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Old 20-08-2012, 04:13 PM
TheDecepticon
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Timelapse-more confusion

I have been trying quite unsuccessfully at doing timelapses. I bought the Timelapse book that Mike was talking about and it says to set the aperture to a large number so more of your field is in focus and a low ISO to control noise.

So, is this the f ratio setting on the camera or is it on the lens? I have several I can choose from.

It also says that the larger the number, the smaller the hole, the better depth of field, but i was just reading Greg Bradleys attempts at "bramping" and he is using a small f number, wide open, and a high ISO.

If you were shooting from day to night, how can you change your f ratio on the fly to compensate.

I am not overly knowledgeable when using daytime cameras. What am I missing?
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Old 20-08-2012, 06:14 PM
Garbz (Chris)
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Changing the aperture changes the depth of field. You'd more likely want to change your shutter speed to compensate for the change in light. Daytime cameras are really not that different to telescopes except the aperture is easily changeable.

I don't understand why you have multiple places to set your aperture (f/number). You only have one set of aperture blades, in the lens, they are controlled from the camera.

My only thought it, is it a Nikon lens with an aperture ring? If that's the case the aperture ring is a throwback to older cameras which didn't have electronic control over the aperture. A modern Nikon camera will REQURIE you to set the lens ring to f/22 or whatever the smallest (in orange) is because it wants to control it electronically. If this is the case it'll show f/EE as the aperture on the camera screen.

Larger aperture numbers (physically smaller iris) means larger depth of field.
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Old 20-08-2012, 06:57 PM
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sheeny (Al)
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Time lapses across the day to night transition are not a simple thing to do. Fred (Bassnut) built a complete system to control his camera to adjust aperture and exposure to accomplish this.

I suggest you simplify your initial attempts till you get the hang of timelapses before launching into the full transition through large light changes. That's enough of a challenge on its own.

Aperture, exposure and ISO are all a bit of a trade off. Longer exposure and higher ISO increase noise, but capture more light. Big aperture captures more light but at the expense of DOF.

For star trails with not much foreground (or the foreground is quite well away) you can use a bigger aperture (smaller number). If you have a close foreground object you also want to capture as well as the stars, you will need a high aperture number (smaller aperture) for the DOF.

If there's action you want to stop in each frame, that will determine your exposure. depending on your lens FL, you might be limited to 15s or 30s before the stars noticably elongate for example.

Then your final trade off will be the ISO. Try to get enough detail without unwanted noise.

Its all trade offs... a bit of a balancing act.

Does that help?

Al.
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Old 20-08-2012, 07:53 PM
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Time lapse questions

I've answered your questions below:

Quote:
Originally Posted by TheDecepticon View Post
I have been trying quite unsuccessfully at doing timelapses. I bought the Timelapse book that Mike was talking about and it says to set the aperture to a large number so more of your field is in focus and a low ISO to control noise.


Is this for a daylight time lapse? Sure a higher F ratio gives a larger depth of field meaning a large amount of your view will be in focus at the same time.

Nighttime is a different story. You want highest ISO before your camera becomes too noisy, you want widest aperture (lowest F ratio your lens will do) to capture maximum light. Generally time lapses are with wider lenses like 14mm or so.


So, is this the f ratio setting on the camera or is it on the lens? I have several I can choose from.



Aperture is usually controlled by the electronics of the camera. Some older lenses allow manual control as well. Use the camera electronics.


It also says that the larger the number, the smaller the hole, the better depth of field, but i was just reading Greg Bradleys attempts at "bramping" and he is using a small f number, wide open, and a high ISO.

If you were shooting from day to night, how can you change your f ratio on the fly to compensate.


You can't easily. I believe there are devices coming out on the market to help but they aren't there yet. There is a bramping device that works on Canon cameras on the market.

I was trying the Triggertrap as I am using a Nikon and that other device is only for Canon's. Nikon inbuilt time lapse will do bramping but not carry through to proper nighttime exposures. It does the transition from day to night well but then once night it does not ramp up to the higher level I use for nighttime exposures. I use auto ISO for that and perhaps the 5D3 has that feature otherwise it may only be a Nikon feature.

I would not let this day to night transition stop you as lots of great time lapses don't do it either. Its not that great an effect.

Greg.


I am not overly knowledgeable when using daytime cameras. What am I missing?
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Old 21-08-2012, 05:13 PM
TheDecepticon
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Thanks guys, all great info. I will continue to fiddle and see what I come up with.
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Old 21-08-2012, 08:24 PM
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philiphart (Phil Hart)
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sounds like the book is optimising for daytime timelapse.. complete opposite of what you want for night. and yes.. day to night in one sequence is not easy.. at least not without a lot of flicker.

you can use your camera in aperture priority mode and keep flicking the aperture open a bit more as it gets darker. or you get into thing like 'little bramper' which is what colin legg uses or custom fun and games like fred and i have been playing with. but like others said.. start simple..

there is of course another book that might help you here too:

http://shop.iceinspace.com.au/shop/s...g-stars-ebook/

Phil
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Old 21-08-2012, 09:02 PM
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Bassnut (Fred)
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Quote:
Originally Posted by philiphart View Post
sounds like the book is optimising for daytime timelapse.. complete opposite of what you want for night. and yes.. day to night in one sequence is not easy.. at least not without a lot of flicker.

you can use your camera in aperture priority mode and keep flicking the aperture open a bit more as it gets darker. or you get into thing like 'little bramper' which is what colin legg uses or custom fun and games like fred and i have been playing with. but like others said.. start simple..

there is of course another book that might help you here too:

http://shop.iceinspace.com.au/shop/s...g-stars-ebook/

Phil
No, thats not right Phil, you just dont know the best publications available for TL.

The best BY FAR is http://philhart.com/shooting-stars. Its a cracker. Very practical and full of really usefull info. A very proffessional effort, well worth the dosh, especially the TL section.
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Old 26-08-2012, 08:50 AM
TheDecepticon
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LOL Fred!

Thanks guys, looks great, I will purchase and have a read!

Yes, now that I have some more info from the great info source that is IIS, it would seem like it is geared for day work, however, still a very good info source.

Cheers and clears!
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