Would a 14-28mm f/1.8 be possible?

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#21
I guess in "theory" prices were just humorously speculative... but mechanically a wide zoom 1.8 built right would be a massive piece of glass and very hard to hand hold... for long periods of time... or to even have around your neck... LOL
ok even on a tripod this would be a massive weight addition... without its own support...
as longer lenses have collars to balance weight and provide H&V rotation... Id think a lens of this design would need the same... not for reasons like the schnider TS super rotators 50 90 and 120...
but like that...
and then all would be grumbling "who would in their right mind want to carry this 8lb piece of glass"
lol its quite amusing to think of this... as my 24 f3.5L TSE II has gotten massive can you imagine an 85 1.0 or then back to a 1.8 zoom... wow...
 
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#22
Not possible enough for Canon's marketing dept. to be able to pitch such a huge heavy expensive thing. If we're talking FF then f/2.8 is the max practical aperture for an ultrawide zoom.

But something closer would be forseeable: a ~18mm wide angle with a very large aperture. For the EOS M system.

EOS M's flange focal distance is 18mm, so anything this wide or longer doesn't need to be a retrofocus design. I would go so far as to suggest that the ~18mm distance of APS-C mirrorless systems was specifically selected because they wanted the FF equiv of a 28mm wide angle without requiring retrofocus lens designs.

This is why Fuji's XF 35mm f/1.4 is small & light & costs 500 bucks, and their 18mm f/2 is a pancake. They've got a stabilized 18-55 f/2.8-4 standard zoom the size of the EF-S 18-55 kit zoom as well.
 
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#23
aroo said:
Canon has super lenses at the telephoto end, could they do crazy things with UWA too?
Click to expand...


This lens would have a 152mm diameter and cost over $7,000 at launch assuming the same optical design as Nikon's was used and Canon's standard mark-up on the cost of ultra large lens elements was used.

In short, there is no way this would ever make it to market.

Canon could sell 10 times as many f/2.8 UWA lenses as they could f/1.8 ones.

In fact to make up the smaller market for the lens Canon would have to charge close to $17,000 for this lens, if not more.
 
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#26
brad goda said:
the want for a lens with large aperture:
bright for viewing
bright for focus... manual or AF
shallow depth of field is image tool for photography.
Click to expand...

Wide aperture is useful, but

A & B. How wide does it really have to be (f/1.8? f/1.4? f/1.0? f/0.7?) and at what point it would become too expensive and/or heavy?

C. I don't see the benefit of shallow DOF for ultrawide. Could you enlighten me?
 
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#27
Ellen Schmidtee said:
C. I don't see the benefit of shallow DOF for ultrawide. Could you enlighten me?
Click to expand...


Shallow DOF helps isolate the subject, no matter the focal length. I notice a big difference between f1.8 and f2.8 @ 50mm. I imagine such a difference would exist also at 15mm.
 
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#28
Aroo
yes at 1.8 on any lens you would see that effect...
8-15 @f4 you do see that effect... @f1.8 it would be stellar... but again at what cost...

canon and all makers have come a long way reducing size and weight through design and materials..
has anyone ever seen how big Nikon's 6mm f2.8 fish eye lens was???

https://www.google.com/search?q=nikon+6mm+f2.8+fisheye&hl=en&client=firefox-a&hs=Vpq&rls=org.mozilla:en-US:official&source=lnms&tbm=isch&sa=X&ei=aDIhUZLFNsGriAKfqoDYAQ&ved=0CAoQ_AUoAQ&biw=1427&bih=940#imgrc=Q9us_E3HiRoq-M%3A%3BJKn3ue5gxvH6gM%3Bhttp%253A%252F%252Fcultofmac.cultofmaccom.netdna-cdn.com%252Fwp-content%252Fuploads%252F2012%252F04%252FFisheye-6mm-28-001.jpeg%3Bhttp%253A%252F%252Fwww.cultofmac.com%252F162652%252Fhuge-11-pound-nikon-6mm-%2525C6%2525922-8-fisheye-lens-goes-on-sale%252F%3B640%3B477
 
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#29
brad goda said:
Uh wait a...

8-15 fish zoom
17mm TSE and 24 TSE with massive image circle and very low distortion...

whats not crazy UWA about these canon lenses... that exist...! :o
Click to expand...

