PMW-F5 Exposure Index vs. Odyssey 7Q+ Exposure Tools

cuervo

cuervo

Veteran
I've posted, in the past, about my preference for setting my exposure accurately with appropriate Zebra, WFM or Histogram. To this end, I've come to really appreciate the ability of the O7Q latest firmware to display a VF LUT of my choice without applying the display LUT to the Zebra, WFM or Histogram of the recorded data. The displayed exposure tools represent the actual unlutted image being recorded.

I've come across a particular issue with my workflow.

The in-camera exposure system will change the exposure tools according to changes to the exposure index (EI) without actually changing the exposure of the recorded file. This is not evident when monitoring on the O7Q. In other words, changes to the in-camera EI has zero effect on the WFM, histo or zebra on the O7Q. Not particularly something I'd classify as a bug, but, certainly something I've been overlooking 'til today. If I wish to intentionally overexpose an O7Q datastream by one stop, say, I'll have to manually determine the native exposure, then manually adjust my exposure setting for example, one stop overexposed.

Like I said, not necessarily a bug, but, certainly something I had not considered before. I'm not sure that having the ability to set EI onboard the O7Q is something others would find useful. But, it's worth noting that, right now, changing the EI on camera has no effect on the display on the O7Q. For example, setting EI1000 on the F5(native ISO is 2000) will cause me to expose one stop over when using the on-camera zebra, because the zebra is now set for EI1000. If I expose with the O7Q zebra, I will not overexpose one stop, unless I manually drop the zebra 1 stop.

I've been going crazy trying to understand why my in-cam histo agrees sometimes with the O7Q, but not other times. well duh!
 
Last edited:
I think it would be dangerous to start changing EI on the Odyssey7Q+. One could quickly lose track of what was set where and under or overexpose footage.

I would say that when you change the EI on your camera, change a tool on your Odyssey. You could do it with an exposure compensation LUT on the Odyssey, or you could do something more simple, such as setting a different threshold on the Zebra or False Color tool. I highly encourage people to try out the new Zebra tool. It's subtle enough that you can shoot with it engaged, and you can have a LUTted image while the Zebra lines themselves are activated based on the underlying exposure level. Or not.

I know that you like to let the tools measure the underlying image only, yet the tools on the camera are NOT doing that, but instead measuring an offset because you are "changing the EI". In fact you are not actually doing anything with that EI change other than shifting the meters around, so why not do the same thing on the Odyssey? Instead of white at 90%, maybe set it to 84%, or whatever corresponds to your exposure offset? The tool would then match. I know you can't do this on the Waveform or Histogram, but you can on the Zebra and False Color.

You have to work the way you're comfortable, but I suggest you try experimenting a bit with the new tools on a low-pressure shoot just to see if something might work for you. I for one am an old dog who likes to learn new tricks.
 
Thanx for the feedback, Mitch. Yeah, I understand what you're sayin'. I think my post was written more out of having learned a new trick, myself, than anything else. It seems there's quite a debate going on over exposing to the baseline ISO, or exposing to a LUTted image. Been playing around with LUTCalc, which is a pretty amazing little bit of freeware. It's a good simulation tool to learn the effects of LUT and EI shifts. Coming from a photography background, this whole EI concept seems somewhat ...hmmm...I'll call it "interesting". But, I will say this, having the exposure tools displaying the info from a LUT, and applying an in camera EI compensation....well, yes, it's quite mind bending, especially when there's an external monitor with so many variables.
 
Last edited:
I would highly advise EITHER using the in-camera EI shift OR a LUT on the Odyssey. Use both and you may get so lost chasing your tail that there's no recovery.
 
I'd strongly recommend leaving the EI setting on the camera alone, and using either false-colour on the O7Q or a lightmeter to decide how you want your image exposed.

Without a light meter though, making accurate exposure calls (i.e. one stop over, one or two stops under) is almost impossible. All you can really check on a monitor is the various IRE values across your image - which can be extremely helpful, but isn't the same thing as knowing what half a stop's overexposure or two-stops underexposure looks like, and using a meter to set those exposures manually so that get exactly what you want.

Also, if you do get a lightmeter, be sure to calibrate it against your camera. From my tests with the F5 I learnt that its native sensitivity is actually only 1000 ISO (NOT 2000 ISO). So I set my meter accordingly, and get perfect results everytime.
 
Grug said:
I'd strongly recommend leaving the EI setting on the camera alone, and using either false-colour on the O7Q or a lightmeter to decide how you want your image exposed.

Without a light meter though, making accurate exposure calls (i.e. one stop over, one or two stops under) is almost impossible. All you can really check on a monitor is the various IRE values across your image - which can be extremely helpful, but isn't the same thing as knowing what half a stop's overexposure or two-stops underexposure looks like, and using a meter to set those exposures manually so that get exactly what you want.

Also, if you do get a lightmeter, be sure to calibrate it against your camera. From my tests with the F5 I learnt that its native sensitivity is actually only 1000 ISO (NOT 2000 ISO). So I set my meter accordingly, and get perfect results everytime.
Click to expand...
And of course, that's also where a good LUT can be useful. If you can see a close approximation of how you wish your final image to appear while at the same time monitor the actual signal with a meter then it's the best of both worlds.
 
cuervo said:
Grug,
Do you rely more on an incident lightmeter or reflected?
Click to expand...
Depends on the nature of the shoot. If I have control of the lighting (fixtures in a studio) then I prefer to measure the light, meaning incident. If I have less control (exteriors with lots of grippage to try to control things) then I prefer to measure how my subjects react to the light, meaning reflected. And that's pretty much always a spot meter. I have an old Weston reflective meter that I haven't used for any real work in 25 years.
 
Thanx, Mitch. So, I assume in a situation that's R&G, on the street talking heads, e.g., a quick facial reflected light reading is the best? Lots of contrast in a scene like this, many times a brightly lit background and faces in the shadows. I tend to want to split the diff so as to not blow out the background. I was wondering if an incident meter might not give me more of an averaged exposure, altho', my method has been working well.

By the way, Mitch, you're entirely correct. I'm just leaving EI at the native setting. Trying to rationalize EI AND an O7Q LUT is bending my brain too much.
 
cuervo said:
Thanx, Mitch. So, I assume in a situation that's R&G, on the street talking heads, e.g., a quick facial reflected light reading is the best? Lots of contrast in a scene like this, many times a brightly lit background and faces in the shadows. I tend to want to split the diff so as to not blow out the background. I was wondering if an incident meter might not give me more of an averaged exposure, altho', my method has been working well.

By the way, Mitch, you're entirely correct. I'm just leaving EI at the native setting. Trying to rationalize EI AND an O7Q LUT is bending my brain too much.
Click to expand...

The advantage of a spot meter in run & gun is that I can check the talking head as well as check that bright wall in the background. I can see what it might take to keep the bright background from blowing out and then where that would drop the reflected value of the face. That way I know if I've pushed it too far down to be able to adjust in post and if I therefore need to add a bit of fill, throw up a scrim behind the subject to knock down the background, etc.
 
Mitch Gross said:
The advantage of a spot meter in run & gun is that I can check the talking head as well as check that bright wall in the background. I can see what it might take to keep the bright background from blowing out and then where that would drop the reflected value of the face. That way I know if I've pushed it too far down to be able to adjust in post and if I therefore need to add a bit of fill, throw up a scrim behind the subject to knock down the background, etc.
Click to expand...

Gotcha..:thumbsup:
 
You must log in or register to reply here.
Back
Top