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Comment by MilesGreen posted on Hello from Corfu at 21/03/2019 - 10:08
So did you do a shootout???
I'm thinking of getting the DFA* 70-200/2.8 for my K-1. I have an old Sigma 70-200, but it's not in the same class mechanically or optically from what i've seen. I want it for horse-riding / showjumping, portraits and landscapes.
I'm thinking of getting the DFA* 70-200/2.8 for my K-1. I have an old Sigma 70-200, but it's not in the same class mechanically or optically from what i've seen. I want it for horse-riding / showjumping, portraits and landscapes.
Comment by MilesGreen posted on CANON 5D MIII , 70-200 2.8, PENTAX K-1 , DFA 70-200 2.8, NIKON D810 , 70-200 2.8 AND PENTAX K-3 , 50-135 2.8 at 31/03/2017 - 07:31
RobL wrote:
No the interval is longer than that. It takes about a second to complete the PSR captures, so about 0.25 seconds between exposures. That's enough to let the moon move.pentaxian450 wrote:
I think you misunderstand me, I agree the exposure for PSR is the same as for a single shot but say you pick a speed of 1/500 then the timeframe for a PSR will be 1/125 sec (4x 1/500). In order to get a timeframe of 1/500 sec in PSR (4x 1/2000) you would need to adjust the ISO by four stops. This of course assumes that the interval between PSR exposures is instantaneous which may not be the case.RobL wrote:
So, to freeze movement in PSR I assume that whatever shutter speed would normally suffice then divide by four: say 1/500 sec would require a setting of 1/2000 sec. If the ISO is increased by four stops to suit I wonder if the noise will cancel any benefit? Further experimentation needed.
Your assumption is wrong. You need the same speed in PSR as in a single exposure shot. The problem encountered in PSR is that the four pictures aren't taken at the same time, but one after the other. If there is any movement in between the different exposure, then you get some blur, the extent of it depending upon how much movement occurred in between the different exposures. To make things worst, when movement is caused by wind, light objects, or objects with low mass and high "drag" will move more than heavy or low "drag" objects.So, to freeze movement in PSR I assume that whatever shutter speed would normally suffice then divide by four: say 1/500 sec would require a setting of 1/2000 sec. If the ISO is increased by four stops to suit I wonder if the noise will cancel any benefit? Further experimentation needed.
Regarding exposure, you could switch spot-metering on in LV, that should let the camera do it correctly. Keep in mind that it's daylight on the part of the moon you're photographing. Think sunny 16 rule, or ISO 100, f/8, 1/250s for starters.
The moon is too fast at that focal length for PS (unless you have an equatorial mount).
Comment by MilesGreen posted on Moon with pixel shift resolution at 31/03/2017 - 07:24
RobL wrote:
the first RAW file of the 4 is available in the RAW file using DCU. Just go to the Pixel-shift icon and select off. It's worth upgrading DCU to the laterst version (5.6.2)Abe_Normal wrote:
It would be interesting to output the four frames of the PSR image as separate files and see how many pixels the moon moves between them
I don't think there is that option.It would be interesting to output the four frames of the PSR image as separate files and see how many pixels the moon moves between them
Comment by MilesGreen posted on Moon with pixel shift resolution at 31/03/2017 - 07:14
I've been shooting with pentax since 1997, with the Pentax 67. I got a K-1000 and SMC-A 50/1.2 a couple of years later, then digital, and now i have a nice K1ii system with an assortment of lenses, both manual and modern. You may have seen me oth other forums too, i've been pretty busy on dpreview. I'm here to talk more about photography, and find some more inspiration rather than dry gear talk.
I live in Corfu, Greece, I am married and we have 2 girls, aged 8 and 4.
Looking forward to meeting new Pentaxians here,
Regards,
Miles Green