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Post by Inspeqtor on Dec 13, 2020 1:57:47 GMT
Inspeqtor Charles, One more thing regarding focus ... The Canon 90D has an APS-C sensor and shooting at ISO 8,000 might result in soft, noisy objects and this would show up on tiny objects vs (say) a tree or building. In addition, the planets and black sky are highly contrasted which probably exacerbates the noise issue. Drop your shutter speed much lower and reduce the ISO to 1,000 if you can. Might help. Worth a try. Clive The reason I used ISO 8000 was to be able to get Saturn into the picture. Otherwise it was very dim. I was afraid it would not show at a lower ISO from what I was seeing on the LCD screen. |
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Post by BuckSkin on Dec 13, 2020 3:32:56 GMT
What were the conditions? I tried to photograph Jupiter and Saturn 2 weeks ago and they were low to the horizon and my photos were not in focus. I shot on the back deck and suspect that it was low level atmospheric distortion and/or heat waves either as I was in town with houses just below the planets or even heat from the nearby city that was also below the planets. When focusing is critical (i.e. planets/stars) and you are using a long lens, and the planets are low to the horizon, the slightest low-level atmospheric interference can affect focus. I am glad that Inspeqtor started this conversation; it is very interesting and I am following and learning. That bit about atmospheric conditions can even mess up focus across an open field, not to mention across blacktop or a lake; I would imagine there are all sorts of interference between here and way out there, even exhaust fumes from the Enterprise. Way back in the 70s, in the hunting magazines, there were often articles on attaching SLR cameras to spotting scopes and telescopes. I have always wanted to try that, but have never had the extra cash to invest in a decent spotting scope or telescope that had T-Ring capabilities. Have either of you guys had experience with such ? Magnification-wise, I would be curious to know how a 500mm or 600mm lens would compare to a spotting scope or telescope. I have looked through spotting scopes that could clearly show a bullet-hole at a thousand yards. |
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pontiac1940
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Post by pontiac1940 on Dec 13, 2020 4:32:58 GMT
atmospheric conditions can even mess up focus across an open field, not to mention across blacktop or a lake Heat waves are evil and can mess low level photos over land or water on warm days and cool days. I have some samples somewhere. Have either of you guys had experience with such ? No. I understand (needs to be verified) that using a telescope for a telephoto lens is not such a grand idea because the aperture equivalent is tiny, like f22 or smaller. In other words, you'd need full sunshine to get a decent photo. Could be wrong. |
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pontiac1940
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Post by pontiac1940 on Dec 13, 2020 5:05:06 GMT
Heat wave distortion examples ... often far more subtle, but small temperature differentials can affect ability to focus.   |
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