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Joshua Cadmium

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  1. I was thinking that the actual price, while high, wouldn't be that bad for high toleranced optical glass, but this filter would actually be $1,176 from Band Pro! That is pretty expensive for a filter. (And it's not just this filter - all of their filters are either $1,176 or $948: https://www.bandpro.com/brands.html/ib_e_optics .)
  2. I have no idea if it's this exact filter, but the images do look a lot like the Rainbow filter from IB/E Optics: https://www.ibe-optics.com/en/products/cine/artistic-tools/organic/rainbow-10585 .
  3. Look up Schneideritis. It can get way worse and still not have much of an optical effect.
  4. There would actually be an increase in the amount of glass in the back of a film lens. That's because in between the PL mount flange and the film is about 52mm of air (plus maybe a rotating mirror). You can use that extra space to add additional optics. On a B4 lens, on top of having each color focused at a different point, the light is also focused through a whopping 46.2mm of glass (prism and filters) before it hits the sensor: https://tech.ebu.ch/docs/tech/tech3294.pdf . The flange distance is only 48mm, so there is barely any room for the optics to go further than the flange before it hits the coverglass. Some manufacturers did design their optics with both formats in mind, albeit as two different, but related lenses. I'm pretty sure all the Canon S16 lenses have a similarly built B4 counterpart. Angenieux's 7-81mm for S16 and 5.3-61mm for B4 are the exact same optics up front, with a different rear group in the back. (You could even buy a conversion kit for the 7-81mm). Angenieux also released their 12x Optimo in a 12x9.7 B4 version and there was also Cooke's 18-100mm in a 8-46mm B4 version. I think someone could technically make what you are proposing (supporting 2 formats in one), but it would most likely be an optical compromise for one of the systems and/or significantly harder and more expensive to make, not easier.
  5. I almost certain that that's not a true Canon 8-64mm. It looks like someone converted a Canon J8x6 B4 lens (what the Canon 8-64mm is likely based off of) with a Abakus 132 B4 to PL adapter. In the pictures you linked, if you compare the rear part of the optics to a Abakus 132, it looks exactly the same. There is no simple way to convert a PL mount to Aaton - there is no off the shelf adapter. For this lens, you would have to have someone completely machine new parts for this already franken-lens. It just wouldn't be worth it. The easiest way to convert a lens to Aaton is finding a lens with a Cooke / Angenieux universal sub-mount and then getting an Aaton sub-mount. You can also find Arri Bayonet to Aaton adapters. So, getting your camera converted to PL is the only real option if you have to have this lens, but you may just want to pass on it, unless you use this info to talk the seller down and make it worth your while to convert your camera to PL. This lens might even be better, optically, than a native 8-64mm, or it might be worse, but it's most likely worth less.
  6. Now that I think about it, the older Vocas 320 and 350 matte boxes used a 4.5x4.5 tray for rotating polarizers on wide angles and they took a square 4.5x4.5 pola. Every other 4.5 filter out there is round, but I don't know if that tray can use round filters. I tend to like Vocas matte boxes better (the 350 has integrated eye brows and takes 4 filters at a time normally or 3 at a time with this lens). However for future compatibility Chrosziel might be better.
  7. If you found a replacement hood, you would need a 127mm polarizing filter in the hood. Either there will be a way to rotate the filter ring in the hood or the filter itself will have rotation built in. A clip on matte box is probably going to be easier to use, easier/cheaper to find a used replacement, and more resale value - but it's going to be bulkier than just the hood. Used Chrosziel or Vocas matteboxes are cheap and designed to work with that lens. You'll just need the proper 95mm clamp (or rubber bellows, if you want to use rods). On that Chrosziel PDF it says it needs a 5x5 filter for rotation, so you'll probably need to get something that size or bigger. You can find used 5x5 polas for cheap since it's not an often used format (you just need an appropriate tray to hold it.) You could also get a 138mm pola and put it a rear bellows or get a 138mm filter in a rotating tray that fits in most 4x5.65 matte boxes.
  8. Here's a better reference: https://www.fujifilm.co.th/globalassets/products/optical_devices/pdf/tv/accessory/tv_converter.pdf
  9. If you wanted to go the super manual (and potentially easier) route, you could also try a Chrosziel Fluid Zoom Drive. They can be very smooth and cranked down so much that they barely move.
