New Sigma Lenses Coming Q1 of 2015 [CR1]

[risc32]

16mm is not really that close to 20mm in my book. sharp at f2? no/very low coma? sounds very good to me.

 

[Chapman Baxter]

I am curious about the 14-24 f/4 lens. If it does not have a bulbous front element and has decent optical performance, I'm all for it.

If the Canon 12-24 is anything to go by then no.

It is curious that the 16-35 doesn't have a bulbous front but 12-24 does.

I wonder at what point in lens design the wide angle lens requires a bulbous front element?

But yeah, a 24-70/f2 would be much more exciting!

I believe the bulbous front element is more of a compromise than anything. At the wider side of things the angle of view gets bigger and bigger. If it had a normal front element it would need to get wider and wider. This would result in filter threads no one could fill and a super expensive front element. So I think they add the bulbous element to use less glass and keep the cost down while still being able to use those square filters with adapters. Realistically you would probably see bulbous elements starting at 15mm and shorter. Maybe if Zeiss made an otus 14mm they would keep it flat.

I suppose size reduction is one way of looking at it but within the constraints of realistic lens design, the bulbous front element design for ultra-wide focal lengths is chosen for optimal image quality and to minimise vignetting. Consider the TS-E 17mm with its bulbous front end. Its focal length wouldn't suggest a need for it, but it's the requirement for very high image quality across a much larger than standard imaging circle that necessitates it for that lens.

TS-E aside, empirical evidence suggests the cut-off point for bulbous front elements is 16mm, where you have the Tokina 16-28mm f/2.8 (with) and Canon 16-35mm f/2.8 (without). Golden samples of the Tokina are typically considered to be sharper than the Canon though, sadly, not all Tokina samples are equal.

 

[denobulan]

Minimal coma, vignetting, and sharp at f2-2.8, that would be an excellent nightscape lens.

My thoughts exactly. Have gone through alot of lenses for nightscapes and Milky Way shots and most of the fast lenses have alot of coma. Shame it doesn't have a slightly larger range though. Would complement Samyang 14mm F2.8 nicely.

 

[StudentOfLight]

Sigma won't tell about 85Art, who gonna buy 85/1.4 from then, when we have a confirmation of a newer version coming?

I wonder if Sigma are delaying the 85 Art whilst they try and resolve AF issues?

That sounds like a reasonable assumption. They could just make it in a manual focus version; good materials and surface finish, smooth manual focus ring and similar optical performance as the 50mm.

 

[dgatwood]

16mm is not really that close to 20mm in my book.

Really? That's only a 1.25:1 zoom ratio. Unless you're shooting landscapes, you can get a bigger framing difference than that by stepping forwards three or four steps.