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Light meter and K3.


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#1 Curtis Bouvier

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Posted 28 February 2007 - 04:00 PM

This is where I am lost. I do know there is a way of working with this.

Basically my question is how do I decide how much light needs to come through the lense so the film isn't over exposed or under exposed.

There is an Iris and you can control the size of it on the K3.

With a light meter, can it give me a reading so I can determin exactly where to set the iris, and at what focal length and etc, etc?

So everything on the film is pristine exposed.

I know the K3 has a light meter inside of it, but I think I would rather use a state of the art light meter if its possible.

what do you guys think?

Edited by Curtis Bouvier, 28 February 2007 - 04:01 PM.

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#2 Sam Kim

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Posted 28 February 2007 - 04:59 PM

get a light meter. learn how to use it. ask tons of questions here and then do it.
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#3 ryan_bennett

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Posted 28 February 2007 - 11:44 PM

Don't use the built in light meter, buy an incident light meter. Now in terms of exposure, you hold the light meter up and take a reading on whatever subject you want properly exposed in the film, if you're using black an white - the incident meter will put that in the middle, 18% gray. You really got to buy a roll and experiment, that's the only way to learn.
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#4 Dennis Kisilyov

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Posted 01 March 2007 - 01:29 AM

Hi,



Um, here are a couple of interesting things.



If your K-3 is well maintained and otherwise not broken than the built in light meter is fine.
But don't forget,

1. That is a spot meter for the - Overall Picture, weighted against a greycard.
(it is not a 1 percent spot)

2. It was created to run on Mercury Batteries, that have a property of Super Steady Voltage, when they run out they just don't supply any current at all. This is a big problem with all old light meters. - So if you use Alkaline batteries for your light meter, you'll have non-consistent readings as Alkaline batteries have voltage flux, and when they run out, you get less and less voltage over time, not just a dead stop like with Mercury.
Zinc-Air and other batteries have less V flux, also are rated at a lower voltage, so you need to "over-expose" a little to get the "0" exposure.

3. K-3 has a clockwork motor, there will be no perfect exposure with the K-3. At the end of the spring wind, you can have an EV of +1/2 a stop due to the shutter opening slower. At like 1/58 sec instead of 1/60

More over, there is no such thing as a perfect exposure. The only thing I can reference is exposing for what you want to see on film, as it sees things differently than the eye.

--- About Incident Light Meters ----

Incident light meter tells you how much light is falling on a subject.
It is great for normal shooting situations, and will provide you with an adequate reading of light falling on your subject or scene.

But:

If your background is blown out, an incident meter will not tell you that, if your subject is caucasian wearing black clothing, your incident meter wont tell you that either.

On film a blown out background will record as error in exposure, as during the TK the color timer will prob adjust for it. Same with the other situation. Even if you shoot a grey scale slate as reference.

Here is where we get to the Zone system and Spot Meters.

----- Spot -----

Usu a 1 percent field of view meter, provides readings from light reflected by your subject into the lens.
Here you can see that the 97% white background paper will reflect +6 stops more than your human does.
Therefore needs to be replaced with some other paper, or the background light needs to be scrimmed a bit more.

Good candy like scenery comes from using both Incident and Spot metering to determine exposure, esp with the Zone system. Sometimes the zone system is inverted into Lux instead of Stops.

To see how this works, check out sample exposures on the Kodak website. They provide Spot readings for up-to 6 things in a scene for their motion picture films.




--- EDIT ---

Also the only way to see exactly what you are exposing is to use revesal or slide film.
Negative films and tk or workprinting process will mask 60-90 percent of exposure errors.

Even if you request that the Telecine guys "Show you what you shot" it cannot happen as their job is sort-of to "expose again" onto a different media off your negative. - Like a photo print.

If you really want to see what you shot, use reversal/positive films.

Edited by Dennis Kisilyov, 01 March 2007 - 01:34 AM.

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#5 Patrick Cooper

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Posted 01 March 2007 - 03:59 AM

One of the first things that you should know about the K3 regarding exposure is that when this camera is running at a speed of 24 frames per second, each individual frame will be exposed for a duration of 1/60th of a second. I would not use the internal meter inside the K3 - I tested it alongside the internal meter of my Canon 35mm still camera (which is usually quite reliable) and the results varied quite a bit. Often the K3's meter reading would be half a stop under or over my Canon's meter reading when pointed at the same subjects. And by the way, the rest of my K3 is functioning fine - Ive never had a jam or scratched film or anything like that.

