Whats the focal length of my lens?

[KPT]

Sorry for such a newbie question. My lens states 13.5cm, what would that be in mm? Thanks!!

[snallan]

Hi KPT, welcome to APUG. That is a 135mm lens.

[Prarry]

There are ten "mm" in a "cm". mm=millimetre (thousandths of a metre), cm=centimetre (hundredths of a metre) so its 135

[bdial]

To convert all you need to do is move the decimal.

1 CM = 10 MM
and 25.54 MM = 1 inch

[KPT]

Hi KPT, welcome to APUG. That is a 135mm lens.

Snallan, thank you for the welcome and the information!

[KPT]

Thank to everyone for your quick responces!! I just bought a 1940 Speed graphic with a Carl Zeiss 13.5 4;5 lens and was confused when i seen the (cm) instead of (mm). this is my first time with a classic large format camera. Thanks again everyone!!!!

[Frank Szabo]

The nice thing about the metric system is everything is based on multiples or divisions of 10.

The bad thing is we have very little in the USA that has the proper measuring scales to deal with metrics.

[Ole]

A lack of proper measuring scales in the USA is not a problem with the metric system, but with...

[Steve Smith]

and 25.54 MM = 1 inch

Too many fives!

1" = 25.4mm.



Steve.

[Dan Fromm]

A lack of proper measuring scales in the USA is not a problem with the metric system, but with...

Ole, the sad thing is that both systems are taught in our schools.

Cheers,

Dan