K10D long (ish) exposures

Maybe this has already been dealt with, maybe it's in the manual, but the other day there was a gorgeous crescent moon, plus a planet (Venus?) in an almost black sky. One sec exposure said the K10D. No problem on the tripod, but at 6.7 aperture, the most the lens would go to, it refused to fire. had to activate the flash, then it worked fine. But surely I can take 1 sec (or slower) speeds without having to use the flash - which for this shot was pointless anyway. Is there a lower shutter speed beyond which the K10D insists on activating the flash? I got my shot - not very good because I forgot to deactivate the SR - but was left puzzled.

I think that if you have it set on M, Av or Tv you can set almost any time you want (up to 30 secs) without the flash being activated. It may say you need flash but it won't force the pop-up flash. Leastways that works on my Ds.

I have just been outside shooting astro shots at 30 seconds with no flash, no problem.

what exact settings were you using?

PS yes the bright planet near the moon at the moment is Venus.

Thanks for your replies. Interesting: I usually use aperture priority, but for the three shots I took (having raised the flash) the data is

Tv, f4.5, ISO400, 80mm, 1 sec
Tv, f8, ISO400, 300mm, 1 sec
Tv, f4, ISO400, 93mm, 1sec

So the camera was trying to find an aperture to suit the shutter speed - interesting shifts in aperture in relation to the focal length.

If my memory serves me correctly I gave up on Av because the little lozenge was flashing on any setting I tried, so I couldn't depress the shutter button, set a 1 sec to avoid shake (I have no remote release) but still had to raise the flash.

Will do more research. I brought it up because I had the same problem when shooting the eclipse but before I loaded 1.11 firmware.

I've experimented with long exposures of many minutes on bulb mode with my K10. At no time did the flash unit try and deploy.

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Tim the Ammonyte
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K10D & sundry toys
http://www.ammonyte.com/photos.html

here is my suggestion for astro shots

AF is irrelevant since if you ever come across an object in the night sky for which infinity is not the correct setting, the sharpness of your photos will be the least of your worries. The phrase "dear God, it's going to hit us!" springs to mind.

Set the camera to Manual focus and set the focus at infinity.

Unless you are using a really long (500+mm) lens and photographing the full moon, metering will be useless because of the large percentage of black sky. Trial and error is the key to success and you'll eventually get to know what settings are likely to work.

For the moon try F8 and 1/ISO as a starting point

For star fields, try wide open aperture and as long a shutter time as you can, probably ISO 200 although 400 is usable if you want to pick up fainter stars and are already at the longest shutter time you can use.

If you don't want to see star trails, and assuming you don't have a driven equatorial camera mount, keep your shutter speed faster than about 500/focal length.

Use the 2 second delay mode since this will "pre-fire" the mirror to reduce camera shake to a minimum.

The K10D's flash unit doesn't auto-deploy as far as I know, it may complain and flash the flash icon in the viewfinder but just ignore it, you know better.

hope this helps

Thanks mongoose for the tips. It makes sense to dispense with the AF. I will - when I can allocate the time - experiment more and take careful note of the settings as I go. If I still get the problem of the camera refusing to fire ie shutter button locks I will return to the subject. Incidentally, the 2 shots at 80 and 93mm at 1sec at 4/4.5 (with a Sigma 70 -300 APO lens) picked up some stars as well as the moon and Venus (thanks for the confirmation).

Given that there would be some camera shake from pressing the shutter and that SR was probably hindering rather than helping, Venus was almost circular. Some CA but not bad for a poor method and an inexpensive lens.