Fast zooms: constant or not?

alphasierra · #1 September 27th, 2011, 11:46 PM

A lot of people seem to be waiting for a fast zoom with bated breath - and I'll probably get one myself if it's not too expensive. One thing that often comes up in that type of discussion is peoples enthusiasm for constant apertures - e.g. hope that the coming 35-100 might be constant f2, or constant f2.8. Often, it seems like this is a really major selling point, rather than just something that's a nice bonus.

I understand the basic idea that a constant aperture means zoom has no effect. But, a question: would people rather have a constant aperture, or one which is faster on the short end? Let's say (for argument only) they can't make a constant 35-100/f2 lens that's an acceptable size/price, but can make a 35-100/f2-2.8 (f2 at 35mm to f2.8 at 100mm). Is it preferable that the short end be restricted to give a constant f2.8 lens, or would people rather have the extra speed available at the short end (to use if desired, or set it to 2.8 if you want constant aperture)?

It seems like it would be easy to make 'constant' zooms by using software to cripple the 'faster' end of a 'variable' lens in software. But this doesn't seem like such a good idea to me...

RT_Panther · #2 September 27th, 2011, 11:56 PM

Quote:

Originally Posted by alphasierra

it's not too expensive. ...

This is the million dollar question....(What's "too expensive"..)

flash · #3 September 27th, 2011, 11:57 PM

Fast zooms are expensive, even the cheap ones like Sigma and Tamron or Tokina. They're just too complex to make on the cheap.

If a fast lens comes out that is a variable aperture, I won't buy it. I'd rather have a constant 2.8 than a 2-2.8. It makes shooting in manual a PITA. I will be sorely disappointed if it's a variable aperture lens. Panasonic already has one good constant aperture zoom (7-14) so I suspect the new ones will also be constant, although if I had a choice I'd rather that it's made by Olympus.

Gordon

hkpzee · #4 September 28th, 2011, 12:15 AM

If they can make the lens not larger than the 14-140, but with a variable aperture of 2-2.8, I would seriously consider getting one (of course depend on price also).

Physically, I just don't think they can make a constant f/2 zoom this small... but then again, what do I know about camera physics...

Biro · #5 September 28th, 2011, 12:17 AM

Quote:

Originally Posted by flash

Fast zooms are expensive, even the cheap ones like Sigma and Tamron or Tokina. They're just too complex to make on the cheap.

If a fast lens comes out that is a variable aperture, I won't buy it. I'd rather have a constant 2.8 than a 2-2.8. It makes shooting in manual a PITA. I will be sorely disappointed if it's a variable aperture lens. Panasonic already has one good constant aperture zoom (7-14) so I suspect the new ones will also be constant, although if I had a choice I'd rather that it's made by Olympus.

Gordon

It's interesting... In the regular four-thirds system, Oly has some very nice zooms. But almost all are variable aperture - even the faster ones. Two High Grade 4/3 zooms come to mind: the 14-54 f/2.8-3.5 and the 50-200 f/2.8-3.5. I personally could live with that kind of aperture range if the optics were very good and it kept both price and size down.

Of course, there's Oly's Super High Grade 4/3 zooms, which are constant aperture, which is generally f/2.0. But those lenses are larger... with price tags in the thousands of dollars each.

hkpzee · #6 September 28th, 2011, 12:25 AM

Quote:

Originally Posted by Biro

It's interesting... In the regular four-thirds system, Oly has some very nice zooms. But almost all are variable aperture - even the faster ones. Two High Grade 4/3 zooms come to mind: the 14-54 f/2.8-3.5 and the 50-200 f/2.8-3.5. I personally could live with that kind of aperture range if the optics were very good and it kept both price and size down.

Of course, there's Oly's Super High Grade 4/3 zooms, which are constant aperture, which is generally f/2.0. But those lenses are larger... with price tags in the thousands of dollars each.

I happen to own both the 14-54 II and the 50-200 SWD for use on my E-P3, and I love the quality of those lenses, so if they came up with the same specs for the m4/3 zoom lenses, but at half the size of the 4/3 zooms, and focus faster than the 50-200 on m4/3, I will be all over them...

Ned · #7 September 28th, 2011, 12:46 AM

Quote:

Originally Posted by alphasierra

But, a question: would people rather have a constant aperture, or one which is faster on the short end? Let's say (for argument only) they can't make a constant 35-100/f2 lens that's an acceptable size/price, but can make a 35-100/f2-2.8 (f2 at 35mm to f2.8 at 100mm). Is it preferable that the short end be restricted to give a constant f2.8 lens, or would people rather have the extra speed available at the short end (to use if desired, or set it to 2.8 if you want constant aperture)?

Of course I'd prefer a constant aperture at the same speed (in your example, both have an f/2 maximum). But the real concerns with that are size and price. Not as much in manufacturing cost as in size... The increase in size just to make that constant aperture is huge, and not necessarily worth the small increase in speed at the tele end.

This is all assuming the same high quality of optics, of course. Yes, Sigma, Tokina, etc. have constant aperture lenses which are no larger and even cheaper than the Olympus versions with variable apertures... but the Zuiko lenses are much sharper and higher quality.

With the increasingly small sizes of our bodies, the oversized lens becomes more and more unwieldly. I think that's the biggest issue these days.

nickthetasmaniac · #8 September 28th, 2011, 12:48 AM

Quote:

Originally Posted by alphasierra

Let's say (for argument only) they can't make a constant 35-100/f2 lens that's an acceptable size/price, but can make a 35-100/f2-2.8 (f2 at 35mm to f2.8 at 100mm). Is it preferable that the short end be restricted to give a constant f2.8 lens, or would people rather have the extra speed available at the short end (to use if desired, or set it to 2.8 if you want constant aperture)?

I couldn't give a flying doodle if a zoom is a fixed aperture or variable aperture, as I never shoot in conditions where that kind of precision matters or is even noticeable, and yes, I would prefer a variable 35-100/f2-2.8 over a fixed 35-100/f2.8...

But, that's in Hypothetical-Land. The fact is that in basically ever case I can think of, it goes the other way... So rather than the short end becoming faster with a variable zoom, the long end becomes slower...

ZD 12-60/f2.8-4
PL 14-50/f2.8-3.5
ZD 14-54/f2.8-3.5
etc etc...

Coming from primes, I'm become accustom to speed, and I'm simply not interested in a lens slower than f2.8 at any focal length...

Ned · #9 September 28th, 2011, 12:54 AM

Quote:

Originally Posted by nickthetasmaniac

I couldn't give a flying doodle if a zoom is a fixed aperture or variable aperture, as I never shoot in conditions where that kind of precision matters or is even noticeable,

To me, I do notice the difference as the long telephoto end is normally where I need the speed the most! I really don't need it on the wide end.

However, I also see enough advantages to variable aperture lenses that I'm happy with both. :) Everything's a compromise.

pharaviel · #10 September 28th, 2011, 12:55 AM

Quote:

Originally Posted by Ned

To me, I do notice the difference as the long telephoto end is normally where I need the speed the most! I really don't need it on the wide end.

However, I also see enough advantages to variable aperture lenses that I'm happy with both. :) Everything's a compromise.

I know it's impossible by design but I would love a 12-60 f 4-2,8.
Yeah, slow on the wide end (more dof for landscapes) and fast on the long end (less dof for portraits).
I know how aperture and focal lenght works so I know this lens isn't coming, but this would be my perfect variable aperture lens.

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