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Brian Caldwell

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Everything posted by Brian Caldwell

  1. The Fuji Premier 14.5-45mm T2.0 ( http://www.bhphotovideo.com/c/product/840519-REG/Fujinon_HK3_1X14_5_F_HK3_1X14_5F_14_5_45mm_T2_0_ZOOM.html ) is pretty well known in the professional cine world. But, if you've ever hefted one in person you know its not only priced like a small house (~$100k), its nearly the same size and weight as well! So, naturally, I'm curious to know how it might perform on the upcoming A6300 in comparison to something much cheaper. Like the Tamron 24-70mm/2.8 with a Speed Booster, which gives you a 17-50mm/2.0. Obviously, the latter is practically $free compared to t
  2. The responses here have been very thoughtful, and have given me much to consider. I may modify my product direction a bit, but on the whole, it seems that my ideas aren't entirely crazy.
  3. Thanks for your comments. I agree regarding the bokeh shape. In the case of my test shot the bokeh is actually nine-sided, which is created by the iris shape in the Nikon 135mm f/2 AiS Nikkor that I used as a spherical backer lens. Upcoming integrated primes will use a very circular iris to yield nice smooth elliptical bokeh.
  4. Thanks for this - its really useful information! Out of curiosity, do you know anything about the Cineroid viewfinders?
  5. Thanks for your feedback on the squeeze ratio - I was definitely interested in what you would think. I own Caldwell Photographic, and I design all the Speed Booster optics.
  6. Monitoring is definitely on my mind. Nothing is easy.
  7. My plan is to do a compact "normal" attachment, a larger wide attachment, and then a series of integrated lenses. The attachments will definitely focus much closer than the Iscoramas. Distortion will be very traditional anamorphic style - definitely not the oddball simultaneous combination of barrel and pincushion shown by the Cookes, although probably slightly less than 2x Panavision lenses due to the difference in squeeze ratio.
  8. I'm working on two attachments, plus a series of integrated primes. The smaller of the attachments would have 72mm rear threads, and I want to price it so that independent film makers and videographers can afford it. I'm not far enough along on the other products to have a good feel for pricing yet, but its my intention to compete with the best products out there (e.g., Hawk, Cooke, Panavision, etc.) at a very compelling price.
  9. Breathing will depend on the product. I am developing two different attachments with variable diopter front focusing, and these will breathe similarly to the SLR magic and Iscorama. BTW, this isn't zero because the focal length always decreases as you focus closer a - + diopter arrangement. See this demo, for example: https://www.youtube.com/watch?v=_tZK5Nm3Gx4 For rear-focus integrated prime lenses the breathing will be much less. AFAIK, the Hawk lenses also use variable diopter front-focusing, so the appearance of breathing will depend on the focal length, the total change in magnifi
  10. I've recently started numerous anamorphic lens projects based on the idea that 1.79x squeeze is the ideal ratio when dealing with a 4:3 sensor . It's often stated that 2x squeeze on 4:3 gives you the DCI standard 2.39:1 scope ratio, but of course this isn't quite true. If you really want a perfect mapping of 4:3 to 2.39:1 without having to crop the sides, then the correct math is: 2.39/(4/3) = 1.7925, which I'll round off to 1.79. So, for the ARRI Alexa, RED Dragon and Panasonic GH4 used in 4:3 mode it seems to me that 1.79x is ideal. Also, if you consider the Alexa in its Open Gate form
  11. No problem! The original points made in older resurrected threads like this often get pretty obscured.
  12. Earlier in this very old thread a comparison was made between the Canon 85/1.2 + Speed Booster and the Nocticron for m43. If indeed the Nocticron is the sharper of the two (likely), then my point was that the problem lies in the Canon 85/1.2 and not the Speed Booster. After all, the latest generation of Speed Boosters is capable of improving on Zeiss Otus sharpness even while increasing the speed to f/1.0 or faster, and I can prove it. So, the 85/1.2 is a fine lens, but if pure sharpness is your metric then it is outclassed by a Zeiss Otus, and is even further outclassed by a Zeiss Otus + Sp
  13. Any chance there will be a 4:3 2880x2160 recording mode for anamorphic, or will cropping on post be the solution?
  14. For anamorphic you may want to do a conventional MTF vs frequency chart for a number of selected field points. For example, when designing anamorphic lenses for Arri Alexa 4:3 I normally use seven field points: (0,0), (0,8mm), (0,11.88mm), (6mm,0), (8.91mm,0), (6mm, 8mm), and (8.91mm,11.88mm). Due to the strange asymmetrical aberrations a plot of MTF vs image height can be pretty confusing. I suppose you could do three separate MTF vs image height charts; one for X, Y, and diagonal planes, respectively Regarding medium format focal reducers, IMO the main problem is that medium format optic
  15. Hi Rich: Your numbers would be for the horizontal dimension of the format, not the diagonal. My numbers indicate the full diagonal dimension. According to my data, the diagonal (corner-to-corner) of the BMPCC sensor is 14.32mm, and the diagonal of the GH4 Cinema 4k crop is 17.4mm.
