![]() The internal design - from hardware to software - was designed completely from scratch. The only thing that IQ 4150 shares with its predecessors is the same physical dimensions and appearance of the case. Of course, if you do really long exposure such as 30-60 minutes, then dark frames are still essential to get very clean images. In fact, if your exposure time is less than a few minutes, you probably will not see much noise difference when turning off dark frames. The system will use some internal algorithms or pre-recorded dark frames to do noise reduction. On the IQ 4150, you can choose to turn off dark frames. Turn off the digital back and turn it back on, and your nightmare will be gone. Moreover, if you forget to close the shutter level when taking the dark frame (we all have done this), some really, really horrible images will pop up on screen. You are certainly going to miss some shots during the rapid-changing sunset/sunrise time. If your previous exposure is 1 minute or 60 minutes, the dark frame will take the same amount of time. To take a dark frame, you must cover the lens cap or close the shutter level on the lens, using the exact same exposure combination to take a shot. I often add some if there was none from the original.Īlso, on the IQ 3100, when you take a slightly longer exposure, or change the exposure setting, the digital back wants to take a Dark Frame, which is used internally by the digital back to get rid of dark current noise. In fact, some form of vignetting can be a good thing, forcing the eyes to the center of the image. If you shoot an LCC file (I still do if I have time), you can do a better job of completely removing the vignetting, but it is not absolutely necessary anymore. However, it can be removed in the post by brightening the dark area. Vignetting, a property of lenses, remains. Color casts (caused by sensors) are mostly a thing of the past. Thankfully, with the IQ 4150, we can skip this step most of the time. In fact, I often wondered why we could tolerate such a ridiculous limitation on such an expensive system for so long. One has to spend a long time in post to manually remove them. Even with an LCC file, for certain lenses such as the HR 23mm, it’s not possible to completely remove the reddish colors. You then shift to the right, shoot, and take another LCC image.Įveryone hates doing so, and rightfully. Then you need to increase the exposure time (covering the lens with the white plastic board will cut incoming light by about 2 stops) and take the LCC shot. Since color casts and vignetting change after shift and tilt movements, one is supposed to do an LCC shot immediately before or after every movement. Software such as Capture One will use data in the LCC file to "subtract" color casts and vignetting from the original image. On IQ 4150, the color cast is mostly gone, leaving only vignetting, which is easy to remove in post, with or without an LCC file. On IQ 3100, the lens shows horrible color cast and vignetting. LCC files of HR 23mm lens on IQ 4150 (left) and IQ 3100 (right). The edges show color casts and vignetting. The center of the image should be white or gray. To correct color casts and vignetting, traditionally, photographers must cover the lens with a piece of semi-transparent white plastic, and take a calibration image (LCC file). The edges show very strong color casts (red-shift) and vignetting. Image taken with a HR 23mm lens on IQ 3100. The result is very strong color casts called lens cast, in the forms of red/purple/magenta colors, near the edge of an image. As a result, when shooting with a wide-angle lens, light at the edges of the image comes from a very sharp angle, hitting the walls of the sensor wells instead of the sensor photocell. The rare elements of technical camera lenses are very close to the sensor surface. The Backside Illumination Sensor (BSI) sensor mostly eliminates the need for LCC on the field. ![]() The real advantages of the new system come in other aspects of the workflow. The resolution improvement over 100MP is evident in fine-detailed areas, however not by a big margin. However, I do feel that IQ 4150 is a much better DB. All of them are top-of-the-line equipment, offering the highest image quality. I also used an IQ 3100T for about 6 months. Prior to this, I used a PhaseOne IQ 3100 100MP digital back for a few years. I have been shooting with a PhaseOne IQ 4150 150MP digital back since the middle of 2019. There is no argument that Phase One makes the best digital backs. Phase One IQ 4150 digital back, front and back views.
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