My First Attempt UV (BG39 + WB2) some portraits and buildings - Any CC Appreciated!

[mason2spectral]

I'm using a Sony A7R + Sony-Zeiss 55 1.8 + ZWB2 and bg39 stack and I'm not sure exactly if I'm doing things correctly or if the filters are working 100% as intended. 

 

I shot a couple of test shots outdoors. I didn't WB the camera and ended up using the same profile I use for 850nm to white balance in Lightroom.

I tried several processes - I put some photos through DXO PureRaw (to clean up grain and correct distortion) then edited in LR while for another I tried editing in DXO PhotoLab 5 and in LR so I will post below the process used for each.

 

Filters:

https://m.aliexpress.com/item/1005003432469423.html?spm=a2g0n.order_detail.0.0.23daf19cQqAl4I

      AND

https://m.aliexpress.com/item/4001322146531.html?spm=a2g0n.order_detail.0.0.4f8ff19cS2QNjD

 

Looking for any CC or suggestions! Also trying to verify the filters are working as they should!

[mason2spectral]

Portrait of Construction Worker

A7R + WB2 + BG39 Knockoff | Sony-Zeiss 55 f1.8

ISO 3200, 55mm f/3.2, 1/100s

 

Edited in DXO PhotoLab 5

 

Same Portrait Edited in Lightroom

[mason2spectral]

Portrait Close-Up of Construction Worker

 

A7R + WB2 + BG39 Knockoff | Sony-Zeiss 55 f1.8

ISO 3200, 55mm f/3.2, 1/100s

 

DXO PureRaw -> Lightroom, Used 850NM Profile then WB and HSL to fix yellows

 

DXO PureRaw -> Lightroom, Adobe Monochrome B&W 

[mason2spectral]

Some buildings on/around my campus:

 

Quick Edits in LR Only:

 

Color Treated with same profile as 850nm | B&W treated with Adobe Monochrome Profile

55mm iso 3200, 1/100s, f/5.6

 

 

 

 

 

                          

 

                                                               

                                                                                                                     

55mm iso 1600, 1/60s, f/4.5

 

55mm iso 2000, 1/60s, f/4

 

55mm iso 1250, 1/60s, f/3.5

[Cadmium]

What is WB2?  Thanks.

[colinbm]

Good to see you having a go at it.
The lens & filters may not be optimum, but you are getting some results.
Is the Sony A7R converted to 'full spectrum' ?

[Andy Perrin]

I had the same question as cadmium, the WB2 filter is unknown to me, so it probably has some other name also? Or it's rare?

 

I am not sure what light you are trying to image (because I don't know the filter) so it's hard to tell what the images "should" look like.

[mason2spectral]

1 hour ago, colinbm said:

Good to see you having a go at it.
The lens & filters may not be optimum, but you are getting some results.
Is the Sony A7R converted to 'full spectrum' ?

Yup! Full spectrum a7r converted by Kolari Vision

 

1 hour ago, Andy Perrin said:

I had the same question as cadmium, the WB2 filter is unknown to me, so it probably has some other name also? Or it's rare?

 

I am not sure what light you are trying to image (because I don't know the filter) so it's hard to tell what the images "should" look like.

I meant zwb2 XD  

This: https://m.aliexpress.com/item/1005003432469423.html?spm=a2g0n.order_detail.0.0.1255f19cACJ5em

 

And This: https://m.aliexpress.com/item/4001322146531.html?spm=a2g0n.order_detail.0.0.4f8ff19cS2QNjD

 

 

[mason2spectral]

1 hour ago, Cadmium said:

What is WB2?  Thanks.

Apologies for any confusion

Updated original post with links to the filters!

[Andy Perrin]

Ahh, I feel like I should have guessed. Anyway, my thoughts are that the grass looks much too light here, and quite a bit of infrared might be getting through. The exposure times you mentioned also seem much too short for pure UV photos. You should be getting a dark photo of grass at 1/100" F4.5 in UV. I can probably test a similar configuration tomorrow using actual Schott glass (the Chinese versions can be out-of-spec sometimes) and see what I get. I own that lens.

 

What are the filter thicknesses please? Thickness is very important info.

 

Here's some more typical examples of what you usually see in UV for grass/ground covering plants:

https://www.ultravioletphotography.com/content/index.php?/topic/4167-mauthausen-in-uv/#comment-39638

 

[Cadmium]

Honestly, none to these really look like UV photos. Some just look like B&W photos.  I don't know why and I don't have any advice.

If your U filter is similar enough to U-360 (UG1) then it should be working when stacked with a BG39 type filter, but if so I would expect different results than what you are showing.

