[LargeFormat] Newbie alert - ? on using a strobe

[Delano Mireles]

Hi all,

a friend of mine has lent me his old B&J 4x5 w/Rodenstock 135mm.  I 
attempted to take some shots for the first time last night and was not 
successful at all.  Now, the lens does have something that trips the 
strobe.  So, using my L-358 I took a corded flash reading of 1/125 @ 
f22 with my Bee.  I then set the lens according to this reading then 
proceeded to take a couple of shots.

After developing the negs I turned on the lights to be disappointed by 
seeing a blank neg.  It looked like there was nothing on the negs at 
all!  After this happened on 4 frames I went back and took a regular 
incident reading and shot two more frames 8 sec. @ f22 and had success.

I'm just assuming that the first run of negs were severely underexposed 
and that's the reason why the negs came out clear.

There is something I am obviously missing here and I come to you for 
any ideas or suggestions as to what could be the case here.  The lens 
does have a "tab" that can either be set to "M" or "X".  I have no idea 
what these are and how they factor in.  I did try both setting and to 
no avail...

Thanks for any insight you could offer this newbie!

Delano