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F2.8 and light with Canon 17-55 and Sigma 18-35

Started Aug 18, 2015 | Discussions thread
OP rweaver85 Regular Member • Posts: 122
Re: F2.8 and light with Canon 17-55 and Sigma 18-35

jitteringjr wrote:

rweaver85 wrote:

Can anyone who has used both of these lenses tell me which one lets in more light at F2.8?

Sounds like you are asking about measured T stop and that can all be looked up on DXO's website. I believe the Sigma 18-35 has a actual T stop closer to the f stop the lens displays than the 17-55. if memory serves me right the 17-55 has a t stop score of 3.4 so it's almost 2/3rd of a stop slower than the 18-35 at f2.8.

That's what I was looking for.  Thanks!

 rweaver85's gear list:rweaver85's gear list
Canon EOS 7D Mark II Canon EF-S 10-22mm F3.5-4.5 USM Canon EF-S 17-55mm f/2.8 IS USM Tokina AT-X Pro 12-24mm f/4 DX II Canon EF-S 55-250mm f/4-5.6 IS STM +1 more
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