Is F2.8 really beneficial over F4?

[specialman]

"With modern bodies being able to reach silly high ISOs with more than acceptable results, the argument about using f/2.8 over f/4 isnt as valid,"

There must still be a speed advantage for some users and then there's the biggie of DoF that's really the biggie for some people.

Personally I don't think I'd ever consider an f4 lens if there was a faster alternative unless there was some other big deciding factor and I'm struggling to think of one.

Oh, without doubt the speed advantage (I take it you're referring to the extra stop?) is a major plus point and combined with the additional (narrower) DoF on a f/2.8, it's a potent package that is hard to resist if there's a product that fits your budget and other buying requirements.

If someone brought out a 17-90mm f/4 for eaxmple, I'd trade my 17-50mm f/2.8 in a flash, providing the newer lens was A) of equal optical quality, and B) wasn't of a wildly prohibitive price. Even on my aging D2Xs without really high ISO capabilities, I'd go for versatility (meaning reach) any day.

But that's me as an individual with specific needs....

 

[Starastin]

With modern bodies being able to reach silly high ISOs with more than acceptable results, the argument about using f/2.8 over f/4 isnt as valid, although it's still a major consideration when thinking about AF and viewfinder brightness. Of course, DoF is more flexible with the wider lens also, which is a given.

However, you're on a 40D, which was never renowned for being amazing at high ISO, so I'd probably opt for a fast lens instead of relying on the sensor to make up the shortfall in available light. Plus, the majority of 17-50/55mm f/2.8 lenses are top-notch and you'll be impressed by the image quality you get from them. Tamron, Sigma, Tokina plus Canon all make variants tht cover that range, all at varying prices. The Canon is supposed to be very good, but the Tamron I use is very good also for half the price.

Plus, 17-XXmm is a much easier option to use every day on a crop body over a 24-105, which although it has the range, is an awkward wide end for crop body use.

Now, a 17-105mm f/2.8 would be handy. but I don't think we'll be seeing one of those any time soon.

try d700 + 24-120mm f4 . I think it would be all I ever needed apart from some 2 or 3 more primes .

 

[PsiFox]

he has the sigma which is sharper wide open.

 

[adsayer]

I have plenty of times where even f2.8 isn't fast enough.

same... thankfully the 1.2 I have saved the day even though it isn't designed for sports use - but it does make for interesting shots compared to the norm

 

[Dr_O]

I am off the opinion that it is better to have it and not need it than to need it and not have it- consequently all my lenses are f2.8 or faster.

It does depend on what you shoot but DOF is important for me- one of the reasons I despair at the slower lenses coming out with VR/IS- there's just no substitute for wide apertures

There is the weight issue but that's why gyms were invented

 

[specialman]

try d700 + 24-120mm f4 . I think it would be all I ever needed apart from some 2 or 3 more primes .

Problem with that is it's full frame and my long lenses would lose that all-important 'extra' length given by the crop conversion.

Money no object I'd get a FF body (for ultimate IQ and high ISO performance) with primes but as it stands there is nothing to tempt me away from crop at this time....

*(Wishes Nikon would bring out a new D2x with an amazing crop sensor....)

 

[Lynton]

I now have 50-150 of f2.8 loveliness..........if they (whoever) want more blurring than photoshop can do it!!!!

Trying to justify (to myself)why I should get a 17-50 f.2.8 as in my experience, landscapes don't often move that much!

 

[martyp]

Starting again I would get the 24-70 f/2.8L over the 24-105 f/4L as the price difference is pretty small now.

However, as a walkaround lens I don't really need f/2.8, sure it'd be nice as it would make use of the numerous cross-type focus points but as its rarely below f/8 in normal use and the view finder is bright enough.

I did need f/2.8 on the 70-200 range which I now have so I'm set...for the moment...

 

[Andrew Evans]

yes. yes it is. especially if you shoot in low light. it all depends how much you're into photography and how much you want to spend.

 

[danbroad]

yes. yes it is. especially if you shoot in low light. it all depends how much you're into photography and how much you want to spend.

Agree and disagree. At the risk of sounding like a stuck record, I agree on the many benefits of faster glass [and there are a great many - AF, focusing, image quality, bokeh, contrast...], but modern DSLR's have ISO controls that make this statement only halfway true.

It's very useful to have that one extra aperture stop in low light, but remember [and let's say we'd previously have shot ASA1600 in the poorest-lit conditions] that now you can find 3 extra 'ISO' stops on even the entry-level DSLR models. ISO as a dynamic variable is probably one of the major DSLR advantages.

ASA1600 was a noisy film, and those of you with D700's/D3's can put an f/4 on and shoot at 25,000 with much the same grain. That's 4 stops from 1600, whereas an f/2.8 glass only finds one extra stop from f/4. Considering what we thought we could shoot even 5 years ago, DSLR's now push the available light boundaries like never before.

The rule is photographers always want an extra stop, regardless of what they have. If we're truly into available light, shouldn't we be shooting f/1.0 to f/1.4 primes only?

 

[Starastin]

Problem with that is it's full frame and my long lenses would lose that all-important 'extra' length given by the crop conversion.

Money no object I'd get a FF body (for ultimate IQ and high ISO performance) with primes but as it stands there is nothing to tempt me away from crop at this time....

*(Wishes Nikon would bring out a new D2x with an amazing crop sensor....)

If the full frame camera has lots of MP, you can crop it nicely. but the crop sensor is limited. but well - we don't live in a dream world where we can afford everything we want in a split second.

