This is a two-page article.
Page one covers:
- An overview of the feature
- How it works
- File sizes to expect
- How shutter speed effects the result
Page two covers:
- Close-up of results
- Compared to Nikon D850
- Lenses and resolution
For some photographers a downside of the Micro Four Thirds system is that the sensors available can’t match the pixel count of some full frame and APS-C systems. The fact that the majority of full frame cameras in use have 24 million pixels or fewer, only marginally more than the 20 million pixels of the Lumix GX8, GH5 and G9, doesn’t seem to dampen the perception that full frame cameras are in the league of 33-50MP. Only half the current range of full-frame DSLRs on the market have a resolution greater than 30MP.
This ‘limited’ resolution of micro four thirds cameras turns off some landscape photographers and still life workers who demand as much detail as possible for their shots.
Fortunately, this doesn’t need to be so much of an issue now, as one of the many great things about the Lumix G9 is its ability to shoot 80-million-pixel images that can record four times the pixel-count of standard pictures. Using its finely tuned in-body image stabilisation system the camera is able to perform a neat trick that allows us to record much finer detail than usual and to produce images that out-resolve the best full frame cameras.
How it works
The G9 has a highly sensitive image stabilisation system that is able to shift its sensor by tiny distances and, crucially, to stop and start that movement very quickly and accurately. With an amazing degree of control, the IS system can move the sensor to the right by exactly half a pixel, and move it to the left, up and then down. By recording an image with each tiny movement the camera can collect images that record four times the amount of data in the area that one pixel usually occupies.
To do this the camera takes eight images as the sensor shifts in a loop pattern, and combines all the information collected into one 80-million-pixel file. The movement of the sensor creates what are effectively off-set pixels that together record four times that amount of data – just as flatbed scanners work with off-set rows of pixels in their scanning heads (but a little bit more complicated.)
The idea of shifting pixels isn’t new and has been used to create high resolution images for a long time, but usually in expensive medium format backs that often record different colours in separate exposures as well.
Implementation in the Lumix G9
In this camera Panasonic uses the shifting sensor technique to record eight images half a pixel apart. The eight images are then combined to produce a raw or a JPEG file, or both. Users can elect to save a normal version as well as the composite file.
The resultant image measures 10368×7776 pixels, and as such will comfortably print to 35x26in using the photo-quality 300ppi print sizing standard.
Users also have the choice of a 40MP mode that produces images of 7296×5472 pixels in what the camera describes as ‘a balance between resolution and file size’, though the drop in resolution doesn’t save as much space as you might think if you shoot raw.
Resolution Image dimensions JPEG file size Raw file size
20MP 5184×3888 10MB 23.11MB
40MP 7296×5472 17MB 125.4MB
80MP 10368×7776 28MB 125.4MB
These quotes file sizes are approximate as file size depends on the content of the image. However, these are all for the same subject matter, so they give you an idea of how file sizes compare.
Shutter speed and working silently
The High Resolution mode uses the camera’s electronic shutter to avoid the internal vibrations that might occur if eight images were recorded in quick succession using a mechanical shutter. This ensures the camera remains absolutely still so the maximum detail can be taken from the scene.
Working in electronic shutter mode means that our shutter speeds are restricted to between one second and 1/32,000sec – though for most such a range won’t sound like too much of a restriction.
The key thing to note though is that we are effectively working with a multiple exposures so we have to take care of how motion in the scene will be portrayed.
When photographing static subjects we don’t have to pay too much attention to our shutter speed, but if there is something moving in the frame how it that motion will be represented in the final image needs to be considered. We have a number of choices but they basically come down to whether we attempt to record the moving object as sharply as possible with a series of short shutter speeds, or allow the motion to blur by using long shutter speeds. If something really is moving and we use a series of short shutter speeds we should expect the edges of the moving object to be staggered, while a long shutter speed creates a smoother edge because the camera is blending slightly blurred edges rather than sharp ones.
I experimented with longer shutter speeds for some landscapes with water in them to see what effects could be achieved. Using a neutral density filter I was able to record images with 1 second exposures which made the motion very smooth and the water surface as you would expect from a long exposure of several seconds. With shorter exposures the water surface looks much more textured – as we would expect from a multiple exposure. The looks are just different and well suited to different occasions.
Click through to the next page to see comparisons with the Nikon D850.
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