Underexposed Ultramax 400

[Truzi]

I think I kind of know the answer to this question ("don't worry about it"), but the lighting wasn't very good so I thought I'd ask.

We rented a cabin Hocking Hills, Ohio, and on an hike my best friend accidentally exposed Ultramax 400 with the camera set to 800. I know one stop isn't a big deal, but we were in a forest with a nice canopy, on a mostly cloudy day, so the lighting was very flat. The pictures were of a dry waterfall with small relief caves in the rock face.
Here is a link to a photo of the "subject" from the cabin-owners flickr stream, in case it helps:
http://farm3.staticflickr.com/2703/4258258984_d1078fbb04_z.jpg?zz=1
Unlike the above photo, there is more cover since it is June and thus the deciduous trees have leaves (plus it's an old photo, so more has grown).

I'm not quite ready to do C-41 myself and she wants the photos soon (I'm stockpiling my film for when I do C-41). We'll use a local printer that will push and pull in one-stop increments. We don't do walmart, and the printer's prices aren't that far from Walgreen's and CVS - with far better quality.
The photos aren't that important (if they were, we'd have used different film), but my friend would like viewable prints.

So, considering the lighting, "one stop push" or "don't worry about it?"

 

[Tom1956]

1 stop push--my vote.fwiw

 

[mablo]

Ultramax 400 is a beautiful film but it's really just barely 400 speed. EI200 is much more like it IMO. In flat light I'd definitely push it one stop.

 

[Chan Tran]

there isn't much latitude in the underexposure side so I say push it 1 stop.

 

[Truzi]

I explained the contrast and grain issue to my friend, which she understands and is okay with. She did take issue with how stops are "numbered," though (400 to 800 is "only" 1 stop?). She can work the numbers (shutter and aperture), but I can't explain _why_ things are numbered that way (it involves some math, which is my great failing).
Unfortunately, my explanations use bad analogies and probably makes things worse. To make a bad analogy about my analogies, it's like using cosine to explain sine - if you don't understand one, it can't be used to illustrate the other.

 

[thegman]

I explained the contrast and grain issue to my friend, which she understands and is okay with. She did take issue with how stops are "numbered," though (400 to 800 is "only" 1 stop?). She can work the numbers (shutter and aperture), but I can't explain _why_ things are numbered that way (it involves some math, which is my great failing).
Unfortunately, my explanations use bad analogies and probably makes things worse. To make a bad analogy about my analogies, it's like using cosine to explain sine - if you don't understand one, it can't be used to illustrate the other.

Shutter speed and ISO works in the same manner though, i.e. doubling the number = 1 stop. 1/500 to 1/1000 is one stop too.

 

[Truzi]

It's the "why" part of the numbering system that I can't seem to communicate. I understand it, but cannot explain it adequately

 

[Chan Tran]

Oh okay you're wondering why the stops, are not spaced by equal amount but rather doubling or half for each step? I think it's because the human eye perceived such a division of steps to be equally spaced. Same thing with sound level.

 

[Truzi]

I like to think of it as needing a certain amount of photons striking the emulsion to give a desired exposure (reaction in the chemistry of the emulsion). If you halve the shutter speed you double the aperture size (whatever combination of settings being manipulated, including the rated ISO of the film, are adjusted in relation to each other to achieve the "balance" desired).

The numbers themselves come from the math, and that is where I lose it

My boss in my old position at the university I work was also a professor in the Math department. We joked that no one could let him know how bad I am at math.

 

[Mustafa Umut Sarac]

What is sine and cosine ? My math teacher been accident victim and we passed the high school 3 math course empty !

 

[Truzi]

What is sine and cosine?!

I'm the wrong person to ask Something to do with math.

 

[MattKing]

What is sine and cosine ? My math teacher been accident victim and we passed the high school 3 math course empty !

I was tempted to post that Umut was sending this thread off on a tangent, but I thought better of it .

This might help a bit: http://en.wikipedia.org/wiki/Trigonometric_functions