Can you advise how you go about stacking these and with what software? I get focus stacking, but don't believe this is what you're doing?
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Focus issues with photographing the Moon
- Thread starter Nabukodonosor
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Can you advise how you go about stacking these and with what software? I get focus stacking, but don't believe this is what you're doing?
Nod
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IME, putting the focus area over the edge gives the best results, probably because it's the highest contrast area. I'll generally take a couple of test exposures to get the best parameters then use Manual mode to lock them in before focussing (well, letting the camera focus for me!)
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I did this in Photoshop (Align layers and then Merge layers).
But DeepSky Stacker is good for this (actually what it's designed for) and is free.
Plenty of YouTube vids about how to use it.
Don't worry about taking Dark frames, Bias Frames and Flats for the moon. It's so bright you won't be bothered by noisy images.
I took this image using a Sony A7R2 connected to my Skywatcher 200P 8" dobsonian telescope, hence the apparent magnification of the moon.
This was an effective focal length of 1200mm.
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sk66
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If the actual focus distance doesn't matter, why would the OP's first example be sharper than the second, when both were focused "on the moon?" And why focus on the moon at all? Why not focus on Mercury or a star instead? Or just set the lens to infinity focus?
According to a calculator you could use any of those methods and all would be acceptably sharp and w/in the DOF standard; but actual sharpness/resolution results will be very different.
sk66
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Keep in mind that even if the lens/sensor can resolve a detail that doesn't mean the camera can focus on it... the resolution of the focus system is necessarily less than that of the sensor; particularly if using a DSLR's phase detection system.
I.e. focusing on the moon (as a whole) is much more likely than focusing on any surface detail; especially when the moon is smaller within the FOV.
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Were they both "focussed" on the moon. No doubt that was the aim,
Setting the lens to infinity has already been discounted as a reliable method.
And the point was your difference in distance between the nearest and furthest points of the moon
sk66
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By infinity I meant actual infinity focus; not using the infinity mark (if there is one).Were they both "focussed" on the moon. No doubt that was the aim,
Setting the lens to infinity has already been discounted as a reliable method.
And the point was your difference in distance between the nearest and furthest points of the moon
I understood the point...
Here is one example of how focusing on the edge clearly resolves more detail along/near the edge than it does on nearer parts; even along the edge that is more frontally lit... I used "emboss" to make the depth of focus more apparent.
I tried to find an open source example that was well focused; but I don't know the specifics (camera, lens, aperture, stack, etc). Maybe I'll take some pics myself to demonstrate the difference.
