ISO 50- Please guide me

"Sunny 16" is an exposure guide that you should research. Essentially it will give you the same exposure advice as one used to find inside each box of film.

Matt tells ya right Sarath. Its a good tool to have in memory.

I have a 7100 & the lowest ISO is 100. Now if your 7200 goes to ISO 50 - you have your light meter. I'd use it in matrix mode & let it do the zone system for you. If it only went down to 100, you could still use it, but for each exposure, you'd need either one stop more open aperture or a shutter speed twice as long - either or - not both.

Have some fun. I think I used my 7100 last Nov. I just enjoy film alot more.

Since your D7200 can meter at ISO 50, why not just use the same technique you usually use: set the D7200 on ISO 50 and replicate the exposure on the film camera loaded with ISO or ASA 50 film.

Just either double the exposure time or open up another stop from what you did for 100 ISO.

You have not said what camera you are to use for the 50 ISO film. Many film cameras have built in meters.

Failing that you can get separate exposure meters.

Or google 'sunny side f 16' as suggested earlier.

A 50 ISO film may have less latitude than a 400 ISO film but with care you should still be ok.

1 stop more exposure than you were using with 100 ISO.

film ISO speeds are relative to one another in terms of exposure. Each doubling or halving of the ISO speed requires a 1 stop exposure adjustment. Halving ISO speed requires 1 stop more exposure. Doubling ISO speed requires 1 stop less exposure.