Fast glass with mid-range Apature

[Freezdriedengineer]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

 

[Gavjenks]

It is often sharper than a lens would be that was wide open at those same apertures, yes.

 

[NikonNovice]

It also occurred to me that "mid" is a relative term, and with fast glass you will have more mid-range than you would with say a slower lens. Then there is the always knowing that you have the extra bright lens if you ever need it feeling.

 

[KmH]

It is often sharper than a lens would be that was wide open at those same apertures, yes.

But the improved sharpness of the stopped down fast lens is more about the quality of the optics in the lens than the stopped down aperture.

Most lens that have a maximum aperture that starts at f/3.5 or f/4 are kit zoom lenses. Kit zoom lens optics are OK but generally wouldn't be considered as good as the optics in even the least expensive fast prime lens - Like Canon's EF 50 mm f/1.8 II

 

[Solarflare]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

No.

The advantage of fast glass is that you can have a very open maximum aperture.

However, in order to have the option to open the aperture this wide, the demands on the lens design increase. This is why usually slower glass tends to be better than fast glass, at the same aperture.

Again, this is a tendency, not a rule set in stone. Zooms have much higher demands on lens design, too, and yet there are exceptional zooms that perform better than some primes. Likewise, fast glass is often a LOT more expensive than slower glass, thus the tolerances can be tighter, the material quality can be made higher, etc.

 

[Gavjenks]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

No.

The advantage of fast glass is that you can have a very open maximum aperture.

However, in order to have the option to open the aperture this wide, the demands on the lens design increase. This is why usually slower glass tends to be better than fast glass, at the same aperture.

Again, this is a tendency, not a rule set in stone. Zooms have much higher demands on lens design, too, and yet there are exceptional zooms that perform better than some primes. Likewise, fast glass is often a LOT more expensive than slower glass, thus the tolerances can be tighter, the material quality can be made higher, etc.

I have never in my life shot with a slower lens that was better than a fast lens at the same aperture, without the slower lens being worth at least 10x as much money.
For example, yes, the Canon 24-70L f/2.8 is probably sharper at f/3 than the Canon 50mm f/1.8 is at f/3. But also costs eighteen times as much. And even then, I'm not even actually sure that's true, since despite using both, I've never really done side by side comparison. Just sort of talking intuitively. It might actually turn out the opposite even despite 18x cost. I wouldn't be terribly surprised if it did. It always does whenever I do do that with any lenses.

Within any reasonably close comparison of equal classed lenses whatsoever (such as the 70-200 f/4 @4, versus the 70-200 2.8 @4), the faster lens is better at the same aperture.
Now, that might very well be because they just tend to have nicer optics all around, as Keith suggested. I'm not suggesting it is some magical optical law or anything. But it is still certainly true in practice pretty much always, for whatever reason it is.

 

[Braineack]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

Just because you have fast glass doesn't mean you should always shoot wide-open. That's like buying a car and only driving WOT.

 

[jaomul]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

Just because you have fast glass doesn't mean you should shoot wide-open. That's like buying a car and only driving WOT.

OP never mentioned shooting wide open.

 

[Braineack]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

Just because you have fast glass doesn't mean you should shoot wide-open. That's like buying a car and only driving WOT.

OP never mentioned shooting wide open.

True, I was trying to suggesting that, yes, there's a benefit to shooting mid-apertures on fast glass. There's more than "a" benefit. Sharpness, dof control, and ambient light control comes to mind.

My analogy was bad and my response was more of a generality.

I'd rather have fast-glass and shoot mid-range apertures where required, than be forced to start at 5.6. Like mentioned above, fast-glass typically tends to be sharper when stopped down and you have the ability to use stops between 1.x-5.6. I'm sure they produce better bokeh stopped-down in comparison as well. For example, compare the sharpness of the 70-200 2.8 at 5.6 vs. the "coveted" 70-300 VR at 5.6, the 2.8 will be MUCH sharper. (It's actually sharper at all stops )

 

[EIngerson]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

No.

The advantage of fast glass is that you can have a very open maximum aperture.

