D800 Portrait Lens Battle!

Started Sep 30, 2013 | Discussions thread
Shotcents
Senior MemberPosts: 4,073Gear list
Like?
Re: D800 Portrait Lens Battle!
In reply to Mariner77, Oct 1, 2013

Dear Robert,

I have found a formula to find effective aperture formula here:

Effective Aperture = Lens Aperture x (1 + Magnification)

There is also magnification calculator here:

http://www.mystd.de/album/calculator/

When I calculate for (Tamron) 90mm focal length, 2.8 f number and 1 meter (about 40 inches) focusuing distance , magnification result is 0.11.

In this case effective aperture=2.8x(1+0.11)=3,10

I am confused how your apperture got f4, because it seems you were not closer than 40 inches acording to your models position.

I may have gotten F4 because I set it there. I'll do a test shortly to see where the values change at various distances.

But I'll tell you that this Tamron 90 VC is a whopper of a lens. For the most part I prefer it to the 85mm 1.8G. But in a light starved space that 1.8 does come in handy as I always want the shutter speed up and the ISO down.

Robert

 Shotcents's gear list:Shotcents's gear list
Nikon Coolpix P7700 Nikon D800 Nikon D5200 Nikon Df Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II +10 more
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