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2x2 Internal Lens Filters


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#1 Ian Cooper

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Posted 17 December 2009 - 04:26 PM

I've recently bought a Kinoptik 5.7mm lens that will accept a 2"x2" internal filter.

Whilst obviously anything introduced into the light path is going to affect the image to a certain extent, is there anything particularly special about internal filters compared to those positioned on the front of the lens? - or are they just the same material?


In the past I've been able to sucessfully cut resin filters then glue them into mounts I've machined to fit non-standard threads on older cameras. Potentially I could easily make a 2x2 filter & mount the same way, but there's no point wasting my time if the material needs to be something special to be positioned between the lens elements.

Finding 2x2 filters commercially here in the UK doesn't seem all that straight forward, hence why I'm considering cutting something larger down and mounting it myself.


EDIT:
Sorry, just seen I've posted this in the 'Cameras' section, not the 'Lenses' section where I'd intended.
Although I can edit the post, I can't now delete it to post again in the more appropriate section of the forum.

Edited by Ian Cooper, 17 December 2009 - 04:29 PM.

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#2 Boris Belay

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Posted 25 January 2010 - 10:15 AM

I've recently bought a Kinoptik 5.7mm lens that will accept a 2"x2" internal filter.

Whilst obviously anything introduced into the light path is going to affect the image to a certain extent, is there anything particularly special about internal filters compared to those positioned on the front of the lens? - or are they just the same material?


In the past I've been able to sucessfully cut resin filters then glue them into mounts I've machined to fit non-standard threads on older cameras. Potentially I could easily make a 2x2 filter & mount the same way, but there's no point wasting my time if the material needs to be something special to be positioned between the lens elements.

Finding 2x2 filters commercially here in the UK doesn't seem all that straight forward, hence why I'm considering cutting something larger down and mounting it myself.


EDIT:
Sorry, just seen I've posted this in the 'Cameras' section, not the 'Lenses' section where I'd intended.
Although I can edit the post, I can't now delete it to post again in the more appropriate section of the forum.


Hi Ian,

I'm pretty sure they are exactly the same materials. In fact I even have 2x2" metal adapters for gel filters that I can use in my Kino TGA.

I think Kinoptik went for internal filters on their TGAs to avoid vignetting problems and having to have a huge filter in front of the lens (given the very wide FOV on those).

You can fing glass 2x2' filters pretty regularly on eBay. I'm not sure whether anybody still makes them new, although t would be simple enough to have them cut from larger filters.

B.
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#3 Ian Cooper

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Posted 26 January 2010 - 02:44 AM

Thanks, I'll try keeping an eye on eBay for the time being then.
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#4 Bob England

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Posted 13 February 2010 - 05:19 PM

Tiffen still offers a wide selection of 2x2" glass filters and here in the US, B&H PhotoVideo carries them as well as some others.
Go to http://www.bhphotovideo.com and search on "2x2" filter" to see 11 pages of filters listed.

A question I have about the Kinoptik 5.7mm lens is whether a filter (or glass blank) is required to be installed in order for the lens to focus correctly?
I recently bought a PL mount version of the Kinoptik off of eBay without any filters and the lens is not focused at all. Everything is a complete blur.

Thanks for any info.
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#5 Ian Cooper

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Posted 13 February 2010 - 06:18 PM

Tiffen still offers a wide selection of 2x2" glass filters and here in the US, B&H PhotoVideo carries them as well as some others.
Go to http://www.bhphotovideo.com and search on "2x2" filter" to see 11 pages of filters listed.


Thanks! :)

A question I have about the Kinoptik 5.7mm lens is whether a filter (or glass blank) is required to be installed in order for the lens to focus correctly?
I recently bought a PL mount version of the Kinoptik off of eBay without any filters and the lens is not focused at all. Everything is a complete blur.



Funnily enough I've only just collected my NPR again from Les Bosher this morning. I mentioned to him about getting myself the Kinoptik. He asked if I'd got the filters, as apparently the lens needs at least a clear one else the focus point is off slightly.

Having got back home I've put the lens on the camera and have to say that looking through the viewfinder it appears sharp and in focus even without a filter. Whilst I realise it might be 'off' slightly, what I can probably say is that yours is a bit poorly if the image is obviously burred and out of focus through the viewfinder. I suspect the difference with and without a filter is too subtle to detect just through the viewfinder?
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#6 Boris Belay

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Posted 16 February 2010 - 07:41 AM

Tiffen still offers a wide selection of 2x2" glass filters and here in the US, B&H PhotoVideo carries them as well as some others.
Go to http://www.bhphotovideo.com and search on "2x2" filter" to see 11 pages of filters listed.

A question I have about the Kinoptik 5.7mm lens is whether a filter (or glass blank) is required to be installed in order for the lens to focus correctly?
I recently bought a PL mount version of the Kinoptik off of eBay without any filters and the lens is not focused at all. Everything is a complete blur.

Thanks for any info.


The Kino 5,7 should definitely focus without an internal glass filter. Or rather, i should say, it should be in focus from close to the front of the lens to infinity, since it's a lens without focusing gears.
Your mount may be off kilter, or your adapter may be badly inserted. Or else, worse, your camera mount may be off. With these very wide focus lens, any discrepancy in lens to film distance is critical and very noticeable.
If the problem is not obvious right away, check the Kinoptik for signs that it was dismantled (on the screws, etc.). As is, the lens is so solidly built that it should not go off focus that easily.

B.

Edited by Boris Belay, 16 February 2010 - 07:42 AM.

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