Bokeh Discrepancy Between EVF and Photo

[Daniel81]

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I just got an SL a few months ago . . . with a Summicron 75 f2 SL lens.  So I am a newbie.  I am noticing that very often the Bokeh as it appears in the EVF is quite different from what shows up on the photo, once taken.  The EVF often shows a larger, smoother, more 'buttery' Bokeh but when I take the photo, the Bokeh is often closer to focus, sharper, smaller, noisier.  Its quite definitely a NOT 'What you see is What you get' scenario.   Is there a reason for this?  Is there anything I can do about it?

[jaapv]

The image on the EVF screen is much smaller than on your monitor and print. As DOF and bokeh are controlled by magnification it comes as no surprise that you notice a difference. 

I think you are confusing DOF and Bokeh. DOF is the zone of acceptable defocus, bokeh the quality of the OOF areas. Obviously DOF will have an influence on the amount of bokeh.

[ZHNL]

OP, Leica SL shooting like SLR that always WO. If your aperture is different than WO, your final image will be different than your view in EVF which is at wide open. 

[Jeff S]

2 hours ago, ZHNL said:

OP, Leica SL shooting like SLR that always WO. If your aperture is different than WO, your final image will be different than your view in EVF which is at wide open. 

Although I believe there is a DOF preview setting option...  as well as exposure simulation. (I don’t own the SL.). Of course one can always check the playback image, but as Jaap notes, not the same as viewing on big monitor.

Jeff

[Daniel81]

yes, the playback of the image through the EVF reveals the same thing I noted in my post - a very different Bokeh than was previewed on the EVF prior to taking the photo.  Further to ZHNL's comment, when I am previewing the image through the EVF,  as I adjust the aperture, I can see the bokeh change in the preview so the preview is not just showing wide open aperture - it is responding to aperture adjustment.  So, I am not sure I have my answer here.

[Jeff S]

Jaap’s response is still relevant.  One can’t expect to judge bokeh (different than DOF) on a tiny camera screen compared to viewing on a big monitor or in a print.  But one can learn the tools and better translate the effects.

Jeff

Edited November 14, 2019 by Jeff S

[Daniel81]

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Perhaps I wasn't clear . . .  I will try to rephrase . . . . I preview through the  SL's EVF and I see a certain Bokeh effect (how the out of focus background is presented) . . . then I take the photo . . . then, viewing the captured image through the same EVF on the SL, the Bokeh in the captured image is much 'sharper', 'noisier', less 'dispersed' than it was in the previewed image . . . . BOTH the preview AND the captured image are viewed through the SL's EVF.  So this is NOT a case of comparing an EVF preview with a subsequent large monitor captured image review.

[Jeff S]

Oh... 

https://m.youtube.com/watch?v=HE6EP3Z0PSU

Jeff

[xrogers]

I don't know exactly how the SL works, but have done some engineering work on similar systems. I expect what you're seeing is the result of video influenced algorithms being used in a fast, high-resolution viewfinder. 

The EVF is, in effect, showing real-time 60fps video on the display, while the image review shows a static jpeg, likely sized to fit the screen perfectly. Video must be pulled off the sensor, demosaiced, adjusted for color, dynamic range and density, and displayed on-the-fly, resulting in significant processing and huge amounts of data transfer. Edge detail must be retained for the finder to look sharp and detailed, but areas with less variation can look quite convincing with less intensive processing, saving system resources for other uses (like maybe a higher resolution finder, a faster frame rate, less heat and/or longer battery life).

Display of a static jpeg is comparatively trivial. A more high fidelity image makes sense here, as it isn't being created and thrown away 60 times a second.

[ZHNL]

4 hours ago, Jeff S said:

Although I believe there is a DOF preview setting option...  as well as exposure simulation. (I don’t own the SL.). Of course one can always check the playback image, but as Jaap notes, not the same as viewing on big monitor.

Jeff

I don't have SL but S1. However, I found out that most setting are shared with Panasonic and Leica. With S1, you could set a customer button to enable either "aperture effect on" or "shutter speed effect on" or both on and off. However, whenever you finish exposure, it will default back to both off which means you only see wide open preview most of time with native lens or supported L mount glass. 

