Record Video with fix exposure

Started by eightcore, October 02, 2012, 08:54:20 PM

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eightcore

Dear community,

is it (logically) possible to lock the aperture during vide recording?


Thanks in advance

eightcore

Francis

Yes. It depends on the model as far as how to.

ilguercio

Quote from: eightcore on October 02, 2012, 08:54:20 PM
Dear community,

is it (logically) possible to lock the aperture during vide recording?


Thanks in advance

eightcore
You can use Exposure override to do what you want.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

eightcore


ilguercio

Quote from: eightcore on October 02, 2012, 10:14:30 PM
aperture, not exposure. Sorry.
???
Exposure override let's you choose any parameter by yourself. Set an aperture and don't change it, it's simple.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

eightcore


ZeroUnityGain

Can someone please shoot me because I really don't see how that can work.  If your lens is a zoom and not a fixed aperture the iris is going to change every time you zoom in or out. 

ilguercio

Quote from: ZeroUnityGain on October 05, 2012, 10:19:12 AM
Can someone please shoot me because I really don't see how that can work.  If your lens is a zoom and not a fixed aperture the iris is going to change every time you zoom in or out.
Blame your lens then. The aperture will stay the same if that f/stop is available at each focal lenght you zoom through. Else, it will obviously change.
As said a million times, ML is a software, it can't do miracles

edit by nanomad: Language ::)
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

Malcolm Debono

Quote from: ZeroUnityGain on October 05, 2012, 10:19:12 AM
Can someone please shoot me because I really don't see how that can work.  If your lens is a zoom and not a fixed aperture the iris is going to change every time you zoom in or out.

If you have an f/3.5-f/5.6 lens, you can always shoot at f/5.6 so that it remains constant at both sides of the focal length. If you're shooting at a lower aperture (for example at f/3.5 when the lens is at 18mm), don't use the zoom (besides, it's next to impossible to get a smooth zoom), especially with non-L lenses which I'm assuming you're using (from the non-constant aperture).
Wedding & event cinematographer
C100 & 6D shooter
New here?  Check out the FAQs here!

ZeroUnityGain

Quote from: ilguercio on October 05, 2012, 11:47:40 AM
Blame your lens then. The aperture will stay the same if that f/stop is available at each focal lenght you zoom through. Else, it will obviously change.
As said a million times, ML is a software, it can't do miracles

edit by nanomad: Language ::)

Hmmmm (I like saying hmmmm)...The author asks, "Is it possible to lock the aperture during video recording."
And I'm very clearly saying that unless your lens is a fixed aperture throughout the zoom range, you can't!


ZeroUnityGain

Quote from: Malcolm Debono on October 05, 2012, 01:13:03 PM
If you have an f/3.5-f/5.6 lens, you can always shoot at f/5.6 so that it remains constant at both sides of the focal length. If you're shooting at a lower aperture (for example at f/3.5 when the lens is at 18mm), don't use the zoom (besides, it's next to impossible to get a smooth zoom), especially with non-L lenses which I'm assuming you're using (from the non-constant aperture).

Hi Mal,
Just to clear things up.  I don't have a problem.  I'm simply stating that the author cannot fix a constant aperture unless the lens is a constant aperture. 

ilguercio

18-55 IS has a biggest common aperture of f/5.6 so i don't see the problem to lock the aperture to that value.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

Malcolm Debono

Quote from: ZeroUnityGain on October 06, 2012, 10:45:06 PM
Hi Mal,
Just to clear things up.  I don't have a problem.  I'm simply stating that the author cannot fix a constant aperture unless the lens is a constant aperture.

Sorry, I must have used the wrong quote. You're perfectly right.
Wedding & event cinematographer
C100 & 6D shooter
New here?  Check out the FAQs here!

Francis

No where does the OP say anything about this being an issue of a non-constant aperture zoom. It sounds like they are unsure how to set exposure to manual in video mode.

ZeroUnityGain

Quote from: ilguercio on October 07, 2012, 03:08:00 AM
18-55 IS has a biggest common aperture of f/5.6 so i don't see the problem to lock the aperture to that value.

I suppose what you are saying is that the 18-55 IS has its widest opening aperture of f/5.6 when at its max focal length of 55mm, and yes of course you can fix that so it stays at f/5.6 with Canon's own firmware to stay at that f stop even at its 18mm setting pulled right back.   But its widest opening aperture at 18mm is f/3.5 and you can't lock that to stay when you zoom out to the 55mm focal length, as it will automatically go to f/5.6.
Since eightcore asked can you "lock the aperture during video recording," I think the information is relevant if he is not using a constant aperture lens.

Cheers




ZeroUnityGain

Quote from: Francis on October 07, 2012, 06:57:52 PM
No where does the OP say anything about this being an issue of a non-constant aperture zoom. It sounds like they are unsure how to set exposure to manual in video mode.

Hey Francis,
No he doesn't mention about non-constant aperture zoom, and it may simply be as you say a case of how to set the f/stop manually, but the information is very relevant if his lenses aren't constant aperture lenses.  For instance when I first started out with a DSLR shooting concerts I'd set the widest opening because of the lack of light and as I'd zoom the aperture would blow out to f/ 5.6 -- then a rival photog at a concert told me about constant aperture lenses, and I was thankful for the information.

Cheers


ilguercio

But in that particular case he can, doesn't matter if he can't lock it at f/3.5.
The question is "can i lock the aperture?" not "can i lock the aperture at f/3.5?". Of course you can't lock the aperture to a value that is not shared among all the focal lenghts but it is so evident that i thought it was unnecessary to highlight this fact.
You can lock the aperture, that's the important thing. He didn't even mention non-constant aperture lenses so i don't see why you should divert the discussion onto that.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

ZeroUnityGain

Quote from: ilguercio on October 07, 2012, 11:40:27 PM
Of course you can't lock the aperture to a value that is not shared among all the focal lenghts but it is so evident that i thought it was unnecessary to highlight this fact.


Yes I know what you mean. It's like when they bring a weapon onto a film set, it's evident that it wouldn't be loaded.
I get it now.

Cheers.