Author Topic: Exposure adjustment finer than 1/3rd stop?  (Read 2502 times)

Roman

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Exposure adjustment finer than 1/3rd stop?
« on: September 14, 2014, 12:05:04 PM »
Hey,

So in the Canon menus you can set the exposure to adjust by either 1/2 or 1/3rd of a stop per click of the dial.

However! There are a few situations where having slightly finer control over the shutter speed would be beneficial.

Panning shots with motorsport, generally I start at about 1/100th of a second exposure time and then dial it up or down to suit distance from the vehicle, vehicle speed, etc.

However the jump from 100th to the next setting up or down can be quite significant, in terms of how much motion blur is in the picture. So sometimes I wish I had finer control.

Is there an ML option to somehow temporarily set the camera to increase/decrease exposure time in 1/10th stops or similar?

Or another option, is there a good way to take 3 shots at differening exposure lengths, say 1/80th, 1/100th, 1/120th while compensating exposure or aperture to keep the same brightness as the first shot? It would be handy for dialing in initially, which shutter speed suits best.

It's probably something that can be acheived already, but I'm not sure which combination of features would allow for it.

Apologies if this is a repeat or annoying question, I've used ML extensively over the last year or two but have not seen a combination which can acheive the above.
Thanks,

dmilligan

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Re: Exposure adjustment finer than 1/3rd stop?
« Reply #1 on: September 14, 2014, 02:52:52 PM »
Finer control is impossible (except in rolling shutter / silent pic mode which I assume would be unacceptable for your purposes). 1/3 and 1/2 stop values are the only ones accepted by Canon firmware.

ML Menu > Expo > Expo Lock

a1ex

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Re: Exposure adjustment finer than 1/3rd stop?
« Reply #2 on: September 15, 2014, 08:09:03 AM »
With expo override you can adjust it in 1/8 EV steps.

If that's not enough, recent cameras have shutter fine-tuning in movie mode (in roughly 20-microsecond increments).

dmilligan

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Re: Exposure adjustment finer than 1/3rd stop?
« Reply #3 on: September 15, 2014, 01:21:58 PM »
With expo override you can adjust it in 1/8 EV steps.
That's only in LV/Movie right? I was under the impression you couldn't override regular photo mode.

a1ex

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Re: Exposure adjustment finer than 1/3rd stop?
« Reply #4 on: September 15, 2014, 02:11:03 PM »
Correct.

In photo mode, you should be able to dial both 1/2 and 1/3 increments from ML menu (or shortcuts). Some cameras even accept all 1/8 EV increments in photo mode (e.g. 550D does, but 60D doesn't).

There is even a small display bug in the shutter rounding routine. For example, on 550D, I get the following speeds (in photo mode):

1/50 - Tv5.6
1/55 - Tv5.7
1/58 - Tv5.8
1/60 - Tv6.0
1/70 - Tv6.1
1/80 - Tv6.2
1/80 - Tv6.3  <- this one matches Canon menu
1/90 - Tv6.5
1/100 - Tv6.6
1/110 - Tv6.7
1/120 - Tv6.8
1/125 - Tv7.0