Quick question - is ZWB3 really passing UV from about 230nm?

[lukaszgryglicki]

I need good OD to block other lines above 253.7nm - I will not be asking if this was possible or simple, this is why I keep searching for something that can be used...

Hmmm - I'm using UV-Nikkor with Nikor-F -> GF mount conversion - I think it is a good idea to try to mount behind the lens, not sure if such adapters exist, but this is a very good idea, I will research this.

 

Regarding stacking 2 interference filters - 1 is not enough and 2 is too much, I just need 20% to 30% thicker glass and I asked for this in my RFQ, will see what they answer.

 

In the meantime do you know any adapters allowing mounting filters behing Nikon-F lenses - I guess such adapter/filter should be generic as all Nikon-F lenses use the same mount ? What size is needed then?

 

[ulf]

Using filters is not that common anymore.

Maybe there are no lens-camera adapters of the type you need with a filter mount.

An alterative would then be to find an adapter with an internal shape at the camera side that might accept filter(s) fitted snuggly inside by other means than filter threads.

That could be a temporary fit by friction or permanently by gluing the filter inside. During experimentation putty mount might do.

 

This adapter looks to be a good candidate:

https://www.kentfaith.com/KF06.351_nikon-lenses-to-fuji-gfx-camera-mount-nik-gfx-adapter

 

As you have the camera you can measure the mount opening and do an estimate from the pictures of what filter diameter might fit. 

Also most technical- (and astro-) filters do not use conventional camera filter threads and many have non-threaded filter cells.

[ulf]

From this drawing it seams like the inner opening diameter towards the camera might be around 58mm:

https://rafcamera.com/adapter-m58x0-75f-to-fuji-gfx

A typical m52 camera filter have an outer diameter of ca 54mm so you have plenty of space for adding mount structures.

A step down ring to m52 filter with a suitable outer diameter could be glued into the K&F lens to camera adapter I linked to above.

[lukaszgryglicki]

Yeah, I actually have that exact adapter KF Nik-F->GFX. I don't see a way to install glass there without leaks, this can probably be done once forever (so it would become an fixed adapter with a filter) but another problem is that the filter ASAHI mentioned before is over 6mm thick and I would need 20-30% more which gives at least about 7.5mm thickness - I will later try to search for mount adapters which already have an option to mount a filter - I think I saw such adapters from Pentax 67 to GFX (becaus ethere is a lot of space there so there are T&S adapters, macro extension/helicoid adapters and adapters with a space for square or circular filters) - now I wonder if I can find something like this for Nikon-F->GFX.

 

[dabateman]

See if you can use a Gf-mount to 52mm adapter,  screw in you filter, then a 52mm to M42 ring, then use a Nikon mount to M42 adapter. That might work.

https://www.ebay.com/itm/165689500242?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=9odjym1cqos&sssrc=2349624&ssuid=RxqKLNPYQr-&var=&widget_ver=artemis&media=COPY

 

https://www.ebay.com/itm/154031643570?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Xfl2EZvmQ6O&sssrc=2349624&ssuid=RxqKLNPYQr-&var=&widget_ver=artemis&media=COPY

[rfcurry]

Lukas,

 

I don't know why the Asahi filter is made 6.4mm thick. The substrate is fused silica, so increasing the thickness of that will do nothing to suppress NIR.
What about using a shortpass filter on the light source, and then a UVC transmitting filter, like the Asahi, on the lens? That would get you the OD you want.

 

Just a thought.

 

[JCDowdy]

Rear mount filters need not be large.

Perhaps something similar to this will give you an idea.

https://www.ebay.com/itm/271699705065

[lukaszgryglicki]

@rfcurry short pass would be ideal, but I can't find ANY short pass filter that passes say below 350 and blocks above. All NIR blockers block IR very well but then they also block UV-C.

Can you share one example of stack that will pass 253.7nm mercury line even just 15% and then OD5+ block above 280nm till 1100nm?

 

I wonder about adapter like "Vizelex ND Throttle" (https://www.amazon.com/Throttle-Compatible-Fujifilm-Mirrorless-Variable/dp/B08158Y5WF) - it is from Nikon-F to GFX and has "built-in" ND filter 1-8 stops - if I could only find such an adapter that has "filter holder" instead of anything built-in - so I can put my own filter there.

 

I also consider just byuing Another K&F Nik-F->GFX adapter and then just 50cm filter without any threads/mounts (just a piece of glass) and then glue that filter inside forever - anybody knows what would be AOI extremes for UV-Nikkor and filter mounted behind the lens inside the adapter?

 

I could try my EdmundOptics 254nm bandpass again - it is very AOI sensitive, in such a way that I can see visible light through it at angle.

 

Regarding: https://www.ebay.com/itm/271699705065 - I would how could I mount it, and what would be the minimal diameter of filter that I can mount behind UV-Nikkor lens (inside adapter F->GFX) not to cause vingetting? my guess was that it needs to be the same size as Nikon-F mount width - something around 43 mm ? (diameter of FF sensor?)

