60mm f3.5 C mount UV lenses on eBay

[Andy Perrin]

Can we see your phosphor images? I don't have a UV-C light source (or associated safety apparatus) to try it out there.

[dabateman]

Yes I will post later tonight.

[Mark Jones]

Dabateman, do you have any photos of how to take apart? I would like to paint the inside black and taking it apart would probably be easier to paint.

Andy actually got one :)

[Andy Perrin]

Just line it with a black material like the Acktar (or something less pricey). Much easier.

[dabateman]

Here are some of the UVc images off the back imager.

I have the lens connected to the imager as intended focused on the same flower that I used for previous tests, which is dry daffodil. To connect the camera to the imager, I took an older T-mount to M42 adapter, drilled some holes threw the holes that hold it together and tightened screws all the way in. So the T-mount to M42 adapter is held on to the Imager with tightened screws. Then I played with my M42 tubes, a 14mm seemed to work for my lens. This did not work connected directly to a camera, So I used my Olympus 30mm Macro.

So its Imager, T-mount -M42 mount adapter, 14mm M42 tube, M42 to 52mm adapter, on Olympus 30mm F3.5 lens.

 

My 34.5 to 52 Raf camera adapter does not fit the eye piece of my imager. My eye piece seems to be a 34mm thread. I didn't go that way as it leaves a female to female connection.

 

I used a Panasonic GM5 camera, as it doesn't weigh anything and can hang off the back of the imager no problem with the equally super light Olympus 30mm F3.5 lens. Setting on Camera were Monochrome mode. I played between 1:1 and 4:3 frames for these images. You need to not only focus the Quartz lens to full Macro mode to get focus in UVC but must also adjust the eye piece focus to get a good image.

 

This Image shows the center Hotspot was taken 1:1:

 

These images are full 4:3 frame:

 

[Andy Perrin]

Quite nice! The focus is decent for macro images. You can always focal stack to improve it. Definitely you need to flock the lens to eliminate the hotspot (and I'm not sure why the company didn't do it for us). It is certainly a dark world out at 254nm ± 25.

 

My 34.5 to 52 Raf camera adapter does not fit the eye piece of my imager. My eye piece seems to be a 34mm thread. I didn't go that way as it leaves a female to female connection.

Interesting. Could be manufacturing tolerance variations.

[Mark Jones]

So the purpose of the image is to boost the signal of the original uv light? I dont understand it's usage? why not just take photos directly with the lens? a photo of the actualy camera/lens setup might help me understand?

[dabateman]

Mark,

I would go as far to say most cameras have little to ok sensitivity in UVb (290nm to 320nm). I have been extremely lucky with the Olympus Em1mk1 to see down as far as into UVc.

Jonathan found that Canon cameras have an optical low pass filter directly on the sensor. It may even be the coverglass, I am not sure. But he couldn't see 313nm until removed by MaxMax. I don't know about Nikon cameras with Sony sensors. I have only been using Olympus cameras with Panasonic sensors.

Ok, so don't expect to see UVC. Now that I know I can. My exposure settings are ISO1600, 50 seconds. This is very hard to focus as live view is grainy and slow. Fortunately Olympus cameras allow upto 60 seconds shutter speeds, so I am not in bulb mode. I still don't have a great direct in camera in focus shot. Also I don't understand why, but using the 254bp25 filter you must be close to your subject. Wide field doesn't seem to focus, even with my other quartz lens, the Pentax UAT. I am not sure if moisture, oxygen or what ever is interfering. But I have decided to just use the imager. Its so much faster to view and nail focus. Using my GM5 setup on the back of the imager, I was using Iso400, F4 and shutter speeds of 1/60 to 1/10.

 

Now the imager that is on the back of this lens takes in the high energy UVc and converts it to low energy green visible light that any camera or human can see. The purpose of this lens unit in real life is to quickly scan a surface with zero depth of field to look for finger prints. And it works well to look through with your eye.

 

The imager should work mounted directly on a camera without a lens. I just haven't worked out the needed tube length. The tube camera adapters sold new by the manufacturer are about $300. But look to be 58mm long, so I may play more. Right now the Olympus 30mm f3.5 seems to work to grab an image off the back screen.

