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Cheap Alternative To IRChrome (Possibly)


eye4invisible

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A little while ago, I posted about the possible use of gobo filter glass - the dichroic filters used for light displays, such as night time architectural lighting:

https://www.ultravioletphotography.com/content/index.php/topic/3457-dichroic-gobo-filters/

 

I ordered 6 pieces of glass (2 lots of 3 pieces each) from a vendor on Aliexpress. These pieces come in 54mm diameter, which fits snugly inside a spare 55mm UV filter ring.

 

One of those colours is cyan. Here is a side-by-side comparison of the colours passed by the dichroic glass (left) and IRChrome filter (right)

post-116-0-90360000-1568310797.jpg

 

Unfortunately, at 0.7mm thick, I managed to crack the edge of the glass. but I was able to "recover" it by sandwiching it between 2 pieces of UV filter glass. No doubt that will affect image sharpness, but the crack is not apparent in the shots I took.

 

What was interesting was that when I mounted this glass and screwed it onto the lens, I got a very similar SOOC render to that of the Kolari Vision IRChrome filter.

 

Here's a shot from my balcony, no processing, just re-sizing using the IRChrome filter:

post-116-0-48044200-1568311007.jpg

 

Next shot is using the cyan dichroic glass, after re-adjusting the WB:

post-116-0-11927000-1568312022.jpg

 

Both shots taken on my full spectrum Sony A7 with 28-70mm lens (the widest native lens I have) at 28mm and 29mm (zoomed in 1mm in error when changing filters).

 

Of course, at a wide angle, the dichroic effect is quite strong, but on a 50mm lens it is not present.

 

Outside of the dichroic discolouration, the tonality is slightly different, but using post-processing, you can still acheive the same aerochrome look:

post-116-0-57024100-1568313056.jpg

 

The dichroic filter itself has a rosé copper tone when viewed across the surface:

post-116-0-64143300-1568313121.jpg

 

Here's the link to the product, in case anyone is interested:

https://www.aliexpress.com/item/32955163599.html?spm=a2g0s.12269583.0.0.5d4026bcoWSZzO

 

So, with some caveats, this glass seems to be a cheap alternative to the IRChrome filter.

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Interesting results, Andy. Thanks!

 

That is a rather strong dichroic effect. Is there a way to subtract the magenta in the converter you use? In Photo Ninja there is a magenta slider which could be turned off which might help.

 

 

I wanted to mention that I liked that first photo as a photo. It's as though someone is holding their glasses away from the face.

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That is a rather strong dichroic effect. Is there a way to subtract the magenta in the converter you use? In Photo Ninja there is a magenta slider which could be turned off which might help.

Thanks, Andrea!

 

Yes, I use Lightroom for most of my edits, and I could play around with the sliders, assuming of course that there are no purple/magenta objects in my shot that would also get desaturated. For landscape photography, it's unlikely to be an issue.

 

Call me weird, but for videography I actually like the effect I get from the dichroic glass :lol:

 

I wanted to mention that I liked that first photo as a photo. It's as though someone is holding their glasses away from the face.

Now that's an idea... infrared sunglasses! :grin:

 

There are 5 other colours that I got as part of the 2 lots: deep red, dark blue, yellow, purple and black. I am going to make a Part 2 post about those.

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Here's the simple edit in Lightroom, Orange hue slider -67, Purple hue slider -100 (not shown: Orange luminance slider -50). Changing the Magenta slider had no effect:

post-116-0-01981000-1568324967.jpg

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This is an interesting find. However, I thought the only point of the IRchrome was that you don’t have to process the image, so if you have to process the colors anyhow, why not just use Tiffen#12 and get the true aerochrome look with red turning yellow and so on?
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Col, The IR Chrome is B-410, which YOU discovered and tested first before anyone, but the IR Chrome is B-410 stacked with KG3 type glass (in my opinion).

If not for you, there would probably not be an IR Chrome.

Stack your B-410 with KG3 and you sill see what I mean.

However, the 729 + KG3 stack is more red out of camera.

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This is an interesting find. However, I thought the only point of the IRchrome was that you don’t have to process the image, so if you have to process the colors anyhow, why not just use Tiffen#12 and get the true aerochrome look with red turning yellow and so on?

I've never been able to get the red aerochrome look from KV's IRChrome filter, straight out of camera, and neither with this filter. The rendering is basically the same, although a little less variation in the foliage (as Col pointed out) plus the dichroic discolouration at wider angles.

