Courtlux
I’ve already asked this on the Leica forum. I’ll give it a go here too:
?
Does rotation affect sharpness? ADOX advises against rotating the CMS20 II. For 120 film, dosing the ADOTECH during tilt development is impractical, especially if you want to switch between 135 and 120. With rotation, this isn’t a problem. Yesterday I slowly rolled a 120 film by hand. The images are slightly blurry and not as sharp as usual with the CMS20 II. I’m not sure whether the images are very slightly blurred (it was cloudy and the camera was on the ground) or whether the rotation actually has a significant effect on sharpness. ADOX advises against rotation without giving any further explanation.
1st image with rotation: cloudy 2nd image: clear sky Planar tilt
?
Urnes
It’s hard to say, as ‘rolling slowly by hand’ isn’t the same as machine rotation. If you develop using a Jobo CPE, the rotation is significantly faster and more consistent than when done ‘by hand’. You’ll run into problems with the machine if you use the slower speed setting (1).
€
Regards, Sven.
Courtlux
Otherwise, I conduct the development of Fomapan in Rodinal using the same method (hand-rolling) and don’t experience any loss of sharpness. My question is whether this is different with the CMS20II and why rotation is not recommended.
MirkoBoeddecker
I think both images are slightly blurred, one more so than the other.
The CMS is much more sharp.
Any theoretical ‘loss of sharpness’ due to rotation is so minimal that it is only visible in a direct comparison of line drawings when viewed with very high enlargements.
You can’t see it in the image, and certainly not on a computer monitor.
The real reason why we advise against rotation with the CMS 20 is the significant loss of sensitivity of 1/3 stop.
This is negligible with a 400 ASA or colour film, but significant with the CMS 20.
€
Best regards,
€
Mirko
Courtlux
Thank you!
Gast
