Attention Tamron 24-70 VC owners

Started Jul 28, 2012 | Discussions thread
Shop cameras & lenses ▾
Veteran MemberPosts: 5,563
Some clarification of the experiment outcomes
In reply to Horshack, Jul 29, 2012

Just to clarify, my first post about this issue where I demonstrated f/2.8 vs f/4 images of the test chart had the f/4 image at 1/2 the shutter speed, so the two images should have had nearly identical brightness (exposure reciprocity) yet the f/4.0 image was twice as bright, indicating that the lens did not stop down properly.

In the experiment I asked you to perform, I asked you keep the shutter speed constant between the f/2.8 and f4 images, so the expected outcome in that case was for the f/4 image to be half as bright.

Both experiments are testing the same thing but the expected outcome is different.

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow