5D3 vs D800 - A Technical Analysis (UPDATED & EXTENDED) - With Samples

Started Mar 30, 2012 | Discussions thread
5tve Contributing Member • Posts: 678
Re: Sigma 70mm f2.8 IS f2.8

Legion5 wrote:

Jan Madsen wrote:

Legion5 wrote:

If imaging resource really doesn't vary the amount of light then, it's likely that the Canon and Nikon varieties of the Sigma 70mm f/2.8 have apertures that are a third of a stop different, which is fairly reasonable in retrospect. In some of Sigma lenses because they lied so much about the maximum aperture of a lens, when you stop down their lenses they only go down a half stop. In this case perhaps Sigma opted to keep the stops uniform and each stop on the Canon version of the Sigma 70mm f/2.8 is a third of a stop less than the Nikon version of the Sigma 70mm f/2.8. Due to the different packaging and focusing motor requirements for Canon and Nikon this sort of difference makes a lot of sense.

I did more digging and found that the Nikon 70mm Macro is well known to over expose by about a half stop, but the Canon version of the lens exposes normally.

I also e-mailed Imaging-Resource about this issue where Nikon cameras are getting 50% more light than Canon ones and they are aware of it. Imaging resources put forward that the the Sigma 70mm Macro has a software bug which causes it to overexpose on most Nikon bodies. On newer Nikon cameras the Sigma reports the aperture incorrectly and lower than it actually is. So if you tell the lens to go to f/8.0 it's actually going to f/7.0. The explanation for this issue is this is a result of Sigma's poor reverse engineering of Nikon's lens communication protocols. (Sigma didn't buy or license Nikon's lens protocols they just tried to figure them out on their own). On older Nikon cameras the Sigma 70mm f/2.8 exposes fine, but on most newer ones it overexposes by half a stop through incorrectly reporting the aperture to the camera.

So there's our answer, the shutter speed is different because the Sigma 70mm f/2.8 for the Nikon mount has a software bug related to the way it reports it's aperture on newer Nikon bodies and needs to be patched.

You are being totally absurd now.

Way back when Image resource provided high ISO samples for the D700 & the 5DMKII it was exactly the same the Canon needed longer exposures which in the real world in poor light means blurry photos.

If you want anyone to believe you start posting something that others can replicate.

I used Lightroom 4.1 RC you can see exactly what steps were taken under history
& I used the Windows Snipping tool to grab a screen shot.

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