DIY Expodisc...save $100

are there any substituted what would allow this to work on a 77mm filter that you can think of?

Though I always liek the idea of saving money, I don;'t like to do so when the time costs more in the long run.
Trips to Home depot, the cost of two clear filter @ 77mm (or approariate) the cost of the white air filter, the lamp cover, and all the work combine to make this not a value iMHO.

I love that Bill tackled this, and I know his resulting product is just as good as the expo disk, but for those of us looking for a cheap alternative, I gotta say, this is the long way around

I keep soem coffee filters in my kit, and have found they five excellent results.

Cybnew wrote in post #4184303
are there any substituted what would allow this to work on a 77mm filter that you can think of?

Bill pretty much pout everything white he could find between two clear filters when he was developing this thing a few years back.. the trouble is the 3M air filter is too small for 77mm in one cut. You can use more than one and risk a seem,. or since you don't need the full filter size to set a custom WB, you can use the 72mm unit with an adapter.

I reckon a cheap and bad UV or 1A filter sanded thoroughly on both surfaces should become white and opaque enough to use as an expo-disk. If it's plastic as opposed to glass then even better!

The 3M p95 filter is the ONLY material that achieved the exact same results as the Expodisc. Even other filters by 3M had different results (too warm, too cool, etc).

Cyber, I can appreciate your opinion but I must disagree. At the time I made this, the 72mm Expodisc was going for $119 + tax (or S&H)...mine cost me approx $20 in materials and only took me about an hour to complete. As far as the drive to Home Cheapo, well, with three acres of landscape maintenance and a wife that finds a new ''project'' every week, I spend half my life at home improvement stores anyway. You actually dont need to use the diffuser material, so you can make one of these in the time it takes to cut the p95 into shape. If you do use the acrylic, you really dont need two UV filters...just sandwich the p95 material between the UV filter and the acrylic and save the cost of a second 72mm UV.

Its all relative, I guess. Sure, it would have been a lot easier to order an actual Expodisc with a simple click of the mouse...but not as much fun. I like to tinker with stuff, especially when I can make a device that achieves the same results for a fraction of the cost. In fact, I'm thinking about ordering an 80mm push-on lens cap, cutting it and attaching it to the WB disc to allow it to attach to the front of my 77mm lenses without having to hold it.

Who's ''Bill''?

David John wrote in post #4189962
I like to tinker with stuff, especially when I can make a device that achieves the same results for a fraction of the cost.

This is the main element that separates people when it comes to subjects like this. If you have justify the effort versus expense to yourself, then you don't have the right personality for it.

It's apples and oranges. People that do have the right personality for it feel that the process of building something and the sense of accomplishment is at least half the value of creating it. The other folks feel like it's time wasted that could be spent doing something more productive.

David John wrote in post #4189962
Who's ''Bill''?

Tom .. DOH! Tom Hicks,..
My mind went to Bill Hicks the comedian..

I think this is great and fun project to build. thanks for sharing.

David John wrote in post #4184267
This is what I paid.

6 pack 3M p95 Particulate Respirator Filter $10.67 + Tax
Bower UV-0 72mm Lens Filter (eBay) $6.95 + $3.00 S&H
Hoya Standard UV Haze Lens Filter (eBay) $3.99 +$8.00 S&H
Acrylic diffuser panels (Plaskolite) FREE
Silicone adhesive $1.89

Hm, not that cheap after all.

Potato chip cover beats it

CyberDyneSystems wrote in post #4190371
Tom .. DOH! Tom Hicks,..
My mind went to Bill Hicks the comedian..

Dude, that guy was awesome!! It was a true loss to the comic world when he died.

Yeah, but MINE looks pro

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loving it

David John wrote in post #4197572
I'm certain there are a veritable plethoria of opaque materials that will give you somewhat similar results, but a Pringles lid will NOT match p95 material for strict tolerences of color neutrality and light transmission. I wish I still had Tom Hicks' original pdf file on his comparison tests. He tried everything from styrofoam to coffee filters, and again, he found the p95 to be an identical match to the material that Expo Imaging uses for their WB disc.

All I know is, this thing has saved me a lot of PP time when shooting under flourescent lighting.

I notice you had made a histogram comparison between the Expodisc and the one you made. Was this a way to prove sort of they are spectrally similiar? Or simply a comparison of the light transmission through them?

Pinto wrote in post #4190070
This is the main element that separates people when it comes to subjects like this. If you have justify the effort versus expense to yourself, then you don't have the right personality for it.

It's apples and oranges. People that do have the right personality for it feel that the process of building something and the sense of accomplishment is at least half the value of creating it. The other folks feel like it's time wasted that could be spent doing something more productive.

It all boils down to how much your time is worth to you. If you typically make $300 an hour, spending and hour to save $80 may not be the best way to use your time. Also, some may choose to pay the extra $80 to have that hour to spend with their children/wife/etc.

I have the personality to do this, but I can't afford the time it would take. I also already own the Expodisc. Great DIY though. Thanks for sharing.

David John wrote in post #4197572
Yeah, but MINE looks pro

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Indeed.

David John,
Taking orders yet?
I need a 77mm one