  10. According to this, it's a 95mm front diameter: https://www.adcom.it/public/images/pdf/chrosziel.pdf
  11. Here's another article I forgot to include that is extremely helpful in visualizing the difference in sizes in different wavelengths of light: https://www.edmundoptics.com/knowledge-center/application-notes/imaging/from-lens-to-sensor-limitations-on-collecting-information/ . Here are some figures from the article:
  12. If you want some more info this page is very helpful: https://luminous-landscape.com/do-sensors-out-resolve-lenses/ . Table 1 and onward goes into things a little more in depth with charts. (Also, I found the lp/mm numbers in that Table 1 chart to be off by a few percentage points from my numbers. I think it might just be rounding errors. I kept everything unrounded on the spreadsheet I have.) This is a short article about the diffraction limit and has MTF(0) numbers for 520nm light at various f-stops at the end of it: https://www.edmundoptics.com/knowledge-center/application-notes/imaging/diffraction-limit . (The video is a waste of time, though). If you want to understand the math for MTF, this helped me: https://spie.org/publications/tt52_151_diffraction_mtf . It has the math for both a square and a round aperture.
  13. Oops! Had an error that I just realized when I went back to check the math. That 2.475 ratio is actually the ratio of lp/mm of MTF(50) over lp/mm of MTF(0) . The actual MTF(50) ratio is 1.971. So you could think of it as multiplying the pixel pitch by that or multiplying the Airy Disk ratio by that, but the 1.971 is just another ratio that would be multiplied by everything. So, f-stop of MTF(50) = 1.971 * pixel size / Airy Disk / wavelength in nm For the Blackmagic 12K sensor at green 550nm, that puts MTF(50) at f3.2 and for the Alexa sensors that puts it at f12.1. At red 700nm light, the Blackmagic 12K would hit MTF(50) at f2.5 Alexa would at f9.5 At violet 400nm light, the Blackmagic 12K would hit MTF(50) at f4.4 and the Alexa would at f16.7 These numbers are theoretical, though, which just means that you would need a perfect lens to hit MTF(50) at these numbers. You are almost certainly going to maximize resolution somewhere between having the f-stop create an Airy Disk the size of a single pixel and having the f-stop at MTF(50), which creates an Airy Disk the size of about two pixels. Again, though, higher temperature light (colder, more bluer) is physically smaller - the Airy Disks have a smaller diameter - so you can capture more of it before the Airy Disks start to overlap too much and lower the resolution by blurring together.
  14. When light passes through an aperture it forms an Airy Disk: https://en.wikipedia.org/wiki/Airy_disk. The Airy Disk is the point of light that we are trying to capture. As you stop down an aperture, the size of the Airy Disk gets bigger. At some point, the size of the Airy Disk can be larger than the size of a pixel. As well, the point where Airy Disks overlap is where diffraction starts. How do you determine the size of an Airy Disk? An Airy Disk does not have a sharp cutoff, but there is a bright central region, similar to a Gaussian distribution, with additional rings around it. The bright central region is measured at about a 2.44 ratio (2.4393 to 5 significant figures.) In order to determine the actual width you also need the f-stop and the nanometer of light. The math is actually really simple - just multiply everything together: 2.44 x f-stop x wavelength in nm. The interesting thing about this is that 2.44 and the f-stop are ratios, or dimensionless numbers, so the only dimension we are left with is the nanometer of light. For instance, the Airy Disk size of far red 700nm light at f2.0 is about 3416nm in diameter or about 3.42um (micrometers). [The math is simply 2.44*2.0*700.] That is smaller than the 8.25um pixels on the Arri Alexas, but much bigger than the 2.20um pixels on the Blackmagic 12K. On the opposite end, the Airy Disk size of violet 400nm light at f2.0 is about 1952nm or 1.95um. That now fits within one pixel of the 2.20um on the Blackmagic 12K. The more light is shifted to the violet or blue end of the spectrum - which we can do by increasing the temperature of the light overall - the smaller the points of light get overall and thus the better they will fit within a pixel. Another way to say this is that you reach diffraction