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Ilkka Nissila

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Everything posted by Ilkka Nissila

  1. I don't think Nikon have any plans to leave the DSLR market any time soon; they are far more successful with DSLRs than with mirrorless and their mirrorless market share is quite small. They announced two new DSLRs this year (D780 and D6) and a DSLR lens (120-300/2.8). Also they in their public messaging have consistently stated that they will continue to develop both technologies taking advantage of each technology's advantages into the foreseeable future. I recall reading a comment from Nikon that at least in the next seven years this isn't likely to change (this suggests that they have prod
  2. It's a little bit more complicated than that. While video users often put cameras on rigs, and fluid heads have stick handles that can be used to pan the camera without touching the camera itself, still photographers who use long lenses on tripod usually have their hands on the camera while shooting on tripod (and they probably shoot in a similar way when recording video, at least when the subjects are moving, since they typically use gimbal heads instead of the more video-oriented fluid heads). So there are circumstances where identifying whether it is safe for the camera surface to heat abov
  3. Here is an article showing that human cells die rather quickly in extended exposure to higher than 43 degrees Celsius: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4188373/ When human cells are at 44 C for a period of 1 hour, only about 10% of the cells survive (Fig. 1). When using external recorder, Canon may have assumed that the camera is no longer hand-held but used on a tripod, since it would be pretty clumsy to hand-held the camera with recorder attached. Thus there is not as much likelihood of long-term exposure of the videographer's hands to the damaging he
  4. 43 C is regarded as the limit of temperature that is safe for human tissue so that it's not damaged due to the heat. That's what is used in medical devices as the safety limit: during use, the device must not heat the tissue temperature above 43 C. If the temperature of the skin does rise above 43 C then you can expect some damage, though I don't know how quickly it happens or how severe it is. Roger writes "we ran it for 18 minutes before getting a temp warning. The hottest part of the camera was the back behind the LCD door (43°C / 109°F)". So it seems that the 43 C tissue damage threshold i
  5. The CPU's topside thermal pad was still stuck to the aluminium plate in the Chinese disassembly: Continuing the disassembly, there is another thermal pad right under the CPU PCB leading heat to the larger metal plate on the underside. In addition to the top- and bottomside plates, the copper layers of the PCB itself conduct heat from the components.
  6. I think the timer's purpose is two-fold in the overheating management algorithm. One is to provide the user with a degree of predictability so that they can decide whether a particular record mode will be usable for the situation at hand. The user can e.g. try 4K HQ and note that the record time is 4 min and then decide that it's safer to go with 4K regular to get the job done. If the overheat warning and shutdown are just reacting to the immediate temperature, then the user is not given any warning of the impeding ending of recording. The second reason is that heat damage depends
  7. Apple did not repair it for free the second time. They offered to fix it for a cost but this was not considered worth it because it was not a real fix to the underlying problem but just replacing the component with the same component which then probably would die again. In my opinion the failure rate of professional equipment should be such that in normal use most people would never experience it during the lifetime of the product. I would consider e.g. 1% failure rate in 7 years of daily use as limit of acceptability for a tool that manages data. I've lost data because of equipme
  8. A friend of mine's 2011 Macbook Pro died twice from overheating (once it was fixed under warranty by replacing the motherboard but the actual problem was not solved and the problem later repeated itself) so it seems clear that this is not a good practice to run at such high temperatures. Also, it is not clear where the R5 measures the EXIF-reported temperature. It might not be the processor's internal temperature but a separate sensor inside the camera.
  9. It is normal that temperature control algorithms include not only the current temperature but also the recent temperature history that are factored into the algorithm calculating "what is the next move". It wouldn't be surprising that if you erase the data of the temperature history and other parameters by removing the battery, the algorithm has to go by without it, but it doesn't mean that it works in the intended way to protect the camera if you do that. It has been shown that the algorithm does monitor the temperature (by the freezer experiments) and others have not been able to reprod
  10. From the CPU, there are layers of static air, circuit board, static air, metal and plastic at least. There is no effective thermal conduction path to the metal chassis either from the outside or from the processor. Thus the processor cannot effectively disseminate heat and outside cooling has only a delayed effect on the internal temperature of the components.
  11. An IR thermometer only records the surface temperature, it may be that components are hotter inside. Putting the camera in a freezer for 25 min reportedly restores the camera's video recording capabilities to baseline (see experiment and observations by Jesse Evans at https://www.fredmiranda.com/forum/topic/1658635/4). Thus the camera is clearly monitoring its temperature and reacting accordingly, but after use that leads to overheating, it seems to be difficult to get the internal temperature to decline sufficiently without extreme measures. I think Canon could tweak the operation
  12. The non-raw video formats are resampled from the original sensor data and 6K->4K conversion can be done by interpolation. This cannot be done for raw video because raw file stores images before the RGBG Bayer pattern is converted into RGB pixels. There is no straightforward way to convert RGR BGB RGR into RG BG covering the same subsection of the image. So they have to skip data. The alternative would be to do the Bayer interpolation and create a 6K RGB image and then downsample that to 4K RGB and finally re-Bayer it to come up with the final 4K RA
  13. Dual pixel AF with 45MP final output image would require a natively 91MP sensor and for continuous AF purposes all of this data would have to be read and processed during focusing. Cross-type phase detection with a quadruple pixel design would require 182MP (if 2x2 are used instead of some other pattern). These things are easier to implement in a camera that isn't intended to produce high-resolution stills. Dual pixel AF is limited by the processing power available and having a high pixel count makes it more difficult. Notice that Canon's 50MP models don't have dual pixel AF either. D2H a
  14. Noise depends on the luminosity or number of photons detected; it is not constant but increases approximately proportionally to the square root of the signal (the luminosity or photon count). The number of distinct tonal or colour values (that can be distinguished from noise) can be calculated if the SNR is known as a function of luminosity or RGB values. From this graphs it is possible to calculate how much tonal or colour information there is in the image which is what DXOMark is estimating. You cannot estimate how many colours or tones are separable from noise by assuming that there is a fi
  15. If you look more closely at DXOMark measurements (the graphs) the D5 has better dynamic range from about 3200 to 51200 than the 1DX II. Which is more important (low ISO or high ISO dynamic range), can be argued depending on the application. Typical sports shooters are shooting publication ready jpgs in the camera which mean their dynamic range is limited at that point in practice even if they once in a blue moon get the chance to use low ISO. Furthermore the tonal range (number of tones that can be separated from each other and noise) and color sensitivity (number of color values that can
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