  16. I do appreciate your open minded spirit about using optics beyond their design intent. But just to be clear about what happens in this case - using the 0.58x Speed Booster on the GH4 in cinema 4k mode - I plotted some MTF curves below. As you can see, the performance is great over the whole BMPCC format, but if you go beyond that the performance falls off a cliff. I'm very cautious about all of this because a few users have purchased the BMPCC S.B. with the intention of using it on a larger format, only to be disappointed with the results. This is why this particular Speed Booster has alw
  17. The 0.58x BMPCC Speed Booster is designed to cover an image circle of about 15mm diameter, which is slightly larger than the BMPCC sensor diagonal. Aberration correction is extremely good within this 15mm diameter, as is the relative illumination. However, for the GH4 4k mode you need to cover at least 17.4mm. Assuming you don't damage your camera by trying to mount the BMPCC S.B. on a GH4, you will encounter vignetting and significant image degradation in the corners. I do not recommend trying this. By contrast, the new m43 XL Speed Booster will cover the entire m43 format, not just the
  18. A caution here: parfocality in a zoom lens is strongly dependent on sample variation. So, even if a zoom is designed to be parfocal, then a typical as-built lens won't necessarily maintain precise focus through zoom. High-end cine zooms rely on post-assembly re-machining of at least one of the cams controlling the various zoom group motions. Needless to say, this is a very expensive process.
  19. Everything I said is true and is backed up with hard evidence. There's no magic here - just good optics. Perhaps you might actually read the white paper I gave you a link to? Eventually, conservative established lens makers in Japan and Germany will wake up and realize the true benefit of the Speed Booster approach for designing high-speed short BFL optics. With any luck I'll be retiring on royalties when they do There are numerous examples of Speed Booster/lens combinations that beat native lenses. For instance, a Voigtlander 90mm/3.5 plus S.B. gives a 60mm f/2.5 that is better than the
  20. I would expect to see some degradation due to the filter stack. However, the 28/1.4 Nikkor is reasonably telecentric AFAIK, so it should have less of the filter-induced astigmatism that plagues other designs. Probably most of what you are seeing is due to the d800 having vastly cleaner and more detailed images than 35mm film, so its just showing faults in the lens that were always there.
  21. This is a false generalization most likely based on weaknesses inherent to teleconverters, which magnify aberrations. A well-designed focal reducer, on the other hand, will *shrink* the aberrations as mentioned above by Araucaria. And with a little know-how you can even do better than that to actually design a focal reducer that compensates some of the aberrations in the master lens. Here's a recent whitepaper that I wrote proving that a Metabones Speed Booster significantly increases the MTF of various lenses, including the extremely challenging case of a Zeiss Otus: http://www.metabones.
  22. The "T" version differs from the "non-T" version only in that the "T" has an improved internal blackening to reduce reflections. The Metabones website shows the original "non-T" version as discontinued: http://www.metabones.com/products/details/MB_SPEF-BMPCC-BM1 , and the "T" version as the current EF-BMPCC model: http://www.metabones.com/products/details/MB_SPEF-BMCC-BT1 . Its possible that B&H are selling old stock of the original version, but I think its more likely that they simply made a mistake on their website. Since you're in Australia, you may get better service simply by orde
  23. Optics is mostly simple, with some occasional complexity thrown in to make it interesting. In fact, I've almost completely forgotten all the fancy math I learned after high school, since by and large all the math you need to know to be a successful lens designer is geometry, trigonometry, and a bit of algebra. In your case, assuming that the anamorphic portion is working at infinity (i.e., parallel light in and parallel light out) the aperture of the optical system is determined by the diameter of the iris diaphragm in the taking lens *unless* there is some other limiting aperture in the syst
  24. Is it possible that you are underfilling the entrance pupil of the 85/1.2, and hence not actually shooting at f/1.2? For example, if you were shooting with an iscorama-36 the limiting aperture would be the 36mm diameter at the rear of the anamorphic section, thus giving you a maximum aperture of f/(85/36) ~ f/2.4
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