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Asa problem with Kodachrome 40


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#1 julien doumenjou

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Posted 06 May 2010 - 11:05 PM

Hi,

today I was shooting with different stocks and when I switch from Ektachrome to Kodachrome I forgot to change the ASA setting on my Beaulieu.

I shot with 80asa for daylight (Ektachrome) instead of 25 (the kodachrome). Do you think my film is going to be completly over exposed ? Is it possible to correct it with pull processing ?
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#2 Ian Cooper

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Posted 07 May 2010 - 01:52 AM

Hi,

today I was shooting with different stocks and when I switch from Ektachrome to Kodachrome I forgot to change the ASA setting on my Beaulieu.

I shot with 80asa for daylight (Ektachrome) instead of 25 (the kodachrome). Do you think my film is going to be completly over exposed ? Is it possible to correct it with pull processing ?


Well I can be absolutely certain it won't be over-exposed.

Metering and exposing at 80asa rather than the correct 25asa means your meter was set for a more sensitive filmstock, which would require less light than the 25asa you actually used.

However, all that means is all your footage will be underexposed, rather than overexposed, so it still doesn't help very much. The difference between 25asa and 80asa is 1-2/3 stops. In round figures that's almost two stops, so it will be very dark! I suppose you could ask for a 2 stop push (not pull), but that's probably going to result in quite a bit higher contrast.
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#3 Jim Carlile

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Posted 07 May 2010 - 03:19 AM

Why would you rate it at ASA 25? Kodachrome Super 8 is ASA 40.

Even outdoors it only acts as ASA 25 with an 85 filter, but it's still rated at 40 as far as the meter is concerned. It's a 40 film no matter how you use it.

So, you're only one-stop underexposed. That'll be OK-- but if you want, Dwayne's can push it a stop for an extra $20.

What's your subject matter?
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#4 julien doumenjou

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Posted 07 May 2010 - 09:00 AM

Why would you rate it at ASA 25? Kodachrome Super 8 is ASA 40.

Even outdoors it only acts as ASA 25 with an 85 filter, but it's still rated at 40 as far as the meter is concerned. It's a 40 film no matter how you use it.

So, you're only one-stop underexposed. That'll be OK-- but if you want, Dwayne's can push it a stop for an extra $20.

What's your subject matter?


Here's the references of the stock I have:

Kodachrome 40 (Type A)
EI 40 Tungsten
EI 25 Daylight (with Wratten 85 filter)
The Kodachrome 40 Movie Film (Type A), is a colour reversal film which features extremly fine grain, saturated colours, high sharpness and excellent resolving power. It has an exposure index of 40, is balanced for exposure, without filters, to subjects lit by photolamps (3400K). Type A film can be used in daylight, using an exposure index of 25, when exposed with a KODAK Wratten 85 filter fitted to the camera.
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#5 julien doumenjou

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Posted 07 May 2010 - 11:19 AM

Well I can be absolutely certain it won't be over-exposed.

Metering and exposing at 80asa rather than the correct 25asa means your meter was set for a more sensitive filmstock, which would require less light than the 25asa you actually used.

However, all that means is all your footage will be underexposed, rather than overexposed


Are you sure? What you are saying seems very logical but on my beaulieu manual they're saying the opposite! I'm using the Beaulieu 4008 ZM II, there's a button (the left one on the below photo), the manual says : if you want to over-expose you can turn clockwise this button one or few points from the proper setting, two points means one stop, if you want to under-expose you do the opposite. When I go from 80 to 25 I turn clock wise so...

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#6 julien doumenjou

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Posted 07 May 2010 - 11:24 AM

Why would you rate it at ASA 25? Kodachrome Super 8 is ASA 40.

Even outdoors it only acts as ASA 25 with an 85 filter, but it's still rated at 40 as far as the meter is concerned. It's a 40 film no matter how you use it.

So, you're only one-stop underexposed. That'll be OK-- but if you want, Dwayne's can push it a stop for an extra $20.

