Underexpose Reversal by 1/3stop when shooting?

Post by **gene_can_sing** » Sat Feb 10, 2007 6:50 pm

I heard from someone that as a general rule for shooting color Reversal Film on Super 8mm, that you should underexpose it by a 1/3rd of a stop.

And that when shooting Negative Film on Super 8mm, you should overexpose it by 1/3rd of a stop.

Any truth to this? Or do I have it backwards??

Thanks in Advance for any responses

Post by **avr** » Sat Feb 10, 2007 8:39 pm

Negative: a bit of overexposed give you less grain and better blacks

reversal : avoid overexposure, a bit underesposure give you better color saturation

Post by **mattias** » Sun Feb 11, 2007 12:26 am

i like to underexpose reversal a bit, to increase saturation and give clean blacks, but it only works if you have plenty of highlights in the frame, otherwise it will just look muddy. as for negative overexposure does decrease grain and give you more punch, but i've stopped doing it in low light situations after i found that a low speed film (200t) underexposed is less grainy than a higher speed (500t), and i like the softer contrast image too. i think if you're just starting out and haven't seen the results of any tests you should strive for perfect exposure but err the "right" way if you're unsure.

/matt

Post by **richard p. t.** » Sun Feb 11, 2007 12:59 am

under exposing with reversal increases colour saturation, contrast and grain. overexposure does the opposite. a slight under exposure is more salvageable in transfer so long as you are using a transfer house with all the requisite grading equipment (as found with flying spot type scanners etc.).
Remember that reversal is less forgiving of error than negative film. If you aim for correct exposure, some shots will err on the side of under and some over, but not by much. whereas the danger with trying to uniformly under by 1/3 might mean some shots go a little too far that way. But you must do a test roll to callibrate your equipment anyway. This is essential. From your bracketing in your test roll, choose the exposure you prefer and call that 'right'.

Post by **mattias** » Sun Feb 11, 2007 1:19 am

richard p. t. wrote:If you aim for correct exposure, some shots will err on the side of under and some over

i see your point, but unless an unexpected cloud hides the sun or and actor move much further from a light than in blocking there's no reason you shouldn't be able to nail the exposure. 1/3 of a stop is actually quite a lot of light. if a light is 3 meters away you need to be an entire meter off to get that difference.

/matt

Post by **David M. Leugers** » Mon Feb 12, 2007 5:23 am

I have always strove to nail exposure when shooting reversal. Even before I shot my first roll, the books I read on film making all stressed the importance of properly exposing reversal. While it is true you can salvage a slightly under exposed shot much better than over exposed, neither will result in the best image obtainable with reversal. Negative has so much more lattitude and the pros all advise that overexposing negative at varying degrees will give the better results in printing or transfer since the finer grains will be forming the image and deeper blacks can be had. I guess as always, shooting tests will help one determine the course one wishes to take. Isn't that the beauty of film?

David M. Leugers

Post by **Angus** » Mon Feb 12, 2007 1:51 pm

It depends what you are looking for....but in general, reversal film handles under-exposure a lot better than over-exposure so if you are not sure that your meter or hand-held readings or guesses are correct......erring on the side of caution suggests under-expose a little.

Post by **MovieStuff** » Mon Feb 12, 2007 1:59 pm

Shooting reversal is a lot like shooting digital. You need to underexpose a bit to preserve the highlight detail, depending on what your subject matter is and how you are viewing it. If projecting it, then I would suggest nailing the exposure. If for telecine, then under exposing a bit would better protect the highlights and then you can adjust the gamma in post to pull information out of the dark areas. Not ideal but workable for telecine. It also depends on what reversal you are shooting. What I just described is for K40 but some of the new Ektachromes work better for telecine with proper exposure, like the E64T or the 100D. But, again, much depends on what the subject matter is. Like Mattias pointed out, if there really are no whites in the scene, then nailing the exposure is best. You almost have to develop a "feel" for shooting reversal. Be one with the emulsion, feel its latitude. Follow the tao of the reversal.....

