gargamel
Hello,
Does the comment in the catalogue stating that the Efke KB 25 is supposed to have a speed of 25 ASA ‘in reality’ refer to the fact that I am aware of – namely, that other film manufacturers often state their ISO sensitivity as being higher than it actually is for marketing reasons? Or is there a difference between ISO sensitivity and ASA speed?
Best
regards,
gargamel
Gast
Hello
There is no difference between ASA and ISO (or DIN) when it comes to measuring sensitivity; everything is now standardised.
The Efke films are further developments of the old ADOX KB14, 17 and 21. When the DIN standard was changed in the early 1960s (I can’t remember exactly when), the 17DIN film suddenly became a 20DIN film!
Efke then simply converted the DIN designations into ASA values.
After all, all Zone System users are still familiar with this difference today, as they lose precisely this sensitivity level.
All Efkes naturally cry out for Beutler developer. I myself use a modern variant of this, the FX37 according to Crawley, which offers a sensitivity gain of approx. 1 f-stop, though I prepare it myself.
Incidentally, I was quite astonished when I recently looked through the book on the American photographer Diane Arbus, ‘Revelations’, and clearly spotted the words ‘ADOX R17’ on the contact sheets. The explanation given was that D. Arbus specifically wanted this particular rendering of the grey tones.
Greetings from Stuttgart
Rolf
