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24fps Shutter Speed on SLR Camera?


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#1 Eric Black

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Posted 12 April 2008 - 07:05 PM

I am curious, what is the proper shutter speed of a digital SLR camera if I was trying to test lenses/stock for 24fps?

Would it be 1 second divided by 24?

60 divided by 24?

Its 1/24 of a second , but what does that translate to in still shutter speed terms?
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#2 Michael Nash

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Posted 12 April 2008 - 07:13 PM

A motion picture film camera running at 24fps exposes each frame at 1/48th of a second. The film has to be advanced to the next frame with the shutter closed for part of the 1/24 second interval.

Shutterspeeds are shutterspeeds. 1/48 second on a movie camera is 1/48th second on a still camera. 1/50th is close enough if that's all your DSLR will do, but I'm not sure how you're going to test film stock on digital camera... ;)
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#3 K Borowski

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Posted 14 April 2008 - 11:53 AM

I don't own a digital SLR, nor do I want to, but on electronic film SLRs, the closest you can usually get would be 1/45 sec. On older mechanical SLRs, you'd have to settle for either 1/30 or 1/60th of a second, either of which is close enough in the ballpark to work, as long as you remember to compensate by the half stop when you're actually shooting through a movie camera.

You need to get ECN-2 respools for 35mm and shoot those. Right now either Dale labs in Florida or A&I Lab will process ECN-2. I'm thinking of starting up a service myself for something more akin to what RGB in California offered. ECN-2 processing, and slide-prints onto ECP print stock.
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#4 Serge Teulon

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Posted 15 April 2008 - 06:16 AM

You need to get ECN-2 respools for 35mm and shoot those. Right now either Dale labs in Florida or A&I Lab will process ECN-2. I'm thinking of starting up a service myself for something more akin to what RGB in California offered. ECN-2 processing, and slide-prints onto ECP print stock.


Eric,

When testing for a lower budget project I usually get some 35mm respools from Kodak. Its a great way to test without spending lots of money. However, the processing is a lot more expensive than developing 35mm that doesn't need to go through the ECN-2 process.
Also, 1/50th is absolutely fine and if your camera doesn't have the option then 1/60th will do too. The difference is 1/10th.

Cheers
S
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#5 K Borowski

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Posted 15 April 2008 - 06:37 AM

Eric,

When testing for a lower budget project I usually get some 35mm respools from Kodak. Its a great way to test without spending lots of money. However, the processing is a lot more expensive than developing 35mm that doesn't need to go through the ECN-2 process.
Also, 1/50th is absolutely fine and if your camera doesn't have the option then 1/60th will do too. The difference is 1/10th.

Cheers
S


Serge, I am curious. As you are from the UK, where do you get ECN-2 film processed? Is there an ECN-2 stills processor outside of the U.S. Even here, the two labs that currently provide it charge much more than C-41. So having to ship it across the ocean twice would make processing exponentially more expensive.

I don't know why ECN-2 should be any more expensive than C-41 to process. Something fair would be maybe $3-4 per 36 exp. (5 foot) roll, and then maybe $5-7 per set of 36 prints one-lite. Maybe $7-9 for individually color-corrected frames. Then $4-5 for scans from either negatives or slide-prints.

As a side note, is it just English where distinguishing between a 35mm still slide and a movie "print" is so confusing, or do other languages muddle this distinction just as thoroughly? ;)

~KB
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#6 Serge Teulon

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Posted 15 April 2008 - 09:29 AM

Serge, I am curious. As you are from the UK, where do you get ECN-2 film processed? Is there an ECN-2 stills processor outside of the U.S. Even here, the two labs that currently provide it charge much more than C-41. So having to ship it across the ocean twice would make processing exponentially more expensive.

I don't know why ECN-2 should be any more expensive than C-41 to process. Something fair would be maybe $3-4 per 36 exp. (5 foot) roll, and then maybe $5-7 per set of 36 prints one-lite. Maybe $7-9 for individually color-corrected frames. Then $4-5 for scans from either negatives or slide-prints.

As a side note, is it just English where distinguishing between a 35mm still slide and a movie "print" is so confusing, or do other languages muddle this distinction just as thoroughly? ;)

~KB


Hey Karl,
I've been using a new lab here in London called 'ilab' they charge about £50 per still roll for an ECN-2 process. Why they charge more than the C-41 process must be down to costs on logistics of processing. Chemicals, machinery etc....I mean, the 'snappy snaps' on the high st has an automated machine that needs an operative to have about 10 mins induction to work it, whereas a pro lab, as you might know, is a 'little' more complicated.
I don't really get too involved in the intricate technical depths of it but I'm sure someone else here that is more technically minded in this dept can help.

