Bolex H16

[David Avila]

Hi everybody,

 

I have a project with a Bolex H16 and Nikor lenses (C-Mount) very soon and I need an assistant. I´m in London.

 

This is an unpaid position, since the film is not for profit and all crew are working unpaid to make the film happen and tell the story.

 

PS: I have a little doubt because of Nikor lenses and C-Mount adaptor I think I´m going to lost 1/3 of light, am I right?

 

Thanks in advance for any suggestion.

[David Avila]

In another site I found that prism light loss is about 2/3... who is right?

[Chris Millar]

If you have a reflex Bolex you will lose a 1/3 of a stop in light - keep in mind this is whatever lens you put on there.

 

The RX lenses do not have adjusted aperture scales.

 

The best advice is to simply forget about any compensation and just use the camera with any lens as you would any other

 

... except... (can't help myself) - be aware that lenses at and certainly below 25mm without 'RX' on them will be not be optically ideal (sharpest) at the open end of the scale.

[Richard Tuohy]

A reflex bolex requires a correction of 2/3rds of a stop. Yes, there is approximately a 1/3rd stop loss of light due to the reflex prism. There is also, however, about a 1/3rd stop difference between the 180 degree shutter opening that your light meter will most likely be assuming and the 130 degree shutter opening of the rx bolex. So you need to factor 2/3rds of a stop for an RX bolex. On top of that, your nikon lens adaptor may itself have a light loss factor to take into account. I can't tell you about that.

cheers,

richard

[Chris Millar]

For the shutter difference:

 

Log2(130/180)= -0.469

 

Closer to half a stop than a third.

 

But you'll find differences of opinion on the actual shutter angle anyway ;)

Edited July 30, 2012 by Chris Millar

[Joel Pierre]

Diaphragm setting of the Bolex H16 Reflex