New Baader U flip question.

[dancingcat]

New Baader U filter.  No side is pink for the “flip”.

The side with female threading is gold/yellow depending on angle to light.

The male-threaded side is green/blue, depending…

So mounting it “normally” on a camera lens would put the gold/yellow side facing the subject.

I do have a male-male adapter so I can “flip” it without any trouble.

Pix below were shot with my iphone under an ordinary desk lamp.

 

So flip or no flip?

 

 

[dabateman]

Don't bother flipping it. 

The reason for flipping it is if one side is extremely reflective.  That highly reflective side you want out facing the world to avoid back reflections to the sensor causing weird ghosts. 

 

 

[Cadmium]

I like David's answer, although I never knew exactly why the flip was recommended in the first place. When I tested it both ways i never found a difference.

Mine is the non green version.

Sue, I like your tests, and your test pattern!

[dancingcat]

@Cadmium lol I’m old enough to remember a pattern like that on the family tv (no color) with an Indian head on it when the one station we got was off the air.  This sheet for me is just for flower colors in herbarium pix.  I will shoot this filter both ways and test just for ducks as I won’t have to take it apart to flip it.  And ty @dabateman.

[Doug A]

@Sue does this mean you canceled the new UVR Optics filter?

Thanks,

Doug A

[dancingcat]

@Doug A yes I did cancel.  I wanted to get going on my plant project and Reed couldn’t provide either the StraightEdge or the new filter at the moment.  The new one isn’t up on his website yet.  Amazon had a Baader U (sourced from Adorama) and that came in a few days.  I’m off now to find some grocery store sunflowers to test my Kolari flash on..   Funky though that the Baader U colors are different from what other folks all seem to have.  

[Doug A]

Figured you ran out of time. The exotic glass shortage is tough on UV shooters. Our handful of filter choices has dwindled. Considering updating my Igoriginal ZWB1 2mm/BG39 2.3mm stack. Unfortunately there aren't any Schott S8612 in 52mm. The SEU is Mia. Worried spring will arrive and there still won't be any filters. Might try the Kolari.

 

I've seen reports of other Baader U filters having different colors. Looking forward to seeing your project and Kolari flash results. 

Thanks for sharing,

Doug A

[Nate]

I have that same one @Sue I think I got mine from Adorama too. I never turned it around, I read gold reflects IR pretty good as our new Telescope in space has gold plated Beryllium mirrors. Does the Baader have actual gold? I don't know, but for $400 it should.

Looking forward to your shots with it!

[Andrea B.]

Let's clarify what is supposed(?) to be Common Knowledge about the BaaderU.

Only for at least the last 10 years......

 

The BaaderU was made for telescopes, so its anti-reflective side must face the telescope. When the BaaderU is used on a camera lens for reflective UV photography, the filter is flipped so that the anti-reflective side faces the subject being photographed.

 

REFERENCE: <> Sticky :: UV/Vis/IR Filters <>

Written in 2014.

In the Sticky scroll down to the BaaderU listing: (1) Baader-Planetarium BaaderU UV-Pass Filter #2458291 350FWHM6

Prior to photographic use, it is recommended that the BaaderU be reversed in its mounting ring so that the pink side faces the subject, not the sensor. When the pink side faces the sensor there can be increased internal flare off its highly reflective surface. The orientation of the filter does not seem otherwise affect the UV image although the pink side is supposedly more IR-reflective.

 

 

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"Pink side?", you ask. "What pink side?"

The pink side, which is the most anti-reflective (AR) side and also the most IR-reflective side (IRR), is no longer pink on some of the BaaderU filters I have. But if you put your brand new BaaderU on a camera lens, then the AR/IRR side will face the sensor. Please make a note of what color is the side which should face the subject on a camera lens.

I did not do this, of course, for some of my BaaderUs. Now they are all mix-edy-uppy. I am frequently a good example for the membership of what not to do.

 

 

Does it really matter if I flip that thing or not?

Most of the time, no. UV transmission is not affected.

But I *always* flip mine because I want the IRR property to work at its best.

 

 

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Side Note:  On current Baader Planetarium unmounted filters there are either arrows or 1mm black edges which indicate the side which should face the telescope. Mounted filters always mount in the proper direction on a telescope.

