Is the Panasonic 25mm a real f/1.4 lens?

Started Feb 17, 2014 | Discussions thread
OP Pixnat2 Veteran Member • Posts: 5,140
Re: DXO : t-stop is the effective way of measuring aperture.

Steen Bay wrote:

MT wrote:

A bit OT, but with all of the talk of T-stop, I wonder how the Oly 12-40 f2.8 lens is wide open at 12mm. I just got it and it feels brighter than f2.8 whenever I shoot with it. Not sure why . But it has a lot of surfaces so I expect the T-stop to be lower than f2.8 considerably but it actually feels brighter than f2.8 for some reason.


According to DxO the t-stop is 3.2 on GH2, 3.3 on E-M1 and 3.4 on E-M5.

(see measurements/transmission)

Yes, in that department, the Lumix 12-35 is better with a t-stop of 3 on the GH2 and 3.1 of the E-M1 and 3.2 on the E-M5.

It's very intersting to note the difference between cameras. How lens can loose 0.2 t-stop between cameras?

I wonder if it's related to ISO sensitivity?

It show well that in the digital photography, the couple sensor-lens is more important than the lens or sensor taken individually.

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