Richard Ashrowan

Thanks Chris - a perfect reply with a useful math tool! Much appreciated.

I have a Vario Switar POE on a Bolex. The film speed dial on the lens only goes to 200 ASA, but I am shooting using Kodak 7222 daylight stock at 250 ASA. Does anyone know what kind of exposure compensation I might need to apply to get a correct exposure using the over-fast 7222 film for this lens?

I am planning on shooting in snow and ice using a Bolex, using b/w 7222 (200) stock. My last attempts at shooting in snow were not great - my lens goes to f22 and even with the variable shutter closed down (for an extra stop), some of my material was over-exposed. I was metering with a Bolex lightmeter (which has built in compensation for the reflex system). Stupidly, I didn't have any filters and sometimes found I simply couldn't stop down enough.

So, time for some ND filters.... I must admit I am relatively new to film cinematography and know next to nothing about filters. I should like to use the Bolex behind the lens filter holder rather than on the lens filters. Can anyone recommend what ND filters I might need to get and where I might source them? Any ideas where I might buy some different ND gelatin filters in the UK (I assume I can cut them out for the filter holder)?

Can anyone explain how much the different ND ratings should actually affect the exposure settings used?

Any other tips for shooting and metering in such conditions (reflected bright light on ice, snow, extreme cold) would be most appreciated.

I'm shooting with a Vario Switar 100 POE with a Bolex RX5, but the built in exposure meter of the lens is dead (tried new batteries, but the contact seems to have been badly corroded away, so no joy), which means I'm working from a manual exposure meter. I wondered if any exposure compensation might be required when closely zoomed in? I would assume being zoomed in reduces the light entering the lens, so would have to open it up a little? Does anyone have any experience of this?

Sadly, I'm not right now in a position to develop any test footage.

I'm using a bolex lightmeter (which has built in compensation for the reflex viewfinder), taking incident lightreadings outdoors, mainly shooting high contrast light/dark subjects. Shooting on double-x 7222 b/w neg stock.

Many thanks,

Richard