• Ultraviolet Photography
  •  

Best way towards trichrome NIR images?

10 replies to this topic

#1 Fandyus

    František G.

  • Members
  • 229 posts
  • Location: Czech republic, Northern Bohemia

Posted 16 June 2021 - 18:36

So, for a while, I was thinking of the cheapest, most practical way to start making NIR trichrome images. I could either go about it by buying three LED light sources at different wavelengths, or by buying three different bandpass filters. I have found options for both of those but I'm not sure how practical either of those are. Obviously the bandpass solution would be perfect but those filters are cheap options on eBay, so I don't know whether they'll be A) optically uniform and B) won't leak other wavelengths. The name of the store implies they're made for lasers, so I suppose optical uniformity is a thing they would want to deliver to keep the beam properly collimated?
https://www.ebay.com...353.m1438.l2649
https://www.ebay.com...353.m1438.l2649
https://www.ebay.com...353.m1438.l2649
https://www.ebay.com...353.m1438.l2649
Has anyone tried those? If you can confirm they are reasonably ok, I'm buying them right away, I would putty mount them on my Industar 50-2 which should be alright for the job with it's tiny front element.

Another option would be buying different light sources and waiting for the night to take three pictures with different illumination, I have thought of those options. They're quite expensive though, and I also wonder which option would be better for the blue channel, 660nm or 730nm? There are also 1w versions of those bulbs but I suspect 1w is too weak, though I don't own any 1w lights so I don't know. Anyone own anything like that? Can I expect to illuminate larger portions of the room with such a light given that I use long exposures? And how long should I expect them to be?
https://www.ebay.com...353.m1438.l2649
https://www.ebay.com...353.m1438.l2649
https://www.ebay.com...353.m1438.l2649
https://www.ebay.com...353.m1438.l2649


And there's a kind of bonus question I have, what is the ideal budget dual bandpass filter to emulate aerochrome? Ideally from Tangsinuo as their filters are the best price-wise. I have a QB29 which looks nice but not quite like aerochrome.
Attached Image: IMG_9452.jpg

#2 Stefano

    Member

  • Members(+)
  • 2,174 posts
  • Location: Italy

Posted 16 June 2021 - 18:53

So... three filters and three light sources should both work well. As you probably know, Bernard used the filter method and I used the light method.

Having experience with the latter, I can tell you that my 10 W LEDs can easily illuminate a room, and my exposures are at most a few seconds at ISO 100 and f/8. So using 21 W bulbs should not be a problem.

As far as those filters, they are very narrow, so this means they are "dark" (reasonably long exposures) and your images will have big spectral "holes" (in a way, it reminds me of a CFL with its peaky spectrum). But should work as well.

#3 Fandyus

    František G.

  • Members
  • 229 posts
  • Location: Czech republic, Northern Bohemia

Posted 16 June 2021 - 19:01

View PostStefano, on 16 June 2021 - 18:53, said:

So... three filters and three light sources should both work well. As you probably know, Bernard used the filter method and I used the light method.

Having experience with the latter, I can tell you that my 10 W LEDs can easily illuminate a room, and my exposures are at most a few seconds at ISO 100 and f/8. So using 21 W bulbs should not be a problem.

As far as those filters, they are very narrow, so this means they are "dark" (reasonably long exposures) and your images will have big spectral "holes" (in a way, it reminds me of a CFL with its peaky spectrum). But should work as well.

Thanks, my problem with the lights was though that the cheaper option I listed was 1w. So I'm really not sure if that's enough. Probably not. And again, with the filters, I'm afraid the glass won't be uniform and that there will be ripples in it, which would cause low sharpness, especially stopped down, this happens with cheap filters sometimes. My ZWB1 has this issue, though it doesn't show until about f/11.

#4 KarlBlessing

    Member

  • Members
  • 29 posts
  • Location: Grand Rapids, Michigan

Posted 16 June 2021 - 19:02

Closest single-filter straight-out-of-the-camera Aerochrome look I've seen has been off the Kolari IR Chrome filter https://kolarivision...me-lens-filter/

But it's not exactly cheap (but nor are most filters I've noticed)

In regards to sort of what you have there, the Schott BG3 seemed like a pretty decent single-filter option resulting in an image like this (white balance custom set by setting it off the grey walkway):

Posted Image

Though since it also passes some green, anything that's a strong enough green that isn't reflecting IR light will show up too.

#5 Fandyus

    František G.

  • Members
  • 229 posts
  • Location: Czech republic, Northern Bohemia

Posted 16 June 2021 - 19:03

That's nice, thanks.

#6 dabateman

    Da Bateman

  • Members+G
  • 3,004 posts
  • Location: Maryland

Posted 16 June 2021 - 22:59

We have a lot of threads on the Aerochrome look. Cheapest is Lee Scuba blue #729 filter and KG3 stack. You can also get away with GRB3 and Lee Scuba blue.
Cadmium used to sell a Hormagorgious filter, which was that. The Kolari filter doesn't work for all cameras.

I would recommend Midopt IR filters.
https://ebay.com/usr/discount-optics

You can save that seller and wait for deals on these filters. They are good. I have the BN850 filter, which is just 800-900nm in 58mm and was only $20.

#7 Andy Broomé

    Invisible Light Enthusiast

  • Members+G
  • 277 posts
  • Location: Mississauga/Toronto, Ontario, Canada

Posted 17 June 2021 - 02:25

View PostFandyus, on 16 June 2021 - 18:36, said:

And there's a kind of bonus question I have, what is the ideal budget dual bandpass filter to emulate aerochrome? Ideally from Tangsinuo as their filters are the best price-wise.
Tangsinuo sells dichroic glass filters (intended for gobo lighting) in 54mm diameter size @ USD 10 for a lot of 3 (you can choose different colours). Their cyan dichroic glass filter emulates Kolari's IRChrome fairly well:
https://www.ultravio...hrome-possibly/

#8 colinbm

    Member

  • Members+G
  • 2,741 posts
  • Location: Australia

Posted 17 June 2021 - 03:47

Yes Midopt are good with a large range of filters both wide & narrow pass.

#9 Fandyus

    František G.

  • Members
  • 229 posts
  • Location: Czech republic, Northern Bohemia

Posted 17 June 2021 - 17:26

Thank you for the advice on aerochrome!

#10 Andrea B.

    Desert Dancer

  • Owner-Administrator
  • 9,115 posts
  • Location: UVP Western Division, Santa Fe, New Mexico

Posted 17 June 2021 - 22:48

Click the ampersand in the upper right corner to go to the big search page.
Enter Aerochrome in the box.
Match: All words. Search title and content.
Search in Section: Forums
Find in Forum: Filter Discussions and Tests.

Should bring up a good list to begin with. Lots of nice examples in this list.
Andrea G. Blum
Often found hanging out with flowers & bees.

#11 Fandyus

    František G.

  • Members
  • 229 posts
  • Location: Czech republic, Northern Bohemia

Posted 22 June 2021 - 22:33

View PostAndrea B., on 17 June 2021 - 22:48, said:

Click the ampersand in the upper right corner to go to the big search page.
Enter Aerochrome in the box.
Match: All words. Search title and content.
Search in Section: Forums
Find in Forum: Filter Discussions and Tests.

Should bring up a good list to begin with. Lots of nice examples in this list.
Thanks! I didn't realize I should've searched first. Sorry.