Zeiss 25 uv ir

[dseelig]

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Hi I was wondering how people are doing with this lens if they have it 6 bit coded with eiteher the 35 or 28 mounts. Also which ir filter is being used with the new firmware 1.10.2 Thnaks David

[DaveSee]

Hiya,

I've been using this lens with great results, uncoded and from f/w 1.06 through 1.102 with the B+W 486, Heliopan and most recently Leica IR cut filters. Yes, I have found evidence of cyan at certain points, regardless the filter, when a nearer white surface is at an oblique angle to the sensor and near the corner of a shot: so, it(cyan drift) is not always evident.

 

As to frame in the VF, I always use the VF border due to the 0.68 magnification and ~90% coverage with an expectation to crop, if needed.

 

Here's a ZM 25 shot(B+W 486, f/w 1.09), setting focus at the lens not through the VF/RF patch, for example:

 

rgds,

Dave

 

PS/EDIT: this attached is straight from DNG through David Coffin's "dcraw" with JHolmes' DCam3 ICC profiles and a Bash shell script on Linux, FYI.

[LJL]

Hi I was wondering how people are doing with this lens if they have it 6 bit coded with eiteher the 35 or 28 mounts. Also which ir filter is being used with the new firmware 1.10.2 Thnaks David

 

David,

Will know in a few more days for sure. Still have not received a new lens mount from Zeiss for the 25/2.8 It ships with a mount that brings up the 28/90 framelines. They have a mount available that brings up the 24/35 framelines. They offer a replacement procedure for 60 euros plus shipping to Zeiss in Gernany. They also sell just the lens mount for 26 euros, plus new screws and shipping. (They recommend only qualified Zeiss repair techs to replace it, as you would expect, but there are only four screws and things line up pretty cleanly right from the start....German precision , so make your own call on that.)

 

Once I have the new lens mount, I will code it as a Leica 24/2.8. The camera should then read it as a 24 and make the corrections for that equivalent Leica lens, which should remove that little extra bit of cyan contamination still seen when coding the lens as a Leica 28/2.8 on its present 28/90 lens mount. I will not know for sure until I actually install and code the replacement mount. I thought several others were trying the same thing, so they may have some results to report. I am also going to be using a Leica 46mm UV/IR cut filter on the ZM 25/2.8, but will test with a B+W 486 also.

 

LJ