Zoom to 200mm question

Joined
Aug 12, 2005
Messages
1,547
Location
Famington Hills, MI
Well, I own the 28-200G and the 70-200 VR.

Here's the question. I put both lens on a tripod and extended both the lens out to 200mm. I also checked the exif data to make sure the lens were at the same focal length. Here's the wierd thing. It is very apparent that the 70-200 VR gives about a 1x times closer than the 28-200. Both lenses were set to f/8 and taken within moments of each other when I tested them. What's going on here? Any ideas?
 
Joined
Aug 12, 2005
Messages
1,547
Location
Famington Hills, MI
I suppose I mean that the 28-200 looks like 9x while the 70-200 looks like 10x. I am no mathmatican so I couldn't express exact numbers. I guess that first statement was a bit misstated. I'll snap a few quick ones tomorrow and put them up replicating it in the same way.
 
Joined
Apr 21, 2005
Messages
3,625
Location
Houston, TX
Make sure you're focusing at something distant, ie at or near infinity. Any claims about focal length of a lens are measured at infinity, and depending on the lens design the actual focal length can change considerably as you focus closer and closer.

That said, it's not really that unusual for there to be a bit of a "fudge factor" in the actual focal range of zoom lenses.
 

Latest posts

Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Nikon Cafe is a fan site and not associated with Nikon Corporation.
Forum post reactions by Twemoji: https://github.com/twitter/twemoji
Copyright © 2005-2019 Amin Forums, LLC
Top Bottom