I haven't had the chance to try any TS-E lenses, the 17mm might take my mind off thoughts of a fast aperture!
 
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#30
 
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#32
It is technically 'possible' - taking into consideration elements diameter and overall massiveness of the lens..
The reason you do not see it is because it is not 'necessary'.

The sensor/film is being provided more light by a wide angle lens to begin with, so it is not necessary from an exposure stand point.

Wide angle lenses have a greatly distorted depth of field by the laws of physics, this would not be changed by a wide aperture. You would simply end up with little more than a small 'area' of the image in focus with the remainder falling out of focus so rapidly that every image would look like impaired vision - it is one of the primary reasons t/s lenses were invented.

From a creative stand point, you can achieve the same thin dof 'effect' with a wide angle lens by simply getting as close as you can to your subject. The effect would be the same on the background elements of the image whether at f/1.8 or f/2.8, the difference being essentially imperceptible.

I think the misconception in desiring such a lens is the expectation that one would get the same flatness of the focal plane at 14mm as seen in 35mm or 50mm - there is a big difference in the curvature of perspective between 35mm and 14mm. The focal plane would wrap around the sides to the extent that nothing would appear in focus except the single point that you were actually looking at - similar to your own eye.
 
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#33
SiliconVoid said:
The focal plane would wrap around the sides to the extent that nothing would appear in focus except the single point that you were actually looking at - similar to your own eye.
Click to expand...

That actually is what I have in mind -- though seeing it spelled out like this makes it obvious there are simpler ways of making those images happen than waiting for a lens to be manufactured.
 
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#37
aroo said:
Ellen Schmidtee said:
C. I don't see the benefit of shallow DOF for ultrawide. Could you enlighten me?
Click to expand...

Shallow DOF helps isolate the subject, no matter the focal length. I notice a big difference between f1.8 and f2.8 @ 50mm. I imagine such a difference would exist also at 15mm.
Click to expand...

If the background is OOF, what does it matter how much of it did you get? You could get pretty much the same thing with a 24mm f/1.4.
 
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#39
RLPhoto said:
Yes, but it would suck or be really expensive.
Click to expand...
TO back this up, the only f/1.8 lens I am aware of at wider than 24mm is the 20mm f/1.8 that Sigma has, and the reviews lean towards the "suck" side of things. And that's not a zoom and not going to 14mm. Seeing how insanely large the element is at 14mm f/2.8 on the Nikon zoom, I'd shutter to think what it'd be at f/1.8

aroo said:
Shallow DOF helps isolate the subject, no matter the focal length. I notice a big difference between f1.8 and f2.8 @ 50mm. I imagine such a difference would exist also at 15mm.
Click to expand...
Except at 50mm, your focus plane is maybe a foot wide at f/1.8, so, you can isolate an object fairly easily. At 15mm, your plane is now 10ft in length, so trying to isolate that same object would fail. The background would have to be 10x as far away to get a similar effect.

I'm guessing you haven't shot ultra-wide; the reality is that even at f/2.8 on anything wide than 20mm, you can pretty much set focus about 1/3 to 1/2 way into a scene and get everything in focus. Not much isolation to be had in the ultra-wide realm without T/S
 
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#40
aroo said:
Ellen Schmidtee said:
C. I don't see the benefit of shallow DOF for ultrawide. Could you enlighten me?
Click to expand...


Shallow DOF helps isolate the subject, no matter the focal length. I notice a big difference between f1.8 and f2.8 @ 50mm. I imagine such a difference would exist also at 15mm.
Click to expand...

Yes, but only in very close focus distances.

On 14mm f/1.8 you would have to focus closer than 3.68 meters because on and after that focus distance the focus extends to infinity. In other way, on that focus distance, anything from 1.84 meters to infinity would be in focus.

The closest focus distance for 14mm f/2.8 that focuses to infinity is 2.33 meters and anything from 1.16 meters to infinity would be in focus.

If you focus really close, say at one meter with 14mm, the depth of field for f/1.8 is about half (0.58 meters) of the f/2.8 depth of field (1.04 meters) so you would get a shallower DOF, but you would be limited to shoot subjects closer than 1.16 meters to get the shallow DOF.

these calculations are based on 5D Mark II/III using the DOF calculator http://www.dofmaster.com/dofjs.html
 
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