 

To get a quartz lens and phosphor imager for under $1000 is still a bargain. Added bonus is that quartz lens can be used on mirrorless cameras directly or for added sensitivity with the imager. I now don't need a monochrome camera. So saved $1500, as have been seriously looking at getting the zwo 1600mm. Its sensor only and needs a tablet or laptop to run.

[JMC]

Well, this tale has taken an unexpected twist.

 

These lenses AREN'T Resolve Optics 60mm ones.

 

I cannot go into details. However what I can share is that the 60mm Resolve Optics lenses were reverse engineered by another company, and that these lenses are those. This will likely explain why at least one of them had some mechanical issues.

[dabateman]

So is everything not in the UK just a Chinese knockoff Jonathan, like the R72 filter?

 

Oh well, I didn't think it was a Resolve len as the specifications are slightly different. The front filter is 37mm, not 30.5mm and there are other difference I think I mentioned in this thread.

 

But it does work and the imager is the cheapest highly sensitive monochrome camera we can get for UV photography.

[JMC]

I would like to believe not everything is a knock off David. I have shared this information, as soon as I was made aware of it, as I know a few of you on here bought one as a result of my original post.

[dabateman]

Yes, I did buy one because of the cost and the risk to benefit expectations.

I am glad I did. So thank you for posting it. I didn't calculate all the benefits. I was hoping for no hotspots. But seems all UV quartz 60mm lenses seem to have a hot spot issue.

Benefits of the lens:

1. It does transmit UVc light, so it is fused silica, quartz or something.

2. Its a very nice macro, can get really close to your subject. Maybe more than the advertised 1.25x. But I do use it extended 5mm from mount so a 75mm on my camera. Others may have a true 67mm that I calculated based on the lens formula.

3.The monochrome imager is really good. Allows for a good boost in UV imaging. Can accept a camera or eye piece.

4. If you got the 253bp25 filter, its the best IR blocked filter I have ever seen. I haven't yet, but you could use this outside.

 

Negatives:

1. Major out of the box hotspot problem. But the $5000 other quartz UV 60mm macro also has same problem.

2. Its slow, acts 2 stops slower than you think. F4 is really f8. But this can be an advantage as the depth of field in UVC is really narrow. My UAT at f8 is the same as this KSS lens at F4, for exposure settings and depth of field.

3. Its only C-mount, so limited to cameras can be adapted to. But as the world has gone mirrorless, this is not an issue for long.

[JMC]

I'm glad you are happy with yours David. Believe me, if I'd known then, what I know now, I'd have thought twice before posting about it. I'd hate to think people were feeling short changed as a result of me posting about it.

[Andy Perrin]

Nah, it was a good buy for the amount of useful stuff we got. My lens works fine, I was able to greatly reduce the hotspot with the Acktar Metal Velvet, and the imager is rather nifty for when I get round to UV-B/UV-C imaging. I didn’t have my heart set on it being the Resolve.

 

Possibly if I had known, I could have bargained a lower price, but that’s eBay.

[JMC]

Added the transmission spectra of this KSS100b lens between 280nm and 420nm - https://www.ultravioletphotography.com/content/index.php/topic/3406-lens-transmission-in-the-uv-latest-update/page__view__findpost__p__31348

[dabateman]

Excellent thank you Jonathan.

 

I guess the next thing to discuss about this lens is how to address the hotspot issue. I painted a thin paper sheet that was not UV fluorescent prior to painting with Semple black 2 paint back in August, but have done nothing with it. I still need to cut it and try taping in.

I am hesitant about painting the inner barrel directly as I don't know what off gasses from this paint and if it woul affect the lens. Also don't want to paint the elements. Its tricky to scrub off the paint as it sticks well.

Andy's Acktar solution mybe best. But very expensive and not sure if adhesive or not is way to go.

 

So far I just tilt my light around to reduce the glow. Sometimes it can add to the drama of the dark photo.

 

[Cadmium]

https://www.ultravioletphotography.com/content/index.php/topic/3406-lens-transmission-in-the-uv-latest-update/page__view__findpost__p__31358

[JMC]

Attached below are the transmission spectra of the 2 filters from the Sirchie lens - there is a UV bandpass, and a clear filter.

 

The UV bandpass is centered around the 255nm region as expected, and looks to have FWHM of about 25-30, again as expected. While not on the graph here, it looks to have good blocking as far as I can get to (about 800nm). When I say good blocking, I mean down as far as about OD4, which is as far as I can measure. It could be better than OD4.