[lukaszgryglicki]

For example for Pentax 67 to GFX there is an adapter which contains filter holder/thread 49mm and also helicoid: https://fotodioxpro.com/collections/fujifilm-gfx-adapters/products/p67-gfx-dlxs

I know P67 has a longer FFD than Nikon-F so there is a place for filter holder and or macro/extension helicoid and/or tilt&shift (I already have P67->GFX t&s adapter and it works OK), but I still think this should be possible with Nikon-F->GFX especially becaus ethere are adapters with built in variable ND 1-8 stops - I just cannot find such.

 

If I can find such an adapter then I could put filter inside, otherwise I can try to glue it inside another cheapest Nik-F->GFX (like K&F).

[JCDowdy]

Something "similar" perhaps a flat plate of a more suitable wider diameter that could be trapped in a threaded junction.

Here is a low profile M65x1 female thread to Fujifilm GFX camera mount adapter that might offer a good starting point.

https://rafcamera.com/adapter-m65x1f-to-fuji-gfx

 

By the way, we are now rather off your original topic............

[JCDowdy]

OK, I love a good adapter puzzle.

 

How I would build a Fuji GFX Camera mount to Nikon F lens adapter with room for a thread trap M52x0.75 filter.

Nikon F flange focal distance, 46.5mm, minus Fugi GFX flange focal distance, 26.7mm, leaves a difference of 19.28mm adapter length to work with.

 

Start with the low profile M65x1 female thread to Fujifilm GFX camera mount adapter.  This has 7mm of flange depth.

Add to that the M65x1 male to M52x0.75 female thread adapter.  This has 4mm of flange depth

Add to that a vintage Nikon K3 Extension Ring.  This has 5.8mm of flange depth.

 

You have 2.48mm left of the 19.28 adapter difference.

 

You need to fabricate a 2.48mm thick flat disk with a diameter of slightly less than 65mm with a threaded female 52x0.75mm hole centered.

Pinch this disk between the two 65mm threaded pieces and you should be at or very near infinity focus with a Nikon lens.

You may need to reverse the 52mm filter ring to face rear if it is to tall to fit between the 65mm parts.

 

Should be fun............

 

 

 

 

[rfcurry]

Lukas,

 

There are shortpass filters out there that seem to meet your needs. Here is one supplier: https://www.materionbalzersoptics.com/en/products/filters/uv-filters.html

Figure 4 is worth a look.

Mid-Opt is good to deal with see https://midopt.com/filters/bp250-2/ Here is the curve based upon their data:

 

Bear with me on this. If you put the XUV0400 on your light source

and a filter like the Asahi ZBPA524 on your camera, at the rear of the lens, you would get the theoretical equivalent of this:

If you don't want to pay import taxes, you might ask this supplier what they can do - https://solarisoptics.eu/products/filters/shortpass-edge-filters/

 

If you need help with an adapter, you can contact me. I have already 3D printed some adapters. Per Ulf's suggestion I have used the PETG to create the shell and use standard metal components for the mount connectors.

Good luck.

 

[lukaszgryglicki]

Thanks, you gave me more options to think, will take a deeeep look, maybe during the holidays, as now I'm a bit busy finishing urgent work before holidayts...

THANKS for helping me.

 

Actually if you cna help with adapters I would be more than happy to let you design Nikon-F->GFX adapther which allows mounting filters inside (there is a lot of space available due to big FFD between GFX & Nik-F).

 

[dabateman]

8 hours ago, lukaszgryglicki said:

Thanks, you gave me more options to think, will take a deeeep look, maybe during the holidays, as now I'm a bit busy finishing urgent work before holidayts...

THANKS for helping me.

 

Actually if you cna help with adapters I would be more than happy to let you design Nikon-F->GFX adapther which allows mounting filters inside (there is a lot of space available due to big FFD between GFX & Nik-F).

 

Yes the GF-mount to M52, then your filter, than M52 to M42 adapter,  then the M42 to F-mount adapter I linked to on eBay will work. You have about 2mm for your filter of choice. 

 

[ulf]

1 hour ago, dabateman said:

Yes the GF-mount to M52, then your filter, than M52 to M42 adapter,  then the M42 to F-mount adapter I linked to on eBay will work. You have about 2mm for your filter of choice. 

 

 

If I understand David's composition correctly, I think that solution might risk reaching infinity as most filter-rings are quite a bit thicker than 2mm.

Also the m42 opening might compromise the image circle causing vignetting on the big sensor.

 

The cavity on the camera side of the K&F adapter might hold a step ring like this:

https://www.ebay.com/itm/195074616137

The outside 55mm thread part can even be filed away to make the ting thinner and gain depth. The important feature is the 52mm thread

A putty mounted ring can be tested in the K&F adapter with any 52mm filter to check for vignetting, before buying another K&F adapter to have the ring permanently glued.

 

Then you keep the correct register of the K&F adapter and avoid restricting the light path more than with a 52mm filter cell.

 

 

22 hours ago, JCDowdy said:

Rear mount filters need not be large.