Roger

Post by **christoph** » Mon Feb 12, 2007 2:15 pm

mattias wrote:[1/3 of a stop is actually quite a lot of light. if a light is 3 meters away you need to be an entire meter off to get that difference.

correct me if i'm wrong, but if take a light reading with your key at 3 meters and then place the light at 4 meters the light intensity will be 56% of the original (3/4 to the power of 2) - ie close to 1 stop under..
if you place it at 2meters instead of three the intensity will be 225% of the original messurement (3/2 to the power of 2), ie more than 1 stop over.

personally i find it kinda tricky to hit exposure more accurate than 1/2 f-stop with super8.. old light meters and notching systems if you use ttl systems, and weird shutter angles/split prisms/no t-stops for external meters make it even harder.. then again i dont find that 1/3 stop is very noticable in projection or telecine.

++ christoph ++

Post by **Justin Lovell** » Mon Feb 12, 2007 2:16 pm

Latley, I shot some 500T in low light, and it looked pretty shoddy underexposed (I rated the camera at 1/90th for 24fps) and should have had normal exposure at 2.0 so says my external lightmeter, but the image turned out underexposed (internal meter on the camera kept setting to 1.9 (wide open).

That was my results... It was shot with 4008 w/ 8-64 angineux lens. The canon 1014 performed much much better in the same circumstances.

Post by **christoph** » Mon Feb 12, 2007 2:22 pm

jusetan wrote:Latley, I shot some 500T in low light, and it looked pretty shoddy underexposed (I rated the camera at 1/90th for 24fps) and should have had normal exposure at 2.0 so says my external lightmeter, but the image turned out underexposed (internal meter on the camera kept setting to 1.9 (wide open).

That was my results... It was shot with 4008 w/ 8-64 angineux lens. The canon 1014 performed much much better in the same circumstances.

the 4008 has a 1/96 shutter, so that was pretty close, but the lens probably has a t-stop around 2.2, depending on how much you zoomed in it could have been been 2.8 .. the 1.2/6-80 looses more than a full stop at 80mm)
++ christoph

Post by **Angus** » Mon Feb 12, 2007 2:28 pm

MovieStuff wrote: Be one with the emulsion, feel its latitude. Follow the tao of the reversal.....

Yeah, man.

I knew there was a reason why I like Roger

Post by **mattias** » Mon Feb 12, 2007 5:28 pm

christoph wrote:correct me if i'm wrong

you're absolutely right for a point source, but in my experience the math doesn't apply until the light is "far away". looking at the photometry data of a flathead for example it shows something in-between my guess and the math. considering bounce and ambient light i think my guess is pretty true. but it was a guess, so i suggest anyone interested in the subject go out with their light meters and check for themselves.

weird shutter angles/split prisms/no t-stops

that's a very very good point, but a correctly notched cart, fresh light meter batteries, and a grey card will give you the correct numbers for your camera in a couple of minutes.

i don't know. you're quite right and i don't feel like arguing against it, i just don't think getting correct exposure is rocket science. exposing creatively for the look you want is much harder.

/matt

Post by **mattias** » Mon Feb 12, 2007 5:33 pm

jusetan wrote:Latley, I shot some 500T in low light, and it looked pretty shoddy underexposed

that's the reason i like to use 200t better even if i have to underexpose it. 500t looks underexposed unless you light everything. it gets very grainy just a couple stops under so it's better to light the shadows to two stops under and overexpose any highlights.

/matt

Post by **Justin Lovell** » Mon Feb 12, 2007 6:15 pm

mattias wrote:
jusetan wrote:Latley, I shot some 500T in low light, and it looked pretty shoddy underexposed
that's the reason i like to use 200t better even if i have to underexpose it. 500t looks underexposed unless you light everything. it gets very grainy just a couple stops under so it's better to light the shadows to two stops under and overexpose any highlights.

/matt

On the other hand, I've shot some 500T outdoors during the day on S8, and it looked fantastic. Fine grain... it was COMPLETELY different from the night stuff I shot... looked more like the 200T, and I'm sure it would have intercut nicely with the 200T during the day.