Low light question

[Buzz Bryson]

To David’s point, if the only variable in a studio set-up is the lens (same lights, camera on manual or at least the settings not changing when changing lens), and the exposure is differeing, what I’ll bet you’re seeing is the, uh, enthusiasm, of some manufacturers in their product labeling.

Just because a lens says it’s f/something-or-other, it might not be.

[Ben Cochran]

Now I am getting confused, as well; common thing for me so I am ok with it lol

I have to go back to my original argument about light frequencies, as I firmly believe that is where the true comparison is better measured. If we were in an evenly lit room and one half of the wall was painted red with black designs in it and the other half was painted green with black designs in it, it would take our eyes longer to adjust from one section to the other. It isn’t because one side is darker than the other as much is it is the fact they absorb light and reflect it back differently, each of the backgrounds reflect a different frequency wave length and our pupil has to adjust to better capture the image. A camera sensor cannot do that near as well so the 3 major frequencies, that we deal with, have to be better controlled and transferred by the lens.

Consider the Nikon 17-55 2,8 and the Nikon 18-55 3.5-5.6  The 17-55 has 14 elements in 10 groups with 3ED glass elements and 3 aspherical lenses. The 18-55 has 11 elements in 8 groups with 1 aspherical lens element. The 17-55 cost a whole lot more than the 18-55 with more elements but works far better in lower light but there is a reason for the extra elements: They better consolidate, balance and transfer the different frequencies of light to the back end of the lens. In the case of these 2 lenses, the 17-55 has a 30% increase in light wave length transfer to the back end of the lens, this supports the findings that David Anderson observed in the studio; better tonal range and contrast due to better engineering inside of the lens. The MTF charts also support this finding.

So, most often the prime lenses have more elements, higher quality of elements and element groups designed for best transfer of color frequency, as compared to the less expensive consumer lenses. Most important”  This is not just due to the f stop potential of the lens, it is the quality of the elements inside of the lens so, not all f 2.8 lenses are better than, lets say, an f4 and this is also the reason why not all 17-55 2.8 lenses are equally the same.

Anything else is over my head, but these are some of the main things that I look into before I purchase new lenses.

[Author]

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