 

[Starastin]

Agree and disagree. At the risk of sounding like a stuck record, I agree on the many benefits of faster glass [and there are a great many - AF, focusing, image quality, bokeh, contrast...], but modern DSLR's have ISO controls that make this statement only halfway true.

It's very useful to have that one extra aperture stop in low light, but remember [and let's say we'd previously have shot ASA1600 in the poorest-lit conditions] that now you can find 3 extra 'ISO' stops on even the entry-level DSLR models. ISO as a dynamic variable is probably one of the major DSLR advantages.

ASA1600 was a noisy film, and those of you with D700's/D3's can put an f/4 on and shoot at 25,000 with much the same grain. That's 4 stops from 1600, whereas an f/2.8 glass only finds one extra stop from f/4. Considering what we thought we could shoot even 5 years ago, DSLR's now push the available light boundaries like never before.

The rule is photographers always want an extra stop, regardless of what they have. If we're truly into available light, shouldn't we be shooting f/1.0 to f/1.4 primes only?

f0.95 is supposed to be like human eye :|

 

[homerdog]

Rather than just asking about the benefits of f2.8 over f4, it sounds like you really want to know which lens to buy. The 24-105 isn't really wide enough on a crop given my experience with it. I sold mine, bought the 17-55 and haven't regretted it once.

 

[ChrisJ_SLH]

Hi Guys,

As the title asks, is F2.8 really beneficial over F4?

I'm talking about the 17-55 2.8 or the 24-105.

What would the different in shutter speed be between the two?

I have a 24-105 which I love on my 5Dmk2. When I had my 40D I had a 17-55 f/2.8 which I also loved.

As far as I'm concerned, on Canon crop, the 17-55 is the walkabout lens to own. Wide enough, long enough, fast enough, good IS and fantastic image quality. Forget the absence of a red ring, not an issue.

I had the Tamron 17-50 before I got the Canon 17-55 and I found it slightly short at the long end as a walkabout. As 50mm on Canon crop is the equivalent of 80mm this is the only thing deterring me from a 24-70, the f/2.8 is appealing though.

 

[Les McLean]

I think a lot depends on what you are using the lens for?
In respect of landscape photography, I'd say no, I've been round the block with this issue a few times, and finally settled on a 17-40 F4 lens for most of my landscapes, finding I didn't need a 2.8 lens, as most of the time I'm shooting at f8-f22, autofocus is a tad slower but not an issue, hunts for focus a mite longer in low light, but the excellent focusing system of a 1 series compensates for this.

If shooting people, or fast sports, birds, transport etc I'd say yes it is beneficial, particularly for kicking cluttered backgrounds out of focus, quicker to lock focus, the increased shutter speed is not such a big plus (IMO) as you only gain a faster shutter speed when shooting at f2.8

 

[bomberman]

Is F2.8 really beneficial over F4?

Of course it is! Unless you shoot landscapes, then f/16 is your friend!

 

[FoG]

:bonk:


sorry to hijack thread but that creased me up *pushes vodka away*

 

[Chaz Photos]

Hi Guys,

As the title asks, is F2.8 really beneficial over F4?

I'm talking about the 17-55 2.8 or the 24-105.

What would the different in shutter speed be between the two?

As other have said it one stop so when taking photos you get one stop more to play with BUT it will also mean it is twice as much light when composing and focusing your image, this is often over looked, so in your viewfinder you will see a much brighter image which is great in low light.

 

[Chaz Photos]

As far as I'm concerned, on Canon crop, the 17-55 is the walkabout lens to own. Wide enough, long enough, fast enough, good IS and fantastic image quality. Forget the absence of a red ring, not an issue.

.

I agree 100% also you will not get a red line on a EFs lens but its as good as

 

[ryanyboy]

I always think of apertures in terms of ISO as I'm often shooting at really high ISOs.

If you're shooting with an older body 1600 becomes 800 ISO when opened up a stop. And that can make the difference between unuseable and useable

 

[Davie]

I've been giving this alot of thought lately too and surprisingly decided to ignore the speed of the 17-55 and have bought a nice shiney new Canon 15-85 f3.5-5.6

Thought if I need something fast there's always the siggy 50mm f1.4 in the bag

 

[specialman]

If the full frame camera has lots of MP, you can crop it nicely. but the crop sensor is limited. but well - we don't live in a dream world where we can afford everything we want in a split second.

Agreed, if it's one of the super-duper ones like a D3x then fine, give it to me now and I'll crop away

On a D700 however, it's still 12pointsomething megapixels (same as my D2x) so it's still a 4200 x 2800 (approx.) pixel image. Cropping down therefore reduces the uses, although I expect the details levels will be greater because of the larger photosites.... I'm verging on something here that my mind doesn't compute so I'll stop

 

[Arkady]

Agreed, if it's one of the super-duper ones like a D3x then fine, give it to me now and I'll crop away

On a D700 however, it's still 12pointsomething megapixels (same as my D2x) so it's still a 4200 x 2800 (approx.) pixel image. Cropping down therefore reduces the uses, although I expect the details levels will be greater because of the larger photosites.... I'm verging on something here that my mind doesn't compute so I'll stop

Actually, cropping the D3 to DX in-camera pretty much matches the IQ produced by the D2x despite the disparity in Mpi at that size...if you needed the extra 'length' for the zooms you mentioned then you can always switch to DX-crop when required.

The D3x produces noise at about the same level as the D2x so is only really useful (to me) when used full-frame at 100iso - and when there's lots of light (or because I brought my own along).