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I am testing three prototypes of the Schneider Xenoplan 5.6/26-001, possibly manufactured for a customer in 2002 and afterwards never produced on a larger scale. As the name indicates, this is a 26 mm f/5.6. They have a number of peculiar characters, including a (likely) very expensive construction and non-standard lens and filter attachment threads (one prototype has a different attachment thread than the other two), among a sleeve of other oddities. A Schneider representative confirmed to me that these are prototypes and sounded curious about how I got my hands on them (an eBay Israel-based second-hand seller of mostly high-tech items), but added that he could not provide any information about the customer and the use of these lenses. I am writing a page for my web site where I discuss these peculiarities more in detail. It is taking a long time to find practical ways to use these lenses (two months so far, mostly waiting for both standard and custom-made adapters to arrive), so I thought of publishing some preliminary results. First of all, these lenses do not cover full-frame, but seem to cover APS-C (possibly except for a loss of resolution in the extreme corners) and of course Micro 4/3. Resolution in VIS is extremely high, they easily out-resolve 24 Mpixel full-frame and 20 Mpixels Micro 4/3, and quite possibly 40 Mpixel full-frame. They are excellent at infinity focus and down to 0.5x macro. They perform quite well in NIR up to 900 nm, but with a hint of a central flare spot. They came with rear-mounted dual-band blue- and NIR-pass filters that completely block UV, so I did not have high expectations about their NUV performance. Instead, NUV transmission is decent, as shown by the samples below, which are straight out of camera except for reducing and cropping. Godox AD200 flash without plastic window, + Convoy S2+ LED torch for framing and focusing (left on while shooting), Baader U. Daylight on an overcast day, front-mounted Baader U. There is a strange yellow flare at the bottom and right. I am not sure about the light blue sky (obviously overexposed), which I suspect might be in part NIR forcing its way through the Baader U. The sun umbrella in the garden reflects a lot of the same light blue. 1:1 pixel crop of the sitting bench in the garden. Image resolution is obviously very high. Same scene with rear-mounted Baader U. The yellow flare is gone. 1:1 pixel crop with rear-mounted Baader U. Resolution is much worse. It is still not a bad image compared with those produced by some low-price accidental UV lenses, but obviously this lens does not behave well with a rear-mounted UV-pass filter. All the more odd, since the lens came with a thick (2 mm) rear-mounted filter that I had to remove for these tests. Rather good false-color in sunlight, except for the yellow flare. There was a strong wind whipping the trees. A lake with distant islands in visible between buildings. Still good results at dusk with overcast sky, in spite of the long exposure time (a few seconds). 1:1 pixel crop of above picture. The terrace at the bottom has venetian blinds (as verified with binoculars) that cause a color moiré, probably the first time I see this in NUV. This is a type of interference at the scale of single pixels, caused by the lens substantially outresolving the camera sensor. The terrace two floors higher has a cloth curtain, which causes no moiré. I bought these lenses on a hunch even though they were in no way cheap, expecting an excellent VIS resolution when reversed in photomacrography (which they also provide), but the above results seem to indicate a relatively rare case where UV performance largely exceeds expectations. The yellow flare with front-mounted filter is a peculiar problem with no easy solution. There is no such flare when the image contains no sky, so still a very good lens for UV macro. The flare cannot be eliminated with any lens shade I tested. The yellow flare only disappears when the sky is entirely left out of the image, even though oblique sunlight still hits the front element. The seller has no more stocks, but I know that there exists at least a fourth prototype that sold before I bought mine.

Hello spectral venturers, has anyone experimented with FE lenses for UV/IR? I've been searching for FE lenses for Sony mirorless full-frames cameras, suitable for UV/IR, out of curiosity and for convenience as opposed to adapting lenses. I tried the Samyang 45mm 1.8 FE. I know, the aperture seems too large for UV capable lenses but the number of elements (7) in the lens is the same as its f/2.8 siblings, so I gave it a try. The lens had hotspots in IR and a heavy color cast in UV (loss of contrast). Manufacturer says that the Samyang 45mm 1.8 has "7 elements in 6 groups, including two aspherical elements and one extra-low dispersion element. There's an Ultra Multi-layer Coating to help reduce flare and ghosting." Not being adept around lens construction, I now realize there is more to a UV capable lens than the number of lens elements. The limited knowledge I have tells me that similar Samyang FE lenses (in the so called "tiny series") would be made of similar types of glass and therefore be unusable for UV (IR). So I have to look elsewhere. I could pull up technical data about lenses from other manufacturers. There is hope, though, for mirorless lenses and UV - I can see that the Sigma's 30mm f/1.4 DC DN (APS-C lens) works well. Thanks

