First Review of New Tamron Prime Lenses

[TWI by Dustin Abbott]

More curious number popping out of DXO...

http://www.dxomark.com/Lenses/Compare/Side-by-side/Tamron-SP-45mm-F18-Di-VC-USD-Model-F013-Canon-on-Canon-EOS-5DS-R-versus-Tamron-SP-45mm-F18-Di-VC-USD-Model-F013-Nikon__1594_1009_1595_0

Apparently the SP 45mm resolves more detail on a 36MP D800E than on a 50MP 5Ds-R.

DXO can always squeeze more resolution out of a Nikon or Sony sensor than a Canon. It's a special gift.

In all seriousness, though, the one number that disappoints among a lot of great information is the rather poor light transmission of the 45mm f/1.8. I have to confess that I'm not really seeing it in real world use, and the lens seems to be exposing appropriately. I wonder if this is one of negatives of having shared design with the 35 VC - perhaps the 45 could have benefited from a larger front element than 67mm?

Here's a question for the physics experts. The Canon f/2 IS has a light transmission (t-stop) of f/2. The Tamron 35mm f/1.8 (according to DXO) has a t-stop of f/2.1. How does this work? Is it the difference in coatings and elements that maximize the amount of light coming through the aperture? How else could the larger aperture lens (1/3rd stop) have less light transmission?

 

[TWI by Dustin Abbott]

One other curious thing from that comparison at DXO. They rated the light transmission, vignette, and chromatic aberrations differently for each camera system (all of these scores better for Canon), and then sharpness higher on the Nikon mount. How does a different lens mount result in all of these differences?

 

[StudentOfLight]

One other curious thing from that comparison at DXO. They rated the light transmission, vignette, and chromatic aberrations differently for each camera system (all of these scores better for Canon), and then sharpness higher on the Nikon mount. How does a different lens mount result in all of these differences?

It boggles the mind...

I think Adam pointed out that sensor stack design might influence transmission and vignette, but I haven't seen any concrete explanation that this is the case.

Also, IRRC 3rd party lenses tested on D800E/D810 generally have less vignette than the on the 5Ds-R. It's curious that the Tamron is worse on the Nikon, curious indeed. Perhaps they have a bad sample, or they mixed up some numbers in the lab.

 

[LSXPhotog]

Hahaha, ohhhh DxO. Making things up as they go right in front of everyone and people just accept it as valid scientific testing.

This one stop gets me rolling. How is this score even possible when the Canon was clearly better in their testing? Haha