Those are shot at ISO 100 Brendan. I don't recommend high ISO for this kind of shooting.
I do use high ISO test shots to help work out exposure times for ISO 100. Such as this one to determine how much light painting I needed: <http://www.arach.net.au/~savage/Misc/Images/K10D/Vacant%20Eyes.jpg> Unfortunately my cable release developed a fault after this shot (I also got attacked by some bees that my torch had disturbed) so I never got the final shot. Cheers, Dave At 01:01 AM 2/07/2008, Brendan MacRae wrote: >David, > >Why high ISOs at all for shots like these? Here's a 36 >minute exposure of some star trails I did last year >with the K10D: > >http://www.primelensphoto.com/star_trails.jpg > >Notice the tiny bit of sensor bloom in the upper >middle left of the frame. > >This was RAW, ISO 100, f6.3. Can't remember which >lens. The white balance was set to AWB but probably >should have been set to daylight (that's what stars >are after all). > >Now, I'm at 2,500 feet above sea level with very >little ambient light around my place so I have much >better natural conditions to shot under for this kind >of shot. >-Brendan >--- David Savage <[EMAIL PROTECTED]> wrote: > > > Now worries Walt (I've posted these before.): > > > > ><http://farm3.static.flickr.com/2209/2258045616_6bbe97702c_o.jpg> > > K10D, DA* 16-50mm f2.8 @ 16mm, 1208 seconds (~20min) > > @ f4, ISO 100 > > > > ><http://farm3.static.flickr.com/2119/2481946623_1e672bebcc_o.jpg> > > K10D, DA* 16-50mm f2.8 @ 16mm, 969 seconds (~16min) > > @ f4, ISO 100 > > > > Now these have been photoshoped to remove 2 sensor > > heat blooms > > inherent to the K10D & miscellaneous noise. > > > > For the heat blooms I use a dark frame that I have > > on file (ie 15 min > > exposure made with the lens cap on) & I use it > > overlayed on the base > > exposure & change it's blending mode to Difference > > to clean up the > > majority of the bloom (sometimes I use 1 or 2 of > > these layers). The > > rest is done using the clone, heal & patch tools. > > > > Here is a full sized version of the second shot BP > > (Before Photoshop > > :-) (~900kb): > > > > ><http://www.arach.net.au/~savage/Misc/Images/K10D/_IGP1494.jpg> > > > > These were taken in very dark conditions. It's about > > 3-4 hours north > > of the city & the only illumination that night was > > from the stars (and > > gelled flashes). > > > > I'm not surprised about the troubles you are having > > at high ISO. These > > sensors heat up quick. If you want to try again, use > > the inbuilt > > multiple exposure feature with EV compensation > > turned off. Instead of > > taking 1x 3 min exposure take 9x 20 second > > exposures. I suspect though > > that the heat will still be an issue. > > > > What I do to guesstimate exposure is take a 30 > > second - 2 min exposure > > (or more, until the lighting looks good) @ ISO 1600 > > and work backwards > > from there to determine the exposure for ISO 100. > > > > Cheers, > > > > Dave -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
