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filter adjustment -- adjust exposure or development?


sblitz

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Forget for the moment the issue of shooting a whole role. The question is this -- using bw iso400 and you put on a filter that needs a 2 stop adjustment. Okay, you can shoot at f/8 instead of f/16, for example, or shoot at f16 and develop at 1600. Once again, let's forget the issue of using different filters for different shots on the role. I am simply asking is there a difference in the end of pulling (in effect) 2 stops in the shooting or pushing two stops in development in terms of the outcome?

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Steve -

 

In your example, if you open up to f8, you are rating the film according to the box speed of 400 (this is not "pulling," but rather adding the appropriate exposure factor to account for the filter). The only thing that will be affected is your DOF. The negatives should have the same tonality, contrast and sharpness as without the filter, except for the very important effect of the filtration of the relevant color (which will alter the tonality and contrast according to the type of filter you are using).

 

If you keep your aperture at f16 and compensate by "pushing", or overdeveloping the film, in your case by two stops, you should expect to see a significant increase in contrast and a decrease in sharpness (particularly with the addition of the filter). The extent of these effects depends on the film you are using. Tri-X, for example, is known to be quite pushable in a wonderful way (many of the great street photographers, such as Winogrand, routinely pushed their Tri-X film to 1250 or 1600). Tmax, on the other hand, would react less favorably to a full two stop push. Part of the reason is that Tmax is known to be more finicky regarding the exposure of the scene; whereas Tri-X is much more forgiving, and over or under (particularly over) exposure can be corrected to a greater degree in the darkroom (or with Lightroom :) ).

 

If you are after reasonably normal-looking tonal, contrast and sharpness, I would be leery to push any film a full two stops unless you absolutely needed the speed and you were otherwise pretty confident in your exposure metering.

 

You (and anyone else) free Thursday morning for some fun in the sun downtown? :p

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If you use a filter with a 2-stop factor, you give the film two stops more exposure. Period. You want to replace the light that the filter "eats" with additional light (of a different wavelength, such that you get the dark sky or light skin or whatever you are filtering for).

 

It can be either a longer shutter speed (if you need the same small aperture) or a larger aperture - no difference unless you are way at the end of the exposure scale (exposures less than 1/10,000 second, or longer than 1 second or so) where "reciprocity" kicks in.

 

Development changes are for -

 

a) controlling contrast.

B) "pushing" to get a usable-but-less-than-optimal picture under bad lighting.

 

Caring enough about the picture to use a filter for tonal control - and NOT caring enough about the image quality to push the film unnecessarily - are mutually exclusive goals.

 

Someone like Ansel Adams might, in the same exposure, use a filter (with the appropriate exposure adjustment via either shutter speed or aperture) - and simultaneously give more development if the subject had low contrast (see (a) above). But he was not using development to compensate for the filter use - he was using it to boost contrast with a low-contrast subject.

 

In fact, in "Moonrise over Hernandez" - he used a green filter, compensated with 3 stops more exposure, and used a water bath development (distant cousin of "stand" development) to REDUCE development and contrast and brighten the underlit foreground cemetery and desert shrubs.

 

Ansel Anecdotes - The Ansel Adams Gallery

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I'd just like to add that if you're going to push when you use a filter, you'd need to push the whole roll. Whereas if you adjust the exposure, then you can change that on a per shot basis. Adjusting exposure means you can use a different or no filter the next shot. Sounds like the best option to me.

 

Cheers,

Michael

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Andy Piper's post reminds me of a total mess-up I made when first visiting Colorado. I had a landscape of what were to me (an East Coast guy) evergreens. I used a deep green filter to lighten the trees.

 

Uh. They were actually blue! Although to me they did not look blueish.

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Yep - the BLUE Spruce is the Colorado State Tree. ;)

 

Technically, the short needles are gray-green, but have a shiny waxy coating that tends to reflect the intense blue skies of Colorado and pick up that color, more so than the needles of the Ponderosa pines or Douglas firs.

 

http://pinecrestfarms.com/wp-content/gallery/colorado-blue-spruce/co-blue-spruce-2.jpg

 

Although, as with all chlorophyll-rich vegetation, it will go white on IR film, or brownish on an unfiltered M8.

 

Kinda like the dress photo that was causing an internet uproar a few weeks ago.

Edited by adan
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