lens recommendation for UV on Sony A7S

[RickyIRVisionary]

I plan on purchasing the QB39 UV pass filter to use with my full spectrum converted Sony A7s however I am struggling to find which lens would be best.

 

I plan on taking videos and photographs of airplanes in the sky in UV so I want a lens that is good at a long distance while being excellent in UV.

 

Any recommendations?

[OlDoinyo]

For long lenses, if you can find them, the most UV-capable seem to be the Staeble/Novoflex 400mm and 600mm optics. Much rarer and not quite as UV-capable, but lacking any focus shift (which can be convenient) is the Goema/Makowski 500mm Katoptaron (but few of these were ever made.) Questar telescopes are said to be UV-capable down to 300nm, but they are very pricy. I have less information on other reflecting telescopes. Most refractive long lenses have a lot of elements and glass thickness and tend not to transmit UV very well. Do not attempt to use teleconverters in UV, as they will exact a considerable penalty.

[nfoto]

I have  both optics mentioned -- Novoflex 400mm and the Katoptaron 500mm. It is true the UV performance of the Novoflex is better than that of the Katoptaron, but you "pay" the price of its simple optical design by getting chromatic errors in UV. In this respect, the mirror lens fares better. Thus the choice is between a rock and a hard place, not easy.

 

By the way, I plan to sell off some of my exotic lenses, the Katoptaron being one of these.

 

And finally, welcome to the UVP community.

[lukaszgryglicki]

@nfoto can you send me a PM which lenses you want to sell ? :P

 

[RickyIRVisionary]

12 hours ago, OlDoinyo said:

For long lenses, if you can find them, the most UV-capable seem to be the Staeble/Novoflex 400mm and 600mm optics. Much rarer and not quite as UV-capable, but lacking any focus shift (which can be convenient) is the Goema/Makowski 500mm Katoptaron (but few of these were ever made.) Questar telescopes are said to be UV-capable down to 300nm, but they are very pricy. I have less information on other reflecting telescopes. Most refractive long lenses have a lot of elements and glass thickness and tend not to transmit UV very well. Do not attempt to use teleconverters in UV, as they will exact a considerable penalty.

Thank you for that.

 

What about lenses below 50mm to give a nice wide view of the sky?

 

Anything you or anyone else can recommend?

[lukaszgryglicki]

Wide lenses are hardest, the best I have is https://www.universeoptics.com/product/uv5035bk-ultraviolet-quartz-lens-assemblies/ but it gives a lot of chromatic abberrations as it is not corrected (quartz only). If you want non-quartz, then Nikkor 28/2 Non-Ai is good IMHO.

 

[ulf]

We have a section with properly measured lens transmission data for several lenses here:

https://www.ultravioletphotography.com/content/index.php?/forum/645-uv-lens-technical-data/

You can find the long Novoflex lenses mentioned above there too.

[nfoto]

11 hours ago, lukaszgryglicki said:

@nfoto can you send me a PM which lenses you want to sell ? :P

 

It's mainly the 500mm f/8 Katoptaron i had in mind.

[lukaszgryglicki]

OK, I don't need long lenses, thanks.

 

[RickyIRVisionary]

21 hours ago, lukaszgryglicki said:

Wide lenses are hardest, the best I have is https://www.universeoptics.com/product/uv5035bk-ultraviolet-quartz-lens-assemblies/ but it gives a lot of chromatic abberrations as it is not corrected (quartz only). If you want non-quartz, then Nikkor 28/2 Non-Ai is good IMHO.

 

I love how they are optimized for 250nm however I don't believe there are any UV filters that allow it to go to that wave length is there?

 

The Baader U-Venus Filter only does 320nm-380nm.

[lukaszgryglicki]

But you can go down to 308nm with "Invisible 308" filter.

 

[ulf]

I think the cover-window bonded above the sensor-chip in a A7S will limit the transmission severely, possibly completely down at 300nm.
Best alternative for that range is a monochrome converted camera where the window is replaced with a different material with good transmission down there.

 

Even then the exposure times will be long if there is'nt a very strong UV-B illumination.

[OlDoinyo]

Chromatic aberration is definitely an issue for wider angle optics; I find it less so for long lenses because the off- axis angles are relatively small; but some photographers are fussier than I am.

 

Many wide-angle lenses are very poor for UV due to a high number of elements and total glass thickness, but my wide angle nominees are:

 

35mm: Kyoei/Kuribayashi 35. A nice, sharp lens and bandpass champion (but make sure to get the right version--some were rebadged as Soligor but other makes such as Komine also were and they are not as good.)

 

20mm: old Asahi Takumar. Sharp and small and light to boot. Needs tape over the auto switch to block IR leak. Likely transmits down to 350 or so.

 

Below 20mm: this is frontier territory. I have an old Tamron 17 that shows some promise. I have not tested the old Asahi Takumar 15 aspheric which is rare and costly--who knows? Some on here have also messed with a Sunex fisheye which is around 8mm. The right software could probably recover a rectilinear image from its output, but at what quality is anyone's guess

[lukaszgryglicki]

I've purchased Nikkor QD-C (from 1975) hoping it is single coated and may transmit some UV, but also mostly to try it on GFX as there are no reports abouts its coverage (image circle) in my usual sources.

Additionally I love old Nikkors - they are build like tanks - all from metal with mostly glass inside, no plastic - they just look like gems, compared to almost everything new from Nikon - cheap plastic offshored to China.