• Ultraviolet Photography
  •  

EIR / Aero Photos

34 replies to this topic

#1 colinbm

    Member

  • Members(+)
  • 1,442 posts
  • Location: Australia

Posted 18 January 2020 - 04:33

What filter combinations give the best EIR / Aero photos, but particularly looking at the best / greatest differences in the vegetation's.
Cheers
Col

#2 Andy Perrin

    Member

  • Members(+)
  • 2,772 posts
  • Location: United States

Posted 18 January 2020 - 04:39

I personally think the IRG is best (after using image subtraction on the channels, which can be done in Photoshop). That is with Tiffen #12. I also add a DB850 filter from MidOpt sometimes because it removes the contamination from the 700-800nm range stacked with the Tiffen #12.

Edited by Andy Perrin, 18 January 2020 - 04:39.


#3 colinbm

    Member

  • Members(+)
  • 1,442 posts
  • Location: Australia

Posted 18 January 2020 - 04:54

View PostAndy Perrin, on 18 January 2020 - 04:39, said:

I personally think the IRG is best (after using image subtraction on the channels, which can be done in Photoshop). That is with Tiffen #12. I also add a DB850 filter from MidOpt sometimes because it removes the contamination from the 700-800nm range stacked with the Tiffen #12.
Oh, that is a strange combination......blocking 700-800nm....why do you call it contamination ?
I have found that 700-800nm is where chloroform is starting to reflect the IR ?
Col

#4 Andy Perrin

    Member

  • Members(+)
  • 2,772 posts
  • Location: United States

Posted 18 January 2020 - 05:03

So, the idea of getting an IRG image in one shot is that you start off with pure IR in the blue channel, but red and green channels have a mix of IR and actual red and green. The problem is that the 700-800nm band goes in red and green channels unequally, so it messes up the subtraction.

With TIffen #12 alone:
original red channel = red light + IR light (800+) + some IR light (700-800)
original green channel = green light + IR light (800+) + some other IR light (700-800)
original blue channel = IR light (800+)

With Tiffen #12 + DB850:
original red channel = red light + IR light (800+)
original green channel = green light + IR light (800+)
original blue channel = IR light (800+)

So the subtraction works perfectly with the Tiffen #12 + DB850, but not with Tiffen #12 alone.

Edited by Andy Perrin, 18 January 2020 - 05:04.


#5 dabateman

    Da Bateman

  • Members(+)
  • 1,415 posts
  • Location: Maryland

Posted 18 January 2020 - 05:58

View Postcolinbm, on 18 January 2020 - 04:33, said:

What filter combinations give the best EIR / Aero photos, but particularly looking at the best / greatest differences in the vegetation's.
Cheers
Col

I would say trick question. Like asking which is the most beautiful person. We all have our different preferences and mood will even change that. I have grown to like more red, but used to only like the golden look.
So Lee 183 with GBR3 filter was my orangey favorite a year ago. Now I would like the Lee 729 with KG3 the best. The Lee 729 with GBR3 is more magenta.
The Kolari IRchrome seems to be too orange now.

Just play around, seems to be many different cheap options. Also since they are cheap, not very consistent. Like GBR3 doesn't equal KG3, but is close.

#6 GaryR

    Member

  • Members
  • 204 posts
  • Location: London, Ontario, Canada

Posted 18 January 2020 - 16:38

Hi Colin,
I've had decent results, using a #12Y + XNite CC2 stack. The KG3 or Kopp 7093 will provide a better IR cutoff (around 850nm), but if you already have a CC2, or weak hot mirror filter, it may be worth a try.

The IR Chrome or Lee729/KG3 filters, will give you an instant aerochrome look, but you won't get red to yellow/green color shifts, or subtle variations of red/magenta foliage. I still experiment with my IR Chrome filter, but don't expect true aerochrome colors.

I still like the SOOC results that you get from the Sigma foveon sensor, but the only way I've found to get a complete aerochrome look, is with a Y/IR cutoff stack and processing.

KODAK AEROCHROME III Infrared Film - Spectral Sensitivity
"... sensitive to ultraviolet, visible, and infrared radiation to approximately 900 nm."

https://www.kodak.com/uploadedFiles/Corporate/Industrial_Materials_Group/ti2562.pdf

Edited by GaryR, 18 January 2020 - 19:07.


#7 OlDoinyo

    Member

  • Members(+)
  • 711 posts
  • Location: North Carolina

Posted 18 January 2020 - 20:21

Do you want authentic IRG, or do you merely want red vegetation? If merely the latter, there are numerous ways to get there, including some that do not even require actual IR (see https://www.flickr.c...inyo/8973905391.) Some of the easiest ways to achieve red leaves are probably those using a red-blocking filter to ensure that the red channel records infrared rather than red. Using a Foveon sensor without a filter will also give you a version of this. These latter two methods require only tweaking to produce the final product (no fancy math or channel swapping.)

If you are after real IRG, the gold standard is the two-image method: separate infrared and visible images with the appropriate channel paste-ins. However, this method may be inconvenient for many types of subject matter. Thus, singe-image methods have been developed which are much more convenient and accurate enough for artistic purposes (if not for scientific use.) Of these, if you are specifically trying to emulate Aerochrome film, Nick Spiker's approach is the most faithful; you can find documentation on his website, although the concept is involved. For more general (non-emulative) single-exposure IRG, a simpler approach using a Pixelbender plugin or equivalent can handle the necessary image processing steps. Key to the last two methods is the use of a sharp-cutoff (blue-blocking) yellow filter such as Tiffen 12 or 525LP dichroic.

