I just published an article on the home page of LuLa about the NEW Sony a7r III pixel Shift feature. The article contains files to view at 100% plus to download. Check it out
Jonathan . . . you are right and wrong. This was done with the Sony guys next to me. We the camera was locked on a very sturdy tripod. It didn't move and when the Phase One was used the seismograph showed no movement. F/8 and f/11 with G-Master lenses are not going to have huge or any diffraction. Even at f/16 they will be fine. There is differences that can be seen at 200% and 300% thus the reason I provided files for download. In the end you still get a 42 MP file. And if you look where I mentioned you can see differences.
Maybe flat field and copy stand will show a difference. I can only work with what I had. The car wasn't moving and the tripod wasn't moving
| f/5.6 | f/11 | f/16 |
| (http://echophoto.dnsalias.net/ekr/images/DoF2/A55_100Macro_small1-5.jpg) | (http://echophoto.dnsalias.net/ekr/images/DoF2/A55_100Macro_small1-13.jpg) | (http://echophoto.dnsalias.net/ekr/images/DoF2/A55_100Macro_small1-17.jpg) |
Jonathan . . . you are right and wrong. This was done with the Sony guys next to me. We the camera was locked on a very sturdy tripod. It didn't move and when the Phase One was used the seismograph showed no movement. F/8 and f/11 with G-Master lenses are not going to have huge or any diffraction. Even at f/16 they will be fine. There is differences that can be seen at 200% and 300% thus the reason I provided files for download. In the end you still get a 42 MP file. And if you look where I mentioned you can see differences.
Maybe flat field and copy stand will show a difference. I can only work with what I had. The car wasn't moving and the tripod wasn't moving.
I'll certainly test this further when I get my own camera.
In real-world picture taking using optimal f/stops is not always possible. I'll never argue with science but when needed you use the f/stop that delivers the DOF needed to get the shot. And, I made it very clear in the article that the result of the Pixel Shift is a perceived improvement in image quality. The test I did was typical of conditions many photographers would use Pixel Shift. While I love the Physics and Science of photography I am a photographer and thus sometimes I have to use not so optimal f/stops like f/22 god forbid. As many know I am a Capture One user and there are tools in C1 that help minimize many of the issues of diffraction and other lens aberrations. Bottom line is that in the end, most people will never know the difference between an image shot at f/5.6 or f/11 or even f/22. Unless you have something to compare to and in most cases, the results will be hard to see. For me, it is getting the best image possible using the tools I have. And, yes many times when I need to leave the sweet spot of my lens I say to myself - ouch, this is going to hurt but at least I got a photograph and usually, I can make the best of it.
Either way, Pixel Shift by Sony and the others is pretty damn cool especially when you consider the science and technology that it takes to make it happen.
For me, I don't let physics and science get in the way of my art.
I don't think this test really shows what pixel shift can do because you need to start with really sharp images at the individual pixel level to get the best results.
There are three reasons you are not getting images as sharp as possible:
1) Diffraction - to get a circle of confusion equal to the pixel spacing on the A7RII sensor, you need to shoot around F/3.5 or less.
2) Depth of Field - depth of field using a circle of confusion equal to the pixel spacing is extremely narrow, especially at F/3.5.
3) Motion blur - the tiniest bit of subject or camera motion can blur images at the single pixel level. This may not be an issue shooting cars with the camera on a heavy tripod, but trees, grass and water will be an issue except on dead calm days.
In my opinion, the best subjects for pixel shift technology are photographing flat objects using a copy stand or some architectural subjects with limited depth of field. I don't think pixel shift will be terribly useful for most landscape photography.
Jonathan Sachs
Digital Light & Color
Erik and Jonathan
Thanks for your input and further explanation. I included the Phase One image just because I had the camera with me and thought it would be interesting to compare. I should have shot at a smaller f/stop great DOF on Phase One. Frankly, I didn't see a lot of advantage with Pixel Shift. The way you guys explained it one would hardly ever use it. It does reduce artifacts, stair stepping in diagonals in an image if you really pixel peep. The feature is there if photographers want to use it. Many photographers aren't going to be aware of much what you discuss regarding f/stops and diffraction.
Pixel shifting aside the Sony a7r III for $3100.00 delivers a beautiful file. I have now shot a lot with the camera. Although we were told we were shooting with production cameras the firmware on mine was .91. I ordered the camera and when it is received I'll share a lot more images in another article. The camera is a big step in features even though it has the same chip as the a7r II. I shot 1500 plus images and was still above half on battery power. The image Stabilization really works great. I was shooting handheld at 1/8th of a sec. with good results. Dynamic range is also pretty impressive.
The thing with Sony is you know it will only get better from here.
Thanks to both of you for good posts here.
In real-world picture taking using optimal f/stops is not always possible. I'll never argue with science but when needed you use the f/stop that delivers the DOF needed to get the shot. And, I made it very clear in the article that the result of the Pixel Shift is a perceived improvement in image quality. The test I did was typical of conditions many photographers would use Pixel Shift. While I love the Physics and Science of photography I am a photographer and thus sometimes I have to use not so optimal f/stops like f/22 god forbid. As many know I am a Capture One user and there are tools in C1 that help minimize many of the issues of diffraction and other lens aberrations. Bottom line is that in the end, most people will never know the difference between an image shot at f/5.6 or f/11 or even f/22. Unless you have something to compare to and in most cases, the results will be hard to see. For me, it is getting the best image possible using the tools I have. And, yes many times when I need to leave the sweet spot of my lens I say to myself - ouch, this is going to hurt but at least I got a photograph and usually, I can make the best of it.
Bill...Thanks....It all gets rather convoluted when in the field. The issue with focus stacking which I did an article on a while back is the same with Pixel Shift. You can't have movement and doing focus stacking outdoors has been hit and miss for me due to the environmental challenges. (being subject movement - water, leaves, grass etc). Even with some of the auto-alignment features it sometimes fails. Phase One XF cameras have a great stacking feature built in. I hope Sony does this someday. I do manual focus stacking when I can. If I tether into C1 I can use the focus mask to make sure I have the right overlap. Otherwise, I overshoot and work it out later.
Once again though, even knowing all the math etc., I doubt if I made an image at F/16 and then focus stacked of say a landscape and then printed them that most people could see a difference. I have done this and you really need to look hard.
When I am in the field I don't like to think scientifically or mathematically as it tears me away from the vision and creative part of photography. Knowing you have good glass and a capable camera allows one to get good images without overthinking. Plus if you know the capabilities of your RAW software you find that 95% of the time you are good to go.
I do want to download the app though and look at it. It does look pretty cool.