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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Focal Length (1 Viewer)

L

lobro45

Well-known member
I have a camera lens of 200mm focal length, plus a 2x converter giving a total of 400mm.
I'm trying to get a 'feel' for a Scope. Would a Scope with a focal length of 400mm, give the same size image? Or are other factors involved.
By way of example, if I was monitoring my nest boxes about 30 - 35 feet away, would I have a better view through a Scope, or could I see the same amount of detail through my camera lens.

The Scope I'm interested in is a Celestron Ultima Refractor 80.

I've been toying with the idea for years, as I could also get into Digiscoping, but I keep thinking that if I could achieve the same results with my camera, - then why should I !

So I'm asking you experts for advice :t:

Thanks L.
 
lobro45 said:
I have a camera lens of 200mm focal length, plus a 2x converter giving a total of 400mm.
I'm trying to get a 'feel' for a Scope. Would a Scope with a focal length of 400mm, give the same size image? Or are other factors involved.
By way of example, if I was monitoring my nest boxes about 30 - 35 feet away, would I have a better view through a Scope, or could I see the same amount of detail through my camera lens.

The Scope I'm interested in is a Celestron Ultima Refractor 80.

I've been toying with the idea for years, as I could also get into Digiscoping, but I keep thinking that if I could achieve the same results with my camera, - then why should I !

So I'm asking you experts for advice :t:

Thanks L.
Click to expand...
Very rough rule of thumb: divide 35mm camera lens focal length by 50 to get magnification. So, your lens will give about an 8x image. Average for good binoculars. At 35 feet you should have a very good view but things would look much larger at 30x in a spotting scope. Only you can say how large is large enough for your purposes.

Best,
Jerry
 
The other factor involved is the eyepiece .The eyepiece acts like the screen in a movie theater..cathes the light from the objective and presents it to the eye..So it creates the view...depending on the focal lenght of the eyepiece ,the image would be larger or smaller..you would divide the scope focal lenght for that of the eyepiece,and the result is the magnification..but this would also work with your lens..You could adapt a prism to correct the i mage and an eyepiece..I think the brand Kenko makes something called lenscope,That would make a more powerful scope out of your lens ,that your camera...
 
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