 

I bought the IRChrome at the same time I got my A7 converted to full spectrum (mostly to save on the shipping costs, since it's USD 75.00 for UPS shipping from KV for the conversion, and no extra shipping on top for the filter).

 

The KV filter is good quality, although a bit pricey (the 55mm version is USD 109.99 before shipping - to compare to the 54mm dichroic glass diameter - although I have the 52mm version which is USD 5.00 cheaper).

 

For just over 3 bucks per piece for a 3 piece lot, plus cheap shipping out of China, plus a few caveats, the dichroic glass is not bad as a backup filter, if I should ever lose/damage my KV one.

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I don't own an IRChrome filter but I can see some better variation in the different IR foliage with the IRChrome filter.

Col

Yes, straight out of camera from raw to jpeg, you're correct.

 

However, using the Vibrance slider in Lightroom (and lowering the Saturation to compensate) I can pull out more variance in the foliage when working with the raw image file.

 

The other possibility is due to a softer image with the dichroic glass being sandwiched between the 2 UV filters (just to stop the cracked edge from falling out - the other 5 dichroic filters I purchased are intact). Plus also the distance of the trees might be a contributing factor.

 

I'll be doing more tests with this filter.

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The GRB3 Chinese glass does work as a cheaper KG3 alternative with a sheet of Lee #729.

I ordered official 2mm kg3 in 16mm round. Was expensive, but fit my 8mm fisheye. The output is similar to GRB3.

 

So if you don't mind Chinese glass thats an alternative.

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Yes, straight out of camera from raw to jpeg, you're correct.

 

However, using the Vibrance slider in Lightroom (and lowering the Saturation to compensate) I can pull out more variance in the foliage when working with the raw image file.

 

Thanks Andy

I really like to see the variance in the foliage....much more scientific....;-)

Col

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  • 1 month later...

Hello !

Nice findings Andy :)

 

As asked by Steve, here is a try of emulating a result by doing the WB differently. Instead of doing it on neutral gray, if a more warm color is used here would be the result (of course done in post but the goal would be to achieve it directly in-camera) :

 

6DWGro6.jpg

T8ameK5.jpg

 

The orange cast on the leaves is shifted to red and the sky blue is more intense.

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Andy, this would be a nice juncture for you to post that balcony pic using the Hrommagicus filter SOOC that you sent me, for comparison here.

How did you WB that one? Did you say concrete, asphalt? I forget.

I use a WhiBal card myself, a big one that fills up the frame.

Time for bed here, Yann. :smile:

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Andy, this would be a nice juncture for you to post that balcony pic using the Hrommagicus filter SOOC that you sent me, for comparison here.

How did you WB that one? Did you say concrete, asphalt? I forget.

I use a WhiBal card myself, a big one that fills up the frame.

Time for bed here, Yann. :smile:

 

Yes indeed, a comparative test between all the methods would be great (but of course in same day/time/lighting conditions and with consistent camera parameters - EXIF are mandatory) and of course comparison with true Aerochrome film just for fun :) The Hrommagicus filter seems a great variation of ScubaKG3 with vibrant reds. I wonder how it compares to the IRChrome in terms of shutter speed ans durability in time. But in terms of SOOC reds of course it outperforms any competitor. Good night Steve :-)

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  • 1 month later...

Thanks for posting this Andy

I wanna give this a try as well but the seller has multiple colors available.

Have you tried cyan, blue and light blue or have you only purchased the cyan filter as shown in your first post?

Just curious how the other two perform.

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Nisei, In my opinion, you will get the same from Hoya B-410 2mm + KG3 2mm.

The B-410 stack has the same 'orange' look as the two filters compared above, and with with no dichroic anomaly that the dichroic version above has.

You might even try B-410 on its own first, but you will see an improvement when stacking with KG3 2mm.

A couple B-410 test examples:

https://www.ultravio...dpost__p__26385

 

The Lee C47 dichroic filter will also works the same:

https://www.ultravio...__fromsearch__1

 

If you want redder foliage (instead of orange) then try Lee 729 stacked with KG3.

See David Twede's page:

https://next-eyes.bl...tal-ir.html?m=1

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This is an interesting find. However, I thought the only point of the IRchrome was that you don’t have to process the image, so if you have to process the colors anyhow, why not just use Tiffen#12 and get the true aerochrome look with red turning yellow and so on?

Well, we all process our OOC images one way or another don't we?

But another great point in using these filters is that you can judge in-camera if a scene looks nice in infrared.

