Fastest EFCS shutter speed usable on the a7RII?

[Horshack]

I plan to profile the shading with a variety of lenses today to help establish the source. Current theories are lens vignetting, sensor vignetting, and projection from aperture blade.

 

[l_d_allan]

I plan to profile the shading with a variety of lenses today to help establish the source. Current theories are lens vignetting, sensor vignetting, and projection from aperture blade.

Thanks.

You may have already mentioned this in a previous post, but what Canon EF lenses do you have? Which adapters?

 

[Horshack]

Shading switches from convex (Sony) to concave (Canon). Recall that the shutter moves upward on the A7s and downward on Canon, and that the top of the image represents the bottom of the sensor due to lens optical inversion.

Samyang 14mm @ f/2.8, Sony A7s vs Canon 5D

 

[Horshack]

I plan to profile the shading with a variety of lenses today to help establish the source. Current theories are lens vignetting, sensor vignetting, and projection from aperture blade.

Thanks.

You may have already mentioned this in a previous post, but what Canon EF lenses do you have? Which adapters?

I have a bunch. Haven't decided which ones I'll be testing though. I want to include the extremes of focal length, aperture size, exit pupil distance, etc..

 

[steelhead3]

Are the shutters bought off the shelf from copal or seiko or are they designed for each camera? What I am trying to get at is that each camera of the same brand may be different from others of the same brand and actually the same camera model may have different shutters on different runs of the same model.

 

[l_d_allan]

Are the shutters bought off the shelf from copal or seiko or are they designed for each camera? What I am trying to get at is that each camera of the same brand may be different from others of the same brand and actually the same camera model may have different shutters on different runs of the same model.

Lensrentals' Roger Cicala has blog articles on tear-downs of several of the a7x family.

http://www.lensrentals.com/blog/2015/02/the-a7ii-teardown-a-look-inside-sonys-new-camera

http://www.lensrentals.com/blog/201...de-sonys-awesome-full-frame-mirrorless-camera

 

[Horshack]

After some basic thought I finally realized this is just simple lens vignetting. I was stuck on the conception of vignetting being just corner shading, forgetting that the shading is actually an ellipse around the image circle, and so it didn't make sense why the convex shading followed the shutter all the way across the frame. For example, see dpreview's review of the 55mm FE here and click the vignetting tab.

Vignetting measurement - Sony A7s with 55mm FE @ f/1.8

 

[jalywol]

After some basic thought I finally realized this is just simple lens vignetting. I was stuck on the conception of vignetting being just corner shading, forgetting that the shading is actually an ellipse around the image circle, and so it didn't make sense why the convex shading followed the shutter all the way across the frame. For example, see dpreview's review of the 55mm FE here and click the vignetting tab.

Vignetting measurement - Sony A7s with 55mm FE @ f/1.8

That doesn't make sense, though.

If it's simple vignetting, why does it only show up on lenses with no electronic feedback to the body? When you look at the files from lenses with no feedback, they have the most severe shading. However, on lenses with electronic contact with the camera, even without a built in profile, there is no shading. My Minolta 100mm f2.8 had no shading, even though there was no profile attached to it when it was developed in RAW. The Nikon 24mm f2.8 had severe shading, and when I applied the correction for it manually, it did not correct the shading.

I think it's something else going on....

-J

 

[Horshack]

After some basic thought I finally realized this is just simple lens vignetting. I was stuck on the conception of vignetting being just corner shading, forgetting that the shading is actually an ellipse around the image circle, and so it didn't make sense why the convex shading followed the shutter all the way across the frame. For example, see dpreview's review of the 55mm FE here and click the vignetting tab.

Vignetting measurement - Sony A7s with 55mm FE @ f/1.8

That doesn't make sense, though.

If it's simple vignetting, why does it only show up on lenses with no electronic feedback to the body? When you look at the files from lenses with no feedback, they have the most severe shading. However, on lenses with electronic contact with the camera, even without a built in profile, there is no shading. My Minolta 100mm f2.8 had no shading, even though there was no profile attached to it when it was developed in RAW. The Nikon 24mm f2.8 had severe shading, and when I applied the correction for it manually, it did not correct the shading.

I think it's something else going on....

-J

It shows up on both native and adaptive lens, with and without EFCS. Refer back to the composite image I embedded in my post last night (link).

 

[jalywol]

After some basic thought I finally realized this is just simple lens vignetting. I was stuck on the conception of vignetting being just corner shading, forgetting that the shading is actually an ellipse around the image circle, and so it didn't make sense why the convex shading followed the shutter all the way across the frame. For example, see dpreview's review of the 55mm FE here and click the vignetting tab.

Vignetting measurement - Sony A7s with 55mm FE @ f/1.8

That doesn't make sense, though.

