lowlight lens Af action resource?

[risc32]

I'm looking for some info on how well different lenses Af in low light conditions. I haven't been able to find much of anything on the net thus far. I know much depends on the camera body, but i'd still like to get any info i possibly can. Anyone got any thing? I'm even thinking about getting my gear out and running it threw a bit of testing in my kids playroom while slowly dimming the lights to see what can be learned. but i have only a small lens collection, and most of the lenses I'm curious about I don't own. Thanks

[robbymack]

It may help if you let us know which lenses you are curious about on what body. For example my 85 1.8 is fast, but the 135L I rent from time to time is rediculously fast. Switching from 5diii to 7d I don't see much of an af speed difference in the two using the most sensitive af points.

[risc32]

well, just the other day i noticed that someone somewhere on here said something about how they loved their 135f2, but the focus was not so great. now, i know that's bull cause i've used one for an indoor soccer tourney, but this is the sort of stuff you can find all over the net. So no one has made an even somewhat scientific test minded test? with all these sites out there, nothing?
   
just stupid stuff, like the site i read the other day where the guy was recommending a 24TS for sports, and a 50mm1.2, and 75-300 IS L as good beginner's lenses.  I forget what the recommended the 90mm TS for, but it was retarded. actually, I don't even have a clue what a 90mm TS might be really good for, but i bet it has a use. 

 it must... right? 
     

[neuroanatomist]

actually, I don't even have a clue what a 90mm TS might be really good for, but i bet it has a use. 

 it must... right? 

Best lens you can find for small product and/or jewelry photography. It's the right focal length, and tilt gives deep DoF without tiny apertures that reduce sharpness from diffraction.  But it won't fare well on a low light AF test, or any AF test for that matter. 

[Mt Spokane Photography]

well, just the other day i noticed that someone somewhere on here said something about how they loved their 135f2, but the focus was not so great. now, i know that's bull cause i've used one for an indoor soccer tourney, but this is the sort of stuff you can find all over the net. So no one has made an even somewhat scientific test minded test? with all these sites out there, nothing?
   
just stupid stuff, like the site i read the other day where the guy was recommending a 24TS for sports, and a 50mm1.2, and 75-300 IS L as good beginner's lenses.  I forget what the recommended the 90mm TS for, but it was retarded. actually, I don't even have a clue what a 90mm TS might be really good for, but i bet it has a use. 

 it must... right? 
   

Most will tell you that the lens focuses quickly. 
In regards to some sort of a scientific test, in order to be scientific, you need a test procedure that is repeatable so others can run the same test and confirm the results.
Any given lens will focus differently on different subjects and test charts, on different camera bodies, and, of course different brightness or color of light.  This means that one person could use the lens in a situation where it was slow to focus while another might use it where it focused quickly.
So far, no one has stepped up to coming up with any sort of test method to determine the speed of a autofocus lens that is scientific or repeatable.