B+W IR cut 486 filter quality??

[cbretteville]

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As far as I can make out from Schneider's available litterarure the 486 filter is not available as an 'MRC' (multi coated) filter. I've never used anything but MRC filters from B+W on my M glass as I beleive it deserves the best. Does anyone know if these are 'plain glass' filters? And does any other manifacturers have MC IR Cut filters?

Cheers,

- Carl

[jlancasterd]

As far as I can make out from Schneider's available litterarure the 486 filter is not available as an 'MRC' (multi coated) filter. I've never used anything but MRC filters from B+W on my M glass as I beleive it deserves the best. Does anyone know if these are 'plain glass' filters? And does any other manifacturers have MC IR Cut filters?

Cheers,

- Carl

 

Carl

 

My reading of the data sheet in the B+W catalogue also indicates that their 486 filters are uncoated. It may be that it isn't possible to coat an IR-cut filter - after all, the IR absorbing layer is itself a coating.

[carstenw]

I don't believe that the 486 are IR absorbing. The 489 filters are, but the 486 are of the type which trap certain wavelengths of light between two layers inside the filter.

[ho_co]

You're right, Carsten. 489 is IR-absorbing, 486 is IR-cut by means of interference.

 

But John is right in his assessment: The 486 does use multi-coating in order to produce its IR interference.

 

Normally, multicoating is used to ease light from air into the glass and thereby reduce reflections. But the IR-cut design actually traps certain wavelengths completely. They enter but then can't get out because of repeated reflection.

 

I'm no optician, but I would guess the two are mutually exclusive.

 

And according to Edmund Optics - Mounted IR Filters, both surfaces do have a standard anti-reflection coating.

 

(I bought one of the Edmund UV/IR-cut filters, and all signs are that it is made by B+W and is identical to the 486, as I've posted a couple times before.)

 

Frankly, I wouldn't worry about the B+W filter quality. Look at how many of us are using it already. On the other hand, there has been a certain amount of disappointment with Tiffen's similar 'hot mirror' filter.

 

--HC