quicker at warmer color temperatures. ----- Going way further, resolution is often calculated using green light, since it falls between red and violet. For instance, green 550nm at f2.0 is about 2684nm in diameter or 2.68um. You'll notice that that is still larger than the 2.2um pixels of the Blackmagic 12K. That means that if you want to get an average of all Airy Disks (an average of the full spectrum of light) to fit within a 2.2um pixel, you'll need to decrease the f-stop. What f-stop would I need to get a 2.2um (2200nm) Airy Disks size at 550nm? To figure that out, you can do the math in reverse: f-stop = pixel size / Airy Disk / wavelength in nm. In this case, f-stop = 2200nm / 2.44 / 550nm = f1.64 That seems like way too low of an f-stop, until you try the math with a bigger pixel. With an Alexa pixel: f-stop = 8250 / 2.44 / 550nm = f6.15 If that still seems too low, that is because the Airy Disks can overlap a bit and still not cause too much of a hit to resolution. This is where MTF plays a role. MTF is actually very simple - it is really just looking at the overlap of Airy Disks. It is measured by imaging black and white lines and looking at the amount of grey that is produced as the lines overlap (which they do from being funneled through glass, an aperture, and the pixel structure.) MTF(100) would be a solid black line next to a solid white line. MTF(0) is where everything is a complete wash of grey. Making the Airy Disk the same size as the pixel puts the MTF at just about MTF(74), but resolution is typically calculated at MTF(50), which is where there is a 50% difference between white and black lines (dingy white next to greyish black). Since MTF deals with line pairs, we need to figure out the line pairs per millimeter of a sensor. To do that, we just take 1mm (which is 1000um) / the pixel pitch / 2 (in order to measure in pairs). The Blackmagic 12K would be 227.27 lp/mm and the Alexa would be 60.61 lp/mm. The actual math for MTF is a little complicated. I'm using the equation found in the middle of the page here (you can relatively easily run it in a spreadsheet): https://www.edmundoptics.com/knowledge-center/application-notes/optics/introduction-to-modulation-transfer-function/ There is a shortcut for the MTF(50) math, though. It is the lp/mm of the sensor divided by 2.475 OR the pixel pitch times 2.475. (If you do the math, it just ends up that way [and at eight significant figures it would be 2.4751447.]) For the Blackmagic 12K sensor, that puts MTF(50) at f4.1 and for the Alexa sensors that puts it at f15.2. Those figures are using 550nm green light, though. If we instead used 700nm light, the numbers would be different. The Alexa would hit MTF(50) at f12 and the Blackmagic 12K would hit that at f3.2 At 400nm, the Alexa would hit MTF(50) at f20.9 and the Blackmagic 12K would hit that at f5.6. So, regardless of the MTF values, it does make sense to shift color temperatures cooler in order to maximize resolution, especially when the pixel size is smaller, unless you want to deal with an f-stop that limits the depth of field you can operate within.
  15. Yes, the Fairchild sensor in the OG Pocket has a ton of dynamic range, which I think helps contribute to its specialness. There are so many options for lenses on the BMPCC, including every single S16 lens ever made. In terms of primes, the Zeiss S16 primes and the Optar / Illumina primes look great. The Cinema Products (made by Kowa) 16mm primes should also look good. There are also the Meike MFT primes that should be just as good as the Veydra's but at a fraction of the price. I have the 35mm T2.2 and I am super pleased with it In terms of zooms, I thought the Angenieux 7-81mm looked fantastic. A second to me was the Zeiss 10-100mm MKII (MK I should look good as well.) While it doesn't natively cover S16, I added a MFT Olympus 1.4x teleconverter on the end of my PL mount to create a 14-140mm T2.8 that looked awesome, albeit a touch vintage. I was able to shim the PL mount to make the whole setup parfocal as well. For B4 mount, there is the Abakus 132 B4 to PL, the Century B4 to PL, and IB/E Optics 1.4x to PL. I have a cheap late model Fujinon A15x8 which looks nice and a HAE Fujinon 5-15mm which is super sharp. There's a whole bunch of C mount lenses as well. There's just a ton of options with that sensor.
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