The focal length is a bit over 600mm. I use a barlow, so the focal
length is around 3000mm effective. The images are from Astia 100f
(35mm), scanned on the Minolta 5400 II, but reduced by two.
Obviously, the image is tweaked quite a bit in photoshop. The raw image
is very blue. I use a long pass filter (optical) to reduce some of the
haze. A bit more OT, but I've discovered that so called UV filters don't
really remove much UV. I have a flashlight made of 380nm UV leds, which
I use as a test source. If you aim the UV at a phosphor screen (such as
an oscilloscope), the screen will glow. This allows me to make a crude
UV filter test. The run of the mill camera lens UV filters are a joke.
My glass is from Andover, and it really kills UV. [Haze is inversely
proportional to the fourth power of the wavelength, so a little
filtering helps a lot.] Schott Glass makes two UV filters in camera
rather than astronomical sizes. I plan on getting one of these for use
in high altitudes, where UV is really strong.
James L. Sims wrote:
>Ah, but you're redefined the scope of reach! Just how long is the lens
>you used for this project? Or, just how small is your sensor? I can see
>that you don't need high spatial frequency, scintillation pretty much
>wipes out resolution at that distance. Great job though! I am
>surprised and impressed at the detail you captured at that distance.
>
>Jim
>
>lists@lazygranch.com wrote:
>
>
>>I have a Tak FS78 and quite a few accessories for such antics, but you
>>can't use them on the fly. This is a panorama I just finished last week,
>>with the distance varying from 15 to 20 miles.
>>
>>
>>
>>
>>>
>>>
>>>
>>>
>>You will need a jpeg2000 viewer such as irfranview.
>>
>>I didn't bring up the term "reach", so I wanted everyone on the same
>>page. I'd like it to be the case that less is more when it comes to
>>sensors.
>>
>>
>>Arthur Entlich wrote:
>>
>>
>>
>>
>>>Based upon what you are shooting, you don't need "reach" you need a spy
>>>satellite ;-)
>>>
>>>It all comes down to how much you want to pay, how much weight yo want
>>>to lug, and how long the lenses are you wish to carry. Have you
>>>considered a Telescope?
>>>
>>>Art
>>>
>>>
>>>gary wrote:
>>>
>>>
>>>
>>>
>>>
>>>
>>>>I'm a person that needs "reach", if you define reach as getting shots of
>>>>distance objects. Now generally a person who needs reach is using a
>>>>telephoto lens and possibly combined with a teleconverter. Such a setup
>>>>doesn't put out a lot of light, so the bigger pixels are certainly an
>>>>advantage. Also, I've been told that even if noise was not an issue, you
>>>>can't simply keep reducing the pixel pitch due to difficulties in lens
>>>>design. If anything, a 10um pitch would be optimal.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
>
>
>
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