What's your subject matter?


I forgot to mention, I'm using a beaulieu 4008 ZM II where you set the asa manually. Does that make a difference?
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#7 Ian Cooper

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Posted 07 May 2010 - 12:25 PM

Are you sure? What you are saying seems very logical but on my beaulieu manual they're saying the opposite! I'm using the Beaulieu 4008 ZM II, there's a button (the left one on the below photo), the manual says : if you want to over-expose you can turn clockwise this button one or few points from the proper setting, two points means one stop, if you want to under-expose you do the opposite. When I go from 80 to 25 I turn clock wise so...


Looking at an on-line manual for the 4008 ZM II I'm not sure I can actually see the reference you're referring to and the context in which the statement is made. But irrespective of the camera - if you set a lightmeter to a higher speed rating than the film you're exposing then the results will turn out underexposed, if you set a lightmeter to a lower rating than the film you're using, then the results will turn out overexposed.


I can't see from the photo you've posted, but in the on-line manual (page 21) it seems to suggest there are x5 marker dots alongside the film-speed dial. The centre one is coloured green and represents the actual speed being metered.

If you want to overexpose the film, there are two further white dots positioned to the right of the green dot. You need to move the film's speed setting away from the green dot in a clockwise direction to line it up with one of the white dots. However, if you look at what is now aligned with the green dot (the actual meter setting) you will see it is a lower asa value than your film. This may be where your confusion is stemming from?

Assuming the ring with the numbers on rotates along with the knob until the desired number lines up with a dot/marker on the orange body (as shown in the online manual), then to move the film speed from 25asa to 80asa will mean turning the knob in an anti-clockwise direction.
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#8 Mark Dunn

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Posted 07 May 2010 - 01:00 PM

Why would you rate it at ASA 25? Kodachrome Super 8 is ASA 40.

Even outdoors it only acts as ASA 25 with an 85 filter, but it's still rated at 40 as far as the meter is concerned. It's a 40 film no matter how you use it.

So, you're only one-stop underexposed. That'll be OK-- but if you want, Dwayne's can push it a stop for an extra $20.


No.
If you had the 85 in, it needed to be exposed at 25. So it is 1 2/3 stops under. Even one stop is a problem for reversal.
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#9 julien doumenjou

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Posted 07 May 2010 - 01:20 PM

No.
If you had the 85 in, it needed to be exposed at 25. So it is 1 2/3 stops under. Even one stop is a problem for reversal.


So you think I should ask for a 1 2/3 stops pushing ?
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#10 julien doumenjou

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Posted 07 May 2010 - 01:26 PM

If you want to overexpose the film, there are two further white dots positioned to the right of the green dot. You need to move the film's speed setting away from the green dot in a clockwise direction to line it up with one of the white dots. However, if you look at what is now aligned with the green dot (the actual meter setting) you will see it is a lower asa value than your film. This may be where your confusion is stemming from?
[/quote]

Of course, I got it now. I was thinking backward! It happens when I don't sleep enough... Thanks!
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#11 Ian Cooper

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Posted 07 May 2010 - 01:45 PM

So you think I should ask for a 1 2/3 stops pushing ?


It'd probably be easier to request a 2 stop push.

The extra 1/3 stop is neither here nor there, but won't do any harm to try and extract slightly more out of the inky black shadows.

If what you've shot is of value and can't be replaced, then the only way to see what it will turn out like is to expose a second 'test' roll at 80asa and ask for that to be pushed X stops to see what it'll turn out like. Based on that you can send the original roll for processing.
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#12 julien doumenjou

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Posted 07 May 2010 - 03:07 PM

It'd probably be easier to request a 2 stop push.

The extra 1/3 stop is neither here nor there, but won't do any harm to try and extract slightly more out of the inky black shadows.

If what you've shot is of value and can't be replaced, then the only way to see what it will turn out like is to expose a second 'test' roll at 80asa and ask for that to be pushed X stops to see what it'll turn out like. Based on that you can send the original roll for processing.



