Fuji Acros and Sunny f16 rule - Puzzled

Discussion in 'B&W: Film, Paper, Chemistry' started by pentaxuser, May 22, 2008.

  1. pentaxuser

    pentaxuser Subscriber

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    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.

    pentaxuser
     
  2. moose10101

    moose10101 Member

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    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.

    What was your meter reading at f8?
     
  3. Fred Aspen

    Fred Aspen Member

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    Hi,

    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,

    Fred
     
    Last edited by a moderator: May 22, 2008
  4. MartinP

    MartinP Member

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    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 . . .
     
  5. pentaxuser

    pentaxuser Subscriber

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    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.

    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

    pentaxuser
     
  6. MartinB

    MartinB Member

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    Pouring rain today in Calgary so you will have to wait for another day or so for empirical measurements. :wink: Odd how the weather conditions are reversed between here and the UK compared to the stereotype.
    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.

    Martin
     
  7. pentaxuser

    pentaxuser Subscriber

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    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.

    I should have said that perhaps some U.K. APUGers would add their twopenny worth as it is their experience that is most comparable.

    pentaxuser
     
  8. david b

    david b Member

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    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.
     
  9. pentaxuser

    pentaxuser Subscriber

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    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.

    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.

    pentaxuser
     
  10. david b

    david b Member

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    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.
     
  11. Fred Aspen

    Fred Aspen Member

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  12. Paul Verizzo

    Paul Verizzo Member

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    Here in sunny Florida...

    ...I have found it about a 1/3rd to a 1/2 stop more light that the rule gives, mostly the latter. That's hard shadow, bright sun, April.

    I remember when in lived in southern CA, it would be easy to be fooled by the Sunny Sixteen rule. Often whole days would have soft shadows due to the scattering of marine haze, yet to non photographers appear bright and sunny. One could still get sunburned, but the light level was about a 1/2 stop less than "the rule." No, it wasn't smog!

    Now for another twist. I spent most of my life living in Colorado. A lot more UV. Would that effect film speed? Would it effect tonality, the high blue and UV perhaps causing a lightening effect? Distant scenes at mountain altitudes in color, including digital, are very blue. I bought a UV cutoff filter from B&H, $24 for a 49mm which helped a lot.
     
  13. Nick Zentena

    Nick Zentena Member

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    Exposure is a combination of F/stop and shutter speed. If you change the shutter speed one way you change the F/stop the other way.

    Should they have said 1/200 instead of 1/250? It's been mentioned but this days most cameras don't have 1/200 on the shutter. The difference isn't huge and the shutter is likely running slow :tongue:

    By using 1/250 instead of 1/100 they made it easier to handhold. Plus why ask a 35mm user to use F/22 or f/16 more often then needed?
     
  14. Baxter Bradford

    Baxter Bradford Member

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    There are better things to do in Cornwall than read film data sheets....!

    Sunny 16 rule is a function of film speed and simply works. There must be a printing mistake. EI80 is right for this film, poss even EI64, using 100 is optimistic, 250 is plain wrong! I wouldn't expect shadows here on South Coast to be too dissimilar and indeed have used at EI80 in the Lake District.

    Off to Cornwall again tomorrow - sans film data sheets!
     
  15. 2F/2F

    2F/2F Member

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    The package is correct.

    The sunny 16 rule is more formally known as Basic Daylight Exposure (BDE) exactly to avoid this sort of misunderstanding. It is just a starting point for guessing exposure. It doesn't mean you have to shoot at f/16. The f/11 on the package is actually BDE, not f/16. This is because BDE states, on a bright, clear day, when film speed equals shutter speed, use f/16. This is based on the assumption that there is an ambient light level that would give you an EV of 14-2/3. Thus BDE would give you an exposure of '100 at f/16, equivalent to '200 at f/11. Fuji figure that anyone who is basing their exposures off of the chart on the box will not have a camera that can shoot at '200. Most cameras have '250, however, so they list BDE as '250 at f/11. The seashore/snow/etc setting is usually one f stop higher than BDE, hence the listing of '250 at f/16. It is also possible that Fuji has decided that a nice round EV 15 is more correct for BDE, which would make '250 and f/11 line up perfectly according to the rule. Also, remember that clear and bright means clear and bright. May places rarely experience these conditions. Here in L.A., CA, I almost always open one f stop from BDE on a day that is bright but not clear.

