[Don Schaeffer]

This may be the ultimate stupid question, but i want to get beyond guesses.
My 55-200 mm Nikkor lens works like an 82-300 mm (in 35 mm terms) becauise of the 1.5 sensor correction. In 35 mm terms (where 50 mm is normal), it should look like 6x telescope through the viewfinder. Now when I look through the vuiewfinder of my SLR am I seeing a 6x telescope (30 mm) through the lens or a 4x telescope (200 mm). Do they used masks on the viewfinder or what?

[NT73]

It depends on the telescope's starting and finishing magnification.
In terms of magnification they will be the same (4 x approx)
Nikkor (55-200) or 82.5 - 300 is still only 3.6363636 times magnification, Because you multiply both ends by 1.5.

(If your telescope has 4 times magnification, and the large end was 100mm, the small end would be 25mm)


The viewfinder is just a glorified square, set to give you the view that the sensor gets from the lens.
If you have an full size sensor camera, then the viewfinder would be set to give you the view that that sensor gets.

[Don Schaeffer]

Gotcha. That's what I thought.

[NT73]

Well it is not quite accurate but will suffice I think.
A telescope (the big ones anyway) have separate eyepieces that alter the effective magnification or something like that.

[Don Schaeffer]

Yes they are just magnifying glasses to magnify the image.