Unfortunately that was my last Kodachrome 40 so I will ask for 2 stops pushing and see what goes on. I'll let you know.
Thanks again!
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#13 Ian Cooper

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Posted 08 May 2010 - 04:30 AM

One other possible area of confusion, concerning whether the film should be exposed at 40asa or 25asa:

If you were using a seperate external lightmeter then it should be set at 40asa when exposing Kodachrome 40 under tungsten lights, or if the film is exposed in daylight then the conversion filter will loose 2/3 stop, so the meter would want setting at 25asa to compensate for this.

HOWEVER, if you are used a camera with a 'through-the-lens' light meter, you should leave the camera meter's asa dial at 40asa (the true film speed). When you put the conversion filter on the front of the lens it will not only cut the amount of light reaching the film by 2/3 stop, but it will also cut the light reaching the light meter by 2/3 stop as well, so the meter reading will automatically be adjusted to suit the film.

It will depend exactly on your circumstances as to which setting you should have used. If you were using a through-the-lens meter, then you should have set the speed at 40asa and your footage will be 1 stop underexposed (ie. request a 1 stop push). If you were using a seperate non-through-the-lens meter, then it should have been set at 25asa and your footage will be 1-2/3 stops underexposed (ie. request a 2 stop push).
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#14 julien doumenjou

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Posted 11 May 2010 - 10:41 AM

One other possible area of confusion, concerning whether the film should be exposed at 40asa or 25asa:

If you were using a seperate external lightmeter then it should be set at 40asa when exposing Kodachrome 40 under tungsten lights, or if the film is exposed in daylight then the conversion filter will loose 2/3 stop, so the meter would want setting at 25asa to compensate for this.

HOWEVER, if you are used a camera with a 'through-the-lens' light meter, you should leave the camera meter's asa dial at 40asa (the true film speed). When you put the conversion filter on the front of the lens it will not only cut the amount of light reaching the film by 2/3 stop, but it will also cut the light reaching the light meter by 2/3 stop as well, so the meter reading will automatically be adjusted to suit the film.

It will depend exactly on your circumstances as to which setting you should have used. If you were using a through-the-lens meter, then you should have set the speed at 40asa and your footage will be 1 stop underexposed (ie. request a 1 stop push). If you were using a seperate non-through-the-lens meter, then it should have been set at 25asa and your footage will be 1-2/3 stops underexposed (ie. request a 2 stop push).


Just to let you know that I got my Kodachrome40 back from Dwaynes after 2 stops pushing and it looks very nice. Thanks again!
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#15 Justin Donoghue

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Posted 12 May 2010 - 08:18 AM

HOWEVER, if you are used a camera with a 'through-the-lens' light meter, you should leave the camera meter's asa dial at 40asa (the true film speed). When you put the conversion filter on the front of the lens it will not only cut the amount of light reaching the film by 2/3 stop, but it will also cut the light reaching the light meter by 2/3 stop as well, so the meter reading will automatically be adjusted to suit the film.


This has confused me. What's the purpose of the ASA dial other than to tell the camera how the TTL light metre should read? I've checked the Beaulieu manual and it says:

Caution:For outdoor filming with "indoor" type film, the "daylight speed" should be set opposite the green dot. Example:For Kodachrome 11 type A film, set 25 ASA for outdoor filming (daylight).

Does this mean the manual is incorrect?

I've exposed 64T as 40ASA (as instructed) in daylight with 85 filter and results were fine.
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#16 Robert Lewis

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Posted 15 May 2010 - 02:49 PM

This has confused me. What's the purpose of the ASA dial other than to tell the camera how the TTL light metre should read? I've checked the Beaulieu manual and it says:

Caution:For outdoor filming with "indoor" type film, the "daylight speed" should be set opposite the green dot. Example:For Kodachrome 11 type A film, set 25 ASA for outdoor filming (daylight).

Does this mean the manual is incorrect?

I've exposed 64T as 40ASA (as instructed) in daylight with 85 filter and results were fine.