    The package is correct.
     
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  16. Steve Roberts

    Steve Roberts Member

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    I've never used Acros (although a roll has been lingering in my fridge for a year or more) so can't comment with reference to that film type. However, I've always regarded the Sunny 16 rule as pretty optimistic for use in the UK as our idea of bright sunshine would probably be a dull day to someone from sunnier climes (ie pretty much anywhere else on the planet). Except for incredibly bright sunshine on snow or sand, I regard Sunny 11 as far more realistic in the UK, although where I live perhaps the Overcast 2.8 rule is more useful!

    Best wishes,
    Steve
     
  17. MartinB

    MartinB Member

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    Reviewing photos I took a few weeks ago in the mountains above tree line, the range of exposures was 1/1500 to 1/750 at f8, EI 100 (not Acros) with most at 1/1000 f8. It was a clear day, very sunny and primarily of snow. It was so bright that even good quality sunglasses were just barely adequate. I could only remove my sunglasses for a few seconds at a time

    In this case, the scene fit the description of the top box on the chart. The light levels were much higher than I normally encounter, possibly as a result of the clear, dry air at altitude. But, probably more important, the subject matter was snow, as is stated on the chart. For me, that level on the chart is exceptional and not that often encountered. If it hurts to look at without sunglasses, it is probably one of those scenes.

    The same light levels in a scene without the snow would be in the next box down on the chart.


    Martin
     
  18. moose10101

    moose10101 Member

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    And since "sunny 16" was not based on seashore/snow scenes, I'd have to say the data sheet gives good info.
     
  19. pentaxuser

    pentaxuser Subscriber

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    It can be dangerous to draw conclusions from low numbers -statistically speaking - and I guess we'd need several hundred APUGers replying from different latitudes before forming any firm conclusions. However I think it's the case that everyone is right based on his own experience. It is difficult for any film company to give a perfect rule for exposure for all customers from latitude 0 to, say, latitude 70 as well as allowing for light clarity differences even at the same latitude.

    I had simply thought that if Fuji were to look at its major customer areas it might have concluded that f11 at 1/250th was a trifle optimistic but it's clear that many in the U.S. and possibly southern Europe from at least the late Spring to mid Autumn would find that 1/200th -1/250th is right and indeed it appears that the meter would indicate such an exposure.

    I think there have been only two replies from the U.K. but both from latitudes where I had taken pictures and these replies seem to indicate that F11 at 1/125th for bright sunshine in non snow or sand scenes is closer to the correct exposure and certainly accords with my gut instinct. The use of an EI of 80 or 64 would, I think, make 1/250th a complete non starter in the U.K. and probably most other places in the world.

    As I said, it would be interesting to see what Ilford, at about latitude 53/54, say about their ISO100 film, Delta 100, in terms of the sunny f16/f11 rule. I must try and find out

    Moose10101 - I couldn't check my reading today. It wasn't even cloudy bright let alone bright sunshine! That's one of the problems with ISO100 film in the U.K even in summer. We get all four seasons in the same afternoon and with MF or 35mm zooms and the need for plenty DoF, there could be handholding exposure problems in all but the best light conditions.

    Fuji should maybe add on its boxes for the U.K. "avoid using except in high summer" High summer of course is always 2 hours on one afternoon anywhere from June to mid September but no-one knows the date in advance!

    I've enjoyed everybody's contribution. Thanks again

    pentaxuser