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03-01-2010, 06:43 PM   #1
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why won't they make zooms faster than F2.8?

Is it physically impossible?

Would be nice to have something like 28-80 F2 right?

03-01-2010, 06:45 PM   #2
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I think they would get too big.
03-01-2010, 06:57 PM   #3
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QuoteOriginally posted by RolloR Quote
Is it physically impossible?

Would be nice to have something like 28-80 F2 right?
Heh, I just started the same topic not long ago: https://www.pentaxforums.com/forums/pentax-beginners-corner-q/91480-why-there...w-f-2-8-a.html

The essence: it would be too big & too costly.
03-01-2010, 07:20 PM   #4
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Olympus makes some f2.0 zooms, although I don't know how many they offer, or what sizes they're offered in.

03-01-2010, 09:01 PM   #5
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see how big those are? try to imagining what it would be like if they are f2 or so...
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03-01-2010, 09:18 PM   #6
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QuoteOriginally posted by luke0622 Quote
those are rather long telephotos though.

do you think (if they make one) 28-50 F2 APS-C may be similar to Olympus' 14-35 size? Filter diameter's 77mm.
ED 14-35mm f2.0
03-01-2010, 10:44 PM   #7
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QuoteOriginally posted by little laker Quote
Olympus makes some f2.0 zooms, although I don't know how many they offer, or what sizes they're offered in.
Are those for 4/3 though?
03-01-2010, 11:37 PM   #8
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QuoteOriginally posted by Blue Quote
Are those for 4/3 though?
I know However it shows that it's possible.
I honestly feel that with today's lighter materials it's possible to make a faster zoom that most people can carry.
However the chances are that they'd suffer with reduced image quality. Which you really don't want, with your more expensive lenses.

03-02-2010, 05:33 AM   #9
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QuoteOriginally posted by Blue Quote
Are those for 4/3 though?
they might be 4/3 but that means nothing to the lens size.

We had a discussion about that a while back only to discover that the DA300F4 was actually heavier and bigger than the SMC 300F4

The image projection circle does not drastically impact the size of the lens,

front element diameter is usually (but not always) determined by the maximum aperture at maximum focal length, and barrel diameter is tdetermined by the mount.

Other factors like filter size are determined by FOV and the need to avoid vignetting.

The lenses would be bigger than present, F2 over F2.8 is one full stop, hence the effective front element area would need to double as a minimum.

For me, it is easier to have some primes in the 28-85mm range if you want the extra stops
03-02-2010, 06:11 AM   #10
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cos the majority of people wouldn't be able to carry em
03-02-2010, 06:11 AM   #11
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I really think that expense is the biggest reason. If you merely double the cost of a lens like the 50-135 or the 16-50, the number of copies you would sell would drop precipitously. f2.8 seems to be the sweet spot where lenses are fairly reasonable in size and affordable. As Lowell says, if you need faster lenses, primes is where it is at.
03-02-2010, 08:18 AM   #12
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Almost anything is possible, but at what cost?
03-02-2010, 08:31 AM   #13
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What about making 16-105 f4? will that be too big too?
if its too big how's 16-105 f4-f4.5
03-02-2010, 08:44 AM   #14
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QuoteOriginally posted by Lowell Goudge Quote
they might be 4/3 but that means nothing to the lens size.

We had a discussion about that a while back only to discover that the DA300F4 was actually heavier and bigger than the SMC 300F4

The image projection circle does not drastically impact the size of the lens,

front element diameter is usually (but not always) determined by the maximum aperture at maximum focal length, and barrel diameter is tdetermined by the mount.

Other factors like filter size are determined by FOV and the need to avoid vignetting.

The lenses would be bigger than present, F2 over F2.8 is one full stop, hence the effective front element area would need to double as a minimum.

For me, it is easier to have some primes in the 28-85mm range if you want the extra stops
The 4/3 sensor is a lot smaller than the aps-c sensor. It would be like comparing a telephoto for a 6x7 to one for a 135. If you want a comparison look at the zooms for the 645n and remember that f2.8 on a medium format is equivalently faster than on 135. The DA* 300mm f4 is not heavier than the FA* F4.5 by much plus the latter is f 0.5 slower. Plus the DA* has the SDM in it. However compare the weight of these since they were designed by the same group.

DA* 300mm f4 at 1070 grams
FA* 300mm f4.5 at 935 grams
FA* 300mm f2.8 at 2495

That f1.2 difference as more than doubled the weight compared to the DA* not taking into account the the DA* was heavier due to SDM etc.

QuoteOriginally posted by rustynail925 Quote
What about making 16-105 f4? will that be too big too?
if its too big how's 16-105 f4-f4.5
There is a big difference in f2 lens and an f4 lens. Take a look at the DA 16-45mm and DA* 16-50mm f2.8 at 365 and 600 grams respectively. I don't see them being able to push the f2.8 to f2 and keep the weight down with it being the cost of a Porche.
03-02-2010, 06:09 PM   #15
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QuoteOriginally posted by rustynail925 Quote
What about making 16-105 f4? will that be too big too?
if its too big how's 16-105 f4-f4.5
16-105 is 7X zoom. The largest zoom range I've seen in an f/4 zoom is about 4X (the 17-70). Yeah, I'd expect a 7X zoom to be a *lot* bigger.
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