50mm f/1.4 or 85mm f/1.8 on a 1.6 Body?

[Gadget]

I've got the 50mm 1.4 and an XSi. Unless you shoot things far away, and in low-light, I'd have to recommend the 50mm. I use my 50mm a lot (it's my only decent glass right now), and I'm finding it a little long for indoor group shots, etc.


I was having the same questions before I brought the 50, and I have no regrets about getting it. On a 1.6x body, the 85mm would just be too long for me. Love my 50mm 1.4 though, it's SOOO sharp, and you can shoot almost anything with just available light.


Plus, the 50mm is faster, but you may not be an apeture whore like me.

[Jon Ruyle]

I have both lenses and don't find them redundant.


It all comes down to style. I quite like a 135mm for portraits on my 5DII, which comes down to about 85mm on a 1.6fovcf. (Not for group shots, I admit).

Plus, the 50mm is faster, but you may not be an apeture whore like me.

I'm an aperture, um, liker, too. But unless I made a mistake with my arithmetic, the 85 f/1.8 actually has more aperture than the 50 f/1.4.


No question, though. The 50mm is more hand-holdable.


Brent, I suspect you'd be happy with either. I also suspect you'd be happy with both []

[powers_brent]

THanks everybody for you opinions and input. Eventually I think I will get both, but for now i will go with the 50mm. I will wait because financials.


But one question Jon, how does the 85mm have more aperture at 1.8 compared to 1.4? Are you talking more bokeh? Because I know bokeh is amplified by focal length, but isn't aperture always aperture. Meaning, isn't 1.8 on the 50mm and the 85mm the same? Thus meaning that that 50mm at 1.4 has more aperture? Please explain.

[Jon Ruyle]

The 50mm is faster (ie, has a lower f number), but it does not have a bigger aperture.


f number is defined as focal length / aperture, so aperture = focal length / f number. Thus the 50mm has about 36mm aperture, the 85mm has about 47mm.


Aperture, along with death and taxes, is one of the Great Universal
Invariants. You can crop a picture and make it look like it was taken
with a longer and slower lens, but aperture always looks the same, no matter the size of your ccd.


I realize now that Gadget- who will do almost anything for aperture- might have meant f number when he said aperture. People sometimes do.