Alex Malm

I'm not talking about dynamic range.

Did you use a densitometer to help determine the actual speed of the film? Or did you do your test based on the EI? Because of batch to batch variances the asa of film won't necessarily match what's printed on the box. Also, I participated in a test of kodak's 5213 this past summer. In the case of that particular film stock we were able to underexpose by more than 2 stops before appreciable differences in quality became apparent. I think it may have even been 3. However, this was scanned at 2k so maybe the differences would be more evident if we viewed a print, as you mentioned earlier. That was a good point. Although that limit is also influenced by how the printer lights are set up since if we're assuming 25 across as our starting point and .025 density per light then we can only compensate by just over 2 stops anyway on a print. We didn't use a densitometer on our test so there could be a margin a error there. You're right, there is one definition of film latitude. That's why I quoted it out of Kodak's reference book just to make sure I wouldn't fudge up the details. What more do you need?

You could open the front of a fresnel so as to avoid using the lens. And set it to flood. If I'm not mistaken the flood setting on a fresnel creates fairly hard shadows.

Would using a polarizer help eliminate some of those reflections?

Well, I'm a student myself so I understand the inability to shoot tests due to budget and time constraints, among other things. I would be hesitant about overexposing by more than 2 stops unless you're prepared to risk loss of detail in the highlights. But I suppose that's a look all of its own. I was just reading some things in Kodak's "The Essential Reference Guide For Filmmakers" about most films having about 2 stops over and 2 stops under of latitude on the negative where the information is still preserved and available to print. If I have time tomorrow between classes I'll see if I can take a look at this one work print my professor has where the class shot incrementally over and underexposure and then pushed and pulled incrementally. But if it was me, I wouldn't overexpose by more than 2 stops. But hey, I'm no expert. And don't worry too much, it's better to experiment while in school than to screw up out in the field, right? Goodnight. :)

One of my professors claims that vision 3 500t is a low contrast stock, but sometimes there's a language barrier so perhaps he meant something else... But yeah, it sounds like you've thought this one through. Flashing can also be used to reduce contrast. It would add a small amount of uniform light over the entire film bringing up the shadows more so than mid tones and highlights. Supposedly, Fuji films don't respond to flashing very well, while Kodak and AGFA faired better. An example of a film that was flashed would be McCabe and Mrs. Miller.

I've shot some of my student films at a ratio of 2.5:1, but that was with every shot at one take and I wouldn't recommend it. I only did it because we had a cap of 200ft. for each short film.

As for the poster's original question here's what I know so far: When to overexpose negative... -When you want more saturated colors overall -When you want to minimize the appearance of grain When to underexpose negative... -When you want desaturated colors overall -When you want to emphasize the appearance of grain

Bear in mind that this is from Kodak's "The Essential Reference Guide For Filmmakers." "Latitude in exposure is the permissible change in camera exposure that can be made without a significant effect on image quality." So far this is the definition you gave so kudos for that, but my reaction was mainly to your claim that film has only 1 stop of latitude because I have personally experienced the saving grace of film latitude of over one stop. "A typical characteristic curve covers a log E [log exposure] range of 3.0. A range of 1.8 can fit inside that range easily with some latitude to spare." Note: 1.8 divided by .3 is 6 stops, which you might notice will account for 3.5 stops underexposure being empty black and 2.5 stops overexposure being empty white. "A normal exposure would be placed at the speed point [ASA rating]. Moving in steps of .3 log E units (one stop), we see that we can move the brightness range left two times before running off the curve." In other words there are two stops of underexposre latitude before D-min is reached at the low end of the curve. "Similarly, we can move right two times before running off the curve." Of course, this is just an example, but here we have four overall stops of latitude. Two up and two down.

You should also set your focus marks with the lens wide open since that will provide the shallowest dof and allow you more precision. Testing the focus ring with a focus chart and a buddy with a tape measure is advisable as well. And sometimes a lens will behave differently in extreme temps so if you plan to shoot in such conditions that's where you should test the lens.

I think we've been taught different definitions for film latitude.

In no particular order... Interior (on location): 1. Tweenie 650 Fresnel 2. Baby 1000 Fresnel 3. Inkie 200 Fresnel 4. Dedo 400 5. 2x4 Kino

What if you go from a small eyelight early on to a larger one when she becomes more lively. It would be more subtle and you'd have the beauty of eyelights throughout the film.

I'll give you an example. You plan to shoot at ISO 800 since it's a night shoot. But how many footcandles do you need for an f4? For the formula to work all you have to do is double or half the amounts and sensitivity one at a time since one stop up or down is doubling or halving the light that enters the camera, respectively. Let's start at step one: ASA F.C. Stop 100 100 2.8 200 50 2.8 Here the sensitivity has doubled so you only need half the amount of light to maintain f2.8 400 25 2.8 Again... 800 12.5 2.8 Again... 800 25 4 Here we have stopped down one stop so we need double the amount of footcandles to maintain normal exposure. Then take a look at the chart I attached to my previous post and see which heads will give you the footcandles you will need; in this case 25f.c.. You should always give yourself a safety margin of some sort since the light might be up high in the air on a stand or it might have both gel and diffusion, which would cut down on the light even more. let me know if this helps.

You should ask yourself what ISO you want to shoot at, which is partially dependent on your budget since higher ISO will mean less light is needed although you will be sacrificing with regard to gain and color. then consider looking at rental prices. Because lights aren't cheap. Here's the basic formula: at 100 ISO/ASA you will need 100 footcandles for normal exposure at F 2.8 (this assumes a 180 degree shutter and 24fps). Here are some common heads with the distance and incident light intensity (footcandles). This information is courtesy of the Set Lighting Technician's Manual, which is a book I would recommend if this information is confusing to you and you'd like to learn more. Head vs. Footcandles at Distances Specified Head 12ft. 15ft. 20ft. 25ft 30ft. 575 HMI 200 89 50 32 22 1200 HMI 600 267 150 96 67 650 Tweenie75 33 19 12 8 1000 Baby 150 67 38 24 17 2000 Junior500 222 125 80 56 5000 Senior356 200 128 89 50 10k Tenner 533 300 192 133 75 1k Mickey 150 67 38 24 17 2k Mighty 300 133 75 48 33 4x4 Kino 32 14 8 5 4 2x4 Kino 16 7 4 3 2 Note: HMI listed are Fresnel. chart_footcandles.doc chart_footcandles.doc