Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: calindustries on July 07, 2014, 09:17:09 am

Title: Filter question
Post by: calindustries on July 07, 2014, 09:17:09 am

So I need UV filter, basically to protect the front element on my HCD 35-90 ($$$$$$$ lens I've ever owned). I'm using a Credo 40 back.

Any reason to get an UVIR over a basic UV?

Here are the 2 filters I'm looking at:
http://www.bhphotovideo.com/c/product/937029-REG/b_w_66_1070172_extra_wide_95mm_486.html
http://www.bhphotovideo.com/c/product/120482-REG/B_W_66_045110_95mm_UV_Haze_010.html

Thanks,
C

Title: Re: Filter question
Post by: Paul2660 on July 07, 2014, 09:53:45 am

My opinion, maybe only due to the cost of the lens and to protect the front element.  The only lens I own where I have a protect front filter is my Nikon 200-400 F4 as Nikon ships the lens with one. 

A good one should have no effect on the image quality and you have picked some good ones in your links.

Paul

Title: Re: Filter question
Post by: Bart_van_der_Wolf on July 07, 2014, 10:58:39 am

Quote from: calindustries on July 07, 2014, 09:17:09 am

Any reason to get an UVIR over a basic UV?

I wouldn't use the 486 with wide angle lenses. The hot mirror function for IR is angle of incidence dependent, which means that the IR rejection varies with angle, most prominently for rays at the corners. I've attached an exaggerated 3D view, which shows that the corners will get a green cast in the image, which must be corrected for.

Cheers,
Bart

Title: Re: Filter question
Post by: Doug Peterson on July 07, 2014, 11:03:03 am

Quote from: BartvanderWolf on July 07, 2014, 10:58:39 am

I wouldn't use the 486 with wide angle lenses. The hot mirror function for IR is angle of incidence dependent, which means that the IR rejection varies with angle, most prominently for rays at the corners. I've attached an exaggerated 3D view, which shows that the corners will get a green cast in the image, which must be corrected for.

Cheers,
Bart

+1

Title: Re: Filter question
Post by: calindustries on July 07, 2014, 03:37:38 pm

Quote from: BartvanderWolf on July 07, 2014, 10:58:39 am

I wouldn't use the 486 with wide angle lenses. The hot mirror function for IR is angle of incidence dependent, which means that the IR rejection varies with angle, most prominently for rays at the corners. I've attached an exaggerated 3D view, which shows that the corners will get a green cast in the image, which must be corrected for.

Cheers,
Bart

What I read was "charlie brown teacher charlie brown teacher charlie brown teacher, the cheaper one is just fine, because if you don't know about how the other one works you are just getting yourself into more trouble, charlie brown teacher"

Thanks!

The only thing that made me wonder about that one is that in their description it specifically said "developed for CCD sensors"

:)

-Craig

Title: Re: Filter question
Post by: Doug Peterson on July 07, 2014, 04:11:34 pm

Basically if you use a IR+UV filter you'll find the corners of the frame take on a strange color.

There is no reason to use an IR+UV filter on a Credo rather than a UV filter.