Cv12 ?

[jackal]

been using one for a year but ive just got one that has a filter holder.....couple of questions:


1. what's this huge filter holder ? why is it so big in diamater ?

2. is there anyway to code this thing to help out on the vignetting and cyan drift (n.b. I dont use IR filters and don't want to, just want to help the lens under normal use)



help appreciated

THANKS
R

[cme4brain]

Originally Posted by jackal

been using one for a year but ive just got one that has a filter holder.....couple of questions:


1. what's this huge filter holder ? why is it so big in diamater ?

2. is there anyway to code this thing to help out on the vignetting and cyan drift (n.b. I dont use IR filters and don't want to, just want to help the lens under normal use)



help appreciated

THANKS
R

Hello there! The filter for the CV 12mm lens is so large (77mm) because the angle of view of the lens is huge! You must use a large filter to prevent the edges of the filter from vignetting the corners. You can code the lens as a 16mm WATE which will apply an in-camera correction to brightness vignetting and cyan drift, however if you don't use an IR filter then the corners of the picture will be magenta (the compensation for an IR filter). I suggest not coding the lens at all if you aren't using the IR filter.

[jackal]

ok thanks

but what about if you dont choose IR in the menu
you just choose detect lens

[Mauribix]

There is a nice smaller filter fitting E55 filters diameter, you have to contact John Milich who produces it for 150$, it's made for the lens to be used with the M8, dunno if it doesn't vignette on film.
The best way is not to code at all the lens.
Then you may leave the lens without the UV/IR filter and correct the colour magenta cast with Jamie's profiles in C1, or use the UV/IR filter and make some profiles with Cornerfix.
Finally, you could use the John filter holder, leave the lens uncoded and put a B+W IR blocking filter n°489, in this case you should avoid the cyan corner issue and have the correction for the magenta cast; you'd only loose 1/3stop...

I hope this help, and I hope not to make mistakes regarding the 489filter.

Some may confirm what i wrote...