Close up filter on GF 670 / Bessa III???!!!

[jamin-b]

On a whim I purchased a +0.5 Rodenstock 40.5 close up filter for my GF670, thinking that somehow I can use it like a Rolleinar on a Rolleiflex. For $0.99 + shipping this is not a big investment (AS OPPOSED TO BUYING THE WIDE VERSION OF THE CAMERA 🙂 ) , but will likely involve wasting some film, as obviously I will need to guess distance.

Has anyone tried anything like this?!!!

One of things that does bug me about the GF670 is that I always want to get a little close in for minimal focus disance. This used to bug me with the Rolleflex until I discovered the wonders of the Rolleinars...😀

 

[sevo]

If you can read German (or live with a googleish translation), there is a pretty cool online calculator at http://www.erik-krause.de/schaerfe.htm which can create a distance translation table for any lens and any close up filter.

In general, 0.5dpt is for cameras with a near limit of 1.5-2m. As the Bessa III IIRC has a close-up limit of 0.7m (or was it 1m ?) and 0.5dpt shift the far limit of your lens to 2m, most of its range will be overlapping the filter-less range - you only gain about 20-30cm to the near. For the Bessa +1dpt would have been appropriate.

 

[jamin-b]

Thanks! Close focus is 0.9 meter on the GF670, so it looks like I will get to 0.6-0.7m. Does that make sense?

 

[sevo]

Thanks! Close focus is 0.9 meter on the GF670, so it looks like I will get to 0.6-0.7m. Does that make sense?

Should be about right. As I said, it is not really worth while bothering with tables for a 25-30% gain. You would really want a dioptre that is identical to or only a little longer than the minimum focus distance, to double the range.