ISO query...

I wasn't quite sure where to put this post - but here goes. I decided use one of my film slrs again. Loaded it with iso400 film, and seemed to get stupidly high shutter speed readings from the meter. I then set my DL2 to iso 400 and pointed it at exactly the same subject. I got a completely different reading from what I know is a reliable meter. so, is it daft to try and compare the iso 400 of film to digital iso400? ie is ISO a universally graded scale or is it arbitrary (might the meter on the film be ok)?

I hope that makes sense

ISO is a standard.
However, many DSLRs vary fractionally from their advertised ISO (by a third of a stop commonly, so ISO100 is actually ISO160).

EDIT:
Your film camera doesn't happen to be an ME Super / MEF does it?? If so, try wiggling the ISO/eV compensation dial - they have a tendency to get dirt into the variable resistor that's used and they massively underexpose (which sounds like your symptoms).

Matt

Well, it should be, as ISO stands for International Standards Organisation (at least that would make sense, although Wikipedia says that it comes from the Greek word Isos, meaning equal). However, different cameras come up with different meter readings (although they shouldn't be wildly different), and different lenses may show variations too. Focusing distance comes into it to, as the effective aperture changes at different focusing distances.

So, were you using the same lens, focused at the same distance, on both cameras?

If so, then one of the meters would appear to be wrong. If different lenses were used, then that may be responsible.

If it was an old film camera, which should have had 1.35v button cells installed but now has 1.5v ones, that may cause a variation too.

Just clutching at straws here.

Hope that helps,
Dan

Thanks for the super quick replies It looks like my (old) ricoh kr-10 may have a problem (apologies its not a pentax ). I just mounted it on a tripod, pointing at a wall. focussed the lens at f2.8 and got 1/125 on the meter. Exactly the same lens on my dl2 at f2.8 gave me 1/250.
good point about the batteries - I'll check that, although for the moment leaving the ev on the kr-10 to -1 would sort it would it not?

Just as a quick check - you have set the correct film speed? It's not set to 200?

Just a thought (we've all done it! ).

Dan

So much for Wikipedia.

Everybody of a certain age knows that ISO was originally ASA (American Standards Association). As the International Standards Organisation spread its wings it adopted ASA into its own ISO standard, and when it did, ASA and the alternative sensitivity measurement, DIN, were dropped. DIN of course stands for Deutsches Institut für Normung, or German Standards Institute.

Isos, indeed! Snort.

G

I've got a KR5 which tends to underexpose in low light by anything up to 2 stops, deppending on just how low the light is.

thanks for all the input guys. daniel - the film dial is set to 400, but after what mongoose said I may jsut live with it by adjusting the ev to suit.