Leica filter factors

[goldian]

Would anyone be able to help point me to a source of Leica filter factors - just bought a set (yellow 0-3, green, orange, red, blue) but oddly i cannot easily find a set of exposure adjustment factors

Any help much appreciated

Many thanks
Ian

 

[Roger Hicks]

Dear Ian,

Filter factors are not a constant, as they depend on the film sensitivity (some films are much more red sensitive than others) and the subject matter (think of a red filter with a blue sky, or with a red brick building), but good starting points are 1.5x for blue, 2x for medium yellow, 3x for green, 4x for orange, 8x for red.

When in doubt, err on the side of over-exposure.

Cheers,

R.

 

[ChrisLivsey]

You have to admire him for some things:

http://www.kenrockwell.com/leica/filters.htm

Note also the intelligent note: with black-and-white films of the 1960s.
which reflects Roger's comment on variability with the film spectral sensitivity, and the range of factors quoted for eg Red again reflecting Roger's comment.

 

[goldian]

Many thanks all very helpful
Ian

 

[shortstop]

Hi,
I recently purchased two chrome Leitz E39 filters.can anyone tell me if he mounted chrome filters on black summicron?
Chrome filter thread can scratch the thread of the black Summicron?
Can I screw them without scratching the thread?
Thanks
Antonio

 

[Roger Hicks]

Hi,
I recently purchased two chrome Leitz E39 filters.can anyone tell me if he mounted chrome filters on black summicron?
Chrome filter thread can scratch the thread of the black Summicron?
Can I screw them without scratching the thread?
Thanks
Antonio

Dear Antonio,

Why would they scratch any worse than black filters?

Cheers,

R.

 

[ChrisLivsey]

Antonio

A touch, I mean a touch, of Vaseline (trade mark) white soft paraffin or candle wax will lubricate enough to ensure a smooth attachement, unless either thread is damaged. I mean a touch!!

 

[Roger Hicks]

Antonio

A touch, I mean a touch, of Vaseline (trade mark) white soft paraffin or candle wax will lubricate enough to ensure a smooth attachement, unless either thread is damaged. I mean a touch!!

Dear Chris,

Or indeed, going around the thread with a SOFT (ideally 6B) pencil lead.

Cheers,

R.

 

[shortstop]

Dear Chris, Or indeed, going around the thread with a SOFT (ideally 6B) pencil lead. Cheers, R.

I confess that my concern seemed excessive. But I see that the solutions that you suggested (both very cool) show that I was not the only one to ask myself the question. Thank you very much for the suggestions. that of graphite fantastic!
Best
Antonio