Thickness test series with ZWB1 filters

[dabateman]

I now have a whole bunch of ZWB1 filters and thought a fun thickness test in sunlight would be ok. So the lighting isn't perfect but mostly clear sky only one had odd exposure time.

 

All these are shot at the same white balance setting except for the first BG38 4mm image. I was using the Nikor 80mm f5.6 lens at F8. However I have my SvBony 0.5x booster lens on as well. Forgot it was there, so the edges will be blurry and the center should be sharper. This also allows for faster shutter speeds. All image with EM1mk1 full spectrum camera set to ISO 200.

 

4mm BG38 ISO 200 1/1000 F8:

 

I have two of the new 8mm solid thickness filters so I tested them first

 

8mm A filter ZWB1 ISO 200 F8 1.6 seconds:

 

8mm B filter ZWB1 ISO 200 F8 1.6 seconds:

 

8mm A + 8mm B ZWB1 filters ISO 200 F8 5 seconds:

 

 

Next I have 6 filters of Zwb1 that are 2mm thick (one is 52mm) the others are 58mm for light modifications

 

2mm ZWB1 (1 filter) only 1/40 seconds:

4mm ZWB1 (2 filters stacked) only 1/3 seconds:

6mm ZWB1 (3 filters stacked) only 1.3 seconds:

8mm ZWB1 (4 filters stacked) only 2 seconds:

10mm ZWB1 (5 filters stacked) only 3.2 seconds:

12mm ZWB1 (6 filters stacked) only 4 seconds:

8mmA ZWB1 stacked with 2 of the 2mm filters (total 12mm) 3.2 seconds:

8mmA ZWB1 stacked with 3 of the 2mm filters (total 14mm) 4 seconds:

8mmA ZWB1 stacked with 4 of the 2mm filters (total 16mm) 8 seconds:

8mmA ZWB1 stacked with 5 of the 2mm filters (total 18mm) 8 seconds:

8mmA ZWB1 stacked with 6 of the 2mm filters (total 20mm) 13 seconds:

8mmA ZWB1 stacked with 8mm B ZWB1 with 6 of the 2mm filters (Total 28mm) 25 seconds:

[Andy Perrin]

What does A and B ZWB1 mean?

[Andrea B.]

A and B refer to the two different zwb1 filters which dabateman has.

 

*****

 

David, this is wild !!! You have enough ZWB glass to pave your backyard !!

And a shot through 16mm of ZWB1 filters !!

 

So it would appear that 6mm is not quite thick enough and 8mm is thick enough, yes???

 

D, could you perhaps test one of your 8mm ZBW1 on a distance photo? Just to check that these filters do OK at a distance unless it happens to be the one owned by Andy??

[Dmitry]

Interesting. Why 4mm ZWB1 (2 filters stacked) not sharp?

[dabateman]

Interesting. Why 4mm ZWB1 (2 filters stacked) not sharp?

 

Its possible I screwed up focus. I needed to adjust it for the first couple IR ones. I tried to shoot 2 for each filter.

 

Also as luck would have it there was absolutely no wind until I got to the really thick stacks. So 25 seconds was windy and there is some motion blur on the flower.

 

Andy yes I bought two 8mm thick zwb1 filters. I want to also use them on UVB lights to try and eliminate visible and IR and just get the deeper UV.

 

Andrea,

I started this as Colin thought 6mm would be better in a different post. I said would leak too much IR. Then I remember that I could actually test that.

Fortunately my backyard is bigger than a bunch of ZWB1 filters.

[Stefano]

28 mm of ZWB1 is impressive. I am not at home, but I would like to see the graph of for example 28 mm of UG11 glass.

[Doug A]

Neat experiment. Thanks for doing the tests and posting the results. Have a few questions. First, when pixel peeping is there any sharpness difference between say a single 4mm stack of glass and 28mm? Seems glass that thick would cause some loss of detail. Two, we look for lenses with few glass elements to pass more UV. How does UV make it thru all this thickness and layers of glass?

Thanks for sharing,

Doug A

 

[dabateman]

Looks like 10% transmission at 330nm for 28mm thick UG11 versus 50% transmission for 8mm thick UG11. So not too bad.

I have a bunch of band pass filters with only about 10-12 % transmission.

[Stefano]

I looked now in the online calculator, it passes UV between about 290 to 370 nm.

[Guest]

When I read your post and saw SvBony all I could think about was the scene from Crazy People the movie.

 

[Fandyus]

Shame those aren't color balanced.

[colinbm]

Thanks Dave, interesting results.