How to use Aperture Priority for loooooong exposure?
I've heard that Nikon FE/2 and F3 are well known to be capable of giving an extra long exposure, i.e. leaving it on AE for star trails and getting 2-3 hours of exposure. My question is how does it deal with reciprocity failure? Do you guys give extra + compensation? What are the tricks?
I have just begun experimenting with star trails myself (8hours bulb mode) and have conducted extra long exposure (1 hour) aperture priority AE with my F3, FA, FE2, FM3A & FG so I this is still new to me. From the very few star trails tests I've conducted, I believe my ideal setting using ISO100 slide film is f8 with bulb mode but more importantly well outside city - or any other artificial lighting, and obviously clear starry night. I also think there should be no moon in the frame at anytime. This is my first attempt taken with ISO50 Velvia, f2.8 from my back porch (city lites, neighbor porch light) and the big white line is the moon coming into frame. This started at 9pm and I ended the exposure about 5:30am with the moon coming in past midway of the time. I am thinking well outside the city, the rest of the frame would be near black and only the star trails will show up white. My next few attempts were worst - and not interesting, due to weather and still not outside the stray light zone!
Extra long exposure AE is not the same as in this case, there will be enough light in the frame to trigger the meter after some extended period of time. I have conducted controlled light setup of up to 2 hours and these long periods are not accounted for by the film's data sheets as usually it only shows compensation for seconds worth and not any longer. In both cases below, there was enough accumulated light to allow the camera to get "proper exposure" and I really didn't know how the waves would look leaving the shutter open for that long. This was taken with Fuji 100 C41.
Anyway, I believe these are two different applications and you'll have to try it anyway as these extremes are not usually accounted for in data sheets.
I can’t see a reason to use aperture priority for star-trail shots unless you have an illuminated subject in the foreground for which you want a ‘proper’ exposure.
You can, however, use either body without battery power to shoot trails. A cable release is required for the FE2 when using ‘B’ (bulb mode) on the shutter speed dial. On the F3 you can do the same – cable release in bulb mode. Or you can accomplish the same (long exposure) on the F3 without a cable. The drill, after removing any filters, mounting on tripod, focusing, composing, setting aperture: 1) set power switch under film advance lever to ‘off’ position, 2) close viewfinder curtain, 3) shutter speed dial set to ‘T’, 4) turn manual shutter release button (under DOF preview button) from 12 o’clock position to 10 o’clock ‘ready’ or stand-off position, 5) using an object such as a baseball hat or equivalent and with one hand, totally obstruct the front element without touching the lens/camera, 5) trip the shutter using the manual release lever, remove hand from camera, 6) wait a half second for vibration to stop, 7) remove baseball hat from front of lens, 8) wait several hours while enjoying your beverage of choice (critical step…don’t blow it), 9) obstruct front element with hat, 10) turn shutter speed dial to ‘B’ or ‘X’ to close shutter. Keep in mind that dew may settle on your front element so you may want to consider how to combat it.
If using a cable release, firmly secure the cable/finger plunger to the camera to keep it from swinging or being jostled by even a slight breeze.
Les, are you saying aperture priority kept the shutters open for one hour in all those cameras you listed? Whoa! I didn't think that was possible given their low-end metering range of EV 1. You didn't go overboard on my Step #8 above, now did you?
Last edited by Aja B; 12-03-2011 at 01:14 AM. Click to view previous post history.
Sorry, star trails may not be the correct example. I meant for object that we want to exposed as 18% grey, for example moonlit landscapes.
Originally Posted by Aja B
Meters cannot account for failed reciprocity. If you insist on using AE for these shots, you'll have to covert your data on reciprocity loss into EI changes instead of time extensions or aperture changes. Then again, unless the meter can tell you how long it plans on exposing the film ahead of time, this is not possible. Is there a camera meter that can display a time longer than 30 sec? Manual will server you far better IMO.
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In the tests I conducted, all of these made very long exposure of more then an hour in the controlled lighting I provided. From much shorter exposure times, the FG consistently terminated exposure well before the others. I also exposed some C41 film in these and they came out perfectly exposed.
Originally Posted by Aja B
I haven't found a device or figured a way of accurately timing such long exposures so I can see where step #8 can be a problem . . .
These Nikons will determine exposure at the time of shutter firing and may successfully take very long exposures. Just exactly how long I have not qualified although I have done more then an hour. I am not aware of a handheld meter that can perform this metering to test just how accurately these are. Of course a potential problem here is if the exposure time calculated extends it past dawn in which case it will result in overexposure. Of all the aperture priority AE cameras I have tested, the only camera that can account for changes in scene lighting during extended exposure would be those that are equipped with off the film metering and those are the Olympus OM-2 & OM-4 and the Pentax LX. I don't have the OM-2 (I have the OM-2N) which I understand can meter for as long as it takes to get a correct exposure but the Pentax LX will.
Originally Posted by MFstooges
None of the cameras would do an AE exposure accurately for such a long exposure time. Although some cameras would have the shutter open for a long time but it by no mean accurate. The light level is well below the metering range. The shutter time is well longer than the designed shutter speed range. Reciprocity failure is not taken into account.
If you get good result it's just luck.
When results are repeatable it is no longer luck. It may be luck that the cameras I have tested have repeatable results since these are well outside their specs so YMMV.
I am particularly interested in aperture priority AE for very long exposures and to that end I did test the following:
- Canon - A-1, AE-1P, Elan 7, EOS-1V, EOS-3 - all stop at 30 seconds
- Minolta - X-700, XD-11, XE-7, XK - anywhere from 8 to 25 seconds
- Nikon - F3, FA, FE-2, FG, FM3A - more than an hour
- Olympus - OM-2N, OM-4T - off the film but ends at 3 minutes
- Pentax - ES II, K2, LX, ME Super, Super Program - LX has off the film and hours long
For full disclosure, I conducted the tests as follows:
- Setup continuous daylight balanced light and verified with Sekonic 758 a proper 1 second exposure on gray card
- Qualify metering at 1, 5, 30 seconds
- Qualify metering at 1, 5, 30 minutes
- Tested more then an hour on F3, FA and LX with C41
Again these are using only my own seemingly fully functional cameras. I don't know if this applies to all of the same models. Repeatable results in the setup and I have more than a handful of repeatable results on C41.