I did some web search for lenses suitable for IR and found something that might be interesting. My primary source for information is Edward Noble's site: https://www.edwardnoble.com/hotspots All Olympus lenses here get high ratings. They look very promising to use for IR, if they also are sharp. Unfortunately Edd's site is not quite clear about details about other resulting lens aberrations, except in text comments about the very good lenses in his list. There is a Swedish site with a blog written by the founder of a major photo equipment web shop. The Captain's log, where he tests some old lenses very much in detail comments them and show high resolution test images. (if you click on the test pictures for each lens, they open up to the 100% image of the image.) Interestingly he is doing the testing mostly on Fujifilm high resolution big sensor cameras, so the test information is beyond the normal full frame area. https://www-cyberphoto-se.translate.goog/captains-log?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp The article list is long and in chronological order, not easy to find a specific lens but if you do a text search for Olympus many of the Olympus lenses in Edd's list can be found. They seam quite good and sharp on big camera sensors too.

Beach huts are common by some beaches. In the area by Skanör at the southwestern tip of Skåne they are standardised in shape, 2m x 2m with a small 2 x 1m veranda. Here is one of the images I got when testing my Irix Firefly 15/2.4 lens, with a small putty-mounted 850nm filter disc at the rear. Shrunk to 50% of the original image. Those huts are placed in a safe distance from the sea to avoid being lost during winter storms. That has lately been a rather common problem in this region. Several other huts were saved the very last moments from floating away during a winter storm last winter. I like the dramatic sky and cloud images you can get with wide angle lenses.

I've recently been doing a bit of microscopy (bringing an old Olympus BHB microscope back from the grave), and while buying bits for it I came across an odd objective lens - the Reichert 40x reflecting objective. I was the only person to bid on it, and a few days later it arrived. It's a funny little thing. It has a dovetail mount for use on a Reichert microscope, but that mount unscrews to reveal a standard RMS screw thread. Here's the lens. Apparently designed for multispectral imaging, I was wondering what it'd be like for UV photography. I mean, what could possibly go wrong?? On the lens it says 250/1.5Qu, which as I understand it means it's meant for a tube length of 250mm and quartz coverslip of 1.5mm. I mounted it on a range of extension tubes to get me out to 250mm, and I could see..... absolutely nothing, couldn't get any focus at any distance. Back to basics, about 10mm extension and straight on to my UV modified d810. Amazingly, moving it back and forth I could see something come in and out of focus. Very quickly in and out of focus. Very, very quickly. Subject is a Dandelion and lighting using my Hamamatsu LC8 200w xenon lamp and collimating lens, setup shown below. And what did it show? Here is a UV image taken with it, full frame (no cropping) and whitebalanced in Darktable. I've upped the contrast and boosted the saturation slightly (and reduced the size for sharing), but other than that unmodified. This is part of the stamen style of the Dandelion, showing some pollen grains, with another part of the flower out of focus towards the right hand side of the image. Pretty trippy stuff, with some crazy reflections and flare. I see Enrico has written a bit about a Spectra-Tech Reflachromat lens, here, but I haven't been able to find out much about the Reichert one anywhere. It's certainly much smaller than the Spectra-Tech one, and is marked up as having higher magnification. Will it be useful? I'd struggle think how I'd use this for photography. Lighting is a nightmare, and fitting a hood would be 'challenging' to say the least. While it's marked as being designed for a 250mm tube length, I had no joy with long extensions. Depth of field is essentially zero, so stacking would be a must. I am planning on building a photomacrography rig in the future, and when I have stacking capability, I shall have another play with it. However despite all this, it is a cool little lens, so thought I would share it here.