 

REFERENCE: https://www.baader-planetarium.com/blogs/english/wp-content/uploads/sites/2/2016/07/filter-frontside-indicator.gif

 

 

[Andrea B.]

OK, just looked at Sue's new filter.

I have no idea.....

 

 

Our member Jonathan made this great test which confirms that the BaaderU is more anti-IR

when the anti-IR faces the photo subject.

https://www.ultravioletphotography.com/content/index.php?/topic/3916-reminder-flip-that-baaderu/

 

 

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I know of 3 different BaaderU labels (on the mounting ring).

• Baader U-Filter 2" (HWB=325-369nm) optically polished #2458291
• Baader 320-380nm U-Filter 2" optically polished #2458291
• Baader U-Filter 2" (CWL 350nm) #2458291

 

 

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The photo on the BaaderU filter box is totally misleading. It appears that the female threads are on the pink side. But the filter inside has the female threads on the green-ish side.

 

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Could Sue's filter already have been flipped??

[dancingcat]

Maybe better pictures will help.

 

The boxtop.

 

The gold side (if the filter were mounted normally on my camera, this is the side facing outwards).

 

The reverse side, blue/green depending on light angle.  I have a male-male ring adapter so mounting this side facing out would be no problem.

 

 

[Nate]

I think we have the same one, here's where I have mine set, minus the 3in hood

[dancingcat]

Here's a little test.. I got a random (rather sad) grocery store sunflower and shot it with the BaaderU mounted as you would mount any other filter.. male threads inwards, which puts the gold side facing the flower.  Then I reversed it with a male-male ring adapter, so the blue/green side faced outwards.  The lighting for the UV wasn't great - used a handheld flashlight as I haven't figured everything out on my Kolari speedlight yet.

 

body: olympus em-1mk2 full spectrum
lens: sigma 30mm DN (60mm full frame equiv)
visible: kolari hotmirror pro 2
uv: baaderU (new)
lighting: vis - ambient room light, uv - convoy s2+
subject: random grocery store sunflower, Helianthus sp., tag says sourced in Ecuador

f/8.0, ISO 400 - as shot, no post adjustments.

shot 1: visible 1/5 sec.
shot 2: uv 1.3 sec., baaderU normal mount, gold side to subject
shot 3: uv 1.3 sec., baaderU reversed with male-male ring adapter

 

I don't see any huge difference... but there might be if I was doing this in the field.  Too cold right now and no native sunflowers out yet.  Remember I am a complete rookie to UV shooting, so there may be things there I don't see.

 

 

Normal filter mounting

 

Reversed filter mounting

[Guest]

With the rear mount system I don’t even pay attention to which way it slides in. 

[Andy Perrin]

Sue, without setting a white balance off PTFE and using sunlight or flash (which have a broad spectrum of UV, unlike the torch) it's really hard to tell if there is any difference to the colors. 

 

Here is a (very poor) simulation of what it might look like if you did a PTFE white balance on the RAW using PhotoNinja or DarkTable etc., where I have increased saturation to the breaking point to try to draw some color out. This would not be necessary with a broader UV light source.

[Andrea B.]

Sue, if you would like to upload the two UV sunflower raw files, then I will run them both through Raw Digger to determine whether there is anything significantly different between the two raw data sets. I do not expect there to be, but why not check anyway?

 

**********

 

Also, what are you using to convert your raw files? Be sure to click on the magenta with the white dropper or whatever white balance tool your converter has. Then the magenta will be gone and the usual false colors will come out.

 

**********

 

I have a BaaderU labeled on the side just like yours. However, mine is definitely pink on one side and a greenish-gold on the other. I am still a bit baffled by your particular BaaderU colors. For yours, I think that probably the gold side should face the subject and the green side should face the sensor.

 

 

[nfoto]

My various Baader U filters are golden on one side and pinkish on the other. They have appreared quite similar over the period they were purchased (time span 2010-2021). The exact labeling varies though.

 

I always use them with the pink side towards the sensor subject.

[Andrea B.]

.....I always use them with the pink side towards the sensor.

 

Birna, why?

