I've read plenty about the importance of acheiving below a 5.6 f-stop on my prime lenses in order to avoid seeing the groundglass. But no one seems to mention the actual Iris on the adapter itself. It is numbered from 1 (widest open) to 7 (most closed).

So my question is this:

Should I feel free to use this just as freely as an ND filter outdoors to maintain my low f-stop? In theory it's always nice to keep as little glass in front of my lens as possible.

So is there any downside to using the adapter's Iris ever?

John,

The back iris was incorporated to help avoid the use of NDs along with allowing for the taking lens to be as wide open as possible.

In a very few cases we've heard that stopped all the way down the rear iris can introduce some anomolies but for the overwhelming majority of cases it will cause no problems.

As far as the taking lens in concerned, in practice it's more like T4 that you have to say below.

So, except for bright outdoor shoots, you can shoot with the Mini35 with just the rear iris without having to worry about NDs.

mizell

Thanks for your response. That's just what I wanted to hear.