If anybody is interested this is what I can do with Fujifilm GFX 50R mono + Fujinon GF 50/3.5 (modern, non-UV lens) on a foggy day (I only have free time on weekends, and I have no luck to weather, fog, tmperature around freezing, very short days - 52 degrees North). ISO fixed at 100. F usually 11-16. T from 20s to 2 minutes. Attaching almost full frames and 100% crops.

I have a Small Dilemma 20x or 2mm. I can now do macro down to 20x, that is 1.8mm on a full frame sensor. But 2mm on the sensor would make scaling measurements on the image easier. Which do I chose ?

An enlarging lens rear element is shedding black edge paint. This causes low contrast. I'd like to restore it. If the paint is too thick it won't go back into the barrel. I've also heard of using a magic marker, but most are dark purple instead of true black. Ideas? Thanks, Doug A

Hi, never researched this area, so maybe there are people who already know... - How good UV-Nikkor is for IR at the edge of silicon sensor sensitivity? I already know that there is focus shift above 900nm, but anything else than this? - What filter can I use to maximally filter out anything below 1 um? - Is UV-Nikkor good for this? I'm speaking about Fuji 50R Full Spectrum + Monochrome + Quartz converted (mono & quartz is not imprtant for IR above 1 micron right?)

I have designed a 70 mm f2.75 lens made of two fused silica elements, that hopefully should replace my SvBony lens as this one is better corrected (especially field curvature), and is sharp from f/8. I already have/have ordered all the parts (a more in-depth description of the lens will follow after I have assembled it). I plan to assemble it just like my SvBony lens: helicoid, aperture, adapter, lens and filter threads. The only issue is that I can't just put the lens inside a filter ring, because it is way too thick and it is also composed of two elements, with a spacing in the middle. Here's a diagram of the lens: The aperture is 6 mm behind the surface of the rear element. I need a spacer 2.2 mm thick and the total thickness of the doublet is about 16 mm. I need to mount the lenses so that they are set in place and with filter threads as close to the front element as possible (to avoid vignetting). The diameter of the elements is one inch (25.4 mm). Thanks in advance.

Like several other forum members, I have been pondering various approaches to the assembly of lenses. While more complex in the disassembly and assembly, I wonder about re-purposing existing manual lenses which have native mirrorless mounts, to avoid multiple adaptors, helicoids, flocking issues, etc. TTArtisans makes a 40mm f/2.8 macro which is available in multiple mirrorless mounts, and at $99 isn’t that much more costly than an adapter, tubes, a helicoid, etc. The lens offers significant front extension, and could be used with additional extension tubes to accommodate longer focal length elements. Thoughts? https://www.ttartisan.com/?list_10/129.html Edit for clarity: Yes, as surmised below, I was referring to removing the existing elements and replacing with one or more fused silica elements.

My workhorse for wide-angle landscapes, the Soligor 21mm f/3.8 in M42-mount. I've used it for the photos in these threads: https://www.ultravioletphotography.com/content/index.php/topic/4167-mauthausen-in-uv/page__fromsearch__1 , https://www.ultravioletphotography.com/content/index.php/topic/3997-university-architecture-uv-ir-700-nm/page__fromsearch__1 , https://www.ultravioletphotography.com/content/index.php/topic/4037-eisenstadt-in-uv-vis-ir/page__fromsearch__1.

I don't like long focal lengths, but I bought this Asahi Super Takumar 135 f3.5 at a good price It should be the 2nd version. LINK I thought I was lucky, a simple scheme with four separate lenses, and no SMC. Before using it, I checked its transparency with the diffraction grating. Unfortunately it is not as good as the Meritar 50mm, or the two Astron (which however do not have a thread for the filters) The comparison test are at the same distance with flash light and fluorescent light, using the emission peaks as a measure. (I discovered that these lights are no longer for sale in Europe and have been banned because they contain mercury) . . .

