Keep my new 50LF1.2 or return it for a 50mmArt ?!?

Started Jul 1, 2014 | Discussions thread
RedYeti Regular Member • Posts: 273
Re: Keep my new 50LF1.2 or return it for a 50mmArt ?!?

Just another Canon shooter wrote:

So, it boosts the ISO for 3rd party lenses as well?

I don't have any non-Canon lenses to test this with myself either, but as I understand it and have seen discussed elsewhere, yes the boost still exists. It makes sense given it is primarily a sensor rather than lens issue that Canon are trying to compensate for so I have no reason to doubt it (I suspect the Canon firmware decides how much to boost purely by the reported f-stop, nothing else).

BTW, the DXO T-stop is measured in the center. Some lenses (see TDP) have a distinct bright spot in the center (different vignetting), and they will appear much brighter than others in testing. Vignetting can affect a lot the overall brightness as well. So I do not take the DXO t-number measurements seriously as a measure of how bright the lens is.

Indeed, the vignetting can vary a lot between lenses at these apertures, and you make a good point about the t-stop too. That's really what I was trying to convey to the OP - that other more significant factors are at play that can outweigh the apparently simple difference between f/1.2 and f/1.4, so it's not a good idea to make a purchasing decision on that fact alone.

 RedYeti's gear list:RedYeti's gear list
Canon EOS 5D Mark III Canon EF 800mm f/5.6L IS USM Canon EF 70-200mm F2.8L IS II USM Canon EF 100-400mm F4.5-5.6L IS II Canon EOS 5D Mark IV +6 more
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