Purpose of SA Control for Macro?

FrenchFry

Wildlife enthusiast!
Jun 14, 2020
484
603
Hi,
I've been watching the early reviews of the RF 100mm f/2.8L lens with interest, as I am greatly looking forward to having a native 1:1 (or better!) macro option on the R5.
All the demos that I have seen of the SA control feature have results where the subject becomes blurred, which is sort of the opposite of what I typically go for with macro, where I am trying to see really fine details.
Is there any benefit of SA control at all to enhance detailed macro photography? If so, what is the benefit?
Or is this feature really primarily for the people who will be using the macro lens for portraits?
My initial impression is that releasing this lens as a dedicated macro without SA could have allowed it to be a bit lighter/smaller/cheaper, which I would have preferred. But, since this feature was added to the lens, is there any benefit to it that I can look forward to for macro?
 
Apr 25, 2011
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Hi,
I've been watching the early reviews of the RF 100mm f/2.8L lens with interest, as I am greatly looking forward to having a native 1:1 (or better!) macro option on the R5.
All the demos that I have seen of the SA control feature have results where the subject becomes blurred, which is sort of the opposite of what I typically go for with macro, where I am trying to see really fine details.
Is there any benefit of SA control at all to enhance detailed macro photography? If so, what is the benefit?
It's for the cases where you cannot keep the whole scene in focus.

No need for it if you only take pictures of flat objects.
 
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FrenchFry

Wildlife enthusiast!
Jun 14, 2020
484
603
It's for the cases where you cannot keep the whole scene in focus.

No need for it if you only take pictures of flat objects.
Hi, Thanks for the reply! I take pictures of flowers, insects, amphibians, etc., so not flat objects. Would the SA control be valuable at all of these or just make them blurry?
 
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Apr 25, 2011
2,502
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Hi, Thanks for the reply! I take pictures of flowers, insects, amphibians, etc., so not flat objects. Would the SA control be valuable at all of these or just make them blurry?
It doesn't make them blurry (or at least not really much). It changes the rendering of the out-of-focus background and/or foreground. Neutral SA correction has flat bokeh in both. Undercorrected lens has sharp foreground bokeh and smooth background bokeh. Overcorrected lens has them the other way around.
 
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FrenchFry

Wildlife enthusiast!
Jun 14, 2020
484
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It doesn't make them blurry (or at least not really much). It changes the rendering of the out-of-focus background and/or foreground. Neutral SA correction has flat bokeh in both. Undercorrected lens has sharp foreground bokeh and smooth background bokeh. Overcorrected lens has them the other way around.
All the examples I saw reduced the sharpness of the subject. Hopefully this is something that can be controlled/avoided while still taking advantage of SA features.
 
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Jethro

EOS R
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Jul 14, 2018
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Yes, there are a limited number of hands-on reviews from people who were able to preview the lens on special loan from Canon.
I'd be interested in any links you can share. I photograph fungi which are small and (per the above discussion) definitely not flat - so the ability to accentuate background bokeh is a matter of great interest to me too! I'm having a lot of success with the 3rd party Laowa f2.8 100mm (2x), but the AF (and enhanced exif) of a Canon lens (1.4x) would be pretty much a dream lens for me.
 
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FrenchFry

Wildlife enthusiast!
Jun 14, 2020
484
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I'd be interested in any links you can share. I photograph fungi which are small and (per the above discussion) definitely not flat - so the ability to accentuate background bokeh is a matter of great interest to me too! I'm having a lot of success with the 3rd party Laowa f2.8 100mm (2x), but the AF (and enhanced exif) of a Canon lens (1.4x) would be pretty much a dream lens for me.
I added some links to reviews/promo videos below. Anyone with early access to the lens may have some extra bias.

I am looking forward to purchasing this lens and genuinely hope to get some use out or the SA control, even if I can't picture what that will be yet.

 
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FrenchFry

Wildlife enthusiast!
Jun 14, 2020
484
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I found the last video to be the most useful. She specifically says that she wouldn't use the SA control because it makes the subject blurry in addition to the background and foreground. And this is coming from a Canon Ambassador. I just hope Canon provides some more information about how to make this feature useful to the people who buy the lens.

One potential use case people came up with in the comments section is to make composite images with sharp subjects and very smooth backgrounds. Of course this would be a lot of work to do for every image, but could produce some interesting results.
 
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Canon used to have an EF 135mm f/2.8 with Soft focus lens that featured selectable soft focus. It was aimed at portraiture. In that lens the level of soft focus could be selected and it could affect all the picture evenly. I guess this new RF 100mm lens tries to reinstate that feature but with a little tweak that affects the picture's corner more and center less. People who prefer dreamy portraits or similar will find good use of it. I personally can think of something like the picture below to be created easily by this lens.
20210618 011-01.jpg
 
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koenkooi

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Feb 25, 2015
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I found the last video to be the most useful. She specifically says that she wouldn't use the SA control because it makes the subject blurry in addition to the background and foreground. And this is coming from a Canon Ambassador. I just hope Canon provides some more information about how to make this feature useful to the people who buy the lens.