Perhaps something similar to this will give you an idea.

https://www.ebay.com/itm/271699705065

I think they do need to be almost like 52mm filters for this lens camera combination, but I might be wrong.

[lukaszgryglicki]

Well 2mm is not enough - looks like filters can even be 8-9mm thick...

Also I cannot use any of those 25mm ones - they are too small, I also think that rear filter must be almost at least as big as Nikon-F mount diameter...

I will have to think about permamently gluying circular filter inside no-glass adapter, like K&F which I already have - will just need to buy a separate one just for this purpose, this looks like a best option right now.

the problem is still to get a filter (or combination) that will pass below 280nm (or just 253.7nm) and then block > 280nm with OD5+, be at least 50mm size... I still don't know what AOI range needs to be supported when using this behing UV-Nikkor - is there a way to calculate this? I can calculate when mounted on then lens by just calculating lens FOV on GFX sensor size...

 

[dabateman]

Well the added glass of the filter will change the focus point. More glass means you need to move the lens further from the sensor.  So adding glass to an already perfect adapter may not work.

Also will you want infinity?  Most subjects will be close. You will want some extra distance, especially for close focusing. 

[rfcurry]

With a difference of 19.8mm between the two FFD's, there is adequate height for a filter drawer for a 52mm filter. I have built drawers such as this:

The filter is fastened in the drawer/ring with the typical retainer ring for a 52x0.75 filter ring. Because the drawer is protected by the wall of the adapter, the drawer wall may be made quite thin.

 

[lukaszgryglicki]

I will ask rafcamera if he can make a custom adapter...

I will also order one more IV308nm filter (but this is for UV-B not UV-C). UV-B now seems easy.

[JCDowdy]

Is the back side, camera mount, of the K&F adapter removable?

 

If so, get inside there with a set of calipers and see what dimensions you have to work with.

[lukaszgryglicki]

I am feeling like a give up :(

Even if I do this it may happen that my camera will not work of UV-C and it is really really expensive.

UV-B in comparision look so easy low...

 

[lukaszgryglicki]

OK I now have two IV308 filters (just received) - it is overcast and rainy, so I can't make any useful photos, but:

- each comes as a 52 mm filter that can be dismounted into a filter frame that holds two pieces of glass - one looks very much like an IR blocker (is pink/green when looking at it from the angle) while another part is a black UV passing glass that probably needs that IR blocker to make its 308nm peak property.

- they are passing >= 57% at around 308nm and then block until 1200nm with OD4 (by the specification).

 

Now when I dismount them I cannot fit all glass in one piece, because it is too thick, but I can remove one filter's blocking thread and then put IR block + UV - pass, screw in another filter "holder" (without locker) and then again IR-block + UV-pass, and finally block it with one blocker. That way I'm getting two stacked connected filters that cannot be separated because the glass would fall, but otherwise they are OK.

 

So, now it looks like a very fat/thick filter with IR-block, UV-pass, IR-block, and UV-pass parts all put in two mounts and blocked.

When I added this on top of UV-Nikkor and GFX mono - I could see something outside, but the window glasses are totally pitch black from the inside (just like IV308+HU340 stack), so this looks like at least the same or better (deeper) UV-B stack than just one IV-308 + Hoya U-340.

 

I'm also waiting for 2nd filter transmission data file, so I can combine them in Google spreadsheet, but simple math gives:

 (55% peak + OD4 block)^2 = about 30% peak and OD8 block (the second is very important for me).

 

When there is a sunny day I'll do tests and will see if that is deeper than the IV308+HU340 stack.

 

[Forensic_Photographer]

Hello, new member here.

 

Found this thread while searching the internet for a shortwave UV 254nm camera filter.

 

I work as a photographer in a lab and we use UV at 365nm regularly - for a project we are now looking at UVC 

 

By chance i found this old filter while going through things at our lab (from a different department) that was going to be discarded.

 

Does anyone have any information regarding what it is ? (could not find any information on the net)

 

It looks like it could be a 254nm filter ?

 

The ziplock label says:

 

Typ: UV-M-IL

Nr: 52599.1

Lambda-m: 254.1 nm

Tmax: .190

HW: 7.2nm

ABM (mm): DU 50.0

Schott Glaswerke

 

 

 

[colinbm]

This looks good. Will be interesting to see the transmittance graph.

[ulf]

It is a narrow band filter with a rather low transmittance.

Some interpretation of the data:

 

Nr: 52599.1

Lambda-m: 254.1 nm.    = wavelength of the peak transmittance

Tmax: .190.       =  maximum transmittance at the peak (= 19%)

HW: 7.2nm.       = Half width of the peak where the transmittance goes below 9.5% (that is at 3.6nm on either side of 254.1nm)

ABM (mm): DU 50.0  This is a mechanical dimension of the filter. I am not sure, but it might be the outer diameter of the filter cell

Schott Glaswerke

 

What is missing in the data is the out of band rejection rate, the OD-number.

Most light sources emit light where camera sensors are several magnitudes more sensitive that at 254nm.

 

What kind of camera conversion and light source are you planning to use?