If it's simple vignetting, why does it only show up on lenses with no electronic feedback to the body? When you look at the files from lenses with no feedback, they have the most severe shading. However, on lenses with electronic contact with the camera, even without a built in profile, there is no shading. My Minolta 100mm f2.8 had no shading, even though there was no profile attached to it when it was developed in RAW. The Nikon 24mm f2.8 had severe shading, and when I applied the correction for it manually, it did not correct the shading.

I think it's something else going on....

-J

It shows up on both native and adaptive lens, with and without EFCS. Refer back to the composite image I embedded in my post last night (link).

Here's the thing, though. In my photos of the trees in my yard, it clearly doesn't show up in the native lens, and the severity of it in the adapted non-electronically connected lens was much greater than you would expect based on your examples.

Also, taking this one step further, with an electronically connected lens that has no profile for it for the camera to correct for, no shading shows up! If the camera is correcting with the specific lens info provided by Sony for its lenses only, then it should not be able to correct for lenses that are not Sony, and those lenses should look as bad as the non-connected adapted lenses...and they do not.

-J

 

[Horshack]

After some basic thought I finally realized this is just simple lens vignetting. I was stuck on the conception of vignetting being just corner shading, forgetting that the shading is actually an ellipse around the image circle, and so it didn't make sense why the convex shading followed the shutter all the way across the frame. For example, see dpreview's review of the 55mm FE here and click the vignetting tab.

Vignetting measurement - Sony A7s with 55mm FE @ f/1.8

That doesn't make sense, though.

If it's simple vignetting, why does it only show up on lenses with no electronic feedback to the body? When you look at the files from lenses with no feedback, they have the most severe shading. However, on lenses with electronic contact with the camera, even without a built in profile, there is no shading. My Minolta 100mm f2.8 had no shading, even though there was no profile attached to it when it was developed in RAW. The Nikon 24mm f2.8 had severe shading, and when I applied the correction for it manually, it did not correct the shading.

I think it's something else going on....

-J

It shows up on both native and adaptive lens, with and without EFCS. Refer back to the composite image I embedded in my post last night (link).

Here's the thing, though. In my photos of the trees in my yard, it clearly doesn't show up in the native lens, and the severity of it in the adapted non-electronically connected lens was much greater than you would expect based on your examples.

Also, taking this one step further, with an electronically connected lens that has no profile for it for the camera to correct for, no shading shows up! If the camera is correcting with the specific lens info provided by Sony for its lenses only, then it should not be able to correct for lenses that are not Sony, and those lenses should look as bad as the non-connected adapted lenses...and they do not.

-J

I thought you were referring to the vignetting shading in my strobe experiment not showing up on native lenses. I didn't realize you were talking about the original EFCS native vs non-native exposure evenness issue that we're still trying to get to the bottom of.

 

[jalywol]

After some basic thought I finally realized this is just simple lens vignetting. I was stuck on the conception of vignetting being just corner shading, forgetting that the shading is actually an ellipse around the image circle, and so it didn't make sense why the convex shading followed the shutter all the way across the frame. For example, see dpreview's review of the 55mm FE here and click the vignetting tab.

Vignetting measurement - Sony A7s with 55mm FE @ f/1.8

That doesn't make sense, though.

If it's simple vignetting, why does it only show up on lenses with no electronic feedback to the body? When you look at the files from lenses with no feedback, they have the most severe shading. However, on lenses with electronic contact with the camera, even without a built in profile, there is no shading. My Minolta 100mm f2.8 had no shading, even though there was no profile attached to it when it was developed in RAW. The Nikon 24mm f2.8 had severe shading, and when I applied the correction for it manually, it did not correct the shading.

I think it's something else going on....

-J

It shows up on both native and adaptive lens, with and without EFCS. Refer back to the composite image I embedded in my post last night (link).

Here's the thing, though. In my photos of the trees in my yard, it clearly doesn't show up in the native lens, and the severity of it in the adapted non-electronically connected lens was much greater than you would expect based on your examples.

Also, taking this one step further, with an electronically connected lens that has no profile for it for the camera to correct for, no shading shows up! If the camera is correcting with the specific lens info provided by Sony for its lenses only, then it should not be able to correct for lenses that are not Sony, and those lenses should look as bad as the non-connected adapted lenses...and they do not.

-J

I thought you were referring to the vignetting shading in my strobe experiment not showing up on native lenses. I didn't realize you were talking about the original EFCS native vs non-native exposure evenness issue that we're still trying to get to the bottom of.

Ah, ok. I was finding this a bit confusing, myself .

-J

 

[Horshack]

Prior experiments show that native lenses exhibit less exposure error than adapted but we haven't quantified the precise amount across the frame. This comparison does that, for the Sony 55mm FE (native) and Mitakon 50 f/0.95 (adapted).

