JMC Posted June 30, 2022 Author Share Posted June 30, 2022 9 hours ago, dabateman said: Well that is quiet an interesting image. That objective must also be supper rare. I think it might be made for a reflectance microscope, as the working distance is quite large at 2.5mm. Thats a huge working distance for that magnification, most likely designed to look at rock or concrete samples. The image looks quite nice and if you did hit a dark field sweet spot, than you should expect up to 10x gain in resolution. Thanks David. I've not seen many for sale and I can't imagine there were many made in the first place. Looking at one of the catalogues I've got, they were supposed to be used with 0.5mm quartz slides, and 0.18mm thick quartz coverslips, so not your usual type of slides. The image I shared was on a 1mm quartz slide and 0.35mm fused silica (or quartz, can't remember) coverslip. Last night I tried using an Edmund 15x reflecting objective, and that too gave a good dark field image at 313nm when the condenser was stopped down. Link to comment
JMC Posted June 30, 2022 Author Share Posted June 30, 2022 This is an image taken with the Edmund Optics 15x reflecting objective at 313nm (NA 0.28). Working distance on this objective is nearly an inch. Condenser stopped right down to create the dark field effect. Cropped slightly from the original and resized for sharing (before resizing the image was 5340x3245 pixels). Link to comment
colinbm Posted June 30, 2022 Share Posted June 30, 2022 Brilliant Johnathan What camera are you using please ? Link to comment
JMC Posted June 30, 2022 Author Share Posted June 30, 2022 40 minutes ago, colinbm said: Brilliant Johnathan What camera are you using please ? Thanks Colin. I'm using a monochrome converted Nikon d800 from MaxMax for most of my work. Funnily enough, despite being a monochrome conversion I do get a slight colour cast in the images depending on wavelength. We've not been able to figure out a definitive reason as to why that is. Sometimes I show them as black and white, others (like this) I leave the colour cast on there as I quite like the toned look. Link to comment
colinbm Posted June 30, 2022 Share Posted June 30, 2022 Thanks Jonathan, so it is good for UVB. I knew someone that got a mono conversion from Max Max & he had colour left on the sensor, it was quite noticeable too. Link to comment
JMC Posted June 30, 2022 Author Share Posted June 30, 2022 10 minutes ago, colinbm said: Thanks Jonathan, so it is good for UVB. I knew someone that got a mono conversion from Max Max & he had colour left on the sensor, it was quite noticeable too. Yes, it is good for UVB. On the d800 I have, it has a Schott WG280 window on it, and will see down to just below 300nm. These days I tend to request fused silica windows, so I can look down into the UVC if needed. I'm surprised to hear that about the conversion, but I hope it was rectified. Link to comment
colinbm Posted June 30, 2022 Share Posted June 30, 2022 Unfortunately Max Max wouldn't rectify that camera, & I have has a problem years ago to with Max Max when I was sent a foggy hot mirror that they wouldn't replace. Link to comment
JMC Posted June 30, 2022 Author Share Posted June 30, 2022 So far my interactions with them have been good. The main gripe I have is the cost of shipping back and forth to the US (and the UK customs fees) but I've found his customer service to be very good. Sorry to hear that is not always the case. Link to comment
photoni Posted June 30, 2022 Share Posted June 30, 2022 5 hours ago, JMC said: These days I tend to request fused silica in my dreams .... I wonder what a 40 Mpx full spectrum Leica M10 monochrom could do I believe the microlenses on the sensor do a great job without cutting the UVC Link to comment
nfoto Posted July 1, 2022 Share Posted July 1, 2022 Interesting news JMC. In particular as I just "happened" to purchase this item. Edmund Optics Infinite Conjugate, UV Coated, 15X/0.28NA HP ReflX objective A whim, being the result of having unexpected tax returns + Long Covid. A costly combination apparently. Even with a UV-Nikkor as "tube" lens, I should get 7-8X captures in UV. Link to comment
JMC Posted July 1, 2022 Author Share Posted July 1, 2022 2 hours ago, nfoto said: Interesting news JMC. In particular as I just "happened" to purchase this item. Edmund Optics Infinite Conjugate, UV Coated, 15X/0.28NA HP ReflX objective A whim, being the result of having unexpected tax returns + Long Covid. A costly combination apparently. Even with a UV-Nikkor as "tube" lens, I should get 7-8X captures in UV. Very nice. I think that is the slightly newer version of mine (yours has 3 curved fins, mine has 4 straight ones), and of course yours is infinite while mine is finite tube length. Reflecting objectives have their 'quirks' but they certainly offer some pretty impressive specs in a small package. Good luck with it. Link to comment
