PDA

View Full Version : Live View Boost & the Histogram


Gwyver
28th December 2016, 05:35 PM
Just in case you aren't aware of this...

A couple of days ago I was adjusting the Custom Mode settings and unintentionally left 'Live View Boost' active (Menu Cog D2).
Today whilst using A mode I was baffled when the histogram in the EVF failed to respond to changes in Exposure Compensation (even though on Playback the images had been adjusted with the expected EV offsets).

I knew that LV Boost affected the brightness of the EVF/LCD and eventually realised that the Histogram must be displaying the characteristics of the image as displayed on the EVF rather than that of the image being sensed with the Shutter/F stop/ISO/ExComp values applied.

The User Manual warns that when S-OVF is active the display is not adjusted for settings (p 121) but doesn't warn about this in the case of LV Boost.

raichea
22nd January 2017, 08:56 PM
I ran into this today, not having made any adjustments to Live View Boost. I was in manual mode and puzzled to see that the histogram was not moving no matter what changes I made to exposure. Switching to PAS modes showed the histogram behaving correctly.

Turns out that for some reason, on the MkII, M mode is singled out to have Live View Boost on by default, for PAS it is off (see P172 of the manual - D2 settings). The original E-M1 has a single setting for all modes, which defaults to Off.

pdk42
22nd January 2017, 11:17 PM
It's very annoying that the histogram and over/under exposure blinkies are driven off the live view image. That means that any viewing effects you set (including JPEG modes etc) will effect the exposure view. For that reason I always turn off everything. I always shoot raw so it makes sense anyhow.

Gwyver
23rd January 2017, 12:24 PM
It's very annoying that the histogram and over/under exposure blinkies are driven off the live view image. That means that any viewing effects you set (including JPEG modes etc) will effect the exposure view. For that reason I always turn off everything. I always shoot raw so it makes sense anyhow.

I think this is a (legacy) issue from earlier versions of the TruePic engine which had less processing performance. By applying all the settings effects (including Art filters and Vivid/other image adjustments) before generating a JPEG for the LCD/EVF and then computing the histogram from the resulting downsized image this would minimise the required computation (and time) - hence allowing higher max frames/sec etc.

It is also logical - for those shooting JPEG and applying adjustments & filters that the LCD/EVF & histogram should bear a closer relationship to the 'finished image'. Clearly however this relationship goes pear shaped when LV Boost is applied and some words in the manual reminding users of this would be useful.

Whilst, like you I only shoot RAW, I think it would be complicated/potentially unreliable to have the histogram generation method change according to image storage mode.

blu-by-u
24th January 2017, 06:36 AM
I find the EVF to behave correctly without the Live View Boost. The Em1 mk1 lost that with one of the firmware update.