First, here are animated GIFs f/5.6 1/8000, EFCS OFF vs ON

Mitakon 50 f/5.6 1/8000, EFCS OFF vs ON

Sony 55FE f/5.6 1/8000, EFCS OFF vs ON

Here is more interesting data - a luminance delta comparison of EFCS OFF vs ON for the same images above, measured at 9 points across the frame in RawDigger. Values are displayed as percentages of how much brighter the EFCS OFF measurement is vs EFCS ON. 25% = 1/4EV, 50% = 1/2EV, 100% = 1EV, etc... Note that the background image behind the measurement is an overlay of the EFCS OFF vs ON images being measured, layered in PS with the difference layer style; areas where the EFCS ON exposure mismatches the EFCS OFF exposure are lighter; areas where the exposure matches are darker/black.

Mitakon 50 vs Sony 55 Exposure Error Measurements

 

[Horshack]

It was a massive brain fart on my part

 

[jalywol]

This jibes with the distribution of shading that I see in my Nikon 24mm f2.8; it's most pronounced on the upper left of the image, and fades down and across diagonally.

Interesting.

-J

 

[Horshack]

Same lenses but this time wide-open, the Mitakon @ f/0.95 and the Sony 55mm FE @ f/1.8. I've combined the EFCS OFF vs ON animated GIF with the measurements into a single composite animated GIF:

Mitakon 50 @ f/0.95 1/8000 vs Sony 55FE @ f/1.8 1/8000, EFCS OFF vs ON

Note how the Mitakon exhibits much less exposure error @ f/0.95 than it did previously @ f/5.6. The Sony exhibits slightly less exposure error @ f/1.8 vs previously f/5.6. In a switch from f/5.6, the Mitakon exhibits much less exposure error @ f/0.95 vs the Sony @ f/1.8.

 

[hiepphotog]

This jibes with the distribution of shading that I see in my Nikon 24mm f2.8; it's most pronounced on the upper left of the image, and fades down and across diagonally.

Interesting.

-J

There is something wrong with your shutter then cause it should be even. The e-shutter doesn't travel diagonally.

--

Hiep Phan

Explore Hiep Phan’s 362 photos on Flickr!

www.flickr.com

 

[JimKasson]

Prior experiments show that native lenses exhibit less exposure error than adapted but we haven't quantified the precise amount across the frame. This comparison does that, for the Sony 55mm FE (native) and Mitakon 50 f/0.95 (adapted).

First, here are animated GIFs f/5.6 1/8000, EFCS OFF vs ON

Mitakon 50 f/5.6 1/8000, EFCS OFF vs ON

Sony 55FE f/5.6 1/8000, EFCS OFF vs ON

Here is more interesting data - a luminance delta comparison of EFCS OFF vs ON for the same images above, measured at 9 points across the frame in RawDigger. Values are displayed as percentages of how much brighter the EFCS OFF measurement is vs EFCS ON. 25% = 1/4EV, 50% = 1/2EV, 100% = 1EV, etc... Note that the background image behind the measurement is an overlay of the EFCS OFF vs ON images being measured, layered in PS with the difference layer style; areas where the EFCS ON exposure mismatches the EFCS OFF exposure are lighter; areas where the exposure matches are darker/black.

Mitakon 50 vs Sony 55 Exposure Error Measurements

Trying to understand this is beginning to make my head hurt, especially the Zony 55 results.

Jim

 

[jalywol]

This jibes with the distribution of shading that I see in my Nikon 24mm f2.8; it's most pronounced on the upper left of the image, and fades down and across diagonally.

Interesting.

-J

There is something wrong with your shutter then cause it should be even. The e-shutter doesn't travel diagonally.

Nope. Take a look at the values that horshack got for his exposure differences: https://horshack.smugmug.com/photos/i-gxjTJDF/0/O/i-gxjTJDF.jpg

If you look, the upper left corner in his was exposed totally differently than the rest of the exposure.

Remember, this is an electronic first curtain we are looking at here, not a mechanical one, so it is entirely possible that it can have a hiccup that causes this kind of exposure error.

-J

 

[Horshack]

This jibes with the distribution of shading that I see in my Nikon 24mm f2.8; it's most pronounced on the upper left of the image, and fades down and across diagonally.

Interesting.

-J

There is something wrong with your shutter then cause it should be even. The e-shutter doesn't travel diagonally.

Nope. Take a look at the values that horshack got for his exposure differences: https://horshack.smugmug.com/photos/i-gxjTJDF/0/O/i-gxjTJDF.jpg

If you look, the upper left corner in his was exposed totally differently than the rest of the exposure.

Remember, this is an electronic first curtain we are looking at here, not a mechanical one, so it is entirely possible that it can have a hiccup that causes this kind of exposure error.

-J

Yep, it's clear from the diagonal exposure errors that EFCS is doing something more complicated than simply resetting rows linearly across the height of the sensor. I'm working on graphing out the exposure error across the entire height of the sensor vs just the 9-point sampling from yesterday - this exercise is producing some interesting clues about how the EFCS progresses across the frame. I'll be posting some graphs within a few hours.