galenapass
Offline
Upload & Sell: Off
|
 EM1x handheld high res - initial review | |
The new EM1x has some new features compared to the EM1ii. One of these was the promise of better AF tracking and another was the ability to capture handheld high resolution images (HHHres). The subject of this post will be HHHres. Camera labs posted a youtube video which implied that the EM1x HHHres results were sometimes good, other times there was not much difference between single shot at HHHres. A separate video by another reviewer also found the same thing, but I cannot remember which one that was right now. I have had this camera now for 2 days with limited use so far. However, one of the first things I wanted to check out was if the HHHres mode was working, and if I could find instances where this mode was not as effective, relative to a standard single frame shot.
For a short review on how this technology works , please see the following link.
https://digital-photography-school.com/understanding-sensor-shift-technology-high-resolution-images/
In summary, Olympus and Panasonic move the sensor ½ pixel, capture an image, then move the image ½ pixel etc…. [Note: if you notice something important that I am skipping or not getting correct please comment below.] The resulting image not only contains more information but also more accurate colors because there is less reliance on neighboring green pixels to guess when a red pixel sees green light (for example). In theory, each static pixel or photosite location will have had a red, green or blue photodiode sample the light collected at that location, because of the underlying sensor shift. Images captured in this manner are then merged and the resulting final image has more accurate colors and more detail.
There are several ways that we can get the photosites to shift while collecting images. Olympus has been using the IBIS to do this in very precise way as mentioned above. Alternatively, Photoshop users have been doing this for years by overlaying handheld images, aligning them and averaging the information in each pixel. This reduces noise and increases resolution. The inevitable small shifts in the sensor while handholding the camera simulates what Olympus does with the IBIS, but in a more uncontrolled manner.
How does all of this relate to the new HHHres ability of the EM1x? Olympus is apparently using an amalgam of both techniques for HHHres. As it has been described (and most reviewers’ explanations get fuzzy at this point), IBIS gets turned off for a short period of time, the photo is captured and then IBIS gets turned back on, then the process repeats itself. It sounds like Olympus uses the handheld shakiness to move the sensor slightly, and the IBIS limits how much movement is allowed to occur over the course of the captured images. The camera takes 16 shots and combines them for one result.
In my first set of shots I decided to shoot some patterns that would confuse the sensor in producing moiré. Sensor shifting should clear up this issue. [A few notes: For these 3 shots the same camera was used, the same lens, etc…. Single shot photos were then uprezzed to the same size as the HHHres photo so that a direct comparison can be made. I admit that this is not ideal but it is hard for the human eye to look at 2 shots that are different sizes and to tell which one has more detail.] In the first shot below you can see that the image is producing some false color, often associated with patterns that produce moiré. In the second image you can see that HHHres has cleared this up and there appears to be more detail. The third image was my attempt to see how HHHres might be working. This image was shot a on a VERY stable tripod with a delay of ½ sec after pushing the shutter button - then HHHres was activated. I reasoned that if HHHres was relying on handheld shakiness to move the sensor, then by removing that shakiness perhaps the false color would still remain. As you can see the false color is not there. I am not sure what to think of this result yet. I need to explore it further.
|