Hi Justin.

I have a Beaulieu 4008 ZMII, and as I understand things when using E64t (64/40ASA) in daylight, the correct camera ASA setting depends on whether you use the built-in 85 filter or an external filter. If one uses the internal 85 filter, the ASA setting on the camera should be set to 40ASA. This is because the filter is positioned immediately adjacent to the gate and so is not taken into account by the exposure meter. If, however, one uses an external 85 filter, this reduces the light passing through the lens by 2/3s of a stop and is taken into account by the exposure meter. Hence in this arrangement the ASA setting should be set at 64ASA because the meter meters the light passing through the lens which is reduced by the filter 2/3s of a stop.

Consequently, if you "exposed 64T as 40ASA (as instructed) in daylight with 85 filter" that was correct.
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#17 Justin Donoghue

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Posted 16 May 2010 - 04:59 AM

Hi Justin.

I have a Beaulieu 4008 ZMII, and as I understand things when using E64t (64/40ASA) in daylight, the correct camera ASA setting depends on whether you use the built-in 85 filter or an external filter. If one uses the internal 85 filter, the ASA setting on the camera should be set to 40ASA. This is because the filter is positioned immediately adjacent to the gate and so is not taken into account by the exposure meter. If, however, one uses an external 85 filter, this reduces the light passing through the lens by 2/3s of a stop and is taken into account by the exposure meter. Hence in this arrangement the ASA setting should be set at 64ASA because the meter meters the light passing through the lens which is reduced by the filter 2/3s of a stop.

Consequently, if you "exposed 64T as 40ASA (as instructed) in daylight with 85 filter" that was correct.


Hi Robert
Thanks for clearing that up. So Ian was correct then sorry Ian! It had never occurred to me that the TTL wasn't "coupled" with the internal filter. Of course it makes sense now and I've observed the internal filter on my ZMII and how close it is to the film plane. It's just as well I understand this now as I've just purchased an external 85 for my camera and now I won't be ruining my last few rolls of K40 due to incorrect ASA dial setting!
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#18 Robert Lewis

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Posted 16 May 2010 - 05:43 AM

Hi Robert
Thanks for clearing that up. So Ian was correct then sorry Ian! It had never occurred to me that the TTL wasn't "coupled" with the internal filter. Of course it makes sense now and I've observed the internal filter on my ZMII and how close it is to the film plane. It's just as well I understand this now as I've just purchased an external 85 for my camera and now I won't be ruining my last few rolls of K40 due to incorrect ASA dial setting!


Hi Justin.

Thanks for the thanks!

I had to work this out too when I got my Beaulieu. I started off with a Nizo 561 Macro and I found it a little confusing when I got the 4008. What caused the confusion was that, unlike on the 4008, the automatic exposure system on the Nizo takes into account the use of the internal 85 filter.

Of course, it will shortly be "all change" with Ektachrome 100D which is available in place of E64T. I have a couple of rolls of 100D but I haven't used them yet. It seems that with this stock one will, on the 4008, set the ASA to 100 and set the internal filter setting to artificial light.

Edited by Robert Lewis, 16 May 2010 - 05:44 AM.

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#19 Andries Molenaar

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Posted 16 May 2010 - 01:07 PM

Are you sure? What you are saying seems very logical but on my beaulieu manual they're saying the opposite! I'm using the Beaulieu 4008 ZM II, there's a button (the left one on the below photo), the manual says : if you want to over-expose you can turn clockwise this button one or few points from the proper setting, two points means one stop, if you want to under-expose you do the opposite. When I go from 80 to 25 I turn clock wise so...


Why do you mark the righthand dial in the photograph instead of the lefthand one? This is making things complicated were they are not. Simply adjust the left ASA dial to fit the film. The correct value is on the box. With and without filter.
The righthand dial is for Frames per second. The change of shutterspeed is automatically taken in account.

Edited by Andries Molenaar, 16 May 2010 - 01:08 PM.

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