Need advice with infrared filter for Tokina 11-16mm

[yummy_waffles]

So I was going to convert my 20D to IR now that I have a 40D, but not sure if I'm ready to spend $200 - 300 on a conversion.

My solution would be to purchase a 77mm IR filter, preferably a cheaper one, so I can experiment with.

I've checked around ebay and the Hoya's and B+W's are almost the same price as an IR conversion. Yikes! However, I did find one that was less than 50 bucks.

So I was curious if anybody has any knowledge with Marumi filters, or better yet, any experience with a Marumi filter on a 77mm size lens. After a bit of online research, the quality seems to be up to par with Kenko's filters.

I'm just wondering if the 77mm will cause any hazing, softness, flares, or vignetting on my Tokina 11-16mm???

http://i475.photobucket.com/albums/rr120/noWAFFLESforU/mar77ir.jpg

[hollis_f]

No experience with this filter, but it'll be totally different from getting the 20D converted.

The problem with using an IR transmitting filter (that blocks all bar IR) is that there's an IR-absorbing filter in front of the sensor. The combined effect is that hardly any photons make it through to the sensor. That means very long exposure times. If you get the conversion done then you can use near-normal exposures.

[RandyS]

As Hollis said - very long exposures. Any slight breeze and leaves/grass/etc will become a blur. In addition to the long exposures, you can't see through the filter. You'll need to set up focus and framing, then put the filter on afterwards.

But ... you can make it work. It's highly unlikely that it's a method that you'll like for the long haul, but you may find it gets you interested enough to get the conversion done. Given that, I wouldn't spend the big bucks on a B+W or a Heliopan either. Not for this application. Think of it as an experiment that will give you a taste of what might be possible.

[RandyS]

ETA: Any normal depth filter is likely to cause vignetting on an 11mm lens. May not be noticeable on a crop body though.

EETTA: Oops - that was supposed to be an edit to my previous post http://i69.photobucket.com/albums/i61/rsamos/smilies/doh.gif