test: extending dynamic range

D

divide

Well-known member
I wonder what is the maximum dynamic range of the GH1.
Most benchmarks test the cam with default settings, but a few tweaks boost DR a lot.

All screens are from video mode:

contrast 0, intelligent exposure off


contrast -2, intelligent exposure off


contrast -2, intelligent exposure low


contrast -2, intelligent exposure medium


contrast -2, intelligent exposure high


to compare, here is a picture with default settings and longer exposure, so that the dark wall inside match the level of exposure of the previous picture (contrast -2/ie high)

notice how surexposed is the outside wall in the background, compared to tweaked settings.

What are your thoughts about it ?
 
Last edited:
I've seen good results with Intelligent Exposure in bringing out detail in dark areas in still photographs. But for video, I suspect it produces a flickering effect from frame to frame.
 
I made a video test and ... guess what, the intelligent exposure doesn't move while recording !
It actually sticks to the auto settings it had before pressing the "record" button.

Here with ie disabled:


Here with ie on "high", starting from the wall (so ie set itself to high because there is high contrast), panning to the window fullscreen, then back to the wall:

I can guarantee exposure didn't change during the shot. That's not the case when you are not actually recording, you can see the exposure changing. But as soon as you press record, the ie settings freeze.

Another proof of that, another video with ie "high", starting this time from the window fullscreen (uniform light, so ie disable itself though I set it to "high"), then panning to the wall : ie is still disabled !

...and I soon as I stop recording, ie goes to high to compensate DR.

So you can actually use Intelligent Exposure without any flickering when shooting a video !

NB: all tests were done in video mode, manual settings, lens panasonic 20mm f1.7, lpowell bitrate
 
Last edited:
wow...this could be huge. any experts can debunk this i.e. show any cons or downsides that we may be overlooking with this evidence?
 
Judging from your results above I think I like the IExposure on "medium." What ISO were you using in the test at the very top?

I have not shot with IExp. on in a while so I don't remember any type of flickering (I do remember it when not actually filming) but will give it a go once I get back off business trip.
 
I can't remember precisely, but most probably ISO 100 or 200 I think.
Yeah I agree it looks best on "medium", "high" raise too much noise.
 
I've been using IE on high for a while and confirm that in my tests it doesn't adjust while recording video. Hadn't considered it an option originally, but a while back I saw Kholi say he'd been using it with iso 320 and was getting amazing results. Gave it a go and haven't changed it back since. Maybe will give medium a go to see if it yields a sharper image. Interested to hear what others think.
 
with me , on solid color, like a blue sky or close up of skin tone , it does have a color shift if the camera moves around..maybe i did something wrong, but once i tool IE out, everything went back to normal, no color or exposure shift.
 
sammysammy said:
with me , on solid color, like a blue sky or close up of skin tone , it does have a color shift if the camera moves around..maybe i did something wrong, but once i tool IE out, everything went back to normal, no color or exposure shift.
Click to expand...

is this while recording? and if so do you have footage demonstrating this?
 
I posted on this a couple months back after doing a bit of research. My findings contradict yours: It doesn't lock when recording, just slows dows its rate of *increase* (but not decrease... actually, it never seems to decrease smoothly, just increase until it's too much then suddenly shut off completely). Here what I posted:

I used to use it for the extra DR but unfortunately it seems to have a mind of its own in terms of when it engages. Look at the symbol for it on the display while shooting. When it turns yellow, the IExposure is engaged. It will slowly ramp up, bringing out shadow detail (but also noise - especially FPN it seems!) then suddenly disengage in the middle of shooting because it's decided it's no longer needed. This makes it look like the exposure suddenly nose-dives in one frame, very jumpy and annoying. I leave it off now all the time for much more predictable exposure.
It also seems to do weird things with highlights while on - it can extend flares and blown-out spots past where they should be. I don't know why.
I get the impression that you really can't know what your overall ISO level is anymore if you turn it on. The base level may be what you set it, but significant parts of the image could effectively be 2 or 3 times higher ISO. Sometimes it affects more of the image than not, so it's like you're (over)exposing to a higher ISO than intended, with all the consequences of such.

And if you needed yet another down-side - try turning it on with the exposure locked at ISO 1600 then put the lens cap on. Blacks are no longer black, they're purple! I think it tries so hard to boost blacks that it just completely fills it with sensor noise. There's no more "0" value possible for deep blacks when the scene is largely very dark.
 
There's an other major problem with it that I've been reading a lot about lately, too. The bottom 30% or so of the GH-1's sensor's dynamic range is by far the noisiest. IE boosts that region more than any. If you'll note in your example shots, the last (ETTR) shot has way less shadow noise and more shadow detail than any of the IE shots. To me this says that if you need shadow detail, then expose for them. The noisy shadows that IE gives you are not at all worth keeping. You'll just want to crush them back down in post to get rid of the noise anyway.
 
You must log in or register to reply here.
Back
Top