Using a Tiffen #12 you'll have to guess how it's going to turn out.

I've had many shots that I thought were going to look great, only to be disappointed when I got home and sat behind my computer.

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Nisei, In my opinion, you will get the same from Hoya B-410 2mm + KG3 2mm. The B-410 stack has the same 'orange' look as the two filters compared above, and with with no dichroic anomaly that the dichroic version above has. You might even try B-410 on its own first, but you will see an improvement when stacking with KG3 2mm.

Thanks Cadmium.

Yes, I've already been reading these threads and find them very interesting.

Problem is I'm on a low budget at the moment even though I have a Sony A7 full spectrum camera. But I bought that before I got divorced :)

I simply can't afford to spend $100 on a filter at the moment. The B-410 alone is already $70 and I can only find KG3 in small sizes or square shaped.

The dichroic filter Andy posted is only $10 (for 4!) so ideal to experiment with.

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The Lee C47 is pretty inexpensive also. I got a special order size which was slightly more money, but still only about $15, plus shipping.

However, I think the test I did shows it stacked with KG3.

 

There are a lot of Lee film filters that will look orange, and they are very inexpensive, again however they look best when stacked with KG3.

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Thanks again Steve.

Just trying to figure out what the KG3 is doing in this stack.

Looking at the graph of KG3 I notice transmittance at 700nm is still 50% but above that it blocks more and more IR.

So which range of the IR spectrum are we aiming for?

 

John

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The way I see it, KG3 does two things.

1) overall it attenuates the amount of IR, especially in the upper range like you say.

2) it transmits mostly in the low IR range, which most camera sensor Bayer filters are more sensitive to in the Bayer red than in Bayer blue and green.

The 729 blocks all visual red light. Other filters can block visual red also, but 729 blocks more red than B-410 and other filters.

The KG3 transmits less of the higher IR that the Bayer blue and green are sensitive to, and transmits more of the lower IR that the Bayer red is more sensitive to,

thereby replacing the missing visual red with mostly low IR that the red is more sensitive to, and reducing the transmission of higher IR to the Bayer blue and green.

This saturates the red channel with more IR than the blue and green channels.

 

There various graphs showing the typical Bayer filter sensitivity up into the NIR. So take your pick:

https://www.google.c...WMvrP35I3xETrM:

 

See how the Bayer RGB transmission evens out at about 850nm. So suppressing IR above about 800nm makes sense, leaving a more intensified red from the 700nm to 800nm range.

It isn't perfect, but it works better with the KG3 2mm. KG3 2mm can do this with other IR false color filters also.

 

I have tried it with KG1 2mm and with KG2 4mm, KG3 2mm + KG1 2mm, and only the KG2 2mm works best.

The other strengths and thickness combinations reduce or transmit more or less of the IR. KG3 2mm seems to be the sweet spot for 729, and other stacks I have tried also.

It is really a combination of those two filter transmissions that makes the red look more red (729 + KG3 2mm).

The 729 is a dark filter, needs longer exposure time than many filters, but it does do red instead of orange, and it is perfectly hand-hold-able at low ISO outdoors,

I never have any problems with that, as Andy mentioned also:

https://www.ultravio...dpost__p__30870

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Ah I see, so what's needed is NIR while suppressing higher IR (this kinda contradicts what I've been reading about there being too much NIR without a KG3 filter).

I was looking into getting a clip-in filter for my Sony A7 and stumbled across this company:

https://www.astronomik.com

Particulary this one caught my attention:

https://www.astronom...tml?___store=en

It seems to rapidly drop down beyond 700nm (too bad the graph doesn't go any higher).

It's not cheap though.

I was looking for some kind of behind-the-lens filter frame to experiment with Lee filters but this one may already be what I'm looking for.

Would be nice to find someone who has one and get some sample shots.

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To be clear, when I say "higher IR", that is a term I made up. NIR is 700nm to 1200nm (in my mind), "higher IR" is whatever part of that range that would be approximately 800/850nm and up.

I don't see any contradiction here at all.

There is less NIR with KG3, because it lessens the upper part of the NIR range.

When I say "higher IR" I am talking about the higher part of the NIR range.

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Oh I didn't refer to anything you said Steve.

I assumed we needed to lower the 600 to 800 range and keep everything above because David Twede wrote in his blog:

The scuba blue still passed a little too much near infrared. I added a Schott KG3 glass in front of the lens.

I interpreted that as there only being too much near infrared.

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