topic Re: RF 100mm f2.8L Macro IS USM SA control ring not working in EF & RF Lenses

RF 100mm f2.8L Macro IS USM SA control ring not working

MarjonM — Sun, 12 Mar 2023 10:30:53 GMT

Last week I used the SA control ring on the macro lens for the first time. (in combination with an R6). I found the effect interesting.

Today I wanted to continue practicing with this effect. Now the SA control ring suddenly stops working. The effect is shown in the preview, but when I take a photo, the effect is not present on the photo.

In the meantime I had gone from firmware version 1.6 to 1.8. As a test went back to 1.6 but unfortunately this did not help.

Does anyone else have this problem?

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

rs-eos — Sun, 12 Mar 2023 11:59:09 GMT

What function did you assign to the control ring?

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

shadowsports — Sun, 12 Mar 2023 15:04:29 GMT

My understanding is the SA does not require assignment. Isn't it just a function of the lens?

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

MarjonM — Sun, 12 Mar 2023 15:14:12 GMT

I use the SA control without assigning an other function to it. The effect shows best at 2.8. When I use 5.0 I see the softness in the preview but no softness at all on the photo. As if I was not using the minus or plus.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

rs-eos — Sun, 12 Mar 2023 15:16:39 GMT

Oh apologies; I had incorrectly been thinking of the front ring.

For the original shots taken vs the new ones, what were all the settings? Page 10 of the User Manual has several notes that the effect may be lessened depending upon several factors.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

shadowsports — Sun, 12 Mar 2023 15:37:01 GMT

@MarjonM wrote:
I use the SA control without assigning an other function to it. The effect shows best at 2.8. When I use 5.0 I see the softness in the preview but no softness at all on the photo. As if I was not using the minus or plus.

I could imagine. The softness of the bokeh balls and front / rear focus would be more pronounced and noticeable when more light is present.

I'm looking now, but I would assume the SA control diminishes as aperture decreases and less light becomes available. To what degree the softness/sharpness is adjustable is not clear. If you see it in the viewfinder or live view, I'd expect to see the same in your image.

**Edit. I did find this.

The SA Control effects will be greater when the lens is used at its maximum aperture. It is recommended to use either aperture priority or manual exposure mode in order to maintain as much control over the bokeh effect as possible.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

MarjonM — Sun, 12 Mar 2023 15:34:11 GMT

At 4.0 I see softness in the viewfinder and live view, but not on the image. I don't know if it is suposed to be like that or not

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

shadowsports — Sun, 12 Mar 2023 15:43:25 GMT

Ken Rockwell states:

At f/2.8 the effect is strong as I show below, even at the most minor ±1 settings. That's OK; if you want a milder effect, stop down to f/4 or f/5.6 where the effects of the SA CONTROL become much less.

I suggest you try shooting in manual or Av mode.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

MarjonM — Sun, 12 Mar 2023 15:46:19 GMT

thanks for your reply. I keep trying!

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

shadowsports — Sun, 12 Mar 2023 19:14:13 GMT

Ricky, you kind sir have nothing to apologize for. I initially thought he was using a Control Ring as well. He hadn't mentioned his camera. I had recently read an article about this lens and remembered mention of the SA feature which is quite remarkable. I do not believe Canon has another lens that moves the entire objective group fore or aft to control the degree of sharpness the lens produces. I almost got the EF 100 way back when, but decided against it because I don't do much macro photography. I must admit the RF version is pretty cool. I always pay close attention to your C70 posts with the 0.71x adapter. I had no idea Canon made an adapter letting the C70 use FF glass and maintain the same FOV. You also showed me how important ND's are for video.

Canon improved the mag on this RF lens also. All of this only became important to me since purchasing the 100-500 with TC. Sorry for going off topic here.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

FloridaDrafter — Sun, 12 Mar 2023 22:00:47 GMT

I use it on an R5, although I also have an R6, I didn't update to 1.8 so I can't say if that messed with spherical aberration (SA).

As mentioned, aperture plays a big part in the effect SA has on the image. I suspect what you are seeing in the viewfinder is its effect at f/2.8. Your camera focuses at f/2.8 (or wide open) to maximize AF, no mater what aperture you have set, then when you take the shot the aperture you have selected is used. I don't think exposure simulation would work for SA, at least that is the way I understand it, and besides, ES is only available in live viewing from the rear LCD.

Attached are some "down n dirty" tests that I just shot with SA at -2. and varying apertures.

F/2.8 with no SA.

F/2.8 - No SA.

F/2.8 and -2 SA.

F/2.8 - Negative 2 SA.

F/4 and -2 SA.F/4 - Negative 2 SA.

F/6.2 and -2 SA.

F/6.3 - Negative 2 SA.

Note that there is very little change in the subject itself from f/2.8 no SA and f/6.2 -2 SA, however, the background is effected. If I had pulled back a little, you would see a more dramatic effect in bokeh at f/6.2.

I hope this helps.

Newton

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

rs-eos — Mon, 13 Mar 2023 00:08:31 GMT

Excellent work on showing the effect on this, Newton. And great callout about the lens always being at it's widest aperture before the shot is taken. That would explain what the OP is experiencing.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

shadowsports — Mon, 13 Mar 2023 12:38:11 GMT

This sounds very likely. 👍

Excellent Newton!

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

MarjonM — Mon, 13 Mar 2023 20:34:37 GMT

Thank you for your answer FloridaDrafter!. I never knew that what you see in the viewfinder is always shown with aperture 2.8. I'm going to continue practicing with the SA ring.

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

FloridaDrafter — Mon, 13 Mar 2023 22:38:01 GMT

@MarjonM wrote:
Thank you for your answer FloridaDrafter!. I never knew that what you see in the viewfinder is always shown with aperture 2.8. I'm going to continue practicing with the SA ring.

You are very welcome. I've been shooting for a long time with DSLR's, and it [AF wide open] was unknown to me as well until I bought MILC's a few years ago. I didn't think about it, I just knew what worked when it came to exposure, LOL!

I don't use SA that often because almost all of my shots with the RF 100mm macro are straight up macro, including focus stacking (Depth compositing). But I did practice using it so I would know its possibilities. Personally, although I don't use it a lot, I think it's a nice feature. Yes, you can create a similar effect in a good post editor, but IMHO, anything that speeds up my post editing is a benefit 🙂

Newton

Re: RF 100mm f2.8L Macro IS USM SA control ring not working

FloridaDrafter — Mon, 13 Mar 2023 22:58:29 GMT

Thanks, Ricky and Rick!

Newton