197 mm instead of 200 mm

[ST]

Hi, All.

I just got my FE 70-200mm F2.8 GM OSS II, and easily half of the shots I intend to take at 200 mm appear to be at 197 mm in the metadata (and in the image review in the camera)

Is my lens defective? Should I go back to the store and exchange it for another one?

Metadata

ILCE-7M4 Sony FE 70-200mm F2.8 GM OSS II (SEL70200GM2) ISO 100 1/100 s f/3.2 197 mm

[MagnusW]

Firstly: Lenses very rarely have exact, rounded focal lengths, or the FL printed on the lens; "70-200" is more referring to a class of lens, the numbers are an approximation. Sometimes the "error" can be significant, like 10%.

In your specific case, however, the lens can go to 200mm, but it likely has a very sensitive sensor for focal length. If you look at this review:

https://www.australianphotography.com/gear/review-sony-70-200mm-f/2-8-gm-oss-ii

...you will see that several of his shots also have 197mm as a EXIF number, but also some at 200mm. It's likely that 197mm is the number you get when not actively pushing the zoom ring against the stop position, making the ring back down somewhat.

Don't worry about it. Some lenses may even say 200mm, but secretly be 185mm. 🙂

[Drew_Geraci]

This is quite common and I don't believe there's any reason you'd need to take your lens back or have it replaced. 

[ST]

This is quite common and I don't believe there's any reason you'd need to take your lens back or have it replaced. 

Thanks for your input folks. This is a new lens and a new pursuit (photography) for me. I'm still learning what is and is not relevant. 

[IraBlock]

Lens focal lengths and f stops are not exact, more so with zoom lens. No need to take it back, just enjoy using it.!!

[ST]

Thanks to all for your inputs. I'll try to make sure I have the lens fully zoomed out when I want that 200 mm.

What was concerning was the inconsistency (sometimes 200, sometimes 197). But I'll accept user-error as an explanation for now.