Either use a 35mm still slr camera or a hand held light meter for taking light readings for your K3. Just make sure that whatever light meter you use, that it is accurate and reliable - otherwise you're going to have a lot of under or overexposed footage. I use my Canon T70 SLR camera to take light readings for the K3 and the results are fine - I just set the shutter speed of the T70 camera to 60th of a second when doing so. Obviously, I also set the asa speed on the Canon T70 to match whatever film speed is loaded inside the K3 and the T70 indicates the appropriate f stop that I should use on the K3. For example, if you were shooting Ektachrome 100D reversal film with the K3, you would select an asa setting of 100 on the light meter, in addition to a shutter speed of 1/60th if you were shooting at the normal frame rate of 24fps. However, if you were shooting negative film, it is usually recommended to over expose slightly which leads to finer grained footage. Underexposing negative on the other hand will lead to an increase in grain. For this reason, many people rate negative film a little slower than normal for optimal results. For example, if you were shooting 250D negative film, you might want to set an asa speed of 200 on the light meter instead of 250. You would still set the shutter speed on the light meter to 1/60th (if you were shooting at 24fps.) Though with reversal film (which has a narrow exposure latitude) your exposures have to be spot on - in which case you must set exactly the same asa speed of the film on the light meter - if the reversal film has an asa speed of 100, then you set 100asa on the light meter as with the Ektachrome 100D example. The only exception to this is some of the black & white reversal films which are not equally sensitive to daylight and tungsten illumination.

Another thing to consider is the filter factor. Many times when you will be exposing cine film outdoors in natural sunlight, it will likely be tungsten film and you will have an orange coloured filter screwed on to your lens which will make the colours appear more natural. Without this filter, colours would look a bit too cool or blueish when exposing tungsten film under sunlight illumination. This filter reduces light by a certain amount - usually half a stop or two thirds of a stop or similar. So with the filter in place, the film 'acts' like a slower speed film because it is receiving less light. When taking a light reading, you need to compensate for this difference in exposure caused by the filter - if you are using an external light meter ie hand held meter or still camera's meter. For example, when I was shooting Ektachrome 7240 tunsten reversal film (which is now discontinued) a few years ago in the snow fields, I was using such a filter on the lens to record natural looking colours. Ektachrome 7240 has a speed of 125 asa but with the filter in place, it 'acts' like an 80asa film. So I set '80asa' on my Canon T70 camera and I also set the shutter speed to 1/60th of course and with these two settings, the T70's light meter was able to give me the correct f stop which I then set on the aperture ring of the K3's lens. If however, I was using this film under tungsten illumination I would remove the filter as there would be no need for it because the film is designed to record natural colours under certain types of artificial lighting unfiltered. With the filter out of the way, the film receives all the incoming light so you can use the full asa speed of the film. In other words, you would set '125 asa' on the light meter with this film in this situation - along with a shutter speed of 1/60th if you were shooting at the normal frame rate of 24fps.

If you were shooting negative tungsten film outdoors under sunlight, you would set an even slower / lower asa speed on the light meter than normal. This is because the film is negative and so benefits from slight overexposure. For example, if you were shooting Kodak Vision 200T negative tungsten film under sunlight illumination, you would be using an 85 filter on the lens for relatively normal looking colours and this will bring the effective asa speed of the film down to 125asa. So in other words, the 200T film would 'act' like a 125asa film with the filter in place. Though on the light meter, you may want to set an asa speed of 100 so that the film receives a little bit of overexposure. Likewise, when using Kodak Vision 100T tungsten negative film under sunlight illumination, the 85 filter on your lens would reduce the effective asa speed of this film to 64. Though instead of setting 64 asa on your light meter, you may want to set 50asa for a slight overexposure. If you used the same Kodak Vision 100T film under tungsten illumination without the filter, the full effective speed of the film (100asa) would normally be restored but again you may wish to give it a little overexposure so on the light meter, you may want to set the asa speed to 80 instead of 100.

