tschopp wrote:
I had the chance to take some more pixel shift images and comparison pano images. I wanted to generate equivalent images that have the same field of view, depth of field, resolution, and diffraction. I used the 35GM for the pixel shift at f/4, one of the 16 images was used for an upscale, I used the 50/1.2 GM at f/5.6 to make a pano that was then upscaled and a Sigma 85DN at f/10 to make a pano that was then downscaled. Since the pixel shift doubles resolution that would be equivalent to shooting a normal image at 70mm assuming the 35GM has enough resolution and the pixel shift works as expected. I chose 50 and 85 to bracket on both sides of the 70mm. Since I did not take a multirow pano for the 85 it was cropped to a different aspect ratio.
I wanted real world images that will reveal real world challenges. Motion is the obvious challenge for pixel shift. The wind was below average for IL at 10 mph sustained, gusting to 15 mph. The tripod was as good as it gets for me, Leofoto LS-324CEX. The ground was good for pushing the spikes into. I'm sure many here have a more robust tripod, but it's what I have. Some parts of the image had movement like the vegetation, golf ball net behind the barns, and clouds. Some parts would be motionless like the barns and shipping container below. For the pano distortion was a challenge in choosing the right projection to match the 35 image.
Based on the last results I was a bit surprised the 35mm pixel shift out resolved the 50mm in motionless areas. There seemed to be some noise in the pixel shift image that doesn't make sense. The colors are a bit different in the pixel shift, I think this is from using imaging edge to develop the raw instead of capture one. Not surprisingly, the 85mm made the sharpest image.
This helped me to understand some of the tradeoffs. As Tim pointed out it's pretty easy to get a pixel shift in addition to a regular if you want, and a bit of storage is the only downside.
Pano’s and ‘Brenizer’ technique photo’s are so easy to do with Back-button focus, exposure-lock and LR/Photoshop, your test shots indicate, to me, that I should just continue to implement such and not bother with Pixel Shift (unless I am lens limited). Thanks for posting your examples!
InFocus2014 wrote:
Pano’s and ‘Brenizer’ technique photo’s are so easy to do with Back-button focus, exposure-lock and LR/Photoshop, your test shots indicate, to me, that I should just continue to implement such and not bother with Pixel Shift (unless I am lens limited). Thanks for posting your examples!
For the back button focus and exposure lock, are these separate buttons for you? So you hold down two buttons and the press the shutter as needed? I never got in the habit of back button focus.
Why are you shooting at F8 with large aperture GM lenses when their sharpness peaks latest at F4/F5.6? At F8 there is already a very strong drop in sharpness with these two lenses. Even the extreme corners hardly improve. In fact, if you got a good lens sample F2.8 will already be almost perfect.
tschopp wrote:
I ran out to get a few shots before sunset. I tried pixel shift with my 135GM and 35GM pointed at some grain bins. All shots were f/8 ISO 100 1/15s (close to sunset).
For 135GM the movement compensation was needed, pointless without that. There was some heat shimmer and a slight wind that moved some trees. The 4 photo image looked slightly better than the single, but not worth the effort. The 16 image looked softer than the 4 or single upscaled to 240MP.
For the 35GM the 16 image had the most detail. There were a few trees that clearly had more detail, but I'm not sure it was worth the effort. I think last time I tried pixel shift was with the Riv, it might have crashed my computer or if it worked I concluded the movement issues were a non-starter.
What I concluded from this exercise is if you want a higher resolution file you should grab a longer focal length and make a pano. I'm sure there are lots of real world issues that degraded the quality of my pixel shift. Wind was pretty light for IL but still present. The shutter speed was slow.
One of the variables I did not correct for on the pano was the f stop. the 35GM was shot at f/8 and the 135GM was shot at f/8. But to keep the same depth of field I would have had to adjust the f stop by the ratio of the focal lengths ie shoot the 135 at f/32. I wouldn't think shooting the 35GM at f/8 would cause diffraction problems, but maybe it did. Probably worth some additional experimentation tomorrow....Show more →
Thanks for doing these and contributing to this thread. The 85 does look great. Seems like the shots with the GM 35 have color errors with the white letters, which goes away on the pixel shift shot (which makes sense, no demosac'ing involved.)
tschopp wrote:
I had the chance to take some more pixel shift images and comparison pano images. I wanted to generate equivalent images that have the same field of view, depth of field, resolution, and diffraction. I used the 35GM for the pixel shift at f/4, one of the 16 images was used for an upscale, I used the 50/1.2 GM at f/5.6 to make a pano that was then upscaled and a Sigma 85DN at f/10 to make a pano that was then downscaled. Since the pixel shift doubles resolution that would be equivalent to shooting a normal image at 70mm assuming the 35GM has enough resolution and the pixel shift works as expected. I chose 50 and 85 to bracket on both sides of the 70mm. Since I did not take a multirow pano for the 85 it was cropped to a different aspect ratio.