Ebay emailed this to me. Not familiar with the lens. Can't read the language. https://www.ebay.com/itm/225128787007?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=uC8bWVocRbe&sssrc=2349624&ssuid=_N8D7FbPROe&var=&widget_ver=artemis&media=COPY Thanks, Doug A

It is raining UAT-lenses on eBay, but they are quite expensive. https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=ultra+achromatic+pentax&_sacat=0&LH_TitleDesc=0&_odkw=ultra+achromatic&_osacat=0

Hi All, Just sharing a lens that I picked up at a local pawn shop. It is the Rodenstock Ysaron Enlarger lens. 75mm f4.5 The closest information I could find on this lens was Andrea's test of it's cousin, the Rodenstock Omegar 75mm f/4.5 for UV There was a little discussion on the difference between the Omegar and Ysaron versions of this lens in the above thread. Given this is an enlarger lens it has no focus helicoid. It also has no front filter thread. This required me to be a little bit inventive to make it work for UV. I went with a rear mounted UV bandpass and a lens adapter with integrated helicoid. I've included a labelled photo of my setup as well as an image taken with it. I do notice that there is some damage to one of the elements in the lens, perhaps some element separation. it is visible in the rendering of the bokeh immediately below the flower. Stopped down this becomes less evident and does not seem to otherwise affect the image. Not bad considering it cost the same as a couple of coffees I hope you enjoy Mat The lens in question: Rodenstock Ysaron 75mm f/4.5 enlarger lens Setup of the lens on my micro4/3, full-spectrum converted Olympus em5 mk1. The extension tube is there just to give me some close focus ability. Example image of a Capeweed flower (Arctotheca calendula) in UV (2 focal stacked images). Natural sunlight only with a very slight breeze. I suspect I could get significantly sharper images with controlled conditions

Link: https://www.ebay.it/itm/225128787007?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=uC8bWVocRbe&sssrc=2349624&ssuid=&var=&widget_ver=artemis&media=WHATS_APP It looks like it is made of two elements that are supposed to be mounted together. The posted image looks quite soft, but not too much (better than a singlet).

As I have already mentioned, I would like to design a UV lens (at least try). I wrote a refraction simulator in MATLAB that only simulates a glass "rectangle" (of infinite length), and writing a lens simulator myself would be too difficult, and Andy adviced me to use software that has already been written. UVP member diant mentioned Zemax, but getting it looks a bit complicated (it looks like it is more company-oriented). Also, I would like a software that legally allows you to use it for personal purposes (I won't sell lenses, but someone here may do it, and sometimes you cannot use software for that goal depending on the license you have). I know that building a lens is not easy, but I'm looking for decent sharpness at apertures of f/5.6 or f/8, I know I probably cannot do better. A lens with similar sharpness as my SvBony focal reducer but without the field curvature would already be nice, for example. What are your suggestions?

I got an EL-Nikkor Nippon Kogaku 50mm/2.8 and I can't seem to get infinity focus, even if I leave off the helicoid and screw it directly to the Sony adapter. Has anyone had this problem? How do I move it closer to the sensor? Is there a shorter Sony-M42 adapter out there? Also, the front element does NOT seem to be the usual 34.5mm, instead it is 40mm! Has anyone ever seen that before? What is going ON with this lens?