One potential use case people came up with in the comments section is to make composite images with sharp subjects and very smooth backgrounds. Of course this would be a lot of work to do for every image, but could produce some interesting results.
I recall seeing someone from Canon saying "You need to refocus after using the SA dial", it's unclear in most of the hands-on sessions above if they focus before or after twisting the dial.
I will reserve judgement till I've used the SA dial myself under controlled circumstances :)
 
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FrenchFry

Wildlife enthusiast!
Jun 14, 2020
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My personal verdict, after using the SA control ring, and carefully refocusing in between each dial change, is that I would never use this dial for macro photography. Sadly, in addition to affecting the bokeh, these settings make the subject blurry. (Mostly it looks like white film or grease was rubbed on the front of the lens.) I am glad this dial can be locked.

This might be a desirable feature for some portrait work, but it's still not something I can find a benefit for when focusing on tiny macro subjects, when extreme detail with good color and contrast is the desired result.

The sample photos below helped me see the impact of the SA dial, but do not reflect the types of insect/flower photos that I hope to take with this lens. Zero post-processing was done as getting nicer images was not the purpose of this test. Focus was on the eye to the left in each case. The subject gets slightly bigger in the frame when going from the minus to the plus side of the SA control.

Just because I won't be getting any use out of the SA control, does not mean that I won't enjoy shooting with this lens. I am actually really looking forward to using it!

Comparison of different SA settings from the same distance, refocusing between each shot.
1626133856069.png
Photos above at 1:1:
1626134814620.png
Photos above at 2:1:
1626135022978.png
Full images captured:
1626134146350.png
1626134271549.png
1626134380580.png
 
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Bdbtoys

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Jul 16, 2020
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My personal verdict, after using the SA control ring, and carefully refocusing in between each dial change, is that I would never use this dial for macro photography. Sadly, in addition to affecting the bokeh, these settings make the subject blurry. (Mostly it looks like white film or grease was rubbed on the front of the lens.) I am glad this dial can be locked.

This might be a desirable feature for some portrait work, but it's still not something I can find a benefit for when focusing on tiny macro subjects, when extreme detail with good color and contrast is the desired result.

The sample photos below helped me see the impact of the SA dial, but do not reflect the types of insect/flower photos that I hope to take with this lens. Zero post-processing was done as getting nicer images was not the purpose of this test. Focus was on the eye to the left in each case. The subject gets slightly bigger in the frame when going from the minus to the plus side of the SA control.

Just because I won't be getting any use out of the SA control, does not mean that I won't enjoy shooting with this lens. I am actually really looking forward to using it!

Comparison of different SA settings from the same distance, refocusing between each shot.

View attachment 198923

Feel like doing one of these side-by-sides for -2, -1.5, -1, -.5, 0, +.5, +1, +1.5, +2? It would be nice to see if any SA is ok... or what point exactly it goes to mush.
 
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koenkooi

CR Pro
Feb 25, 2015
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My personal verdict, after using the SA control ring, and carefully refocusing in between each dial change, is that I would never use this dial for macro photography. Sadly, in addition to affecting the bokeh, these settings make the subject blurry. (Mostly it looks like white film or grease was rubbed on the front of the lens.) I am glad this dial can be locked.

This might be a desirable feature for some portrait work, but it's still not something I can find a benefit for when focusing on tiny macro subjects, when extreme detail with good color and contrast is the desired result.[..]
Thanks for doing these tests! I think this might be a nice effect for flower macros where sharpness isn't needed. I have a few shots where the wind blew the flower completely out of focus, making the picture look like a watercolour painting. But the colours were very pleasing, so I printed it 32" wide and hung it in the living room :)

For pictures where you want to show off details, I completely agree, SA doesn't seem suited for that.
 
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john1970

EOS R3
CR Pro
Dec 27, 2015
969
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I have a copy of the RF 100 mm macro lens and while I have not done as much testing as French Fry above I do echo their opinion and feel that I would rarely if ever use the SA for macro work. In my limited experience this weekend with the lens I found that engagement of SA where I could visibly see a change in the background or foreground also caused a loss of detail in the subject. Now I could see SA being used for artistic purposes where one wants to have a more soft focus effects, but beyond that I do not see any major applications. Definitely nice of have the SA control option, but for most of my photography where I like to keep the subject sharp I will likely keep the SA control ring locked. Weather permitting I will try to test out the SA control ring this weekend.

Below is a photo I took this past weekend of a baby snapping turtle at a local wildlife refuge. I guess I could have used the SA control ring to blur the face of the turtle, but as a wildlife photographer I prefer my subject's eyes to be sharp and in focus. If one prefers a more artistic (soft focus) effect you could engage the SA control.

turtle1_SM.JPG
 
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YuengLinger

Print the ones you love.
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Dec 20, 2012
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The lens does seem to produce lovely results, with maybe slightly smoother (and dreamier/creamier) out-of-focus areas. I can't remember ever being too excited about soft-focus effects, and often found them distracting in movies and TV shows when a female actor was given soft-focus, but a quick cut to a male actor would not have the same lens.

Maybe as Kit. suggests, shooting more at an angle produces more of the intended results? Kit. seems to be almost describing a tilt-shift effect, but I have yet to see this in the reviews.

But it must be compelling for some photographers. Hoping to see what those who do like it do with it. For now I'm still happy with my ef 100mm f/2.8L IS. For now!
 
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