Filter thread/Cokin P?

I have a Schneider Angulon 90mmF6.8 with a filter thread size of 40.5mm. I use the Cokin P filter system and cannot find an adaptor ring for this size, any suggestions?.

I'm 90% sure that Cokin make a 40.5mm as I had one for a

100mm Apo Symmar. If not try a step up ring.

Step up ring to a size for which there is an adapter ring? (If you

can't find a step up ring, then you would seem to have a real

problem...)

If you use a screw-in type filter on a 90mm lens you may get corner cut

off on extreme displacement / shifts.

Use a bellows type lens hood that accepts filters.

If a screw-in filter is going to cause problems with cut-off, then a

bellows-filter holder will only be worse - much worse!

A bellows lens hood / filter holder should be attached OUTSIDE the

lens, NOT screwed into the lens thread!

(The lens shade / filter holder should be clamped on the lens on the

outside...)

The best system is what SINAR uses: an extra bellows as a lens shade,

with the ability to dial in flat "blinds" to minimize flare and get

maximum contrast.

 

<p>

 

 

 

<p>

 

The way to check if you get cut off with a lens shade is to look

through the camera, from the front, at the working aperture, with the

shutter open, Look at each corner of the ground glass (from the front

of the camera). If you can see each corner clearly there is no cut off.

Dont try to look at the groundglass from the rear to check for cut off

- the ground glass will fool you.

Lee,

 

<p>

 

The Cokin A range has a 40.5mm adaptor ring and works with the

Angulon 90/6.8 without vignetting.

Cokin doesn't sell a 40.5mm adapter for the P holders.

 

<p>

 

I had a similar problem some time ago and resorted to use a step-up

ring (by the way, the best quality step-up rings IMHO are those by

Heliopan - and they cover all your possible needs).

 

<p>

 

You may risk vignetting ... another option would be to have an adapter

custom made for you.

I had the same problem when looking for a 40.5 adapter ring. I

couldn't find one and ended up having one made by Steve Grimes.

I had the same problem and I just bought 40.5-52 stepping ring, I

think from Kaiser, Germany. It is not quite top quality, but I never

had any problems unscrewing it. And Cokin makes P ring for 52mm

diameter.

Best regards,

www.janez-pelko.com

Hi Lee, I had the same problem. It was solved by the wonderful folks

at Calumet, San Francisco. They sold me a 40.5 to 49mm step up ring

from Tiffin and a 49mm Cokin P HOLDER, which also fits another lens in

my bag. I belive the ring was less than $20.00 and works very well.

 

<p>

 

good shooting,

Bill

Cokin makes a universal adapter for cheap and is handy in cases like this. check it out:

http://www.bhphotovideo.com/bh4.sph/FrameWork.class?FNC=ProductActivator__Aproductlist_html___14101___COARPU___REG___CatID=3848___SID=F585CC90040

 

I would be more worried about the vignetting issue- but it is worth a try! maybe you could mount it onto the rear element.