500 asa film, 400 asa camera...

[Hanthx]

Hi Guys

Quick question.
Lets say I want to shoot some 500 speed film, and my camera Zm2 maxes out at 400 asa, will I incur some problems?
I know that you manually set the asa on the Zm2, but what about camera's that read the notchings and only read to 400 asa.
Just wondering what is going to happen.

Scott

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[MovieStuff]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by Hanthx:
Hi Guys

Quick question.
Lets say I want to shoot some 500 speed film, and my camera Zm2 maxes out at 400 asa, will I incur some problems?
I know that you manually set the asa on the Zm2, but what about camera's that read the notchings and only read to 400 asa.
Just wondering what is going to happen.

Scott
<HR></BLOCKQUOTE>

If you're talking about negative, you should be just fine setting it at 400 ASA. In fact, your grain would look tightest if you set your ASA at 200-300 ASA. Overexposing negative by 1/2 to a full stop will increase shadow detail without sacrificing highlight information. ASA 500 is simply the highest you can index the film without losing too much shadow detail or gaining objectionable grain. But if you need the stops, just set it to 400 and shoot. It'll be fine.



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Roger Evans
MovieStuff
http://www.afterimagephoto.tv/moviestuff.html

[Hanthx]

Roger

Thanks for the reply.
I having a little hard time with "how much latitude I have with other film stocks," and how the index rating will affect them.
So if I set my index to 400, and shoot 500 film, Im actually overexposing the stock, for some reason it seems that I would be underexposing.
Ive been told before with negetive stocks that overexposing 1/2 to 1 full stop is best...so im not in the dark there, its just this index thing...rating it below or above the actual asa value of the film.
Guess I have a lot to still learn!

Scott

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[Hanthx]

I still thinking...essentially, I can get the same affect by either changing the index rating of the film on the camera, or change my f-stops/t-stops...right?

Scott

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[Hanthx]

Sorry if Im talking out-loud, but its helping me. So, if I shot 500 speed film and rated for 400, I would be over-exposing it 1/4 of a stop. (Having to remeber my photography principles!!)
Or...the converse...lets say I was shooting 100 asa film, and rated it for 200 asa, I would be under-exposing it 1 full stop...because the 200 speed needs less light.
Ok, I think I got it...anybody want to reassure me!

Scott

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[MovieStuff]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by Hanthx:

Or...the converse...lets say I was shooting 100 asa film, and rated it for 200 asa, I would be under-exposing it 1 full stop...because the 200 speed needs less light.
Ok, I think I got it...anybody want to reassure me!
<HR></BLOCKQUOTE>

You are correct.

The thing to remember is that there is no "right" way to expose film. I recently went though this same conversation with someone else. Basically, the rating that Kodak gives film is ONLY a reference point that you dial into your light meter. How you deviate from that reference point is dependent on your own personal tastes, the light loss in your filters or camera lensing, the needs of the story, etc.

Now, if you want a lot of grain and blacks that look grey (pretend you're David Lynch) then you just MIGHT want to expose 500 ASA film at ASA 1000 or even 1500. That would give the film that kind of a look which, if appropriate for the story, is the right thing to do. If you want the finest grain you can get but still want some latitude in reserve when you need the extra stops for low light, then rate 500 ASA film at ASA 250. If you find that you don't have enough light, then change the rating to ASA 500 right in the middle of a roll, it's okay.

Now, someone might very well ask,"Well if ASA 500 looks better at ASA 250, the why doesn't Kodak just label it ASA 250?" That's a valid question and the answer lies in marketing. Why SHOULD they label it at only ASA 250 when you can still get a perfectly usable image rating it at ASA 500? See?

The ratings that Kodak gives film is the "worst case" ratings, not the "best results" ratings. That is why the DP that wants excessive grain will look for ways to achieve that effect through deviations from the listed ASA while the DP that DOESN'T want grain will ALSO do tests to achieve his desired effect. In short, the ASA rating is only a starting point. YOU decide what you want the image to look like.



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Roger Evans
MovieStuff
http://www.afterimagephoto.tv/moviestuff.html

[Actor]

Rating ASA 500 at ASA 400 is over exposing by 1/3 stop, not 1/4 stop. Remember the ASA scale is logarithmic.

ASA 500 = DIN 28. ASA 400 = DIN 27. The DIN scale is linear and DIN 3 = 1 stop. Thus a difference of DIN 1 = 1/3 stop.

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[mattias]

actually, it's the asa scale that is linear and the din scale that is logarithmic. using a logaritmic scale to describe a logarithmic function results in a linear curve.

/matt

[AlexGfromUK]

no, I'm pretty sure it is a quarter of a stop, as 800asa would be the next full stop.

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[mattias]

people, will you stop this endless flow of misinformation disguised as expert advice on this board?

i'm 100% sure it's one third of a stop, so it's obvious you're just guessing. counting your way is like saying 50% is medium gray, when we all know it's 18%. if you had actually owned a light meter you could have easily double checked this.

if you know the answer to a question, answer it. if you don't know the answer, answer it anyway if you like, but indicate that you're guessing or speculating. don't say you're pretty sure.

/matt

and then, after one night of sleep, i added this:
sorry, that wasn't really motivated. it wasn't directed at anybody in particular, and i realize everybody can be wrong once in a while. i do stand behind the general opinion i tried to express though...

[This message has been edited by mattias (edited November 05, 2001).]