Gelatin infrared filter?

[cm1]

Here comes a question...

 

My Canon 15mm Fisheye only allows only filters behind the lens... I have to cut

something like one of those old fashioned Kodak gelatin filters to fit it to the

rear lens.

 

Are there infrared filters available that are not made of glass or other thick

material? I did not find a supplier..

[Fotohuis RoVo]

The only IR filter I know made of polymer is from Cokin (007), available in A and P and Xpro system. I have cut this filter for the Horizon 202 panoramic camera.

 

For my C.V. Super wide Heliar 4,5/15mm I am using the Heliopan RG715nm (72mm) with an especially made (72mm) filter adapter.

 

some result:

http://gallery.fotohuisrovo.nl/displayimage.php?album=2&pos=4

 

Best regards,

 

Robert

[richard_cochran]

Lee makes a polyester based #89 infrared filter. I've ordered a couple of them from B&H, for use to tape over a flash to block visible light, while allowing IR through to trigger slave lights.

[wirehead]

Lee makes 87 and 87C polyester "gel" filters (sadly, they don't seem to be making an 89 right now) Kodak still markets 87 and 89 gel filters (although they are actually sold by Tiffen at this point)

 

And the Ilford SFX gel filter is about the same as an 89.

[frank.schifano]

Yes. A friend of mine has one of these though I don't recall the manufacturer. It is a gel filter and totally opaque to visible light. He has it mounted in a cardboard mount for use in a Cokin filter holder in front of the lens. The material can be cut to any size, but must be carefully handled. It is easily scratched.

[cm1]

Ken,

 

are these gel filters really thin or as thick as the Cokin filters?

[adrian_wilson6]

Hi,

If your back ends up to the wall, try a roll of 120 Kodak ektachrome and have it processed unexposed, the resultant film is supposed to be an excellent IR filter. I believe Kodak also make or used to Wratten gel filters of the type you are looking for.

 

Cheers,

 

Adrian.

[helenbach]

Most polyester filters (eg Lee, Optiflex) are about 0.3 mm thick. Wratten gelatin filters are 0.1 mm thick. 'Wratten 2' filters are available now - they are more robust than the original Wratten ones. I'm not sure what they are made of, but they seem more like polyester than gelatin.

 

If you wanted to use a gelatin or polyester filter on the rear of a lens that didn't have a rear filter holder you could follow the common practice of using little rolled up pieces of 'snot tape' (Scotch ATG double-sided tape) to attach the filter to the rear element.

 

Best, Helen

[conrad_hoffman]

The thin Wratten filter will have the least effect on optical quality. Putting anything of thickness behind a lens is less than ideal.

[frank.schifano]

Guys, I did a little research. The lens uses a drop in filter. There is a filter holder that fits into the lens barrel. You trim the gel filter to fit the holder, then "drop" it into the slot in the barrel. It doesn't go behind the lens element and you don't tape anything to the lens.

[helenbach]

Frank,

 

I only mentioned the use of snot tape for lenses that didn't have a filter holder. I thought that it was worth mentioning, even though it doesn't apply to this particular lens.

 

Best, Helen

[profhlynnjones]

Kodak Gel filters are made from all standard Wratten numbers including F29, A25, 87, & 88 all of which can be used for IR.

 

Kodak sold the sales rights to somebody, perhaps Tiffen, but they still make the products.

 

Lynn

[stephen_denby]

Clemens,

I use an Ilford SFX gel filter cut to suit the gel clip at the back of my Pentax 67 35mm Fisheye (it is no thicker than regular film). You need to allow 5 stops as I find it has about the same cut-off wavelength as my Heliopan 715 (kodak Wratten 88A)

The Ilford SFX filter to fit a cokin P system is 75mm x 75mm so you will have plenty to cut to fit the back of your lens and they are very inexpensive!

I have worked with IR extensively, check out results at www.stevedenby.co.uk

hope you have fun,. Regards Steve

[joseph_wisniewski]

Lynn, Kodak sold the factory to Tiffen, who supplies them to Kodak for distribution under the Wratten name. They also doubled or tripled the price.

[joseph_wisniewski]

Clemens, if your Kwanon lens has a filter holder anything like the ones on my Nikon 14mm wide and Sigma 800 fisheye, you want the Lee Polyester filters. The Cokin will not mount: even if you cut it to size, it's way too thick.

 

The Tiffen Wratten filters will work, but they're so hard to handle in a slide in rear holder it's not funny. They scratch easily, fold up when you try to slide them into the holder, a suck up finder prints if you even get your finders within a cm or two of the filter (you don't actually have to touch them). The tinyist drop of water and they're dead. And, all of mine decomposed on me since the last time I used them (some bacteriological or fungal agent ate all the gelatin, leaving sticky glop in the holders).

 

The Lee filters are comparable in thickness to the Wratten, but don't scratch, fold, or spontaneously turn to glop.

[joseph_wisniewski]

Oops, thats Sigma 8mm fisheye.