Do you agree with DXO ratings on the Nikon AF-S Nikkor 24 mm f1.8G

rmp

I did not expect such a difference between the Sigma 20mm Art and the Nikkor 24. Do you think the difference is that large?

starralazn

idk, maybe i'm blind but i can't compare the 20mm 1.4 art to the 24mm 1.8g (on a D810 at least).

(whoops wrote 1.4g there earlier)

and no, it doesn't really surprise me. that 2/3rd stop difference seems to make all the world, and i don't think the 20% difference between the 24mm 1.8g to the 24mm or 20mm 1.4 art lenses would allow sigma to make a better 1.4 lens..

Ironheart

@starralazn, it looks like DxO doesn't have a rating for the 20mm 1.4 Art, just the 1.8.

One thing to note is that the Sigmas have worse transmission values that the Nikons, undoubtedly due to the larger number of glass elements in the formula. This will effect exposure value, but not DoF.

For example, the Sigma 24mm 1.4 has a transmission value of f/1.7 vs the Nikon 24mm 1.8 which has a transmission value of f/1.8; less than a 10th of a stop less light. Hardly worth thinking about.

starralazn

@starralazn, it looks like DxO doesn't have a rating for the 20mm 1.4 Art, just the 1.8.

One thing to note is that the Sigmas have worse transmission values that the Nikons, undoubtedly due to the larger number of glass elements in the formula. This will effect exposure value, but not DoF.

For example, the Sigma 24mm 1.4 has a transmission value of f/1.7 vs the Nikon 24mm 1.8 which has a transmission value of f/1.8; less than a 10th of a stop less light. Hardly worth thinking about.

ohh okay.

i wonder what T-stop the sigma gets at f1.8... hopefully it's 1.8...

Ironheart

The T stop or transmission stop values will essentially scale across the entire f stop range. Using the siggy 24mm f/1.4 as an example, rated at a T stop of 1.7, is letting in a half stop less light. This is means at f/1.8 it is letting in a T stop of of 2.2, a half stop.
Here is the 1/4 stop scale:
1.0 1.1 1.2 1.3 1.4 1.5 1.7 1.8 2 2.2 2.4 2.6 2.8 3.1 3.4 3.7 4 4.4 4.8 5.2 5.6

I want to correct my statement above, as the difference between 1.7 and 1.8 is 1/4 stop not a tenth.
In any event it is not much. The point being you are buying DoF not necessarily more light with a siggy f/1.4

Personally I'm still staring at the hole between my 20mm and 28mm f/1.8...

rmp

Thanks Ironheart, et al, I just purchased the Nikon 24mm f1.8 for my landscape prime.

fiziks

I purchased a Sigma 24mm 1.8 when I got my D80 years ago. It is an incredibly sharp lens. I tried it on the D610 and it is still incredibly sharp.

[Deleted User]

Ephotozine review shows the lens is pitiful until F4, though rather great thereafter. Yet their high res image at 1.8 shows excellent sharpness in the POF. Maybe this is a function of severe curvature of field. This in contrast with DXO. Who is right? Diglloyd will provide reviews this month apparently. Though I am very pleased with results even wide open, resale may be hampered if its reputation is checkered. My frustration with Nikon grows if QC is not on par.

[Deleted User]

Lloyd Chambers states the new 24mm produces exemplary results and I believe he is rather conservative in his views. For a few $$ membership you can obtain detailed comparisons with the new 24-70mm E VR zoom and testing of each.