filter factors

[Ian_the_framer]

Not sure if this is the right place to post this

I recently bought 3 ND filters, ND2 ND4 and ND8 (I,2 and 3 stops) having checked them on my camera and with a hand held meter I note they actually measure; ND2= ½ stop. ND4= 1 1/3 stop and ND8= 2stops is this usual for the stated factors to be so vague? Obviously not a problem with TTL metering, but a concern when using a manual MF camera and hand-held meter.

[beejaybee]

having checked them on my camera and with a hand held meter I note they actually measure; ND2= ½ stop. ND4= 1 1/3 stop and ND8= 2stops

Sounds like you're getting some reflection from the back of the filter....

[taxor]

Are you actually measuring through the densest part of the filter?

[Ian_the_framer]

Yes I was fairly careful to measure the centre and trying to avoid light from the sides with the Gossen meter The camera was an Olympus OM4Ti and the filter was attached

[Gordon_McGeachie]

But surely ND filters are the same density all over,its only graduated filters that vary in density

[taxor]

But surely ND filters are the same density all over,its only graduated filters that vary in density

Yes, you're right! I've re-read the question. Got it into my head that he was talking about ND Grads. Duh!