Leitz yellow filter

[Blank288]

Another question evoked by my newly acquired Summaron 35mm lens. It came with a (middle?) yellow filter, marked only 'Leitz Wetzlar Germany' and the number '1'.
I measured it with a Gossen CdS exposure meter, and came upon an exposure correction factor of hardly 1/2 stop. This seems too little to me; most yellow filters I know require exposure compensation of one full stop or more. Maybe CdS meters are lowly yellow-sensitive?
Does anyone know this 'number 1' Leitz yellow filter and what is the prescribed exposure compensation?

Thanks!

 

[Jocko]

Eric, I had a similarly marked filter from another manufacturer which also indicated a half stop difference via TTL metering. This seems to be others' experience too, judging from this discussion of your filter: At the least, half a stop seems a good place to start - http://photo.net/bboard/q-and-a-fetch-msg?msg_id=009Lq0

Cheers, Ian

 

[Blank288]

Ian, thanks for the link. In that case my readings actually are correct. I'll start trying it at 1/2 stop extra.
Anyhow: I've read somewhere that compensating less (and thus underexposing) amplifies the filter effect. It's worth some experiments.

 

[john neal]

I may be wrong here - shoot me down if I am, but the filter factor printed on the side normally shows what compensation to make - a 2 = twice exposure indicated (or +1 stop), 4 = 2 stops etc. This would suggest that a 1 = indicated exposure, no?

I have some pale, mid and dark yellow filters from days of yore where the pale and mid say, use indicated exposure, but the dark one says +1 stop, and the orange, +2 stops.

I guess a trial is in order 🙂

 

[Rob-F]

The amount of light a filter passes depends only partly on the filter. It also depends on the color of the light passing through it. Filters pass freely their own color, and block strongly the complementary color. If you measured it under a yellow tungsten light, the filter factor will appear lower. Against a clear blue sky, it will appear greater. Against a gray card illuminated diredtly by the sun, you will get yet another result. I agree that the Leitz #1 is a bit of a lightweight. I just checked mine against a gray sky with my Gossen Luna-Pro and got differential readings of around 0.8 to 0.9 stop. Interestingly, my Kodak K3, a heavy-duty cloud filter (Wratten #9), read about the same. And they look about the same, too. If this proves anything, it is that reading filter factors with a meter has limitations!

So yes, do try under practical photography situations, with a variety of subjects. And when in doubt, bracket the exposure!

 

[Stu W]

I too am confused by filter factors. I have Leitz yellow filters marked with a factor of "0"? I also did the "through a meter" test and found that a medium yellow or green had no effect on the metering? So far, I've been overexposing by 1 stop with the yellow and 2 with the green and have had good results. I wish someone could set me straight on this filter factor thing. Stu

 

[Chris101]

Metering through filters is misleading, as you need to take the spectrum of the light and the spectral sensitivity of the sensing element into account. The only good way to determine a filter factor is to try it out in photos.

 

[Stoneaxe]

As Rob-F says, the effect of the filter depends on the colour of light you are in. I use no correction under sunny warm light and open up 1 stop in the shade where the light is bluer. Mine is also the Leitz yellow marked with a 1.

 

[Blank288]

I'm going to give it a try with these suggestions. Thanks for the input!