leethecam Offline Upload & Sell: Off
|
Here's a peculiar thing...
I'm using the new Bowens White Beauty Dish. Similar in profile to perhaps the Profoto, with a deepish bowl and a tightening curve towards the edges, (a bit like a big salad bowl rather than the gentler curves of some 3rd party dishes.)
I've been calibrating my light meters and getting consistent and accurate results now - all at a range of powers and f-stops etc.
Strange thing is when I use an ND sheet on the dish. My ND is cut to cover the front of the dish, rather than go around just the tube and is a 3 stop reduction.
Ideally I like to think I'm getting the same characteristics of the dish - but just 3 stops less lower, (so I can run the flash harder at shallow DoF or get those crazy F1.2's...)
However when I meter the light with it's new ND sheet on and do a test shot, the exposure of the shot is about 1/2 stop or 2/3 underexposed. Essentially the new metered reading and the subsequent shot with the camera do not now agree. Meter readings and camera shots did without the ND.
Checked with two meters and get the same results so it's not a strange fault.
I should clarify that I am doing a fresh meter reading with and without ND and of course resetting the camera appropriately each time according to those readings.
I can only assume the ND is causing an issue with how the light behaves from the dish - although as I'm metering at the same point as the 12.5% card I'm using as an exposure guide it seems strange.
When I pop the diffuser cap on I get no issues.
It is weird that without an ND there is an agreement between meter and camera, but with ND on the dish there is a disagreement...!
|