Getting Perfect Color From A Full Spectrum NEX-5 Conversion
We have talked several times here about using a Full Spectrum Infrared converted camera to shoot normal color images. Discussions have been around the B+W 486 and the LDP CC1 UV/IR Cut filters (now would be a good time to go back in the blog and read these posts). The B+W 486 filter alone will generate blue skies with a slight green cast and the LDP CC1 filter leaves something lacking. The light response charts for these 2 filters show a slight difference between them.
The B+W 486 is basically a clear filter with a slight gold cast to it while the LDP is turquoise. If you take a close look at the internal Sony UV/IR cut filter (Hot Mirror) you will notice that it is really 2 filters stuck together, one with a slight gold tint and the other aqua!
This got me thinking that with either add on filter on the end of the lens of a Full Spectrum Infrared converted camera system that I was just not getting the proper UV/IR Cut action. I searched for weeks on the internet and could not find one filter that had both response charts overlaid. I couldn’t put both filters on the end of the camera lens because of the vignetting at the image edges. BUT when I tried this for testing purposes you couldn’t believe my surprise when I discovered that the color image were perfect! I cannot find a chart for the B+W 486 but believe that it is close to that of the CC2 filter from LDP. Technically speaking, the CC1 filter should block any effect of the CC2 if stacked because is is narrower and inside of the CC2 passband, BUT it does not work as I would have thought! The only thing that I can think is that the combined effects of the 2 filters within the passband of the CC1 have changed the sensitivity of the passband.
What was I to do? I couldn’t stack the filters…. Hmmm.
OK, I looked in my box of old 58mm filters until I found one with a 1/4 inch ring (thick). I took it apart and removed the original filter (LDP). I then took apart the LDP CC1 filter, cleaned it and set it aside. I then took the B+W 486 apart which was pressed together, so I held the glass on the top and bottom, twisting and turning and the entire filter fell apart! I then cleaned it and put it on top of the CC1. Stacked I then put them into the old LDP ring and re-assembled the spanner ring. NOW we are talking! The new filter ring wasn’t too tall and it worked perfectly! Pay attention to how you remove the Cut filters from their rings and place them the same way into the new ring. I put in the CC1 first then the 486 on top.
You will NOT believe how great the color images now look on the NEX-5 Full Spectrum camera conversion. It is like shooting an un-modified system! So I decided to test this new filter combination on my Olympus E-PL1 Full Spectrum camera conversion as well. All that I can say without tissues is YES, I HAVE FOUND IT!!! As I stated above, the 2 filters are mutually exclusive and the CC1 should block the effect of the 486 or CC2, but for some reason it does not. I do not have the equipment to test the response of these filters and must rely on published data found on the WEB and on my own results which clearly say that this works!
I think that since LDP makes custom filters that one could contact them directly and have them build this custom filter for you but have not tried yet.