#8 Cadmium

    Member

  • Members(+)
  • 3,146 posts

Posted 18 January 2020 - 21:25

"The KG3 or Kopp 7093 will provide a better IR cutoff (around 850nm), but if you already have a CC2, or weak hot mirror filter, it may be worth a try."

KG3 and Kopp 7093 should be the same at the same thickness. Use 2mm, thickness is essential.
CC2 is KG1, it will not work like KG3, unless double stacked (4mm) and even then it is not exactly the same. KG1 4mm should work about the same as KG3 2mm, but KG3 2mm would be best.
CC1 = Schott BG38 (used primarily for visual photos with a full spectrum converted camera).

Again, thickness is essential.
Attached Image: KG_All_CC2_Kopp7093.jpg

#9 GaryR

    Member

  • Members
  • 204 posts
  • Location: London, Ontario, Canada

Posted 19 January 2020 - 00:12

Steve, Yes, the KG3 is a far better choice. Hope to acquire one someday.

Clark, I use the Nick Spiker profile on my a7R, but I still like the foveon reds from various Sigmas that I've owned.

#10 colinbm

    Member

  • Members(+)
  • 1,442 posts
  • Location: Australia

Posted 19 January 2020 - 04:17

Thanks for the input everybody....
Yes I am interested in seeing what gives the best separation of the reds in the vegetation, over the 'pop' of the reds.
I will try these with a Bayer & Sigma Foveon cameras.
I am a bit reluctant to go the software way....consider me dumb, but with a bit of basic processing.....
Cheers
Col

#11 dabateman

    Da Bateman

  • Members(+)
  • 1,415 posts
  • Location: Maryland

Posted 19 January 2020 - 06:12

View Postcolinbm, on 19 January 2020 - 04:17, said:

Thanks for the input everybody....
Yes I am interested in seeing what gives the best separation of the reds in the vegetation, over the 'pop' of the reds.
I will try these with a Bayer & Sigma Foveon cameras.
I am a bit reluctant to go the software way....consider me dumb, but with a bit of basic processing.....
Cheers
Col

Colin the Sigma camera is a totally different beast. For that try a X1 filter or green if you have one.
Gary posted about it here:
https://www.ultravio...h__1#entry21026

and so did Jonathan with his Sd14:
https://www.ultravio...dpost__p__25898

Edited by dabateman, 19 January 2020 - 06:23.


#12 colinbm

    Member

  • Members(+)
  • 1,442 posts
  • Location: Australia

Posted 19 January 2020 - 07:23

Thanks Dave
Yes I have mucked around with my Sigma cameras before....SD15, Dp1 & 2 without hot mirrors, now to try with the SDQ....& a full spectrum Bayer camera...
Col

#13 Cadmium

    Member

  • Members(+)
  • 3,146 posts

Posted 19 January 2020 - 09:07

Andy's original Tiffen #12 + DB850 topic:
https://www.ultravio...__fromsearch__1

#14 colinbm

    Member

  • Members(+)
  • 1,442 posts
  • Location: Australia

Posted 19 January 2020 - 13:32

Excellent, thanks Steve

#15 Andy Perrin

    Member

  • Members(+)
  • 2,772 posts
  • Location: United States

Posted 19 January 2020 - 15:28

The last post in the link Cadmium posted explains how to do the processing in Photoshop

Edited by Andy Perrin, 19 January 2020 - 15:28.


#16 Timber

    Member

  • Members
  • 231 posts
  • Location: London

Posted 19 January 2020 - 20:49

well if you are on a very tight budget and want to have the EIR SOOC, like me, then Hoya 80C + Lee 729 Scuba Blue Gel :)

#17 Cadmium

    Member

  • Members(+)
  • 3,146 posts

Posted 20 January 2020 - 01:29

We don't know what 80C does above 750nm, and that is the range we are using KG3 for with the 729 stack.
Looking at the 80C graph, one could imagine that the transmission flattens out above 750nm, and that is not what we are wanting it for, we want to drastically slope the IR transmission down above 780nm/800nm.
Unless someone has a graph of 80C above 750nm, or perhaps a direct comparison (all things being equal) between a 729 + KG3 2mm stack and the 729 + 80C stack, then...who knows.
Attached Image: Lee_Scuba_Blue_729_KG3_80C_Bayer.jpg

Edited by Cadmium, 20 January 2020 - 01:43.


#18 colinbm

    Member

  • Members(+)
  • 1,442 posts
  • Location: Australia

Posted 20 January 2020 - 03:05

While looking for stuff, I found this....
https://www.yumpu.co...sic-photography

#19 Andy Perrin

    Member

  • Members(+)
  • 2,772 posts
  • Location: United States

Posted 20 January 2020 - 04:16

That seems interesting but I kind of wonder if it’s true? Certainly the Schott filters are not gelatin. I suppose Kodak might be different.

#20 Cadmium

    Member

  • Members(+)
  • 3,146 posts

Posted 20 January 2020 - 07:53

Col, I am not sure what you are pointing out in that link.
Andy, what part are you wondering about?

Edited by Cadmium, 20 January 2020 - 13:19.