problem with LF exposure

I'm new to LF photography and have as yet been able to produce a properly exposed negative. I am shooting a new Tachihara 4x5 field camera with a Schneider Symmar S 135mm 5.6 lens. My problem is that my negatives are underexposed by at least 2-4 stops. I am using the light meter in my Nikon FG to determine exposure. Exposures are fine using 35mm film with this camera. I'm shooting Ilford FP4 125 film. The bellows extension is about 5 1/4" (shooting landscapes), and I'm using no filters. Today I shot 4 images, on a relatively sunny day, at the following exposures: 0 (= f/16 at f1/125), +1 stop, +2 stops, and +3 stops. The best shot was +3 (=f/16 at 1/15) and it was still underexposed by a stop! What am I doing wrong? Could the shutter be off? Or the apperature? Is it more likely something mechanical or am I missing the boat somewhere? My development is ok as my 35mm film comes out fine. Any suggestion would be greatly appreciated! If I have no success, look here for a good price on some 4x5

equipment!

Apart from a possible shutter problem,

there is another problem I can think of: are you

sure you are loading your film on the correct side ?

otherwise you would be shooting through the base of

the film, which would cause a significant light loss.

If you were shooting color the color cast would be obvious

but in B&W it might be difficult to notice.

Gawd, I spent nearly three months loading all my film backwards when I got my camera. It drove me absolutely nuts trying to figure out why my film was so underexposed - never occured to me the film notches are supposed to be on the top right HORIZONTAL edge; I was loading it with the notch on the "top" right vertical edge - which is backwards. Finally I took my film in the holders to my father, experienced in sheet film from press camera days, and he had a long hearty laugh at my expense. I feel better somebody else had this problem too!!

When I rented a Toyo 4x5 during one of their promos while I was waiting for my first camera to arrive in the mail I used my 35mm to obtain exposure and wasted half the polaroids they gave me. I know that spotmeters are expensive but if you plan on shooting a lot of sheet film and use the zone system, well... its definitely worth the expense. And it makes you look like a pro, too! 'cause isn't that what using a view is all about? Heck sometimes I just set the thing up just to impress people...not.

See "Darkroom Innovations" for non-spotmetering procedures. They really slam us spotmeter users.