There is a certain website, I won't say any names, that is known for it's dynamic range tests. It is really one of the few websites that consistently comes out with these Dynamic Range Test Scores for new cameras, and something about it has always driven me absolutely bonkers; the do not publish their methodology
, which in the land of science is just craziness. If you don't publish your methodology, how in the world can your peers scrutinize what you are putting out there? How can the results be duplicatable or confirmed? They can't. HUGE problem. I do wayyyyy too many little tests that I shoot down and do not actually talk about or publish because I do not think the method is good. If I can't publish the methodology, in that sense, the test is basically meaningless because I could just be making stuff up and no one would know the better. Thats my soap box about that certain website for now at least.
For years I have been trying to figure out a reliable and cost-effective way to measure a camera’s Dynamic Range, on my own. I have seriously tried just about everything and while I sometimes had interesting results, the method was either not convincing enough, too expensive, too hard to replicate or too complex. I was looking for something anyone could replicate with minimal equipment, expertise and cost.
Ive been working on and tweaking this one technique..yes, there are still some problems with it that Ill address some below, but suffice it to say, this is how it works:
Maven Dynamic Range Test Methodology:
1. I purchased a $14 transparent strip from a printing calibration company called Stouffer
. The strip has 41 increments, of what is essentially 1/3 stops for each increment. It is calibrated and used in printing processes. This particular strip has about 13.7 stops of dynamic range.
2. The strip was installed into a black poster board that I could hang in front of an 1600 Alien Bee, powered at 1/32
3. With my test cameras, I framed up the strip close to edge to edge and did some test shots testing different apertures until I was essentially clipping out the first interval on the preview.
My exposure settings are 1/10, f10, ISO 100 and the camera is on a tripod triggered by a timer, and the flash is triggered by a pocket wizard.
4. I then import the files in to Camera RAW, again, intentionally clipping out the first stop. I then inspect at what point the borders between 2 adjacent stops are no longer visible.
A few of the problems with this technique:
1. It is not a great technique to measure overall dynamic range, there is some more head room on the bright side of the strip that can be recovered. Im not exactly sure where this is, but I do know that the strip is limited to 13.7 stops, so I also have to keep this in mind. I do believe that with more testing, Ill eventually figure this out.
2. Another problem is that once noise starts coming into play, it is difficult to determine at what point noise renders the dynamic range measurement irrelevant, as you will see below. Not really sure how to calibrate a signal to noise ratio for this that would give me a reasonable, consistent cut off point.
I did get my hands on a brand new Canon 7Dii
and put it through this little test, comparing it with the Nikon D750
While Adobe Camera Raw doesn’t support the Canon 7Dii at this time, there is a little free app called “Raw Therapee
that will allow you to access the RAW files of both the 7Dii and the Nikon D750. (You can download the latest Beta version of Abobe Camera RAW 8.6 candidate for D750 RAW Support in Camera Raw: Camera RAW Plug-in For Nikon D750
Some of you will wonder where the heck all this noise is coming from. Its from stretching the RAW files as much as possible with things like Shadow Recovery. Otherwise, the cut off point is much sooner (because the swatch is so dark).
Take a look for yourself:
At what point can you no longer differentiate between 2 adjacent stops?
At what point does noise ruin the measurement?
Here is the Canon 7Dii:
Again both cameras shooting through the same strip, same power flash, same exposure settings.
Anyone can see that the performance of the Nikon D750 is simply phenomenal when compared directly with the Canon 7Dii, which is actually much closer to the result of the Canon 5Diii
, which I have also tested:
I am excited with this promising result of my new Dynamic Range Test, I know it can be improved and tweaked to get it better, so I invite your criticism, scrutiny and suggestions, Thank you!