Mine is made from a circular polarizer, I then used a piece of uv glass and because I didn' t have another I used some plastic, but the easiest way is to just sandwich the 3M material between two uv filters .
Hi, I'm having trouble finding these 3m filters. When I google 3m R95 replacement filter I get a surgical style mask. Somebody earlier mentioned N95, but Tom originally said R95. The Staples link above no longer seems to work. I went to Home Depot today and couldn't find one of these for the life of me. I'm very interested in making my own Hickspodisc, so any help in finding these filters would be appreciated. Even a link to a picture of the packaging would help. Even what department at Home Depot to look in would help.
As you can probably imagine, respirator filters aren't my area of expertise and I have no idea what I'm actually looking for.
I searched FM and the Hickspodisc PDF would have answered my question I'm sure, but unfortunately it's not up anymore.
The R95 is for oily particulates, and it does not look like 3M makes this pre-filter material with this rating (checked their website).
I checked my Sherwin Williams store this weekend, and they didn't have any, although they did carry the respirator that uses these filters.
If you get desperate, you can order them from McMaster-Carr, or pick them up at a Grainger if you know someone with an account (they don't sell retail).
Yeah, grey cards are nice in a bathroom or a studio - but if you're at the zoo the hickspodisk is the clear winner.
You may find a tiger or king cobra willing to hold your card for you, but explaining to them how to hold it might be a bit tricky, not to mention getting through the glass or fence to hand it to them.
I've been reading through the comments rather closely. Really, a custom WB needs to be set for the color balance of the incident illumination. The Hickspodisc, as it is used in this thread, isn't measuring the incident illumination. It is measuring the light reflected off the subject. Measuring the light reflected off of a gray card or white card will give a more accurate reading of the color balance of the incident illumination.
All is not lost, however, for the Hickspodisc. All you have to do is point the Hickspodisc at the light source. The camera's meter will automatically compute a middle gray exposure and the WB function of the camera will set the custom WB based on the illumination source. Used in this manner, the Hickspodisc should be quite accurate.
I've been reading through the comments rather closely. Really, a custom WB needs to be set for the color balance of the incident illumination. The Hickspodisc, as it is used in this thread, isn't measuring the incident illumination. It is measuring the light reflected off the subject. Measuring the light reflected off of a gray card or white card will give a more accurate reading of the color balance of the incident illumination.
All is not lost, however, for the Hickspodisc. All you have to do is point the Hickspodisc at the light source. The camera's meter will automatically compute a middle gray exposure and the WB function of the camera will set the custom WB based on the illumination source. Used in this manner, the Hickspodisc should be quite accurate.
Thanks tom , this is exactly how I use it , hold it in front of the lens point at light source and WALA.
To use this (the Hickspodisc) or the actual Expsodisc - do you necessarily need to screw the filter on to take an accurate color balance reading? can you get a 77mm, and just hold it over the lens of like a 58mm lens? would that work?
All you need to do is hold it tight to the lens , the filter is a pad type material that is made up of 3 different types of material it is fused together but if you cut it to fit you will separate them.
OK. I pucjed up 3 of then for $2 and some change each, incase I mess one (or two) up in the process! It seems kinds thick and was wondering now if the whole thing is used or just a layer or two?
With Tom's permission I will leave a link up to his older post showing the pieces that made up the famous Hickspodisc. This is actually a copy of the htm that Dr. Cliff Moore had posted. I do not know if Clff has any more info on Tom's original article.