I wanted real world images that will reveal real world challenges. Motion is the obvious challenge for pixel shift. The wind was below average for IL at 10 mph sustained, gusting to 15 mph. The tripod was as good as it gets for me, Leofoto LS-324CEX. The ground was good for pushing the spikes into. I'm sure many here have a more robust tripod, but it's what I have. Some parts of the image had movement like the vegetation, golf ball net behind the barns, and clouds. Some parts would be motionless like the barns and shipping container below. For the pano distortion was a challenge in choosing the right projection to match the 35 image.
Based on the last results I was a bit surprised the 35mm pixel shift out resolved the 50mm in motionless areas. There seemed to be some noise in the pixel shift image that doesn't make sense. The colors are a bit different in the pixel shift, I think this is from using imaging edge to develop the raw instead of capture one. Not surprisingly, the 85mm made the sharpest image.
This helped me to understand some of the tradeoffs. As Tim pointed out it's pretty easy to get a pixel shift in addition to a regular if you want, and a bit of storage is the only downside.
Maybe he wanted the depth of field? Is this what we can officially call "aperture shaming"?
In any case I often shoot at f/8...f/11...sometimes all the way up to f/16 if I need the depth of field.
pwpub wrote:
Why are you shooting at F8 with large aperture GM lenses when their sharpness peaks latest at F4/F5.6? At F8 there is already a very strong drop in sharpness with these two lenses. Even the extreme corners hardly improve. In fact, if you got a good lens sample F2.8 will already be almost perfect.
I've noticed the color differences too, I think there is some kind of profile or alteration of the data when running through the software, like you suspect.
tschopp wrote:
I had the chance to take some more pixel shift images and comparison pano images. I wanted to generate equivalent images that have the same field of view, depth of field, resolution, and diffraction. I used the 35GM for the pixel shift at f/4, one of the 16 images was used for an upscale, I used the 50/1.2 GM at f/5.6 to make a pano that was then upscaled and a Sigma 85DN at f/10 to make a pano that was then downscaled. Since the pixel shift doubles resolution that would be equivalent to shooting a normal image at 70mm assuming the 35GM has enough resolution and the pixel shift works as expected. I chose 50 and 85 to bracket on both sides of the 70mm. Since I did not take a multirow pano for the 85 it was cropped to a different aspect ratio.
I wanted real world images that will reveal real world challenges. Motion is the obvious challenge for pixel shift. The wind was below average for IL at 10 mph sustained, gusting to 15 mph. The tripod was as good as it gets for me, Leofoto LS-324CEX. The ground was good for pushing the spikes into. I'm sure many here have a more robust tripod, but it's what I have. Some parts of the image had movement like the vegetation, golf ball net behind the barns, and clouds. Some parts would be motionless like the barns and shipping container below. For the pano distortion was a challenge in choosing the right projection to match the 35 image.
Based on the last results I was a bit surprised the 35mm pixel shift out resolved the 50mm in motionless areas. There seemed to be some noise in the pixel shift image that doesn't make sense. The colors are a bit different in the pixel shift, I think this is from using imaging edge to develop the raw instead of capture one. Not surprisingly, the 85mm made the sharpest image.
This helped me to understand some of the tradeoffs. As Tim pointed out it's pretty easy to get a pixel shift in addition to a regular if you want, and a bit of storage is the only downside.
I have the focus function removed from the shutter button. Then, I have Focus mapped to the AEL button and Exposure Toggle on the bottom of the rotary dial.
Actually, I use two back-button focuses. The one I mentioned, above, then a second for action shooting mapped to the AF-ON button (Recall Custom Hold 1). Under Recall Custom Hold 1, I use action settings like H+, Auto ISO, 1/2500, Zone Focus, etc. I use first button for static shots and the second for BIF, sports, etc. Going from one mode to the other is nearly instantaneous.
I did reprocess the image that I posted in the opening of the thread. I took more time correcting the symmetry, but I don't think it really changed anything greatly. The first one I also did this, but used "auto" instead of taking the time to try to use the guided approach in LR.
Here is a single frame that I processed, from that set. May sharpened a little aggressively.
pwpub wrote:
Why are you shooting at F8 with large aperture GM lenses when their sharpness peaks latest at F4/F5.6? At F8 there is already a very strong drop in sharpness with these two lenses. Even the extreme corners hardly improve. In fact, if you got a good lens sample F2.8 will already be almost perfect.
If you’re talking about the first set. Basically to get more depth of field. No real careful thought involved. I saw Tim’s post and had wanted to try pixel shift, but hadn’t yet. It was 15 min to sunset, so it is what it is. If I had thought about it I wouldn’t have chosen a target 1 mile away that involved more heat shimmering that made the effects of diffraction irrelevant.
For the second set, I wanted equal depth of field and diffraction in the comparison shots. With diffraction deconvolution enabled I find max sharpness is typically f/5.6. At 240MP I could see that shifting to f/4, but I haven’t tested it. That is why I set the 35 at f/4, and that determines the f stop for the rest of the shots.
I probably shoot the GM primes wide open 95-99% of the time.
