thrice wrote:
You answered your own question. If the cameras are ISOless you gain no further dynamic range by shifting the ISO, but you may permanently clip highlights.
phototiimo wrote:
Fred Miranda wrote:
At ISO 100, one would get the highest dynamic range but ETTR is not only restricted to this ISO setting.
DaveFP wrote: Fred Miranda wrote:
For those looking for an easy way to expose to the right (ETTR) and improve S/N ratio and with that, cleaner shadows, I have found a very easy way using your A7RII zebra function. It probably works similarly with the A7R and other models but the settings presented here are for the A7RII only.
In the past I have used the "blinkies" in playback mode or live histogram to determine when highlights get clipped but with zebras it's way easier to preview and get more consistent results.
By trial and error I have determined the amount of highlight latitude between the RAW and JPEG (Which zebras are probably based on), and can calculate a safe exposure setting based on zebras to get the most S/N ratio without sacrificing any highlight detail.
Camera settings:
Set Zebra to "100+" to display any overexposure. (similar to highlight "blinkies" alert)
Set Metering Mode to: Multi.
Shoot in RAW mode.
ISO 100 or higher
Creative Style set to standard with default settings
How to ETTR?
Expose until you get no Zebra strip pattern on the highlights areas. Then add "2EV" to get your ETTR exposure. That's it!!!
+2.3EV is the max but I found that +2EV is safe preserving 100% of highlights.
Yes, an additional 2EV (after no zebra stripes) is a safe setting and you have successfully exposure your image to the right. (ETTR)
When bringing your RAW image to LR or CaptureOne, reduce the exposure back to normal and/or recover the highlights.
PS: Sometimes, to get no zebra pattern in the highlights areas you may need to actually underexpose your shot. That is perfectly normal as with ETTR we are exposing to the right of the histogram as much as the scene allows.
___________
How about bracketing when the scene exceeds the camera DR?
I would recommend bracketing mode: (-2, 0, +2) for most scenes. You can shoot at continuous bracketing and silent shutter as the drop in resolution precision won't matter as we are increasing DR and S/N ratio in a very big way.
Expose until you get no Zebra strip pattern on the highlights areas.
Change the exposure by Adding +4EV to the scene.
The camera will reduce 2EV for the first bracket exposure ("-2" setting) which is actually our ETTR setting.
So, the camera bracketing script will run the following settings automatically:
-2 (no zebra + 2EV) ** That is our ETTR setting which saves all highlight data
0 (no zebra + 4EV) That is our initial exposure with no zebra + 4EV as described above.
+2 (no zebra + 6EV) Extra 2EV for the deepest shadows.
Tip: When shooting in manual mode, set your camera Exposure Step to "0.5EV" instead of "0.3EV". It's just easier to turn 2 vs 3 notches to the left on the shutter speed dial for every full EV.
For example, if you need to add +4EV, you would need to turn 8 notches to the left on the shutter speed dial. (instead of 12)
In aperture mode, you can either use the top dial or the exposure compensation slider (Add EV compensation to the functions button)
I hope many of you find this helpful. Here is an example showing this technique:
All the best,
Fred
Shouldn't they ISO be strictly set to base ISO and not "ISO 100 or higher"?
How does this work if you ETTR by raising ISO? Just curious as most people encourage others to expose to the left when adjusting ISO because the a7iii and a7riii are supposedly "ISO-less" (apart from the dual gain design). Jim Kasson has made some posts on this.
Then why do so many encourage a7iii series owners to ETTR?
Aug 10, 2018 at 05:24 AM
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