 

The clear filter surprised me, in that it has a very gradual cutoff, and even overlaps with the UV bandpass filter slightly. Above 400nm it is pretty flat transmission up to as far as I can measure.

[dabateman]

Excellent, thank you Jonathan.

The peak max of the 253bp25 is a little less than I expected. But it looks like I guessed correctly and the clear is a WG280 filter.

Also it may help me to remove it for my 303bp10 shots as looks to be about 25% there.

I think I need to compare images with and without filter combinations. From force of habit I add the U330WB80 improved filter. But I don't think I need to as the phosphorus is not seeing above 500nm and my filters just leak IR or 620nm+.

So I may be able to drop the noise and increase my signal.

 

This was helpful.

[Andy Perrin]

I see. So when you say OD4, Jonathan, you really mean “OD4 or better, can’t tell how much.”

[JMC]

I see. So when you say OD4, Jonathan, you really mean “OD4 or better, can’t tell how much.”

Yes Andy. Updated.

[dabateman]

Today,

I ran a filter test. With/without the clear filter and with/without the U330WB80 improved filter. Interesting I only need the U330WB80 improved filter with my 303bp10 filter. All other filters it dramatically kills the contrast. Surprisingly, the clear filter had little impact. I could use with or without. Only one with slight improvement without was the 303bp10 filter shot, as expected.

 

Also, when dismounting my camera. I found that the eye piece fully unscrews. Its just a magnifying group. Behind it is the amplifier which says "Hamamatsu made in Japan" I may test mounting my camera directly to it without the eye piece magnifier. However, I have seen that adjustment of the eye piece is necessary to gain non macro only plane focus. As in if I want to focus on a whole flower rather than a cell, you need to adjust the eye piece magnifier. That was my problem using the 253bp25 filter directly on the Em1 with quartz lens. The focus is only tight macro for some reason.

[Andy Perrin]

When you say with/without the clear filter or 330wb80, does that mean stacked with the 253bp25 or...?

[dabateman]

When you say with/without the clear filter or 330wb80, does that mean stacked with the 253bp25 or...?

 

Sorry no. I use just the 253bp25 on its own. No other filters for my set with that one. Also found today that the amplifier and my ExoTerra lights are low enough pressure for the first 5 minutes or so to get an image. So if you want to avoid UVC lights, a UVb light can be used during the warm up period for a cool old look grainy photo off the back of the imager. I didn't test my 302nm lights, as being long tubes are harder to work with.

 

For my filter series images, 303bp10, 313bp25, 335bp10, 370bp15, I stack them on top off the U330WB80 improved filter. Also leaving the clear filter inplace on the lens. But after today, I found I don't need the U330WB80 improved filter, and it actually makes the image worse. The clear filter inplace was better for the 370bp15, 390bp25, and 405bp10 images. Since the imager cuts off into the 500nm range to give the green image. It makes sense that I don't need the U330WB80 improved filter to cut out the IR leak from these filters.

 

I am not sure why the 303bp10 filter didn't look good on its own. I may need to retest it. Also I want to stack it with my U340 filter to see if thats better. As its not a dichroic filter and I think that is the issue I am seeing.

[dabateman]

Well the Imager seems to work down to atleast 200nm. I got a 193bp20 filter and it works to hit the first mercury line or whatever emmits slightly above 185nm. The filter bleeds a little into UVA, as I can get an image when boost the exposure from 1/4 seconds to 1 second and the aperture from 5.6 to f4. So about 3 stops. But I see less through my 330WB80 improved filter than with the 253.7bp25 filter. So I think I am catching the lower 200's of UVC. Whatever bleeds through in UVB and UVA would not affect the UVC image as much dimmer.

Problem is the hot spot is even more of an issue. So I will need to fix that to get less cloudy image.

I also got some brand new germicidal bulbs without any ozone removal layers. So I should be getting that elusive 185nm band.

Fun times.

 

Also update on the 303bp10 filter. It is very reflective and adds to the hotspot problem. Placing a U340 2mm filter behind it helps significantly, as its not mirrored. The 193bp20 filter is also a very shinny mirror. Problem is I don't have any absorbing filters that transmit that low.

So I will need to fix the hotspot problem.