nfoto Posted July 12, 2022 Share Posted July 12, 2022 The EO 15X Reflex objective arrived and looks to be in excellent condition. Although the UV-Nikkor can be used as a "tube" lens, it turned out to be far from ideal as there is severe vignetting and spherical aberration when used in this manner with the EO. Thus I had to bite the bullet and get a proper UV tube lens with f=200mm instead. So now I'm awaiting the Mitutoyo MT-L4 UV lens. Apparently I have initiated a chain reaction .... Link to comment
JMC Posted July 13, 2022 Author Share Posted July 13, 2022 11 hours ago, nfoto said: The EO 15X Reflex objective arrived and looks to be in excellent condition. Although the UV-Nikkor can be used as a "tube" lens, it turned out to be far from ideal as there is severe vignetting and spherical aberration when used in this manner with the EO. Thus I had to bite the bullet and get a proper UV tube lens with f=200mm instead. So now I'm awaiting the Mitutoyo MT-L4 UV lens. Apparently I have initiated a chain reaction .... Shame that the UV Nikkor wasn't suitable. I look forward to seeing how it works out with the UV tube lens though. I have personally stayed way from going down that route (I have too many things I am spending money on at the moment without getting in to infinity length UV lenses) so it'll be interesting to see the results. Link to comment
nfoto Posted July 13, 2022 Share Posted July 13, 2022 Such is life in the invisible lane. Link to comment
nfoto Posted July 14, 2022 Share Posted July 14, 2022 The plot thickens. Turns out I forgot the UV-Nikkor is not telecentric. Thus one should neither mount the EO with the usual frontal airspace (as with the Mitutoyos), nor should there be a filter box in front, all filtration should occur to the rear if required. Attached straight onto the UV-Nikkor, the EO 15x reflex delivered better performance than in the first disappointig trials and if I added enough extension to make the UV-Nikkor go to 1:1, I got rid of almost all the vignetting and other nasties. Magnification in the latter case is about 9X vs 7.6X for the naked UV-Nikkor set to infinity. A final touch is adding a tripod mount to the UV-Nikkor as the entire assembly gets a bit longish. I'll have to experiment over the weekend to learn what can be achieved. Link to comment
JMC Posted July 14, 2022 Author Share Posted July 14, 2022 1 hour ago, nfoto said: The plot thickens. Turns out I forgot the UV-Nikkor is not telecentric. Thus one should neither mount the EO with the usual frontal airspace (as with the Mitutoyos), nor should there be a filter box in front, all filtration should occur to the rear if required. Attached straight onto the UV-Nikkor, the EO 15x reflex delivered better performance than in the first disappointig trials and if I added enough extension to make the UV-Nikkor go to 1:1, I got rid of almost all the vignetting and other nasties. Magnification in the latter case is about 9X vs 7.6X for the naked UV-Nikkor set to infinity. A final touch is adding a tripod mount to the UV-Nikkor as the entire assembly gets a bit longish. I'll have to experiment over the weekend to learn what can be achieved. Interesting. Good to know that the UV Nikkor has potential to be used in this role then. Look forward to seeing the results. Link to comment
Lou Jost Posted December 18, 2022 Share Posted December 18, 2022 On 7/14/2022 at 9:52 AM, nfoto said: The plot thickens. Turns out I forgot the UV-Nikkor is not telecentric. Thus one should neither mount the EO with the usual frontal airspace (as with the Mitutoyos), nor should there be a filter box in front, all filtration should occur to the rear if required. Hmmmm...Tube lenses are not generally telecentric. There's no reason that this should cause problems for your UV-Nikkor. Regardless, the place to put filters is always in the "infinity space" between the objective and tube lens. The existence of this infinity space is the reason why modern microscopes all use infinity-corrected optics; we can put lots of thick filters or other modifiers in that space, without causing any optical problems. Link to comment
nfoto Posted December 19, 2022 Share Posted December 19, 2022 Part of the issue might be the unusual shape of the exit pupil of the Reflex objective. Since I'm now effectively grounded by heavy frost for the [winter] season, I might experiment with different combinations. I recently got the UV tube lens Mitutoyo MT-L4 so have an alternative to the UV-Nikkor anyway. Link to comment
JMC Posted December 24, 2022 Author Share Posted December 24, 2022 Sorry I'm being very lazy not writing a full post on here, but here is some of my recent work using UV light on my microscope and imaging with the camera with a Sony IMX487 UV sensitive sensor. https://jmcscientificconsulting.com/mini-uv-camera-diatoms-at-313nm-including-amphipleura-pellucida/ https://jmcscientificconsulting.com/microscopy-resolution-comparison-between-visible-and-uv-light/ Link to comment
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