Finalized: Work in progress. Last Update: Note: Additional information or links about this lens are welcomed and will be incorporated into the first post as time permits. Nikon 105mm f/5.6 EL-Nikkor: old metal version Manufacturer: Nikon Manufacturer's lens designation: EL-NIKKOR 105mm f/5.6 Currently manufactured: No Lens type: Enlarger lens for film up to 65mm x 90mm ( Ø130mm ) Design: 6 elements in 4 groups Focal length: 105mm Aperture range: f/5.6 – f/45, Manual, 8 blades Format coverage: up to 65mm x 90mm ( Ø130mm ) at 0.2 x magnification Recommended magnification range*: 0.1x – 0.5x. Optimal magnification*: 0.2x *Definitions reversed from normal enlarger definition, referring to the motif not the negative-plane Mount: M39 x 26tpi thread + hidden 32.5 x 0.5mm thread behind a built in step ring. Reverse mount: M39 x 26tpi thread, hidden under a cover ring outside the filter thread. Helicoid: No Flange focus distance: 90 mm Front filter: 34.5 mm x 0.5 mm Introduction year: pre 1960? S/N of test object: 354015 Lens review (VIS), on the web: Lens Manual on the web: http://www.savazzi.n...El-Nikkor_2.pdf Transmittance SummaryDefinitions of the parameters below Range: The EL-Nikkor 105mm f/5.6: old metal version lens transmits 0-70% in an increasing slope from 316nm to 400nm. TVISmax (%) = 92% T400nm (%) = 89% T365nm (%) = 75% This high percentage indicates a relatively short exposure time under typical UV-pass filtration peaking around 360 nm or when using 365 nm UV-LED illumination. λUV HMvis(nm) = 345nm λUV HM400 (nm) = 344nm λUV Zero (nm) = 316nm These three values indicate that the lens is UV-capable into the upper UV-B range under appropriate filtration. Image of test object: Spectral Transmission GraphsUV-NIR, EL-NIKKOR 105mm f/5.6, old metal version The transmission measurement accuracy into the end of NIR range is less good due to limitations in the light source. UV, EL-NIKKOR 105mm f/5.6, old metal version UV-Log, EL-NIKKOR 105mm f/5.6, old metal version Numerical Spectra Data available: Yes General comments about the UV-reach: tba Filters and how to use them on this lens:The front filter thread is rather odd, but a suitable adapter can be found at RafCamera: https://www.ebay.com...amera?_bkw=34.5 It is also possible to use rear mounted filters, either in lens mount adapters for mirrorless cameras like Sony A-series etc, or placed directly in the camera. Handling and focussing:This EL-Nikkor 105/5.6 must be used with a helicoid or macro bellows to set desired magnification. The lens's long FFD easily permits focus to infinity with careful sizing of the helicoid or bellows. Flare and sun-stars: TBD Sharpness: TBD Lens distortion: TBD Chromatic Aberration / fringing in UV: TBD Image samples:UV: image Filter: UV, Fringing: image Filter: UV, Fringing 100%: image Filter: VIS+NIR: image Filter: NIR: image Filter:

Anybody knows anything about UV transmission of this lens? 9/6 design - any chance for UV AF with 50R debayered fullspectrum quartz? That would be !! light !! overkill wift AF and UV reach? Why ask? I'm making photos through window - 3 glasses - normal winow indoor - I see no difference when I put open door vs. that 3 glasses window... but when I focus especially on open doors vs. window with 3 glasses I alosy see 1-1.5 stop difference using UV-Nikkor + Hoya U-340 4mm + BG39.... isn't it supposed to block almost everything? Like charts showing all lenses go down to almost zero in 350nm while "my windows" showing only MAX 2 stops?

theory and practice of basic UV lenses having no measuring tools, I took as an example the graphs of the objectives tested by ULF and the graphs of the filters of Jason / Tangsinuo it is a pragmatic and basic test that “seeing” theories and non-certified graphs. after the first tests I realized that in order to focus correctly with different lenses I needed a filter that let through part of the visible. i used the QB29 (it should be similar to the BG25) This is the light band I am interested in to emulate wet collodion (325 ~ 510nm) To "see" the depth of the UV I added to the QB29 a ZWB1 (similar to UG11) all 2mm thick contamination of IR in this case does not disturb, on the contrary it helps to read the spectrum of emission of light. NOTE: I didn't add IR cut filters like QB39 ~ BG39 ~ TSN575 because they cut the lower part of UV (= green) Unfortunately I don't have an S8612 which seems to be the only filter that lets 325nm pass and cuts red and IR [if someone wants to give it to me is welcome] For all images i used same aperture f:11 the power of the studio flash was always 1000w with a clear flash tube, the ISOs set were the same. The filters were applied to the end of the cone of light ø52 (not on the lenses) the Raws were developed with Capture One, with white balance with a Teflon ball. Conclusions: the best 35mm is the Soligor KA, the Prinzgalaxy is the poorest of the three, but much better than others tested. I only tried two 50mm the Meritar sees green well… so it should reach 325nm my Helios 44-2, considered by many to be good… is very dark. Unfortunately I cannot find information on the jagged IR spectrum of the flash light, I asked the Italian distributor, but he has no news. Any of you have any idea if the emission peaks in IR have an atomic element and nm signaled? Thank you Antonio . . . . .

So, here is an interesting test... I used my S8612/2mm + U360/2mm stack with 4 different lenses on my camera to compare exposure but at the same time I also got very different results with the camera "auto exposure" metering and color (I used a white PTFE Film card to white balance). Here is the results: Voigtlander 58mm f1.4 (at f4): ISO 1000, 1/60s Sony FE 28-60 kit lens (at 28mm f4): ISO 4000, 1/60s Takumar 35mm f4: ISO 2000, 1/60s Canon 50mm f1.8 STM (at f4): ISO 1600, 1/60s So... why the color is so different?

