum but don't understand why this doesn't take the amount of light into account?
I saw the beautiful night shoots by Tom Paiva in the View Camera Journal and regretably was unable to attend his the Louiseville conference where he presented.
My Sekonic L508 measures theoretically up to 30mins but can't get it to actually measure this amount of exposure.
Does someone have a few basic pointers please.

[Ron Marshall]

The site at this link has lots of info about determining exposure for night photos.

Pay particular attention to reciprocity effects. Fuji Acros is the best film for very long exposures, since it has the best reciprocity characteristics.

http://www.thenocturnes.com/resources.html

[steve simmons]

Pick a film and then go on the mfg's web site to check the reciprocity failure rate. Generally, but not always, rf starts at about 1 second. They used to put info sheets in the film boxes but not any more.

steve simmons

[Uusilehto]

Consider picking up an older Quantum Calcu-Light XP exposure meter. It can accurately measure (Reflective and incident metering) down to about -7EV (ISO 100)

[Daniel Geiger]

You may also just jump in. Try a few sheets and see what's happening. Did that a while ago with some city glow silhuetting some trees in mist. Shot three sheets at 1, 5 and 20 minutes, two stops down from open. The 20 minute shot actually turned quite nicely (IMHO). I've found with several new approaches, that the quickest way to learing is to do it.

my 2c

[Thompsonr]

Tks everyone.
The Noctures website is very interesting.
I shot a few sheets of Tmax100 in my lighted back garden this evening and will develop them Saturday. Fingeres crossed although based on Daniels input, I may have underexposed. I can see that the reciprocity curve gets very steep, very fast.
Thanks for all your inputs, I will follow your recommendations.
Ralph

[CG]

Hi,

"... I shot a few sheets of Tmax100 ... "

Hope you have your results processed by now.

"... I may have underexposed. I can see that the reciprocity curve gets very steep, very fast ..."

You may be pleasantly surprised. Tmax is a very modern film with quite moderate need for recprocity compensation. Not quite as amazing as Acros, but TMax loses a only a manageable amount of speed at long exposure times.

Best,

C