Visit my new blog

I´ve decided to split my blog in two. I will continue to post DIY projects and musings here, but (serious) pictures, taken on film of course, will be posted in my new blog "Silver Halides"

I now consider Caffenol to be a developer like any else. As such the new blog will focus more on the pictures, rather than the process.

Monday, 15 October 2012

Focusing off

After swapping to the Ektar I collimated the lens yet again.

Now with Kodak Ektar 127/f4.7 in Synchro-Compur shutter

The shutters are not the same, and even if they were (the same thickness for instance), the two lenses would have different film to flange distances anyhow. But it would seem I got it wrong. Didn´t show up too distinctly on 400 speed films as the aperture tended to be f8 or smaller. But on 100 ASA film and low autumn light and big apertures there was a visible back focus on all images.

Another go then. Ended up moving the lens forward just over 1mm.

And performed the following test.

Can you tell where I focused?

The back of the Photography Encyclopedia is in plane with the bottommost Asterix volume, The Lord of the Rings with the 5th volume, the outer two volume 10 and 13 respectively.

More background data:
The volumes are tiered 10mm in from the one below, 130mm in total bottom to top.

Shot a f4.7, distance 91cm from front of lens, 107cm from film plane (approx). DoF approx 58.3mm, 28.4mm in front of subject distance, 29,9mm behind. Which should mean that the same number of volumes are in focus above and below the one IN focus.

A bit dark (my two kids got bored of holding the dark background up - made do with the one shot), but can you guess which Asterix volume I focused on, and did I get it right?