300mm f2.8 filters

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alsos

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Al
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I recently managed to get my hands on a 300mm f2.8, non IS, I would like to get a CPL for it, but not having much joy in finding one for what I or the girlfriend oe importantly would call a reasonable price. I have found one for £130+ del from the states.
My question is can I buy a 48mm CPL remove the frame and use it in the drop in holder?
anyone tried this approach? or should I just not tell HiD how much it was?!
 
Al,

There are a couple of potential problems with your plan but nothing's impossible.

Firstly....if you simply replace the current filter (plain optical glass actually) then you have no way of turning the polarising filter when it's in situ.....the Canon version has an outer ring gear on the frame which messhes with a thumb wheel for adjustment.

Secondly.....don't assume that a regular 48mm C-PL will have the same diameter glass. The "48mm" refers to the thread size and not the glass diameter. 48mm filters from different manufacturers will have different diameter glass installed if the frames are thicker/thinner. I would guess that your 48mm requirement will actually utilise glass from a regular filter a few mm's smaller.

It's also worth looking at some of your existing shots and judge from the EXIF if you could still have got it with 2 stops less light.

Bob
 
thanks Bob, pionts well made.
Some of the time I know I would need the two stops.
the one which is in there has a green tint, not what I would think would be a green filter causing colour cast, but I would asume its the geltin filter which is standard?
the one which is in there does seem to be very thin.


Canon Bob said:
Al,

There are a couple of potential problems with your plan but nothing's impossible.

Firstly....if you simply replace the current filter (plain optical glass actually) then you have no way of turning the polarising filter when it's in situ.....the Canon version has an outer ring gear on the frame which messhes with a thumb wheel for adjustment.

Secondly.....don't assume that a regular 48mm C-PL will have the same diameter glass. The "48mm" refers to the thread size and not the glass diameter. 48mm filters from different manufacturers will have different diameter glass installed if the frames are thicker/thinner. I would guess that your 48mm requirement will actually utilise glass from a regular filter a few mm's smaller.

It's also worth looking at some of your existing shots and judge from the EXIF if you could still have got it with 2 stops less light.

Bob
Click to expand...
 
The puka Canon C-PL is also tinted green so it's probably by design and not insignificant.

Bob
 
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