When taking a light reading, avoid pointing your light meter at anything dark or light coloured. Dark coloured objects will usually cause overexposure. Light coloured objects will usually cause underexposure. Look for a medium toned object to take your light readings from - and remember not to cast your shadow over whatever you are taking a reading from as this will ruin your exposure! You can buy a photographic grey card from some camera shops. This a card that is coloured just the right shade of grey and reflects 18% of the light falling on it. Taking readings from the grey card will usually lead to more consistent exposures than looking out for mid tones objects in your surroundings. Though you must follow the instructions supplied with the card about the angle that you set the card to in relation to the light source. If you see shiny reflections on the card, angle it to remove those reflections.

Finally, there is a certain order of doing things when setting exposure and focus on your camera. The first thing you must do is zoom in fully on your subject - all the way to the maximum focal length setting on your zoom which is 69mm on the Meteor lens. Also make sure that the aperture is set to it's widest. With the zoom set to it's maximum focal length and the aperture wide open, depth of field will be at it's minimum and the viewfinder will be at it's brightest so your focusing will be the most precise and accurate. Just remember not to move the camera forward or back while focussing otherwise all your effort will be for naught. Once focusing is completed, zoom out wider to your desired composition and then close down the aperture ring to the appropriate f stop setting. Then you can start shooting!
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#6 Joe Gioielli

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Posted 02 March 2007 - 09:35 AM

If you can afford a spot meter and understand the zone system, go for it. It is the best way to go.

If you have to make a compromise, I would still recommend and incident light meter. naturally, you will have to learn how to overcome certain problems, but I much perfer them to relective meters.

Think of the black cat on a black pillow. There isn't going to be a whole lot of light coming off that. A reflective meter will think there isn't enough light, tell you to use a larger apeture, and you get an over exposure. An incident meter will measure the light hitting the kitty. This will give you a better reading.

I recommend going to the sekonic homepage and doing a little home work. There is a lot too it, but once you get the idea it will come easier. Then hit your local camera shops and look for a second hand meter. GET A GOOD ONE :) Cheap will always hurt you in the long run. Sadly, many photographers have abandon light meters (using the built in ones) so many dealers will give you a good price. My meter cost more than the camera did. I paid 175 USD, new it was 250 USD. I use it for all my photography.

Best Wishes and keep asking questions.

Joe
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#7 Curtis Bouvier

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Posted 03 March 2007 - 06:58 AM

I do have a Nikon D70s digital SLR, could I use this as a light meter for the time being?
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#8 Patrick Cooper

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Posted 03 March 2007 - 11:48 AM

Theoretically, I think this would work but I remember on another forum, someone recommended against the use of a digital camera as a light meter for a film camera - there's probably some technical reason behind this.
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#9 adam berk

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Posted 03 March 2007 - 02:51 PM

Theoretically, I think this would work but I remember on another forum, someone recommended against the use of a digital camera as a light meter for a film camera - there's probably some technical reason behind this.



I've actually used a D70 for a spot meter with much success. It saved a shoot just a few weeks ago.
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#10 Dennis Kisilyov

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Posted 03 March 2007 - 10:18 PM

I've actually used a D70 for a spot meter with much success. It saved a shoot just a few weeks ago.



Only thing to keep in mind about DSLR s is that their ISO speed is not more that 100, with Nikon ISO 200 is minimum. Also the sensor reacts differently to light than film does. Also DSLR is a positive RGB, vs Negative CMY, yeah it's sort of easy to calculate from 200 to say 50 speed, but not that easy. :-).
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#11 Curtis Bouvier

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Posted 04 March 2007 - 05:31 PM

Patrick, I've studdied your information and read over your response numerous times and its working it's way in.

I have alot of experience with digital photography, but almost nothing of Film and light readings. Now i'm starting to get a much better understanding of how this works.

I totally understand the grey card thing, its right in the middle so it will give you the best exposure, rather then focusing on a black cat ona black carpet or a white painting on a white wall etc,

Over expose the film by half a stop to a fullstop to reduce grain and simpley lessen the exposure once in post production, I can do that no problem

the filters counter the the type of film when filming tungsten in daylight or vice versa.

since the filters reduce light coming into the lense you need to compinsate for this by allowing more light to pass through the lense.

for the most part I will be using natural daylight balanced film. as all my footage will be outdoors.

I am going to purchase a grey card and a light meter asap.

Its cool that I have my Nikon D70 to help me out with this.

Let talk about a Spot Meter vs an Incident Meter.

what type of benefits and differences are we looking at between these 2 types of meters?