Hi, I was googling a bit and I can't find... So I was always buying UV/IR filters from a member of this forum but it seems like he no longer sells filters or anything... I just need a handy IR blocker in a standard 52mm thread - anybody knows where can I order it, say 2-3mm thick? Can't find any on ebay etc. If not S8612, then what is another very good alternative to it? I need to block IR or even slightly visible, say from 650-680nm with at least OD4.5 - better OD5? And if there is any filter that does the samy but from anywhere starting at even 420nm (and keeping OD >= 4.5 until 1200nm) then what is it? Also I don't want to create a separate ticket for this, so I'll just ask here: is there any Nikon-F -> GFX adapter that also includes macro helicoid? FDD difference is almost 20mm, so there certainly is space for putting a small helicoid that would allow extra extension for even that 20mm ... same situation - googled, searched on ebay - found nothing - I'm able to find adapters with macro/helicod for GFX but from other systems (with longer FDD) like P67, P645...

Motivated by these threads https://www.ultravio...technical-data/ and https://www.ultravio...-uv-at-the-zoo/ , I decided to run my mirror lenses through a quick test - and I have more of them than I remembered I own the following lenses, all in M42-mount: MC 3M-5CA 500mm, f/8 MC 3M-6A 500mm, f/6.3 Soligor 500mm, f/8, /11, /16 (via a aperture weel, but I restricted myself to f/8 [Edit]this one is T-mount with EF-adapter[/Edit]) MC MTO 11CA 1000mm f/10 I took some shots in UV, VIS and IR, using the following cameras: UV: Canon EOS 6D, bayer-removed, internal X330C filter (I only show these, I also took control shots with the S8612, but on this subject the difference is basically half a stop in terms of brightness. Also good luck trying to fit a filter to a front lens of 105 mm, or squeeze it in somewhere at the back. For this basic comparison I didn't think it worth the hassle) VIS: Canon EOS 5DSR IR: Canon EOS 6D, fix converted to 700nm First an admission: not all of them were taken off the tripod, because especially with the 1000mm, I would have had to carry a very hefty tripod, and only had my small Manfrotto befree. So don't look too closely at sharpness, I rested the lenses on my rucksack and had to almost lie down to focus, so please go easy on me. If properly focussed, the Russian 500 f/8 and f/6.3 do have really good quality, and even the 1000 does not fare too bad, one just has to have a rock steady base, a lot of patience to focus in life-view, and no wind whatsoever Also, it's not possible to handhold the 500mm for UV-shots, but definitely for shots in VIS and IR, or at least leaning on something stable will be enough. That's why I'd be interested to see how far it reaches into UV, because this is a lens which might tag along on tourist trips, being quite small for a 500. A travel tripod will also be more than enough to stabilize this lens. In terms of bokeh, I chose bad subjects, because not shooting into the light there are not many of them What else, yes, distance to the building in front was about 190 m. Now, the photos, in post the only thing I did was to use a profile for white-balance to make the IR more easy on the eye, and to tweak exposure on the UV, to make them all about the same. MC 3M-5CA 500mm: UV, 0.6s, f/8, ISO 800 (-1 in LR) MC 3M-5CA 500mm: VIS, 1/60s, f/8, ISO 100 MC 3M-5CA 500mm: IR, 1/60s, f/8, ISO 100 MC 3M-6A 500mm: UV, 0.6s, f/6.3, ISO 800 (-1 in LR) MC 3M-6A 500mm: VIS, 1/100s, f/6.3, ISO 100 MC 3M-6A 500mm: IR, 1/60s, f/6.3, ISO 100 Soligor 500mm: UV, 0.3s, f/8, ISO 800 (-0.5 in LR) Soligor 500mm: VIS, 1/100s, f/8, ISO 100 Soligor 500mm: IR, 1/60s, f/8, ISO 100 MC MTO 11CA 1000mm: UV, 8s, f/10, ISO 800 (-1 in LR) MC MTO 11CA 1000mm: VIS, 1/100s, f/10, ISO 200 MC MTO 11CA 1000mm: IR, 1/40s, f/10, ISO 100