The pink side is the anti-IR side. So you want it to face outwards towards the subject.

 

Our member Jonathan made this great test which confirms that

the BaaderU is more anti-IR when the anti-IR side (i.e. PINK SIDE) faces the photo subject.

https://www.ultravioletphotography.com/content/index.php?/topic/3916-reminder-flip-that-baaderu/

[Andrea B.]

Here is an example of why the pink side of Baader U must face the subject. In 2016, I used the BaaderU on a Vivitar 35/3.5, but the two did not interact well. Dichroic filters can produce circular discolorations when used on wide-angle lenses. But when used over the Vivitar, I also got some reflection artifacts.

 

Camera:  Sony A7R

Lens:  Vivitar 35/3.5

Filter:  BaaderU UV-Pass

 

I photographed an artist's canvas painted black. The original photos were mostly black. I pushed the Levels to an extreme to bring out the artifacts. The light scuff marks are exactly that - scuff marks on the old black canvas.

 

In row one the light was behind me.

In row two, the light was perpendicular to the lens axis.

In row three, the lens was turned about 30° into the light.

 

For the left side photos, the BaaderU had its pink side facing the subject (the black canvas).

For the right side photos, the BaaderU had its pink side facing the sensor.

 

 

 

Here are the originals (after conversion/resizing) for the bottom row.

 

 

This is a photo made where the light is at about a 45° angle to the lens.

The GREEN SIDE of the BaaderU faces outwardly and does NOT suppress the reflection at all.

 

 

What I learned from that experiment in 2016 was this:  do *not* use the dichroic BaaderU on the Vivitar 35/3.5. They simply do not play well together. And I also produced a useful example with which to convince people that artifacts are possible if the BaaderU faces the wrong way.

 

I do grant -- and have said before -- that most of the time, it does not matter which way the BaaderU faces. But, when it goes wrong, it can go very wrong. Also note that if the BaaderU does induce some milder reflection artifacts than what I got here, then they might not be seen until conversion when it is to late to reshoot the work.

 

So just face that BaaderU pink side outwardly towards the subject and you will have done as much as you can. (Well, not shooting into the light is also a good move.)

[Guest]

Looks like some paranormal activity going on with that last photo. 

[nfoto]

Perhaps I shouldn't answer late in the night when my wordblindness increases? Replace 'sensor' with 'subject' .... (both have an initial 's' and that triggers the wrong response in writing. My bad).

 

My workhorse D3200 has a built-in Baader U and if I look into the camera, all I see is pink.

 

My filter drawer for rear-mounting, showing the Baader U,

 

Sometimes the filter itself can be used for pictorial purposes, like this

 

 

Whilst the filter might have been in the appropriate direction, my former self wasn't. Life is full of surprises. They even transcends UV (!).

[Doug A]

@nfoto would love to see a picture of the D3200's built in Baader U filter. It is such a unique piece of equipment. Trying to visualize if the filter fits in front of the mirror or behind it.

 

Thanks,

Doug A

[nfoto]

The Baader U sits directly on top of the sensor, i.e. behind the mirror.

 

At Ruth's place now, will make an attempt of making the requested photo later.

[nfoto]

Just "pretty in pink" ...

 

 

The lip arrearing to be intruding (upper lef corner) of the sensor is the reflection of the edge of the bayonet mount. And of course the reflection of my hand holding the phone :)

 

Interestingly the internal Baader U is much cleaner than any of my other filters, since it sits well protected behind the mirror and shutter curtain 99.999% of the time. I'm having it professionally cleaned every second or third year as I don't trust my own capabilities for this task.

[dancingcat]

@Andrea B. the original RAW ("ORF" in Oly-speak) files of "normal mount" and "reverse mount" you asked for are in Dropbox here https://www.dropbox.com/sh/xhr2j0gslkotu4t/AAD7D5GC-Ya15xUVUiIwSbFda?dl=0.  

I didn't want to clog up things here with big files.

I did get rid of the pink by running the WB temp down to 2K in Lightroom, but the originals are as-shot.  I do all my work in Lightroom, so don't use any other RAW converter.

I'd be interested to know the details of what you are doing to wrangle RAW files...