As for the grammar question, a still slide is a single frame that is put into what we call a slide case where as a movie print is a roll of several frames. Unless I'm not getting your question I don't particularly think that our grammatical differences have any play in this instance.

Cheers
S
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#7 Richardson Leao

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Posted 15 April 2008 - 12:28 PM

a c41 kit from novadarkroom costs 11 pounds... washing the remjet from a meter or so of film is a deadeasy job... and, btw, not all cameras have 180o shutters (then there are variable angle shutters)... But I use 1/60 in a slr as there's no 1/48 setting. It's less than 1 stop difference (3/5th of a stop).

Hey Karl,
I've been using a new lab here in London called 'ilab' they charge about £50 per still roll for an ECN-2 process. Why they charge more than the C-41 process must be down to costs on logistics of processing. Chemicals, machinery etc....I mean, the 'snappy snaps' on the high st has an automated machine that needs an operative to have about 10 mins induction to work it, whereas a pro lab, as you might know, is a 'little' more complicated.
I don't really get too involved in the intricate technical depths of it but I'm sure someone else here that is more technically minded in this dept can help.

As for the grammar question, a still slide is a single frame that is put into what we call a slide case where as a movie print is a roll of several frames. Unless I'm not getting your question I don't particularly think that our grammatical differences have any play in this instance.

Cheers
S


Edited by Richardson Leao, 15 April 2008 - 12:32 PM.

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#8 Chris Keth

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Posted 15 April 2008 - 12:38 PM

By the way, the shutter speed of a film camera is calculated thus:


(1/fps)*(shutter angle/360)=shutter speed


So a normal shutter speed for most cameras=[(1/24)*(180/360)]=(180/8640)=1/48 of a second
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#9 Serge Teulon

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Posted 15 April 2008 - 02:39 PM

By the way, the shutter speed of a film camera is calculated thus:


(1/fps)*(shutter angle/360)=shutter speed


So a normal shutter speed for most cameras=[(1/24)*(180/360)]=(180/8640)=1/48 of a second


Hey Chris,

Just tried the formula you gave and I'm getting 2.08=(1/24)*(180/360).....my maths is my weakness so can you please detail that calculation?

Cheers
S
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#10 Michael Nash

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Posted 15 April 2008 - 03:36 PM

Should be 0.0208333 in decimals, so not sure what you're doing wrong.

In any case, keep it as fractions since that's how shutterspeeds are expressed.

(1/24)(180/360) = 180/8640. Reduce that to lowest common denominator by dividing both numerator and denominator by the numerator: 180/180 = 1, 8640/180 = 48. 1/48.

Or, convert your decimal back to fractions by multiplying it by 100, then show that product over 100 and reduce. 0.0208333 x 100 = 2.08333. 2.08333/100 = 1/48.

And math isn't my thing either!
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#11 K Borowski

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Posted 15 April 2008 - 08:38 PM

Well, using non-cine processors, the most labor-intensive part of the process would be the rem-jet removal. Even still a dollar or two more than C-41 seems reasonable to me.

I have yet to do the cost analysis, and there is no apparent interest in the thread I have on bringing the service back in the "Film and Processing" section, but the big (pun intended) problem is the large 40-L kits.

Even still, with a good sealed tank, and a 4-week lifespan, or maybe mixing the kit in quarters, the prices I quote will probably be close.

L/ 50 (sorry, not pound key!) is ridiculous.

What do they charge a foot over there in the U.K. in a normal movie lab? I can't imagine it being more than a few shillings a foot.
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#12 Serge Teulon

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Posted 16 April 2008 - 06:33 AM

Should be 0.0208333 in decimals, so not sure what you're doing wrong.

In any case, keep it as fractions since that's how shutterspeeds are expressed.

(1/24)(180/360) = 180/8640. Reduce that to lowest common denominator by dividing both numerator and denominator by the numerator: 180/180 = 1, 8640/180 = 48. 1/48.

Or, convert your decimal back to fractions by multiplying it by 100, then show that product over 100 and reduce. 0.0208333 x 100 = 2.08333. 2.08333/100 = 1/48.

And math isn't my thing either!


Aaah got it!!
Thanks a bunch Michael, that really helped!

Cheers
S
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#13 Serge Teulon

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Posted 16 April 2008 - 06:38 AM

L/ 50 (sorry, not pound key!) is ridiculous.

What do they charge a foot over there in the U.K. in a normal movie lab? I can't imagine it being more than a few shillings a foot.



I understand your point but that is what they seem to charge over here unless on an extensive job.
On a film I shot last week the charges were 19pence (9.5 cents?) per foot including best TK and transfer to digi (digi stock incl).

What's the norm over the pond?
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