ISO in relation to old film speeds

I may need some persuading here, but I am of the old mindset that ISO 125 was fine and 400 was grainy and fast, when using (usually Ilford) BW film.
How does this relate to ISO settings now? The digital numbers are so big that they seem wrong.
In today's digital world what do the old film speeds equal?

hum good Q

bet some boffin on here will come up with a quercky awnser but it wont be me

Your the King when it comes to quercky awnsers stu

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https://www.techwalla.com/articles/what-is-the-difference-between-asa-iso

As digital technology continues to improve any correlation will change. With my old K10 I tried to keep to 400 ISO and below as going to 800 or 1600 would introduce noticeable noise. My K1 now produces noiseless pictures at 1600.

An exposure meter will tell us that the ASA/ISO figures are just as applicable to film as to digital in terms of setting the exposure. So we could use a Weston Master meter (selenium cell) to gauge exposure for a new K-1.

As regards grain/noise there are two totally different worlds. In black and white, ISO 400 film is grainy. In colour, likewise. On digital we can now expect to be able to use our cameras up to ISO 1600 with no problem, and I frequently and happily go up to ISO 3200.

However, given that my favourite black and white film was Kodak Tri-X (ISO 400) developed in FX-39, clearly I like sharp, crisp grain structure in an image. So when making monochrome images I sometimes Add Noise in Photoshop.

Also let's remember that over time the grain in films was reduced as things progressed, particularly with colour negative. I remember using ISO 800 Kodak Portra that was very smooth, nothing at all like the usual associations with 'high speed film' that were common at the time.

So even film types had the variations that we now think of that exist between different camera sensors.

The big liberation that our latest DSLR models give us is to reduce the worry about high ISO if it's needed ..... We have a far higher range of options for correct exposure control when speed or aperture are more important. Did many people use the TAv or Sv modes on their film SLRs ...?

Hello Mr Processor, I would like the first six negatives pushed two stops, and rest pulled one stop please.

Most high street processors couldn't cope with push processing at all.

As to TAv and Sv, mine were either fully manual or aperture only. The term Av came in later!

. Ah, push & pull processing..... The forerunners of Auto-ISO !

That's right - and same with colour (ie white) balance so it was all pulled back to 18% grey level or whatever!

I like to please I see John as bought my son into it lol. Asa

I am not sure even a pro lab would cope with my request !! Cut the film while it was still in the dark bag ?

Ever realised half way through exposing a film you forgot to set the ISO?