Material to stick on LED panel for flats

[a6400]

Hi,

My LED panel for flats is too bright, I don't want to use a t-shirt or a4 paper.

Perhaps someone knows some form of plastic sheet that would be good for this and provide even illumination?

Thanks

[Elp]

A few 3mm sheets of opal/lightbox perspex/acrylic (easy to keep clean), been using it for years, lots of sellers on eBay unless you have a plastics signmaking place near where you live, they may just give you a free offcut or two (you'd need three at least at 3mm, you can't really go much thicker I've tried as you can see grain within the plastic), black gloss also works in helping dim it further. You need to make sure it won't be too heavy to put on top of your dew shield if you do that, sometimes now I just hold it in front of the OTA and quickly take a set of flats.

Are you positive you can't dim your panel, mine I hold the on button down and it dims/brightens.

 

Edited January 2 by Elp

[a6400]

10 minutes ago, Elp said:

A few 3mm sheets of opal/lightbox perspex/acrylic (easy to keep clean), been using it for years, lots of sellers on eBay unless you have a plastics signmaking place near where you live, they may just give you a free offcut or two (you'd need three at least at 3mm, you can't really go much thicker I've tried as you can see grain within the plastic), black gloss also works in helping dim it further. You need to make sure it won't be too heavy to put on top of your dew shield if you do that, sometimes now I just hold it in front of the OTA and quickly take a set of flats.

Are you positive you can't dim your panel, mine I hold the on button down and it dims/brightens.

 

I have 3 brightness settings but it's still too much if shooting without a filter.

Which one would you get? I know nothing about these materials...

https://www.amazon.co.uk/s?k=3mm+acrylic+sheet&crid=3P2YF17CI6ZKC&sprefix=3mm+acr%2Caps%2C317&ref=nb_sb_ss_ts-doa-p_1_7
https://www.amazon.co.uk/s?k=3mm+perspex+sheet&crid=2P4RO3NUFENE9&sprefix=3mm+perspex%2Caps%2C143&ref=nb_sb_ss_ts-doa-p_1_11

I need it to Redcat 51 so I don't need it to be very large.

Thanks

 

[Elp]

Search for Trent Plastics Opal on eBay, that's the type you need, there's a few listings so look for one that shows A5 size. Maybe worth getting one black gloss too, I use 3 white, one black, my optics are usually at F2 so I need a few.

Edited January 2 by Elp

[a6400]

1 minute ago, Elp said:

Search for Trent Plastics Opal, that's the type you need, there's a few listings so look for one that shows A5 size

Something like that?
https://www.trentplastics.co.uk/acrylic-plastic-perspex-sheets/opal-acrylic-perspex-sheets

[Elp]

Yes, if you're unsure you can also order small samples and try it with your panel.

[michael8554]

Opal white Neutral Density Filter sheet from companies that supply to movie and theatre production companies.

Michael

[wimvb]

I couldn't get opal white acrylic, so I put car solar film on clear acrylic, and frosted window film on the other side. Seems to work ok.

[Elp]

I've tried ND film but the problem is it creases and also attracts dust incredibly easily. Mine was rolled up originally so it was difficult to keep it flat onto the panel I wrapped with it.

Edited January 3 by Elp

[tooth_dr]

On 02/01/2025 at 16:51, Elp said:

A few 3mm sheets of opal/lightbox perspex/acrylic (easy to keep clean), been using it for years, lots of sellers on eBay unless you have a plastics signmaking place near where you live, they may just give you a free offcut or two (you'd need three at least at 3mm, you can't really go much thicker I've tried as you can see grain within the plastic), black gloss also works in helping dim it further. You need to make sure it won't be too heavy to put on top of your dew shield if you do that, sometimes now I just hold it in front of the OTA and quickly take a set of flats.

Are you positive you can't dim your panel, mine I hold the on button down and it dims/brightens.

 

Also use 3mm opaque acrylic A4, two sheets of it for luminance, one for narrowband.  Bought grey too, also works. 

[geeklee]

2 hours ago, Elp said:

I've tried ND film but the problem is it creases and also attracts dust incredibly easily. Mine was rolled up originally so it was difficult to keep it flat onto the panel I wrapped with it.

I had exactly the same issue - handling it was a nightmare.  For a "setup each session" person like myself I could see many problems ahead so ditched it for now.

I stuck with some acrylic and this works well.  This thread reminded me I need some bigger sheets and also to try and add some tinted stuff (I went for grey).

I tried some opaque stuff previously, but I must have got it all wrong - it was so opaque, my flats would been measured in minutes... or hours 🤣

[Clarkey]

I use clear acrylic over plain white paper. This way you can adjust the density by adding or removing layers. Works well for me. 

[a6400]

Bought this one:
https://www.ebay.co.uk/itm/112389232082?var=412794291047

[michael8554]

I resized a wood picture frame to hold the light panel and ND.

I haven't noticed dust or creasing affecting the results, perhaps because the panel is so far out of focus.

Michael

[a6400]

Received the "plastic" but it doesn't seem to dim it that much, even though it's relatively thick.

Perhaps I will need to add another layer.

[Elp]

Get a few black

[Carbon Brush]

Two thoughts here that may or may not be applicable.

Do you have access to the light panel electronics? If so it my be possible to reduce brightness.
The methods used depend on the type of drivers.
With luck you can find a simple component swap to alter PWM or peak current.

The second approach is to dim at the camera end - which I appreciate involves disturbing the optical train.
For example a moon or (other ND) filter. Maybe a variable polarising filter?

Daft ideas? Maybe? I will get my coat😁

 

[Elp]

If it's usb powered an easy fix is an inline regulator/controller which reduces the voltage so panel would likely dim, or maybe it'd just turn off.

[Tiny Clanger]

Random recollection from a previous life (and a previous century) when our studio 'pack shot' advert specialist guy set up a photo he often used aerosol cans of clear matt dulling spray to reduce unwanted reflections, and had a can of stuff which was not only dulling but a neutral grey too. The stuff wiped off with ispopropyl if the prop was for re-use. I've no idea if in these days of photoshop the stuff is still used by stills photog.s, but I bet it's useful on film sets. Try a search for 'studio dulling spray' and see if there's a grey variant available, I guess it wouldn't be a cheap product to buy though, it's a bit niche !

[a6400]

On 07/01/2025 at 19:21, Elp said:

Get a few black

Ordered one will see how it goes.

12 hours ago, Carbon Brush said:

Two thoughts here that may or may not be applicable.

Do you have access to the light panel electronics? If so it my be possible to reduce brightness.
The methods used depend on the type of drivers.
With luck you can find a simple component swap to alter PWM or peak current.

The second approach is to dim at the camera end - which I appreciate involves disturbing the optical train.
For example a moon or (other ND) filter. Maybe a variable polarising filter?

Daft ideas? Maybe? I will get my coat😁

 

I'm not touching electronics with my 2 left hands, also I doubt there is an easy way to open it, but who knows.

As for adding filter, wouldn't it cause the flats to not calibrate properly against the lights?

[wimvb]

https://tintdepot.com/product-category/car-window-tint-rolls/

Like I said, this works for me. I put it on oversized acrylic, which I lay between the scope and flat panel. There are a few air bubbles, but those are only visible when viewed from a glancing angle, and don't affect the flats.

[michael8554]

Before my final solution of ND sheet, I tried PWM power control.

At the desired setting it caused flicker.

Not visually noticeable, but present on the Flats.

Michael