Dynamic range of the em1 evf

Discussion in 'Open Discussion' started by DoofClenas, May 27, 2015.

  1. DoofClenas

    DoofClenas Who needs a Mirror!

    949
    Nov 9, 2012
    Traverse City, MI
    Clint
    Not sure if I'm asking the question right, but would the dynamic range of the em1's evf be the same as the sensor.
     
  2. David A

    David A Mu-43 All-Pro

    Sep 30, 2011
    Brisbane, Australia
    Probably not.

    I haven't seen any measurements or objective data but I can say this. I shoot RAW and I can have the highlights and shadows clipping warnings blinking in the viewfinder or on the screen and there is no clipping in the files when I open them in Lightroom. OK, a lot depends on how much things are showing clipping in the camera but if thee camera is just starting to show clipping, then the file definitely won't be clipped. There's a good half stop of leeway at that point, sometimes more.

    The other thing is that the viewfinder and screen are both displaying a JPEG image and the camera has done a RAW to JPEG conversion in order to provide that viewfinder/screen image for you. You have a lot more control of the extreme highlights and shadows in the RAW data if you are performing the conversion in a processing application on your computer than if you're using the camera's JPEG conversion firmware. I don't know how out of camera JPEG files compare to the viewfinder rendering but you do get more range in the RAW data than you do in the viewfinder.

    Now I've compared the range of files to that of the viewfinder but the files are what the sensor captures and that's the only baseline I have for making comparisons.

    Finally, I'd suspect the same is true for all EVF's at this stage of the game.
     
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  3. DoofClenas

    DoofClenas Who needs a Mirror!

    949
    Nov 9, 2012
    Traverse City, MI
    Clint
    Anyone else?

    I've scoured the web for some hard core data. I have someone telling me that it's only like 5-6 EV. The sensor is rated at 12.7 EV. That to me sounds like quite the discrepancy. Personally I don't have any issues with it but would like some facts to come back to the other photographer.

    How, dynamic range wise, would it differ from an OVF?
     
  4. Carbonman

    Carbonman Mu-43 All-Pro

    Jul 10, 2014
    Vancouver BC
    Graham
    The dynamic range of the image captured by the sensor is compressed before the image is fed to the EVF. It's the same as what happens with your television or computer monitor. There's no need to have the same DR throughout the system.
     
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  5. David A

    David A Mu-43 All-Pro

    Sep 30, 2011
    Brisbane, Australia
    I thought about that when I wrote my reply above, and I think the problem is going to be one of comparing apples to oranges.

    The dynamic range of an OVF is going to be higher than that of an EVF because there's no compression due to conversion to JPEG, however the DR of an optical viewfinder is also going to be greater, not smaller, than the DR of the sensor. Theoretically an OVF should give you an image with the same DR as that of the scene you're shooting. In some cases that's going to be many stops wider than the DR of the sensor.

    The simple fact is that there is currently no camera viewfinder which is going to deliver the same dynamic range as the sensor. An EVF is going to have to give you less DR than the sensor because it's displaying the sensor data after JPEG conversion. An OVF is going to give you more DR because it isn't displaying the sensor data in any form, it's a straight optical system so it's basically showing you the DR of the actual scene.

    Which is better? No clear answer there in my opinion. The EVF will be better at showing you what the sensor is going to deliver because it's using sensor data and with Olympus bodies (don't know about Panasonic, no experience) if you have Live View Boost turned on you will always have a clear image displayed no matter how dark the actual scene is. With Live View Boost turned off, dark scenes are going to look dark in the EVF. With an OVF what you see is going to depend on the actual lighting conditions of the scene so dark scenes are always going to be dark, you don't have an option to turn something like Live View Boost on to brighten your viewfinder image. There's also the problem with high contrast bright scenes that you may be able to see clearly in the brighter parts of the scene but you may end up seeing less clearly in the darker parts of the scene because of the high contrast range so having a greater DR in the viewfinder may not actually be a benefit when it comes to trying to make out detail across the whole of the frame. In addition you've got no option with an OVF to magnify the image.

    So, there's plusses and minuses to both and neither is capable of showing you exactly what the DR of the sensor is capturing. It could be argued that the EVF can actually give you a more accurate idea of what the sensor can capture since you can turn on the highlights and shadows clipping display and the viewfinder will then show you what areas of the image are outside of the dynamic range of the JPEG conversion displayed in the EVF though the DR of the actual RAW file is going to be a bit greater than what the EVF is showing you.

    It could also be argued that you don't need a viewfinder with the same DR as the sensor. After all, back in the old days of film when there were only optical viewfinders, the DR of the viewfinder and the DR of whatever film stock you were using were never the same and sometimes the DR of the film stock would be greater than that of the film, sometimes lower when the DR of the actual scene was quite low. That's still the case with EVF's. While the DR of the EVF is always going to be less than the DR the sensor is capable of, the DR of the actual scene itself can be high or low and when it's lower than that of the sensor it may also prove to be lower than what the EVF is capable of displaying. We've never had a viewfinder that accurately displayed what the DR of the image being captured was at all times, not with digital photography and not with film photography. Basically viewfinders have always shown you an indication of the area of the scene being captured and a display that helped with focussing but they have never given an accurate idea of what the actual finished image was going to look like. In some ways EVF's go closer to doing that than an OVF does, simply because they're actually showing you an image conversion of the actual data being captured. Ultimately, however, it's always been the case that what you see in a camera's viewfinder is not what your photograph is going to actually look like in a number of ways.

    You said in your initial post "Not sure if I'm asking the question right…" so I'll ask why you're asking this question, what are you trying to find out? If you give us some more info about why you're asking and what is concerning you, perhaps someone can provide an answer that may be more useful to you.
     
    Last edited: May 28, 2015
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