A7Riii and EFCS

Started 3 months ago | Questions
il_alexk Senior Member • Posts: 2,636
A7Riii and EFCS

I've found a lot of inconclusive discussions for using EFCS on some Sony cameras, so I wonder if anyone can give the full list of reasons why/when EFCS should not be used with A7R3.
I'm sure this would be useful to all A7R3 newbies

Thanks

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Cheers,
Alex

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ANSWER:
techjedi
techjedi Veteran Member • Posts: 3,828
Re: A7Riii and EFCS
2

il_alexk wrote:

I've found a lot of inconclusive discussions for using EFCS on some Sony cameras, so I wonder if anyone can give the full list of reasons why/when EFCS should not be used with A7R3.
I'm sure this would be useful to all A7R3 newbies

Thanks

The only one I have personally experienced and am aware of is:

- When using HSS flash with shutter speeds above 1/1000 or 1/2000, you will likely see banding in the resulting image.

I have used EFCS on multiple Sony bodies for years and never experienced any other negative issue. Fully silent shutter I have the expected issue where some LED lighting causes banding.

I run with EFCS on by default all the time.

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SQLGuy Veteran Member • Posts: 8,562
Re: A7Riii and EFCS

EFCS in general has issues where the speeds of the electronic and mechanical curtains don't exactly match. This becomes more of an issue at shorter exposures and can lead to uneven exposure for 1/1000th and shorter. Jim Kasson did some testing of this. Not sure whether the A7R3 was specifically included, but I think we would have heard if it were immune. This effect is not, IME, dramatic, but it's something to be aware of.

Also, for reasons I do not understand, bokeh artifacts can be "chopped" by EFCS. I think maybe this is something that's more of a concern with adapted AF lenses. It might have something to do with bad stop-down timing during the shorter lag of EFCS. I certainly have not noticed it with manual lenses.

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kennedmh New Member • Posts: 4
Re: A7Riii and EFCS
1

You don't want to have EFCS on if you are using a very fast aperture. I think it makes a difference for something like f/2 or faster.

This link to another dpreview post explains the physics of it all

selected answer This post was selected as the answer by the original poster.
moficera Regular Member • Posts: 362
Re: A7Riii and EFCS

SQLGuy wrote:

EFCS in general has issues where the speeds of the electronic and mechanical curtains don't exactly match. This becomes more of an issue at shorter exposures and can lead to uneven exposure for 1/1000th and shorter. Jim Kasson did some testing of this. Not sure whether the A7R3 was specifically included, but I think we would have heard if it were immune. This effect is not, IME, dramatic, but it's something to be aware of.

I think uneven exposure can be quite obvious, when the top (or bottom, not sure) is darker.

Also, for reasons I do not understand, bokeh artifacts can be "chopped" by EFCS. I think maybe this is something that's more of a concern with adapted AF lenses. It might have something to do with bad stop-down timing during the shorter lag of EFCS. I certainly have not noticed it with manual lenses.

Bokeh is affected because with EFCS the plane of shutter differs, when you use full mechanical shutter or full electronic shutter bokeh is not affected.

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SQLGuy Veteran Member • Posts: 8,562
Re: A7Riii and EFCS

kennedmh wrote:

You don't want to have EFCS on if you are using a very fast aperture. I think it makes a difference for something like f/2 or faster.

This link to another dpreview post explains the physics of it all

Thanks. That article definitely helped. Explains why I hadn't noticed with my faster manual lenses: I typically shoot those wide or near wide open at night, so without the narrow slit between the electronic and mechanical shutter curtains.

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Entropy512 Veteran Member • Posts: 4,816
Re: A7Riii and EFCS

kennedmh wrote:

You don't want to have EFCS on if you are using a very fast aperture. I think it makes a difference for something like f/2 or faster.

This link to another dpreview post explains the physics of it all

Not just that - fast aperture AND short shutter speed.

In general if you're at or slower than 1/1000 you should be fine under almost any circumstance.

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OP il_alexk Senior Member • Posts: 2,636
Re: A7Riii and EFCS

kennedmh wrote:

You don't want to have EFCS on if you are using a very fast aperture. I think it makes a difference for something like f/2 or faster.

This link to another dpreview post explains the physics of it all

Fantastic, makes a lot of sense. The most important part for me is to realise that different restrictions of EFCS on different cameras are a reflection of different strategies to prevent the common problem. Nikon blocks EFCS at 1/2000, Sony allows its users to decide.

And I also read it as the DR is expected to be the same with EFCS on and off. The difference that some users might observe with EFCS can be explained by the upper area of the screen getting less light due to the reasons stated in the link above.

Simples! 

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Cheers,
Alex

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