Having an f/1.4 lens and not using it wide open ...

Bend The Light wrote in post #12122963
If you have a faster lens, say a 1.4 as opposed to a 2.8, then would the sweet spot be at a slightly wider aperture? This would mean you would get the benefit of sharper images whilst using a wider aperture (but still not have to use the widest)

^this is how ive always thought of it and is the reason i love shooting primes over zoom - super sharp images at 2.5 on a 1.4 lens!

rusty.jg wrote in post #12123334
It looks like the restriction to an apparent f/3.5 through the view finder only applies to the 7D (see post number 25 onwards):
https://photography-on-the.net/forum/showthre​ad.php?t=844294

However I know I read it somewhere else as well that in some cases the viewfinder will not show the DoF of fast lenses. I will see if I can dig further....

My T2i won't show DoF at 1.4, but will from 1.6 and down.

Bend The Light wrote in post #12122963
Related to this, can you tell me:

A lens has a sweet spot in the aperture which is not at it's widest, and not at it's smallest.

If you have a faster lens, say a 1.4 as opposed to a 2.8, then would the sweet spot be at a slightly wider aperture? This would mean you would get the benefit of sharper images whilst using a wider aperture (but still not have to use the widest).

Absolutely. I've had 50 f/1.4 lenses from Sigma and Canon and both of them were acceptable at f/1.4 but amazing starting at f/2.

1Tanker wrote in post #12123437
My T2i won't show DoF at 1.4, but will from 1.6 and down.

Do you mean to say that nothing happens when you press the DOF preview button? If so, the aperture is at already at f/1.4 so of course nothing happens when you press that button. What could happen?

rusty.jg wrote in post #12123334
It looks like the restriction to an apparent f/3.5 through the view finder only applies to the 7D (see post number 25 onwards):
https://photography-on-the.net/forum/showthre​ad.php?t=844294

However I know I read it somewhere else as well that in some cases the viewfinder will not show the DoF of fast lenses. I will see if I can dig further....

This is well documented and I'm pretty sure it is explained in the user's manuals. The only thing about the 7D that is different than other Canon SLRs is that the 7D focus screen cannot be removed. Other cameras have user-replaceable focus screens so that you can put in a focus screen that will show the more narrow depth of field. The trade-off is that the viewfinder will be very dark when using lenses that only open up to f/4 or f/5.6.

krb wrote in post #12124034
Do you mean to say that nothing happens when you press the DOF preview button? If so, the aperture is at already at f/1.4 so of course nothing happens when you press that button. What could happen?

Doh! I'm gonna go to bed now.

Bend The Light wrote in post #12122963
Related to this, can you tell me:

A lens has a sweet spot in the aperture which is not at it's widest, and not at it's smallest.

If you have a faster lens, say a 1.4 as opposed to a 2.8, then would the sweet spot be at a slightly wider aperture? This would mean you would get the benefit of sharper images whilst using a wider aperture (but still not have to use the widest).


Cheers

it honestly depends

Theres a lot of zooms out there that are pretty much as sharp at f/2.8 as say a 50mm prime at f/2.8..The 17-55 comes to mind as my copy and someone elses both performed just as well if not better than the 50 at f/2.8...

I know my Sigmalux stopped down a little is easily one of my sharpest lenses, however Not necessarily sharper than my 15-85 at f/5.6-8 and since it lacks IS if im not using it at wide apertures id rather use my 15-85...

I just came across this thread, and have gotten some chuckles -- how do we thoughtfully respond to a remard that is not well-thought-out? Not to act like a jerk and yet send the asker a little reminder to think twice before they make a remark that carries a criticism in it? Like "it sure was dumb of you to buy that f/1.4 lens..."

Just take the replies that have been mentioned and wrap them in a nutshell and toss it out:

You get a very sharp f/2 lens!

You get a nice wide opening that can give some assistance to AF but is also a real benefit if you are doing Manual Focusing because you can use that wide aperture/narrow DOF to really nail your AF with precision using Live View or using a add-on focusing screen!

And, hey, you may not be in the habit of shooting f/1.4 but dang it, when you want to it's there for your creative use!

And then say something like "See, I'm not as dumb as you think!"!

Hey, when I shoot with my 85L or 50 1.4, I very often have them stopped down to whatever gives me the depth of field that I want. So what? If I want to go wide open I can, which I occasionally do for the creative narrow DOF if I decide it will "fit". And, because I do this thoughtfully I typically get rewarded with some nice results, although also typically ones where I messed up with movement/camera shake, but hey, that's the price you pay!