Edited by Curtis Bouvier, 04 March 2007 - 05:35 PM.

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#12 Patrick Cooper

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Posted 04 March 2007 - 11:34 PM

Looks like you're getting the hang of things! However, just a few little refinements needed.

"Over expose the film by half a stop to a fullstop to reduce grain and simpley lessen the exposure once in post production, I can do that no problem."

Only overexpose negative film, try to avoid doing this with reversal film! In general, I notice that people tend to overexpose negative film by about half a stop or two thirds of a stop. Overexposing a whole stop might be okay, depending on the exposure latitude of the particular film stock. Though I have heard that too much overexposure can introduce 'noise' in the telecine transfer, particularly if there are bright areas in the footage. By the way, it's the job of the telecine colourist to adjust the brightness level of the footage that has been overexposed - in relation to telecine.

"since the filters reduce light coming into the lense you need to compinsate for this by allowing more light to pass through the lense."

Not if it?s the correct amount of light entering the lens in the first place! It depends on if you are using an external hand held meter or the camera?s internal meter. If you were using an external light meter as discussed, yes some compensation would have to be made to counter for the light reducing effect of the filter. You would set the asa speed on the meter slower in accordance with the ?filter factor? so that the correct amount of light enters the lens to expose the film.

If however, you were using a camera with a reliable internal light meter, the meter is reading through the lens so it would be ?seeing? through the filter and the exposure will be fine. So no compensation would be required in this case.

?Let talk about a Spot Meter vs an Incident Meter.

what type of benefits and differences are we looking at between these 2 types of meters??

A spot meter is a type of reflective light meter that reads a small portion of the overall scene so you can be very selective about which part of the scene you want to meter. Thus if there is a lot of exceptionally dark and light areas in the scene, you can avoid your readings being influenced by those light and dark areas by pointing the spot meter at an area that you perceive to be a mid tone, excluding all the ?distracting? areas. However, occasionally, we can be fooled a little by mid tones ? for example, what might look like a mid tone may not be reflecting exactly 18 % of the light falling on it. So your exposure could on occasions be a fraction off ? not much of a problem if you are using negative film but a little bit more critical if you are shooting reversal film with it?s narrow exposure latitude.

As incident readers read only the amount of light falling on the subject, theoretically they should not be ?fooled? by the colour of the subject. So there is no issues of misinterpreting mid tones here. Although I have never used an incident meter myself, I do know that you stand where your subject is (making sure that the meter is in the same light as your subject) and point the meter back at the camera. However, suppose you were filming a landscape in late afternoon sunlight ? close to sunset with long shadows. Imagine you were composing the viewfinder frame with a majestic looking mountain peak illuminated by the beautiful light. But all of the area around you is covered in shadow so an incident meter seems out of the question. And walking 2kms and scaling up the mountain to take a reading with the incident meter and then returning to the camera in the brief period before sundown does not sound very practical! So in this situation, a spot meter would allow you to ignore all the shadow areas and only select the sunlit mountain peak while standing by the camera?s side.

So regarding a spot meter and an incident meter, I don?t think one would be necessarily better than the other. They both have their advantages and disadvantages.

Edited by Patrick Cooper, 04 March 2007 - 11:38 PM.

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#13 Curtis Bouvier

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Posted 05 March 2007 - 02:11 AM

I'm starting to understand now, Film is so much more fun and challenging than digital, I can't wait to replace my D70 with a high end Nikon 35mm Film camera. The F6 to be exact as seen here..

http://www.vistek.ca...yID=FilmCameras


Anyhow, thats a little off topic haha but I had to get that out.

In about a year I certainly plan on picking up a pro 16mm package, I will pay between $5-$10G for one. Currently looking at the Arriflex SR1. They seem to be had for about that price range. And from what I hear it's a great camera that can be serviced by most film camera shops.

but for now my K3 is what I will be learning on independently.

Now speaking in terms of light meters, it seems there might be more flexibility involved with the spot meter since you can take a reading on any lighting condition no matter where the location resides? as you said a mountain far of, or somthing 2 feet away..

whats a good brand name for spot meters? Canon, Nikon, etc?

i will have a look over on Vistek.ca for now while I wait for some more posts.

Absolutly amazing the information that comes from these forums, I can't thank you guys enough for the responses. I will have many more questions coming up! :D
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