I just did a check on S1. if I shoot WO, my preview before taking and image after taking are very similar. There might be minor color or contrast setting difference between EVF preview and final image, I see very little difference between bokeh and it really doesnt bother me.  

Having said that, out of all EVF based camera, there will always be discrepancy between EVF preview and final images depend on implementation. 

Edited November 14, 2019 by ZHNL

[giampo]

Exactly. Only with M lenses, where you set the aperture on the lens you will get a real time bokeh effect (very similar to what the final image will be).
While with autofocus lenses the evf works just like on every reflex. The lens it is always wide open and that it is what you see, but for example if you set the aperture at f8, through the evf you will see the image at the maxium aperture. It is only when you clik and take the photo that the camera will close at f8. So what you look in the evf could be very different from the final image. Only way the get an idea of what the real bokeh will be is to set a botton with the function wrote by ZHNL.

 

[ZHNL]

2 hours ago, giampo said:

Exactly. Only with M lenses, where you set the aperture on the lens you will get a real time bokeh effect (very similar to what the final image will be).
While with autofocus lenses the evf works just like on every reflex. The lens it is always wide open and that it is what you see, but for example if you set the aperture at f8, through the evf you will see the image at the maxium aperture. It is only when you clik and take the photo that the camera will close at f8. So what you look in the evf could be very different from the final image. Only way the get an idea of what the real bokeh will be is to set a botton with the function wrote by ZHNL.

 

Minor correction, it seems only Panasonic and Leica implement this way. Nikon will show you preview until f5.6, after that it will stay at f5.6 even you stop down. Sony camera is all over the place in term of implementation depend on firmware and generation but I don’t remember they will Ever show you preview at wide open aperture. they do have different setting to change focus behavior either focus WO, or shooting aperture or somewhere between depend on lens. 
 

because I am SLR lover, I happen to prefer Panasonic Leica way. However, I am pretty sure many prefer WYSIWYG. 

Edited November 14, 2019 by ZHNL

[Daniel81]

OK - thanks everyone - I now see several of you were totally correct.  Just did a test and its very clear that yes, the preview is with lens wide open so of course, the preview and the captured image only match Bokeh-wise if the image is also shot wide open.  The smaller the aperture of image capture, the greater the discrepancy between preview and captured image.  Got it. Thanks for the clarifications!!  (This is my first EVF experience - I've been a Nikon DSLR optical viewfinder guy for decades - so its a real adjustment - things are very different in this world!)

Edited November 14, 2019 by Daniel81

[helged]

1 hour ago, Daniel81 said:

OK - thanks everyone - I now see several of you were totally correct.  Just did a test and its very clear that yes, the preview is with lens wide open so of course, the preview and the captured image only match Bokeh-wise if the image is also shot wide open.  The smaller the aperture of image capture, the greater the discrepancy between preview and captured image.  Got it. Thanks for the clarifications!!  (This is my first EVF experience - I've been a Nikon DSLR optical viewfinder guy for decades - so its a real adjustment - things are very different in this world!)

Yes, the SL behaviour is identical to that of the electronic Nikon lenses. For manual lenses, whether on the SL or a DSLR, you see what you get, blur- and dof-wise

Edited November 14, 2019 by helged

[Chuck Albertson]

15 hours ago, Jeff S said:

Although I believe there is a DOF preview setting option...  as well as exposure simulation. (I don’t own the SL.).

There is - a short press of the Func button on the front previews the depth of field, a second squeeze adds a preview of the effect of the shutter speed (very handy for those slow exposures where you want to show some motion in the picture). This feature didn't make it to the SL2, for some reason.

[Jeff S]

13 minutes ago, Chuck Albertson said:

This feature didn't make it to the SL2, for some reason.

Meaning DOF preview or shutter speed effect, or both?

Jeff

[Chuck Albertson]

4 hours ago, Jeff S said:

Meaning DOF preview or shutter speed effect, or both?

Jeff

Both, as near as I could tell in handling the SL2 for a few minutes.