Fuji Acros and Sunny f16 rule - Puzzled
Courtesy of another APUGer I was given 2 rolls of Acros recently, one of which I loaded a few days ago when on holiday in Cornwall(U.K.) and happened to look at the packaging.
Fuji has given users the sunny f16 rule on the side of the box but it puzzled me a lot. I always thought that the rule was that in bright sunlight, exposure was the reciprocal of the ISO speed so for Acros that makes it 1/100th second at f16.
However Fuji gives a constant exposure of 1/250th, varying the aperture for different light conditions. So bright sunshine is f16 for seashore and snow, f11for "ordinary" bright sunshine; f8 for hazy sunshine and f5.6 for cloudy bright.
A 1/250th is, I think, one and a half stops less than I would have expected.
I tried to think of a way of reconciling Fuji's recommendations of 1/250th with my understanding of the sunny f16 rule indicating 1/100th and came up with the following:
The f16 rule depends on what latitude in the world the user is based. So if f16 is right for part of southern Japan at say latitude 33/34 then sunny f11 is more appropriate for the U.K. at latitude 53/54. If we then allow for the various light conditions needing one stop more in the U.K. and most shots being taken without the exceptional reflectivity of snow or bright sand at the seashore then "ordinary" bright sunshine in the U.K is now f8 and not f11 as in Japan so becomes 1/250th at f8 or 1/125th at f11 which is close to the 1/100th sunny f11 exposure rule applicable to the U.K.
However if one reads the f16 at 1/250th as only for the exceptionally bright conditions of snow and sand then Fuji is also following the sunny f11 rule which might be right for all of Japan as it is for the U.K. and that still makes f11 and 1/250th puzzling.
It was bright sunshine today in my part of the U.K. at about noon but at f8 my in-camera meter wasn't reading anywhere near 1/250th, nor would I have expected it to be.
So while I can manage to reconcile, after a fashion, Fuji's 1/250th exposure with the sunny f11 1/100th exposure for a ISO 100 film, I can't help wondering if Fuji's recommendations aren't at odds with what's required for good shadow detail even in southern Japan and certainly at odds with northern Japan which is very close to Rochester latitude-wise.
It seems to me that anyone blindiy following the f11 and 1/250th for most of the temperate zones for bright sunshine would be underexposing and my further assumption is that for all but those in the tropics 1/250th at f11 would involve an element of underexposure which most B&W film is relatively intolerant of. Or could it be that Acros is the exception here and that like it's ability to cope with reciprocity failure, it also copes with underexposure better than most other B&W films in terms of recording shadow detail?
Thanks in advance for all comments on this.
Following the sunny 16 rule, Acros would be exposed at f16 and 1/100, which is equivalent to f11 and 1/200. While 1/250 is an underexposure at f11, it's less than 1/2 stop. Also, many cameras don't have 1/100 or 1/200 for shutter speeds, but they do have 1/125 and 1/250. If you prefer to err on the side of overexposure, you can set the aperture between 11 and 8 at 1/250.
Originally Posted by pentaxuser
What was your meter reading at f8?
I just shot a few rolls of Acros 100 in Northern Montana this past weekend and with the bright clear sunny skies there, an exposure of f11 @ 1/250 was just right. Of course Fuji can't cover all the possibilities around the world but for the most part their instructions on the box have been correct for me in Montana, Utah, and Texas but the East Coast was more like sunny 11 1/2.
Of course, YMMV,
Last edited by Fred Aspen; 05-22-2008 at 04:26 PM. Click to view previous post history.
Clearly, don't worry about apertures and shutter-speeds - just think of the exposure-value. Not forgetting the time of year and the time of day, if one wanted to nitpick. And also the fact that any particular batch of film may vary by a fifth of a stop, or more depending on age and storage conditions . . .
Thanks all so far. Can't recall my reading. I'll check it again tomorrow. A good indicator of brightness, I guess, is the depth of shadows which I notice more than I used to since the "photography bug bit". At this time of year at these latitudes in the U.K. shadows are still quite light, even though it's only about a month from the summer solstice. The light will intensify but clearly at 54 degrees North we are even 10 degrees North of the likes of Rochester and whole world away from Utah and especially Texas.
Originally Posted by moose10101
Maybe some Canadians from say Edmonton or the top end of Lake Winnipeg will give us their findings. It's their light levels that are probably comparable.
The other thing I didn't add is that many seem to rate Acros at about EI80 presumably for full shadow detail and this of course makes things even worse for those of us above latititude 50 whoi may be tempted to follow the 1/250th exposure.
Given that Ilford D100 is produced at about latitude 54 North, I wonder what rule, if any that Ilford prints on its box?
Maybe someone will supply that info as well
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Pouring rain today in Calgary so you will have to wait for another day or so for empirical measurements. Odd how the weather conditions are reversed between here and the UK compared to the stereotype.
Originally Posted by pentaxuser
My memory of using Acros is that the box measures are pretty good for a sunny day in Alberta. I think that haze and humidity in the UK may account for the differences you noticed. The low humidity (when it isn't raining) and lack of haze generally mean pretty bright light in Calgary.
Thanks Martin. Thinking about it, I am sure you are right about humidity and haze. The light here in the industrial Midlands is seldom clear the way I suspect it is in Canada or Utah.
Originally Posted by MartinB
I should have said that perhaps some U.K. APUGers would add their twopenny worth as it is their experience that is most comparable.
FWIW, I am in sunny New Mexico.
I do shoot a lot of Acros. When I am planning on using rodinal, sunny 16 is f16 at 60.
When I am planning using xtol, sunny 16 is f16 at 125.
Always comes out nice.
Thanks. Given where you are, this again suggests that the sunny f16 rule indicates about 1/100th or 1/125th rather than 1/250th and yet as far North as Canada 1/250th isn't underexposure. Maybe clear air is a better determinant of correct exposure than the height of the sun as determined by latitude, So Ole in Norway at maybe a further 5-8 degrees North may need less exposure than we in the hazy Midlands of England.
Originally Posted by david b
All thing considered and given that B&W handles overexposure much better than underexposure, it seems that more exposure is the safer bet. Unless of course there is evidence of Acros' ability to handle underexposure better than most B&W films. No comments on that aspect as yet.
I think Acros is a pretty amazing film. When not shooting FP4+, I shoot Acros. I really like quick loads for my 4x5 so this is my film of choice.
The latitude is pretty hard to beat.