Zoom Lens Ratio 18-200mm

B

Bob Dee

New member
Hi All,
Could I get a confirmation of what I believe is true.
I Bought a used Nikon 18-200 VR II lens from a Camera shop on eBay.
They have a good reputation on eBay and their store website.
The problem is that this lens does not seem to be a true 11 to 1 zoom ratio.
It only seems to be about 8 to 1 , and I have compared to a friend using his lens.
Question:: If I stand far enough away from a block wall such that 11 blocks fill my
frame at 18mm, when I zoom in to 200mm should my frame now be filled with only one block?
Meaning that the view of one block has been enlarged by 11 times?
But with this lens, When I view 11 blocks then zoom in I still have about 1.35 blocks in frame.
This would equate to a zoom ratio of about 8.1 to 1.
A true 11 to 1 would give me 37% more zoom.
SO an 18-200mm should provide very close to 11to1 zoom, Not 8.1to1 Correct??

Thanks So Much in Advance, Bob
 
W

WayneF

Senior Member
Bob Dee said:
Hi All,
Could I get a confirmation of what I believe is true.
I Bought a used Nikon 18-200 VR II lens from a Camera shop on eBay.
They have a good reputation on eBay and their store website.
The problem is that this lens does not seem to be a true 11 to 1 zoom ratio.
It only seems to be about 8 to 1 , and I have compared to a friend using his lens.
Question:: If I stand far enough away from a block wall such that 11 blocks fill my
frame at 18mm, when I zoom in to 200mm should my frame now be filled with only one block?
Meaning that the view of one block has been enlarged by 11 times?
But with this lens, When I view 11 blocks then zoom in I still have about 1.35 blocks in frame.
This would equate to a zoom ratio of about 8.1 to 1.
A true 11 to 1 would give me 37% more zoom.
SO an 18-200mm should provide very close to 11to1 zoom, Not 8.1to1 Correct??

Thanks So Much in Advance, Bob
Click to expand...



How far was the block wall?

Marked focal length is only correct (nominally) for infinity focus.

Speaking of prime lenses, as you focus closer, the focal length necessarily changes. Zooms too, however zooms do all sort of internal tricks, most bets are off.

Try your test focused at infinity, where the marked numbers have meaning. I feel sure the lens does what it should, but it might not be what you are expecting.
 
B

Bob Dee

New member
OK, Second try at a post......
Thank You !! Thank You Wayne,
A detail I should have known but overlooked.
I Was too close. SO...
I found a fence with large 15' panels. I backed off to 11 panels in frame, Then was able to zoom to about only one panel in frame
so that equaled very near the 11 to 1 zoom I was expecting. How is that for some ' Sy In Tific' Data.
Just bought a D5200 and the 18-200mm. First Nice camera I have had in a while. Opened the manual.. Wow, Have I got a long road ahead !

Thanks Again,
Bob
 
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