[IMPOSSIBLE] Shutter Speed Compensation

[lamella]

Hi!

There is a feature I'm dreaming about for ages, maybe it's not that hard to implement in ML. It goes about the Auto Exposure calculation of all important modes: P, A, T, M+Auto ISO. The problem with the standard calculation is that it is based on the rule of thumb that the image won't be blurred in a hand held camera if the exposure time is less than 1/focal length of the lens. But it's not always true, because of two main reason:

1) your hand can be more shaky or more calm than the normal,

2) your lens has Image Stabilization! In this case the exposure time can be 3-4 stops longer than the 1/focal length. But the automatic calculation does not take that into consideration, that's too bad. You can exploit the IS fully if you use Manual mode with fix ISO setting like 50 years ago!...

The requested feature would change the calculation: the user should be able to allow longer or expect shorter exposure time as the default. This could be called "shutter speed compensation".

Maybe there is a better explanation of the topic here: http://forums.usa.canon.com/t5/EOS/5D3-Firmware-Hiccups-2-No-IS-Image-Stabilizer-support/td-p/13759.

Is it theoretically possible to change the default AE calculation by ML? The ideal solution would be that the lens IS is detected automatically and SSC ist set to 3 or 4. As far as I know the body does not know if the lens has IS, is it true? Then a manual setting would also be amazing.

[Audionut]

You're talking about general metering performed by the camera correct.  And the shutter speeds it uses while doing this metering?

Try this.

[lamella]

Thank you for your comment. I think ETTR is a powerful help to lower the noise, especially in shadows, but the shutter-speed-compensation is another thing.

Suppose you shoot a far away house with a telephoto lens like 200mm/2.8. The automatic metering calculates that you need 1/200s exp time and aperture 2.8 on ISO100 to have a well exposed image. But the subject is not flat, so you want deeper depth of field, which means higher aperture like 8.0. Since you have IS on the lens, you know the shot can be taken with 1/25s 8.0 ISO100. But the automatic metering does not allow that for you:

- If you switch to Av mode and set 8.0, the automatic metering sets shutter speed to 1/200 but ISO800 =>  unnecessary big noise.

- If you switch to Tv mode and set 1/25s, the aperture remains 2.8 and ISO 100 => you don't have more depth of field.

- If you switch to M mode and set 1/25s and aperture 8.0, the ISO stays at 100 because there is enough light, but you had to do the math, automatic metering helped nothing. And if you change the focal length (if it's a zoom) to eg. 70mm, you have to do the math again.
And this is the annoying part: automatic metering does the math well but lucks an important parameter: how stable is the lens, what is the lowest exposure time allowed to take an sharp picture.

This is where the shutter-speed-compensation parameter comes in: if I could set it to 3 EV that means for the calculator: OK I know the lens has focal length 200mm, but it can be handled as a 25mm lens! Because the hand movements does not shake it so much, thanks to the IS.

So my question in other words, would it be possible to mock the automatic metering with a focal length changed with a given factor? If I have IS I would set it to 3 EV, and if I put the camera in my grandfather hand , I would set it to -2 EV. (The latter means: the lens should be used as if it's a longer lens (800mm), shaking much more than we think.)

[brapodam]

Thank you for your comment. I think ETTR is a powerful help to lower the noise, especially in shadows, but the shutter-speed-compensation is another thing.

Suppose you shoot a far away house with a telephoto lens like 200mm/2.8. The automatic metering calculates that you need 1/200s exp time and aperture 2.8 on ISO100 to have a well exposed image. But the subject is not flat, so you want deeper depth of field, which means higher aperture like 8.0. Since you have IS on the lens, you know the shot can be taken with 1/25s 8.0 ISO100. But the automatic metering does not allow that for you:

- If you switch to Av mode and set 8.0, the automatic metering sets shutter speed to 1/200 but ISO800 =>  unnecessary big noise.

- If you switch to Tv mode and set 1/25s, the aperture remains 2.8 and ISO 100 => you don't have more depth of field.

- If you switch to M mode and set 1/25s and aperture 8.0, the ISO stays at 100 because there is enough light, but you had to do the math, automatic metering helped nothing. And if you change the focal length (if it's a zoom) to eg. 70mm, you have to do the math again.
And this is the annoying part: automatic metering does the math well but lucks an important parameter: how stable is the lens, what is the lowest exposure time allowed to take an sharp picture.

This is where the shutter-speed-compensation parameter comes in: if I could set it to 3 EV that means for the calculator: OK I know the lens has focal length 200mm, but it can be handled as a 25mm lens! Because the hand movements does not shake it so much, thanks to the IS.

So my question in other words, would it be possible to mock the automatic metering with a focal length changed with a given factor? If I have IS I would set it to 3 EV, and if I put the camera in my grandfather hand , I would set it to -2 EV. (The latter means: the lens should be used as if it's a longer lens (800mm), shaking much more than we think.)

-Auto ETTR does not change aperture, it only modifies ISO and shutter speed
-You can select "link to Canon shutter' in the advanced options for Auto ETTR, so you can use the scroll wheel to change the minimum shutter speed allowed for ETTR on the fly

With these 2 points, I think Auto ETTR satisfies your needs. Of course Auto ETTR isn't perfect because it has to have either live view on or you'll have to shoot at least 2 shots to get the correct exposure.

[a1ex]

Keep in mind that we can't read focal length and IS status outside LiveView.

[lamella]

Keep in mind that we can't read focal length and IS status outside LiveView.

Oh, that's bad . Then this feature seems to be impossible indeed.

BTW there is another feature that I would attach here. Is it possible to in Manual mode to set the exposure values automatically? My concern with M is that you should set the shutter speed, aperture and ISO setting by hand and check the light metering (or histogram), if they are correct. It would be great feature if I press eg. the * button, the values are set by the automatic metering, and then I can tune them further. It would mean two benefits:

1) sometimes you have to roll over the exposure time from 30s to 1/500 and Aperture form 2.8 to 16 just because you used with that settings last time. It is so lame. Why can't I copy the automatic metering values to M mode?
For example I'm shooting in Av mode (most often), but a given problematic scene needs Manual settings. After I switch to M I have to set everything as if the camera don't have any idea about the right metering settings.

2) It would help for the issue of this topic: using IS optimized shutter speed. I would the do an automatic metering setting (eg with *) then change the values: longer exp. time + bigger aperture or lower ISO - depending on the light conditions.

So in short: can you change the current Manual mode settings by ML?

[Audionut]

There's a reason they call it manual mode 

I recall a topic on this a while ago, but can't recall what the outcome was.  Personally, I would just use AutoETTR for this also.
Set it to the set button or double click half shutter. 

Walk into a new scene with old settings.  Double click the half shutter, job done!