# EF 600 f4 IS L II filter holder glass, what is?



## victorwol (Jan 10, 2013)

Hi! I just got my 600, and I noticed that the filter holder it actually contains an installed glass, what is that glass for? Is an UV filter or something?


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## Radiating (Jan 10, 2013)

My understanding of this is that the filter is part of the optical path in this lens, it has to be in that position, so for the lens to function it has to have a piece of glass in that location which is that shape.


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## victorwol (Jan 10, 2013)

yep... I saw in the manual after posting that says its need to be there... but looks like a piece of glass with some treatment, so I was wondering what it is... just curious.


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## neuroanatomist (Jan 10, 2013)

It's a clear filter, and as Radiating stated, it's part of the optical formula of the lens. It's actually designed to hold a gelatin filter (cut to size), although with digital the need for color correction is moot. I suppose one might want an ND gel in the 600 II to shoot Yosemite Falls from Merced  . 

So...leave it in, unless you replace it with the drop-in CPL when you want polarization.


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## wickidwombat (Jan 11, 2013)

neuroanatomist said:


> It's a clear filter, and as Radiating stated, it's part of the optical formula of the lens. It's actually designed to hold a gelatin filter (cut to size), although with digital the need for color correction is moot. I suppose one might want an ND gel in the 600 II to shoot Yosemite Falls from Merced  .
> 
> So...leave it in, unless you replace it with the drop-in CPL when you want polarization.



you can just get a B+W ND they are nice and cheap in the small sizes and I would think better quality than a gel, no?


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## neuroanatomist (Jan 11, 2013)

wickidwombat said:


> neuroanatomist said:
> 
> 
> > It's a clear filter, and as Radiating stated, it's part of the optical formula of the lens. It's actually designed to hold a gelatin filter (cut to size), although with digital the need for color correction is moot. I suppose one might want an ND gel in the 600 II to shoot Yosemite Falls from Merced  .
> ...



Well, the OP was asking about the included drop-in holder, which only takes gels. To use a B+W ND filter (which is what I'd do if I encountered a need for an ND with my 600 II), you'd need the drop-in holder for 52mm screw-in filters - and it's perpetually out of stock, from what I've seen. The drop-in CPL was like that, too - they stopped production and released a WII version (to match the new 'white' paint was the only difference). I suspect a WII version of the screw-in holder will show up eventually, but until then the used market is the only option, seemingly.


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