[nfoto]

None of the photos bear any identifiable UV appearance .... Telltale signs of UV would be very bright skies (and water surfaces),  dark ground vegetation, dark foliage on trees, very hazy scenery at distance, and so on. Humans, in particular of the male kind, appear dark-skinned/swarthy.

 

For testing get a few flowers with known UV signature and see how they look like. That will tell what might be off in terms of filtration or technique.

[ulf]

I also suspect, without knowing anything about the lens, that the Sony-Zeiss 55 1.8 is not transmitting much UV.

[nfoto]

Salient point, Ulf -- easy to overlook if one is accustomed to the luxury of UV specialist lenses !!

[mason2spectral]

6 hours ago, Andy Perrin said:

Ahh, I feel like I should have guessed. Anyway, my thoughts are that the grass looks much too light here, and quite a bit of infrared might be getting through. The exposure times you mentioned also seem much too short for pure UV photos. You should be getting a dark photo of grass at 1/100" F4.5 in UV. I can probably test a similar configuration tomorrow using actual Schott glass (the Chinese versions can be out-of-spec sometimes) and see what I get. I own that lens.

 

What are the filter thicknesses please? Thickness is very important info.

 

Here's some more typical examples of what you usually see in UV for grass/ground covering plants:

https://www.ultravioletphotography.com/content/index.php?/topic/4167-mauthausen-in-uv/#comment-39638

 

Should be 2mm bandpass. Not sure on the ir cut... maybe 1mm for that?

[mason2spectral]

5 hours ago, nfoto said:

None of the photos bear any identifiable UV appearance .... Telltale signs of UV would be very bright skies (and water surfaces),  dark ground vegetation, dark foliage on trees, very hazy scenery at distance, and so on. Humans, in particular of the male kind, appear dark-skinned/swarthy.

 

For testing get a few flowers with known UV signature and see how they look like. That will tell what might be off in terms of filtration or technique.

I'll try white balancing some images in-camera today if I have some time after my classes.

[colinbm]

1 minute ago, mason2spectral said:

I'll try white balancing some images in-camera today if I have some time after my classes.

The tiniest amount of IR will drown out any UV.

[ulf]

The glass thickness is a very important aspect of a filters IR rejection. In some cases going from 2mm to 1mm increases the amount of IR leakage tenfold or more.

[Andy Perrin]

9 hours ago, ulf said:

I also suspect, without knowing anything about the lens, that the Sony-Zeiss 55 1.8 is not transmitting much UV.

This is not quite true. I own the lens and it definitely passes enough to show some false color. I’m going to try to take some photos with it later. 
 

I actually think a too-thin BG39 equivalent is the culprit here and the images are swamped with IR. 

[ulf]

I agree that the main problem is IR-contamination, but a marginal lens can also show some false colours, but then also make the UV / IR ratio worse, enhancing the IR-component.

Until you have transmission measurements or some reasonable comparison with a known good lens it is extremely difficult to tell the UV-capability.

[Andy Perrin]

Ok, here is what I get from a quick test using BG39 2.5mm and UG11 2mm on (full spectrum) Sony A7S. The top row is the Sony 55mm/1.8 and the bottom is the Kuri 35/3.5 (which is known to have good UV pass). For the left side I took a photo using normal settings (whatever looked nice, this is just so you can see the colors), and for the right photo I used the same F/5.6 1/100" ISO3200 that was used by mason2spectral. As I expected, at 1/100" the image is very dark in both cases. The Sony clearly is transmitting much less UV than the Kuri, as we would expect.

 

All white balances were done off of PTFE in PhotoNinja on the computer (not in-camera).

 

The grass is dark and the sky is light, which is normal for UV pictures. The Sony has much less color and obviously a much-reduced bandpass. I also noticed that the Sony did not like to focus well in UV.

 

[Yves W]

I have different models of BG39=QB39. I have Tangsinuo and I'm not sure they're the best for IR cutting.

I am looking for others that I have already purchased but whose contact details I have lost.

[Andy Perrin]

The best for IR cutting for UV photography (not visible) is S8612 2mm. If you get some of that, you are pretty much set for life. The BG glasses are all inferior to S8612, and knockoffs may be even worse.

[Yves W]

Thanks Andy, I know, I've been following the forum for a long time. The problem is that I have different filters ZWB1, ZWB2, ZWB3, ZB1, ZB2... There is only the Baader U which I have been using alone for 10 years.

 

[Andy Perrin]

Baader U should be fine by itself in sunlight? You shouldn’t have to add additional blocking unless you have nonstandard lighting (eg night photos). I think I do not understand your problem maybe?