However, in order to have the option to open the aperture this wide, the demands on the lens design increase. This is why usually slower glass tends to be better than fast glass, at the same aperture.

Again, this is a tendency, not a rule set in stone. Zooms have much higher demands on lens design, too, and yet there are exceptional zooms that perform better than some primes. Likewise, fast glass is often a LOT more expensive than slower glass, thus the tolerances can be tighter, the material quality can be made higher, etc.

I have never in my life shot with a slower lens that was better than a fast lens at the same aperture, without the slower lens being worth at least 10x as much money.
For example, yes, the Canon 24-70L f/2.8 is probably sharper at f/3 than the Canon 50mm f/1.8 is at f/3. But also costs eighteen times as much. And even then, I'm not even actually sure that's true, since despite using both, I've never really done side by side comparison. Just sort of talking intuitively. It might actually turn out the opposite even despite 18x cost. I wouldn't be terribly surprised if it did. It always does whenever I do do that with any lenses.

Within any reasonably close comparison of equal classed lenses whatsoever (such as the 70-200 f/4 @4, versus the 70-200 2.8 @4), the faster lens is better at the same aperture.
Now, that might very well be because they just tend to have nicer optics all around, as Keith suggested. I'm not suggesting it is some magical optical law or anything. But it is still certainly true in practice pretty much always, for whatever reason it is.

What?

 

[jaomul]

Just because you have fast glass doesn't mean you should shoot wide-open. That's like buying a car and only driving WOT.

OP never mentioned shooting wide open.

True, but I was suggesting that, yes, there's a benefit to shooting mid-apertures on fast glass. There's more than "a" benefit. Sharpness, dof control, and ambient light control comes to mind.

My analogy was bad and my response was more of a generality.

Sorry was not intending to call you out on something. I know sometimes when reading the posts people sway from the original post.kind of a Chinese whispers thingy

 

[Braineack]

Sorry was not intending to call you out on something. I know sometimes when reading the posts people sway from the original post.kind of a Chinese whispers thingy

no, it's fine. I was off-point.

 

[Gavjenks]

What?

When both shot at 50mm, of course, sorry.

I'm just saying I wouldn't be surprised either way if the 50mm 1.8 for $100 looked better at f/3, or if the 24-70L f/2.8 for $1800 looked better at f/3 and 50mm. That's about the only extreme comparison I can think of where a slower lens might prevail at the same f/stop, and it's still not obvious.
And when you have lenses actually close to each other in price and class, it virtually guaranteed the faster one would win at the same aperture and focal length.

Even my large format lenses from 60 years ago are sharper than their slower modern equivalents at the same apertures and FLs...

 

[bratkinson]

Just because I have fast glass doesn't require that everything be shot at or near wide-open. Just this past September, I used my 135mm f2L lens while walking in downtown Chicago in late-morning for a couple of shots. Because of the bright sun, I had slowed down the ISO speed 400 but was shooting about f4 to get a 'good' DOF and still capture the moving subject.

As others have said above, most lenses are typically sharpest near their mid-aperture sizes and at their least sharp at either extreme. So it's not uncommon I shoot my 135 stopped down just a tad to still (intentionally) get a thin DOF and a touch more sharpness on an already super-sharp lens.

The 'advantage' of having fast glass is having the option of a wider range of apertures at ones' disposal to get the desired shot. Thin DOF when desired and 'more light' when needed are the primary advantages in my mind. But that doesn't stop me from using any of the f2-f32 settings available on that lens when needed.

Here's that Chicago shot...

 

[Tailgunner]

Is there a benefit to having fast glass when you are shooting with mid-range apertures?

No.

The advantage of fast glass is that you can have a very open maximum aperture.

However, in order to have the option to open the aperture this wide, the demands on the lens design increase. This is why usually slower glass tends to be better than fast glass, at the same aperture.

I'm confused: My 18-200mm VR is sharper at 85mm/F/4 than my 70-200mm 2.8 VRII at 85mm F/4?

Anyhow, I use a lot of Mid-range apertures shooting our son's basketball games. I do this in order to help turn up the shutter speed.