Morning half moon - April 17, 2009

Morning folks.

Got up this morning and went to grab the news paper out of our mail box. I noticed this nice bright half moon shining down. Luckily, I had my camera and tripod sitting by the front door and was able to set up quickly to take this image.

Took some shots with my S3 at full 12X optical zoom. Went full manual with ISO 80, 1/30 and F8. Too bad the S3 only goes as high as F8. Even though the manual focus was set to infinity and looked sharp on the LCD screen, it is still slightly out of focus. It was especially evident when I looked at the digital zoom images on my computer monitor.

I have a question. If the image below was done with 12X optical zoom, what type of zoom or magnification are others using to get the really close up views of the moon?

Anyway, I put the best 5 images together in DSS and came up with the shot below.

Al

Chopper Al wrote in post #7748751
Morning folks.

Got up this morning and went to grab the news paper out of our mail box. I noticed this nice bright half moon shining down. Luckily, I had my camera and tripod sitting by the front door and was able to set up quickly to take this image.

Took some shots with my S3 at full 12X optical zoom. Went full manual with ISO 80, 1/30 and F8. Too bad the S3 only goes as high as F8. Even though the manual focus was set to infinity and looked sharp on the LCD screen, it is still slightly out of focus. It was especially evident when I looked at the digital zoom images on my computer monitor.

I have a question. If the image below was done with 12X optical zoom, what type of zoom or magnification are others using to get the really close up views of the moon?

Anyway, I put the best 5 images together in DSS and came up with the shot below.

Al

Looks good, Al. I would like to see a version with some of the sky cropped away so that the image can be shown at full scale (i.e. number of image pixels equals number of screen pixels).

Expressing zoom in terms of a multiplication factor is sort of nebulous (bad pun for an astro forum) since it depends on the referenced 1X scale. As far as I know, there is no precise definition of a "normal" lens for a SLR/DSLR camera, but my personal definition would be a lens that results in about the same geometrical perspective to a vanishing point as perceived by the unaided human eye.This generally means that a lens with a focal length around 50 mm is about "normal" for an SLR, but not a P&S camera. That means my 400 mm lens might be considered about eight times "normal" except that nobody actually thinks of it in those terms since it doesn't really tell you things that you need to know such as the field of view angle. I have gone so far as to stack both of my teleconverters onto the back of my 400 mm lens to give a total focal length of 1120 mm. That sound great at first glance, but it is a bear to focus precisely and any sort of vibration in the camera and tripod leads to considerable motion blur. A slight breeze or just walking around a tripod can cause noticeable shake. Then there is vibration caused by the mirror in an SLR and also a bit caused by the curtain. This means that there are a lot of "it depends" answers to getting a good image and it is not simply how much enlargement that you can get from the lens.

Thanks for the reply Bill. I've been doing some more reading on 'optical zoom' versus true magnification. A 6-72mm lens (if there is such a thing) will have a 12X zoom as well as a 100-1200mm lens. Even though both are 12X optical zoom lenses, the 1200mm lens will give you a higher magnification than 72mm. Still soooooo much more to learn....

Here is an actual pixel size image you requested. Dummy me just resized the original image instead of cropping it. Still soooooo much more to learn....

Al